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Administrative Appeals Tribunal of Australia |
Last Updated: 14 October 2003
CATCHWORDS - COMPENSATION - Workers' Compensation - heart condition/myocardial infarction - physical and emotional stressors - whether Comcare liable to pay compensation for the applicant's condition - whether injury suffered in the course of or arising out of the applicant's employment - whether condition an existing condition - whether applicant's employment was a contributing factor which aggravated or accelerated the applicant's existing condition - decision affirmed.
Safety, Rehabilitation and Compensation Act 1988 ss. 4 and 14
Workers' Compensation Act 1926 (NSW) s. 6
Commonwealth Employees' Compensation Act 1930 (Cth) s. 9
Workers' Compensation Act 1951 (ACT) ss. 6, 7 and 9
Veterans' Entitlements Act 1986
The Darling Island Stevedoring and Lighterage Co Limited v Hankinson (1967) 117 CLR 19
The Commonwealth v Ockenden (1958) 99 CLR 215
Kavanagh v The Commonwealth (1959-1960) 103 CLR 547
Zickar v MGH Plastic Industries Pty Ltd (1996) 140 ALR 156
Kennedy Cleaning Services Pty Ltd v Petroska (2000) 200 CLR 286
Charles R Davidson v M'Robb [1918] AC 304
Humphrey Earl Limited v Speechley (1951) 84 CLR 126
Commonwealth v Wright (1956) 96 CLR 536
Danvers v Commissioner of Railways (NSW) (1969) 122 CLR 529
Hatzimanolis v A.N.I. Corporation Ltd (1992) 173 CLR 473
Comcare v Mather and Mitchell (1995) 37 ALD 463
Gregory v Comcare (1997) 72 FCR 196
Comcare v O'Dea (1997) 26 AAR 252
Re Daykin and Department of Defence [1998] AATA 370
Re Commonwealth Bank of Australia and Wark (1995) 37 ALD 697
Australian Telecommunications Commission v Treloar (1989) 90 ALR 202
Repatriation Commission v Bendy (1989) 18 ALD 144
Federal Broom Co Pty Ltd v Semlitch (1964) 110 CLR 626
Casarotto v Australian Postal Commission (1989) 86 ALR 399
Ogden Industries Pty Ltd v Lucas (1967) 116 CLR 537
Australian Telecommunications Commission v Tzikas (1985) 5 AAR 173
O'Neill v Commonwealth Banking Corporation (1987) 75 ALR 154
ADMINISTRATIVE APPEALS TRIBUNAL )
) V2001/1588
GENERAL ADMINISTRATIVE DIVISION )
Re ROBERT JOHNSON
Applicant
And COMCARE
Respondent
Tribunal: Deputy President S A Forgie
Dr P D Fricker (Member)
Date: 29 September, 2003
Place: Melbourne
Decision: The Tribunal affirms the reviewable decision of the respondent dated 24 July, 2000.
S A FORGIE
Deputy President
On 24 August, 2000 the applicant, Mr Robert Johnson, lodged an application for review of a reviewable decision made by a delegate of the respondent, Comcare, on 24 July 2000. The decision affirmed an earlier determination made pursuant to the Safety, Rehabilitation and Compensation Act 1988 ("SRC Act") on 29 June, 1999 that Comcare was not liable to pay compensation for Mr Johnson's heart condition. In the determination the delegate stated:
"For a claim to be successful under the Act, the evidence has to show that it is probable, and not merely possible that your military service contributed to a material degree to either the causation, aggravation, acceleration or recurrence of the disease."
2. At the hearing Mr Nathan Moshinsky QC appeared on behalf of Mr Johnson and Mr Robin Gorton QC appeared with Ms Ann McMahon on behalf of Comcare. The documents lodged pursuant to s. 37 of the Administrative Appeals Tribunal Act 1975 ("T documents") were admitted in evidence together with further documents, to which we will refer in these reasons. Mr Johnson gave oral evidence in support of his case together with Warrant Officer Hyndman, Mr Johnson's immediate superior at the relevant time, Dr René Dupuche and Professor Paul Nestel. Evidence on behalf of the respondent was given by Professor Michael O'Rourke and Professor Malcolm West.
THE ISSUES
3. There are two main issues in this case. The first is whether Mr Johnson suffered an injury simpliciter, or the aggravation of such an injury, arising out of, or in the course of, his employment. If he did not suffer an injury simpliciter, the second issue is whether he suffered an ailment, or the aggravation of any such ailment (and so a disease) that was contributed to in a material degree by the Commonwealth.
BACKGROUND
4. Some of the facts forming the background to the issues that we must decide were not in issue between the parties. In light of that and on the basis of the evidence, we have made the findings of fact that we will set out in the following paragraphs.
5. Mr Johnson was born on 29 November, 1948. His father suffered from a heart attack when he was 50 years of age and his sister suffered from cancer. Mr Johnson suffered from a hernia from 1995. He also suffered from alcoholism but conquered that problem from about 1981. For the past 18 years, Mr Johnson has been told that his cholesterol reading is too high. He has followed the instructions that he has been given and, after his heart attack, began to take medication. Mr Johnson used to smoke about 40 cigarettes each day but then reduced it to 15 to 20 each day in 1996 and then reduced it further. He did not reduced his smoking because he was suffering from any symptoms.
6. Mr Johnson joined the RAAF on 20 May, 1980. After three months basic training at Edinburgh Air Base, he became a cook's assistant and continued in that position until 1993. His duties included setting up and clearing dining rooms, making tea and coffee, doing dishes and sweeping and mopping floors. He attained the rank of Sergeant after six years. In 1993 he completed a stewards' course. On its completion, he continued to perform his previous duties in the dining room but also cleaned and cared for accommodation in the Officers' Mess on the base at Wagga.
7. Mr Johnson was transferred to the Tindal Air Base ("the Base") in the Northern Territory.. Tindal is located some 17 kilometres south of Katherine. He was a Sergeant and responsible for the Sergeant's Mess. His duties were similar to those he carried out in Wagga. He assumed responsibility for the accommodation from a civilian, who had been caring for it up to that time, including the Tindal Emergency Accommodation Line Camp ("TEAL Camp"). It comprised approximately 1,000 beds in all. TEAL Camp held 511 when it was full. Blocks in TEAL Camp, each comprising five rooms, were grouped into four groups. Some rooms had single beds but most had double bunk beds.
8. His responsibilities included booking people into and out of the accommodation. In his early days, this was done without the benefit of a computer. Mr Johnson was later required to maintain a computerised accommodation system based in part on a hotel computerised accommodation record system. An employee at the level of an ASO2 assisted him with his administrative duties. Mr Johnson's other duties required him to oversee cleaners caring for the Officers' Mess and the Sergeants' Mess. The airmen were required to clean their own quarters and to care for the gardens. Mr Johnson's duties required him to inspect them to ensure that they were kept at an appropriate standard.
9. Each week, those in the accommodation would bring their dirty sheets to Mr Johnson and he would give them clean sheets to take back to their rooms. Mr Johnson would put the dirty sheets into bags of 20 together with pillowslips. Each bag weighed approximately 20 kilogrammes. He would then place the bags in a van parked next to the office. From there, the bagged sheets would be transported to the bedding store or accommodation cell on the Base. Normally, Mr Johnson would not mop the floors in the accommodation blocks but would do so if they were "really busy" and people were going out and coming in almost immediately. Usually, the job was undertaken by one of the cleaning staff.
10. On 11 May, 1998 Mr Johnson was admitted to hospital for a hernia operation and returned to work on 19 June, l998. Although he was not completely fit initially, he built up his fitness and was at his full fitness by the beginning of August, 1998.
11. At some time after his hernia operation, he was transferred from the Sergeants' Mess to the Accommodation Cell. He was there for three weeks before being sent to an advanced stewards' course in Wagga from 3 August to 24 August, 1998.
12. On the weekend of Saturday and Sunday, 29 and 30 August, 1998, Mr Johnson attended the Base for several hours each morning in order to prepare accommodation. On Sunday, 30 August, 1998, while at home in the early afternoon, Mr Johnson experienced chest pain that led him to seek medical treatment at the Base. He was subsequently transferred by the RAAF's air ambulance to the Katherine Base Hospital ("KBH"). From there, he was transferred by the Royal Flying Doctor ("RDF") to the Darwin Public Hospital and then the Darwin Private Hospital ("DPH"). He was later transferred to the RAAF Base in Darwin and then to the Queen Elizabeth Hospital ("QEH") in Adelaide.
13. On 16 February, 1999, Mr Johnson lodged a claim for compensation claiming that on 30 August, 1998 he had suffered a heart attack in the course of his employment.
THE EVIDENCE
Mr Johnson's exercise regime before 29 and 30 August, 1998
14. Before the weekend of 29 and 30 August, 1998, Mr Johnson said that he walked up to six kilometres three times each week. In addition, he and his wife walked 2.4 kilometre each night as they walked the dogs. In addition, Mr Johnson said, he rode his bike 1.5 kilometres to and from work each weekday, played volleyball each week and also played soccer. Each year, he was required to undertake a physical fitness test. To complete it, he had to walk 5 kilometres in 44 minutes, which he could do in 40 minutes, raise himself by his arms so that his chin was level with a bar and hold the position for 20 seconds, and do 20 sit ups. He did not find it a strenuous test.
Work-related matters at the Base prior to his being transferred to the Accommodation Section
15. At the beginning of 1998, Mr Johnson was working as the Sergeant's Mess Manager but began a period of leave on the Friday before the 1998 flood in Katherine. In an attachment to his claim giving details about all the events which led up to the injury he wrote:
"To start back to the beginning when I first notice that the work I was doing began to become stressful for me was:
During the Flood in Katherine 1998, I was working a 12 hr shift in town, and put in charge of people and RAAF personnel I had never worked before and, some of whom were of a higher rank than myself. This in itself was quite stressful as people were coming in at all hours of the night wanting food stuff without paper work or authority, and it became stressful having to turn them away during such a time of need for everyone. Also after the food when we went back to our normal work and messes, there was a bit of a difference between to civilian personnel in the Airmen's Mess Dining Room, one of which happened to be my wife and the other being a Officers wife who had just started working for the Dept of Defence on the 4th Jan 98. I was working as the Sergeants Mess Manager and was asked to try and sort the situation out. This at the time I thought was a reasonable request. I tried to do this task to my best ability and without being bias to either side or person. In the end the situation got out of hand and I was told to look after both messes being the Airmen's and Sergeants, this in itself was quite a task having to go back and forth between the messes and also look after all the my secondary duties these duties included doing rosters for ground defence, duty member, PFT and leave, for all of Catering Section. I was working overtime just about everyday plus working on weekends just tom (sic) finish my workload. All of this work was (now I think about it) getting to me and health." (T documents, page 11)
16. In evidence Mr Johnson said that his wife and the officer's wife had both been employed as civilians in the Messes under his supervision. Amongst other duties, the officer's wife, who was employed as a General Services Officer level 2 ("GSO2"), was required to set up and clean the dining rooms. Although she was required to sweep and mop the floors, she refused to put the chairs up on the tables and just swept and mopped around them. She told him that she had a bad shoulder but, as she had not provided a medical certificate, he said that he regarded her as fit and she had to do the work. He said that the officer's wife, went to his supervisor and said he was harassing her. Mr Johnson said that he was later called into the office and "got a dressing down for harassing her".. Mr Johnson said that he denied that he had harassed her and that he was only doing his job to get her to do her job.
17. The trouble between his wife, who worked as a GSO2 in the Airmen's Mess and the officer's wife began when the officer's wife would not do her job, Mr Johnson said. He tried to mediate between them. When he went to a superior officer for assistance, he was told that he was their supervisor and that he should sort it out. When he tried to do that, the officer's wife said that he was siding with his wife in the matter. He had trouble sleeping and felt that he was "going through the mincer all the time". Mr Johnson said that he felt angry with both the officer's wife and with the officers. In cross-examination, Mr Johnson said that he did not tell doctors anything about this. He coped with it himself.
Mr Johnson's transfer to the Accommodation Section
18. Flying Officer Johns spoke with Mr Johnson on 16 July, 1998 and recorded their conversation. They spoke of the reasons for Mr Johnson's transfer to the Accommodation Section from the Catering Section. The reasons were said to be to overcome the level of stress that Mr Johnson appeared to be under because of circumstances due to his wife's health and his own, the number of secondary duties for which he was responsible and the unworkable situation that had developed professionally between himself and the officer's wife. The transfer was not intended as punishment and Flying Officer Johns pointed out to "... SGT Johnson that he now appeared to be happier and considerably less stressed in his new work area, to which he agreed." (T documents, page 20).
"On call"
19. In giving evidence, Mr Johnson said that people would arrive at Tindal at various times. Most were expected but, on occasion, some would come earlier than expected and would need to be accommodated. If people were expected, keys would be left for them with security located some 3½ kilometres from the accommodation. If they were not expected, security would call the person who was on call for the accommodation. At one time, any of the Leading Aircraftsmen or Women Stewards ("LAC/WS") in the Catering Section could be called.
20. On 7 July, 1998, Mr Johnson wrote a minute to the Messing Services Manager and headed it "Accommodation Cell Pager". The minute advised that, as of 8 July, 1998, only those working in the Accommodation Section could be paged as they were the only persons who could operate the accommodation computer. In practice, this meant that only he and ACW Dixon were on call (Exhibit J). From 1998, there was a roster as to when each was on call. Being "on call" meant being on call at any time of the day or night. If they were actually called to do some work, they were given leave to be absent for an equivalent amount of time during the normal working day. They would not be paid overtime but, when they accumulated eight hours of "on call" time, they would take a day off and put "LIL" (i.e. leave in lieu) in the roster. Mr Johnson was given nine days leave in lieu after his work during the Katherine floods.
21. When he was on call, Mr Johnson would either stay at home, some 2 kilometres from the Base, or would go to the pool at the Base. He would not travel to Katherine. In 1994, he was given a pager when on call but it proved unreliable. Sometime in 1998, Mr Johnson was given a mobile telephone. When he received a call, Mr Johnson would go to the Base where he would get a key from a locked cabinet, check the room to ensure that it was empty and give the key to the person.
22. In cross-examination, Mr Johnson said that, until approximately July, 1998, he had not been working in accommodation in Tindal but was in the Catering Section. As a member of the Catering staff, he was called on occasion as he lived closer to the Base than those who lived in Katherine but others could be called. It was a matter of convenience that he was called but he agreed that he had not been on call in relation to accommodation before mid July, 1998. Other members of staff did take the pager before that time and took it with them to places such as Katherine or on other activities. Mr Johnson said that the pager was unreliable. Whether being on call stopped a person following his or her domestic or social activities, Mr Johnson said, depended upon the person. He agreed with Mr Gorton that he had made the choice to stay at home or at the pool.
Wagga
23. In giving oral evidence, Mr Johnson said that he had felt a pain when he was walking down the road at Wagga while he was attending the advanced stewards' course. He thought that it felt like a stitch. In cross-examination, Mr Johnson said that he was walking at about 7:00 or 7:30pm outside course hours at some time about two weeks into the course. He did not regard himself as exerting himself but experienced a pain that was sharp and like a stitch for a very short period of time. He described it as being sharp and as extending from his left side just below his rib cage to an area forward and up to about the nipple area. Mr Johnson pointed to an area of his body that was in the mid clavicular line. The pain lasted for only one or two seconds. While he was in Wagga, he had not done anything that he would say was moderately strenuous. He had played some sport "but not all out". He did not have any recurrences of the pain in Wagga and neither sought any treatment for it nor took any medication. Mr Johnson said that he did not experience any pain in his chest, side or ribs again until 29 August, 1998. His hernia always played up but it hardly ever stopped him from doing anything.
Events at Tindal on return from Wagga
24. Mr Johnson was working in the Accommodation Cell for three weeks before he left to go on a course in Wagga. In the attachment to his claim, he had described the duties during these three weeks as more stressful as there was double handling of the bookings with a lot of walking and phone calls between a lot of people. On 24 August he returned from the course and was told that the Americans on third phrase of an exercise had been lost from the computer while he was away and they wanted to know what happened to it. He said he did not know as he was not responsible.
25. In cross-examination, Mr Johnson said that the ASO2 and he had to re-enter each of the people who had been lost from the computer.. Mr Johnson said that he was upset because he was getting the blame for the problem. In that first week on his return, Mr Johnson said that he had also become upset when he had been dealing with one Captain and then had been told by another Captain to take no notice of the first. Both were senior to him and he had to deal with their contrary directions.
Events of Saturday, 29 August, 1930
26. In his oral evidence, Mr Johnson said that, prior to the weekend of 29 and 30 August, 1998, there were two squadrons accommodated at the Base. They were to leave on the Tuesday, 25 August, 1998, but the Hercules that was due to take them became unserviceable in Darwin. Consequently, the two squadrons had to be accommodated for a further period until one squadron could leave on the Saturday and the other squadron drove to Darwin on the Sunday. Mr Johnson said that he found out about these arrangements on the Friday, 28 August, 1998. He was on call for the weekend.
27. He then arranged to go to the Base at 6:30am on the Saturday, take the soiled sheets as they were handed back in the normal way, hand out fresh ones and do an inspection of the rooms. When he arrived at the Base, he said in giving evidence that he found that some had already gone to board the plane and not taken the sheets from their beds. He had to strip the beds himself and stripped about 40 beds in all. He carried them back to the Accommodation Cell and carried clean sheets back to the rooms where he placed them on the bed. Although he did not make the beds, he swept and mopped the rooms. Mr Johnson said that he finished his work at approximately 11:00am.
Events of Sunday, 30 August, 1998
28. On the Sunday, Mr Johnson said in giving evidence, he returned to the Base at 6:30am to repeat what he had done the previous day. He found that the whole squadron had gone and he had to strip all the beds, carry clean linen to place on each bed and clean the rooms. The job could not be left until the following Monday as there was an exercise starting on that day and the accommodation was required. He was told by an officer from an advance party from the Army that he wanted the toilets cleaned. The officer gave him a private to assist in the task. Mr Johnson said that the private assisted for 30 to 45 minutes.
29. After he had done all of the work with the rooms, Mr Johnson said, he decided to do the night accommodation for Friday, Saturday and Sunday nights. He had to enter details such as whether the rooms were clean or dirty and whether occupied or not. That task normally took him 40 minutes to complete each night. In addition, he bagged the laundry. Mr Johnson said in giving evidence that he felt tired on the Sunday and rather warm in his full uniform as he was required to be.
30. While he was carrying the sheets, Mr Johnson said, he had felt what he thought were stitches. He felt that he did more lifting and carrying on that day than usual. Had he been doing the work during the week, there would have been people there to give him a hand but he could not leave it as more people required accommodation on the following day.
31. In cross-examination, Mr Johnson said that he started work on the Sunday between 6:30 and 6:40am. In his claim form for compensation dated 15 February, 1999, Mr Johnson had said that he had:
"... started work at 0600hrs to clear the last personnel out of Teal Camp and get the keys ready, a member of the advance party for the next the exercise informed me that the toilets needed a good clean, so I got all the cleaning gear ready and started them went some help came and I left to go back to my office and check all the leaving members out and count and bag all the laundry they had used. ..." (T documents, page 12).
He had not made any mention of these pains in this statement. In cross-examination, Mr Johnson said that no-one from the squadron had been there to bring back their sheets. This was the true situation and that his earlier evidence had been incorrect.
32. In a statement dated 8 November, 1999 written to his solicitor, Mr Johnson had written:
" I left home at 0600Hrs drove to RAAF Police Section to collect keys for Accommodation Cell Office, to collect the master rooms key for Teal Camp. Arrived at Teal Camp approximately 0615Hrs. I seeked out the Officer in Charge of the members who were leaving, asked him to have his members clean their rooms and come and collect clean linen from the Office, as 75% of the members had already departed. I had to clean the rooms and carry the dirty laundry and replace it with clean ones, this is so to have the rooms ready for the next contingent (two single bed sheets and two pillowcases) back to the office. Then take clean laundry back to the rooms, this distance (is showed on the map enclosed) is approximately 250 to 300 Metres in length. With 75 members leaving on that morning, I had to carry most of the laundry by hand, (as the trolleys were waiting to be repaired. I was only able to carry about Ten to Fifteen Sheets (approximately 9 to 15 Kilos) at a time, you can image how many trips I had to make. With the weather being about 24/26C also humid plus being in uniform I sweated a lot. I had to stop on a few occasions while I got my breath back also I had some pains in my chest area. All of this took me from 0615 till approximately 1030Hrs. While I was doing this, the Army Captain said that the toilets and showers needed cleaning before his contingent arrived. After I finished the rooms I started on cleaning the toilets and showers, then the Army sent me some help to finish these off. At roughly 1130Hrs I departed Teal Camp with the van full of dirty laundry and proceeded back to the Accommodation Cell Office. Once there I unloaded the dirty linen from the van into the Store and started to bag the dirty laundry into 20 sheet lots (there weigh 20Kilos), also at this time I started to do the Night Audit on the Accommodation Computer (trying to get head for the next day). So in fact I was doing two jobs at once, going back and froth (sic) from computer and bagging up the laundry. While doing this I had a crushing pain in my chest which made me stop doing the bagging up, after a short time the pain receded and I carried on till I had finished. Then drove back to RAAF Police Section to hand the keys back in, and drove home." (T documents, page 51)
33. When Mr Johnson was reminded that he had said in this document that 75% had departed, Mr Johnson said that he had been incorrect in saying in his oral evidence that everyone had gone; 25% were still there. There had been no-one from the squadron to bring their sheets. It had been a long time since the events had occurred. He also agreed that he had been wrong when he had said in his oral evidence that no-one else was there and that he had no assistance. His reason for the error was that it was some five years since the events occurred.
34. In a statement dated 10 September, 2001, Mr Johnson had said that Corporal Neighbour, who was then in charge of the Accommodation Cell, had measured the distance between A block and the place where the van was parked. The distance along the pathway between the van and rooms 41-45 and 46-50 was 144 metres. The distance to rooms 21-25 and 26-30 to the van is 145 metres. Both measurements were for a one way trip. Fifteen sheets weighed 15 kilogrammes and 20 sheets, 20 kilogrammes (Exhibit H).
35. He agreed with Mr Gorton in cross-examination that he had started between 6:30 and 6:40am and that he had to carry sheets to and from, and to clean, no more than 30 rooms. Mr Johnson agreed that he would pick up approximately ten to fifteen sheets at a time and carry them to the Accommodation Office. He completed that job in three or four trips. The distance that he walked each way had been measured by his friend and former colleague, Corporal Neighbour as 140 steps. Mr Johnson agreed that Corporal Neighbour's steps were not a metre in length and agreed with Mr Gorton that the estimate of 250 to 300 metres that he had made in his letter of 8 November, 1999 was a gross exaggeration. In re-examination, Mr Johnson reasserted that the distance was 250 to 300 metres. In his letter, he had estimated 75 people as leaving the base but Mr Johnson said that 30 to 40 was a more accurate estimate.
36. In cross-examination, Mr Johnson said that he had to collect sheets from rooms 21 to 40 and 41 to 60 in A and B Blocks. Each was a double room but occupied by only one person. Therefore, only 40 people were leaving on that day. He did not place the sheets in the van parked next to the Accommodation Office but threw them all in the office. The temperature increased during the day to about 24 to 26oC. Mr Johnson moved sheets until approximately 10:30am. He said that he found the work strenuous. Although he had passed his physical fitness test, he was not used to carrying weights. He said that he used a mop and broom to clean the rooms, each of which measured approximately ten feet by eight feet. In order to get the dust out from under the bottom bunk, he had to bend down or to get on his hands and knees.
37. Mr Johnson said that he started to clean the showers and toilets by himself but was then assisted by an Army private. He could have chosen to let the private do the work but they were his responsibility and he wanted to ensure that they were cleaned properly. It was not a job that he found particularly stressful. Although there were other people on the Base, he could not ask for their assistance as they were there for an American exercise and not for the exercise involving the Australians. It was not the case that 300 people, or any number of people, had arrived unexpectedly at the Base on Sunday, 30 August, 1998. Mr Johnson said in cross-examination that he had not sought the assistance of anyone to help him over the weekend. It should have been an easy job if people had taken their sheets to him and returned the clean ones to their rooms.
38. Also in cross-examination, Mr Johnson said that he had driven the sheets in the van to the Accommodation Cell's office some 5 to 6 kilometres from TEAL Camp. He left the camp at about 11:30am and left the office for home at about 12:30pm. Bagging the sheets was not part of his responsibilities but he did that job in order to get ahead for the week as there was to be a change over of people and a new lot would be moving in. He then drove home.
39. In giving evidence, Mr Johnson said that he arrived home at approximately 12:30pm after completing his work. The man from next door came in with lasagne. He experienced "a bit of stitch" and then felt a pain as if his chest were being crushed with a vice. Mr Johnson told his wife to get the car to take him to the Base and to call the service police to call the medical staff. The medical staff first attended Mr Johnson at the office of the service police. He had an electrocardiograph ("ECG") at the Base and was given an angina tablet before being taken to KBH and then to the Darwin Public Hospital. At that hospital, he asked for a pan and then said that he was going to be sick. Mr Johnson said that he woke up with the staff performing CPR. He said that he was going to be sick again and he underwent CPR again. After being transferred to the RAAF Base in Darwin, Mr Johnson was flown to the QEH where he underwent an angiogram and remained for two weeks.
40. In the document accompanying his compensation claim, Mr Johnson had described events after he had finished his work:
"... I finished all that at about 1230 hrs and went home for some lunch and to watch football on the TV.
At approximately 1430 hours I felt a crushing pain in my chest and rang the RAAF police to get the duty medical assistance out and meet me at the medical centre, as I came through the gate my wife and I where stopped by the guard and asked for our passes, I had my ID pass but my wife in the rush to get help for me forgot hers, we were then told to pull over to the hard stand as we needed passes to get in. The medical assistance came and we drove to the medical centre where I was diagnose as having a Heart Attack." (T documents, pages 12-13)
In his letter of 8 November, 1999, Mr Johnson had referred to a crushing pain in his chest at home but made no reference to any other episode of pain.
41. In cross-examination, Mr Johnson said that he experienced a pain for one or two seconds when he was walking but it stopped when he stopped walking. When he was in the Accommodation Cell's office, he experienced a second one on the Sunday. It was similar to the first one that he had experienced that day. Mr Johnson agreed that he had made no mention in his compensation claim of these pains. He said that he had thought that only the "big one" needed to be mentioned and had thought that the earlier ones were just a stitch because he was walking and lifting sheets. He included the pains in a later document which he prepared after his solicitor asked him to include everything that was relevant.
42. Also in cross-examination, Mr Johnson said that he felt the crushing pain in his left lower chest to his central mid chest and around to the middle of his back. At the time, he was only sitting in his chair. He was given an angina tablet at the medical centre on the Base and the pain went away but it returned.
43. Mr Johnson said in cross-examination that he could have told the doctor at the Base that the pain had been building up over the previous two days (T documents, page 26). When asked how he could have said that, he replied that he did not have an answer. What he was saying at the hearing was as accurate as he could be. It was also noted in the notes of the Base's medical centre that he had been experiencing pain lasting two to three minutes over the previous one to two weeks. Mr Johnson said that he had said one to two weeks because he was including the pain that had occurred in Wagga. He could not recall saying two to three minutes.
44. The In-Flight Patient Report of the Aerial Medical Service recorded on 30 August, 1998 that Mr Johnson had experienced increasing chest pain on exertion over the previous two weeks. It had been relieved by nitrates but on that day he had experienced the sudden onset of severe chest pain for 20 minutes. In cross-examination, Mr Johnson said that he had told them that he had increasing amounts of pain on the Sunday. The pain at Wagga and on the Sunday morning was the same and then there was the "big one".
45. Mr Johnson said in cross-examination that he had not experienced any symptoms of ill-health while he was working during the Katherine flood. He was just tired.
Warrant Officer Hyndman
46. Warrant Officer Hyndman, who had worked as the Caterer at the Base, from July, 1997 to June, 2001, said that Mr Johnson would have been working physically quite hard to clean the numerous blocks on his own but, after some time, Army personnel were used to assist him (T documents, page 14).
MEDICAL EVIDENCE
Base's Outpatient Clinical Records dated 30 August, 1998
47. The history taken on Mr Johnson's presentation at the Base was:
"Complained of central chest pain radiating across chest heavy in nature over last 1-2 weeks lasting 2-3 minutes usually. Occurs with exercise or at rest. Today finished work at home developed chest pain lasting 20 minutes and radiating to back. Associated shortness of breath diagnosis of ischaemic chest pain/unstable angina was made."
At 14:30, it was recorded:
"Presents with severe chest pain radiating to back. Complains of chest pain severity 10/10 `Feeling like chest would cave in.' Has been building up for last 2 days. Was sitting at home - nil exertion."
The notes indicate that, at 14:15, there was a recurrence of pain. Sub lingual arginine was given at 14:55 leading to a rapid resolution of the pain.
ECG reports from Katherine Hospital
48. On the ECG taken at the Katherine Hospital, 14:35 hours was marked on Mr Johnson's arrival in Accident & Emergency. The essential features of the report were:15:16:16 marked, actual time incorrect and no pain; 15:24:37 marked, with pain easing; 15:34:58 showing clear ST segment elevation on V1, V2, V3 (the anterior chest leads) and marked with pain and decided to strep the patient on this ECG; 15:49:13 marked uring streptokinase and with pain; 16:12:43 during streptokinase and no chest pain; 16:30:10 during streptokinase and no chest pain; 17:08:37 post streptokinase; 17:57 1/24 (one hour) post streptokinase therapy and nil chest pain. There are no ST elevations or other ischaemic changes in 15:24:37 or following, up to and including 17:57:49.
Aerial Medical Service
49. The In flight patient report of the Aerial Medical Service dated 30 August, 1998 stated:
"Increasing chest pain on exertion over past 2 weeks removed by sub lingual nitrates. Today sudden onset severe chest pain for 20 minutes. ... Transferred to ambulance at 19:45." (Exhibit A)
A diagnosis of "Anterior ischaemia/threatened MI" made. An attached document under notes was the history which recorded:
"50 year old sergeant had chest pain this morning and again lunchtime. ECG normal. 4th ECG showed some ST elevation.
Anterior AMI?? - Cardiac enzymes normal!" (Exhibit A)
Subsequent medical care
50. Professor O'Rourke summarised Mr Johnson's subsequent medical history at the Darwin Public Hospital, the DPH and the QEH:
"... While his chest discomfort had settled initially in Katherine, this apparently had recurred and he was transferred by air to Darwin Hospital where the electrocaardiogram had changed and showed acute evolving anterior myocardial infarction. The electrocardiographic changes were associated with right bundle branch block, indicating extensive evolving anterior infarction. Mr. Johnson was treated with streptokinase in an attempt to lyse the responsible coronary artery thrombus. CK level rose to over 4000 with MBCK index over 5.0 - consistent with extensive myocardial infarction. Mr. Johnson suffered an episode of ventricular fibrillation which required defibrillation and also showed signs of cardiac failure which also required treatment. After five days at the Darwin Hospital he was transferred to Darwin Private Hospital and then following conduct of a Sestamibi modified stress test, he was transferred to the Queen Elizabeth Hospital in Adelaide for coronary angiography. Coronary angiography showed complete occlusion of the left anterior descending coronary artery proximally together with 70% narrowing of a large lateral ventricular branch of the circumflex and an 80% stenosis of the right coronary artery in its mid part. Ventriculography showed evidence of a large anterior apical infarct with apparent aneurism formation and poor left ventricular systolic function. In the Queen Elizabeth Hospital Mr. Johnson developed episodes of atrial fibrillation and was anticoagulated. He had a number of syncopal episodes. His electrocardiogram showed evidence of bifasicular block (left posterior fascicular block and right bundle branch block). Electrophysiological studies showed inducible ventricular tachycardia. A pacemaker was inserted and he was treated with Amiodarone - the pacemaker was used to prevent ventricular asystole, the Amiodarone to prevent ventricular tachyarrhythmias.
Mr. Johnstone was transferred back to Katherine where he made a slow convalescence. He was subsequently discharged from military service." (Exhibit 3, pages 2-3)
Dr René Dupuche
51. After seeing Mr Johnson, Dr René Dupuche prepared his first report dated 19 November, 2001. In a second report dated 19 June, 2002, he gave references to articles regarding the relationship between the emotional state and coronary artery disease. Dr Dupuche set out Mr Johnson's history as he understood it to be in his first report:
"In a month or so before the heart attack he was subjected to greater stress than usual, arising directly out of extra work load. This stress appears to have been of substantial degree.
In the two or three weeks before the 30th August he had had episodes of chest pain which in retrospect were clearly anginal and indicative of a pre infarction situation. This is a common prodrome.
On 30th August, 1998 he arrived at work in the morning. A short time later chest pain occurred, but seemed to subside and he carried on with his work at a fairly intensive level both psychologically and physically. From his description there was the carrying of quite heavy weights. Pain appeared to occur later in the morning and assumed a severe level. He then returned home, apparently with the pain having subsided and it was some time later, perhaps two hours that a much more severe pain occurred.
He sought medical attention and then occurred a cascade of events with admission to the Katherine Hospital, air transport to the Darwin Hospital, the development of clear signs of myocardial infarction, the administration of appropriate treatments, and ultimately transfer to Adelaide where angiography was performed which revealed severe arterial occlusions, particularly in the critical left anterior descending coronary artery, with clear signs of major anteseptal myocardial infarction, aneurysm formation, heart failure and the need for a pacemaker. All indicators are those of a major myocardial infarction. ..." (Exhibit B, pages 1-2)
52. Dr Dupuche then went on to consider the relationship between stress and coronary artery disease:
"The role of stress in the causation of coronary artery disease has long been debated, but it does seem clear that there are many articles demonstrating not only a relationship between stress and the development of coronary artery disease but also between stress and the induction of acute myocardial infarction.
This matter has been considered by the Stress Working Party of the National Heart Foundation, amongst others, and in their conclusions they have not refuted stress as a cause of coronary artery disease when it works in conjunction with other more established risk factors such as, in this case, smoking, family history and hypercholesterolaemia." (Exhibit B, pages 2-3)
53. In his oral evidence, Dr Dupuche said that he had been a long time in clinical practice and had accumulated a great deal of evidence suggesting a close relationship. He said that the report of the Stress Working Party of the National Heart Foundation ("NHF Report") has said that there was a plausible relationship between stress and the development of pulmonary artery disease particularly if the stress was substantial and accompanied by other risk factors. The concept of "plausibility" was something that interested him and to him it implied that there is value in the association in the sense that it does not reject but tends to accept the relationship. In cross-examination, Dr Dupuche said that the NHF Report had not ruled out the relationship.
54. Of work factors, Dr Dupuche said in his first report that work was increasing in difficulty for Mr Johnson, was physically arduous and psychologically stressful. All of these were important, he said, as they all represented risks in a coronary setting. In his oral evidence, Dr Dupuche said that Mr Johnson's other risk factors were that he was a heavy smoker, had high cholesterol, had a family history and was glucose intolerant.
55. Dr Dupuche said that, given Mr Johnson's vascular and coronary risk factors and the severity of his left anterior descending coronary disease, it was perhaps inevitable that he would develop a major myocardial infarct or some other expression of his coronary stenotic disease. What was not inevitable, he said in his first report, was that it would occur on 30 August, 1998 with rather rapid progression to major acute myocardial infarction. The mechanisms that induce or contribute to the induction of the infarction include increased thrombotic tendency and plaque destabilisation and rupture (complicated lesion), he wrote. The closer the occurrence of infarction to physical exertion, the more persuasive is that association, but a time interval of several hours is not such as to break that association.
56. Dr Dupuche described coronary artery disease as proceeding in two stages:
"... The first stage is pre clinical and asymptomatic. The patient has no symptoms and is unaware of his disease. There is progressive narrowing of the coronary arteries, not of critical degree, under the influence of risk factors.
Eventually the condition proceeds to the second stage where the patient has symptoms and this usually corresponds to the development of a critical degree of narrowing, often associated with plaque destabilisation and the development of a complicated lesion. ..." (Exhibit B, pages 3-4)
57. In oral evidence, Dr Dupuche said that a person develops an infarct because there is a critical deficiency of blood flow to the heart muscle. That leads to a depression of oxygen to the heart muscle and the heart muscle dies in smaller or greater degrees. An artery becomes constricted because of plaque. Plaque comprises a combination of scar tissue, calcium and fat cells. The plaque is covered with a cap comprising fibrous tissue. It grows incrementally over a long period of time and, as it does so, constricts the blood flow. If the cover of the plaque is fissured, a clot is formed. That causes a physiological change.
58. In a person such as Mr Johnson, Dr Dupuche said, it is fair to say that there was a build up of plaque over time before the infarction occurred. That process was not presenting itself symptomatically to Mr Johnson. Had the surface of the plaque not cracked, Mr Johnson would have noticed the increasing levels of occlusion plaque in his reduced capacity to walk distances and in angina pain. Eventually, there would be occlusion sufficient to cause an infarction. The cracking of the surface of the plaque led to the formation of a clot and occlusion of the artery and then to an infarct. Mr Johnson would have felt pain on the Sunday morning because the increase in the degree of his occlusion was starting to cause insufficiency of his blood flow..
59. In relation to the first stage, Dr Dupuche said, the relationship between the disease and Mr Johnson's work is less clear. Work related stress over a sufficient period could have increased his smoking and raised his cholesterol levels and so accelerated the formation of atheromatous lesions that were the ultimate cause of his myocardial infarction. Articles in Medical Journals discuss relationships but care must be taken with them as:
"... their conclusions (medical articles) must be seen as `averaging' and similarly difficult to apply to the single case." (Exhibit B, page 4)
In his oral evidence, Dr Dupuche said that, if the body is acutely stressed, it pumps out adrenalin and cortisone. There is a consequent increase in the rate of the heart beat and in blood pressure and so in the force of the contraction of the heart. The heart becomes more "jerky".. All three consequences are disadvantageous to fragile plaque. In cross-examination, Dr Dupuche acknowledged that the body is designed to produce adrenalin in stressful situations but the ancient response was a physical one of fight or flight. In that way, the adrenalin was dissipated but, as that response is not available in modern life, the adrenalin cannot be dissipated.
60. Exercise in the second stage of the disease is a complex matter, Dr Dupuche said. It is easy to see risks with major exercise as well as major psychological stress in a situation of unstable atheromatous plaques and active angina. Fitness and exercise will not cause a deterioration in a patient's condition and has no protective role but is very likely to have an injurious role. If plaque is starting to fissure to an extent, a run around the TAN is likely to markedly exacerbate the situation. A patient with established angina would not, therefore, be encouraged to sprint and Mr Johnson's work on 30 August, 1998 could perhaps be seen as "repetitive sprints".. There could be quite a period of time between physical work and an infarction. Dr Dupuche continued to maintain his view that it is his "... opinion that there is a convincing case of a significant and material, but not exclusive, relationship between his work on the day of his infarction and that infarct." (Exhibit B, page 4) If a person has unstable plaque and is running to make the beds, that activity tends to promote the fissuring of the plaque.
61. In conclusion, he saw "... a rather strong relationship between this man's work on the day of his infarct and perhaps in the days and weeks before and his ultimate myocardial infarct on that day" (Exhibit B, page 4). In Dr Dupuche's opinion, on "... the balance of probabilities the episode of pain whilst moving laundry on 30/08/1998 was the commencement of a process that reached its fruition at home with the development of the major coronary obstruction. ... With the onset of pain at work and the commencement of the coronary occlusive process, continuing to work would have accelerated and aggravated the process which reached its finality at home." (Exhibit B, page 5). In his oral evidence, Dr Dupuche said that he was speaking in this passage of the final phase of Mr Johnson's plaque rupture and occlusion. He was saying that the rupture appeared to have occurred at work and did so because he believed that fissuring occurred from the time at which Mr Johnson began to feel pain. On 30 August, the process suddenly accelerated when he experienced pain and it was completed when he arrived home.
62. In his first report, Dr Dupuche wrote that "Certain factors could and probably did bring forward this catastrophic event" (Exhibit B, page 3). Dr Dupuche explained in his evidence that he meant that the plaque was changing from not producing pain to producing pain. In a matter of weeks, it would produce a major myocardial infarction. It was changing because certain things were going on in his life that were deleterious to his fragile plaque. In giving oral evidence at the hearing Dr Dupuche said that, in the month or so before the myocardial infarction, Mr Johnson had experienced extra stress arising out of a greater than normal workload. He experienced chest pain earlier on the Sunday but it subsided and he carried on with his work. On that morning, Mr Johnson had been carrying quite heavy weights. He was under some form of stress and duress to complete the work. Dr Dupuche said that the pain appeared later in the morning and "assumed quite a severe level of chest pain later in the morning".. Pain is a clinical sign of insufficient blood flow to muscle representing an increased degree of occlusion due to change in the plaque, that is, a fissure with a degree of overlying thrombosis.
63. Dr Dupuche said that the details provided to him were that the man was stressed by his duties and that there was a substantial physical component to his work. He understood that Mr Johnson was making beds which he thought was difficult. He said that stress is part of every day living and does not produce physiological change. Stress which is physiologically important is such as that which would put the blood pressure up for "hours on end" and there would be grades within that. He agreed that there was no material to show that Mr Johnson's blood pressure had been elevated. When asked by Mr Gorton whether he had any basis for drawing the conclusion that Mr Johnson's blood pressure was elevated, Dr Dupuche said that it was possible to adopt a reasonable position that there was no smoke without fire. If Mr Johnson was feeling stressed in his work, it could be assumed that his blood pressure had gone up. His being asked about the lost booking records on 24 August when he had been absent from work for a three week period could be regarded as a stressful episode. Even though his being asked might be regarded as a transient episode, whether he had a transient response to it is a different matter. It is something that Dr Dupuche did not know the answer to and so was not in a position to tell if the event had had any effect on him.
64. In cross-examination, Dr Dupuche said that, in view of Mr Johnson's myocardial infarction on that day, the episodes of chest pains he experienced in the two or three weeks before 30 August must have been of coronary origin. He is known to have suffered from coronary disease. The pain typically associated with angina occurs fairly broadly across the chest. It may radiate down the left arm but not always. Occasionally, it may occur in the right arm rather than the left arm and may occur in the abdomen or other atypical areas. Pain in the ribcage or well out to the side would be unusual and, unless it came to settle in the chest, it could be assumed that it was unlikely to be a pain associated with angina.
65. In the case of Mr Johnson, a pain occurring two weeks before the myocardial infarction suggests some form of breaking or fissuring of plaque. It can progress or fissure or it may repair itself and subside. If it progressed, it can lead to an infarct. The fact that Mr Johnson was walking down the street when he first experienced the pain was irrelevant, Dr Dupuche said. Even a moderate amount of walking may cause a small fissure. The majority of fissures occur without any major identifiable exertion. A small fissure might have led to a small clot and so a little pain. It could then repair itself and so his condition could wax and wane. Such pains are often thought to be indigestion. At the same time, walking can lead to a sudden rupture and the sudden onset of severe symptoms.
66. Dr Dupuche rejected Mr Gorton's suggestion that the absence of symptoms in the two week period before 30 August meant that he was not suffering from any problems associated with plaque in that period. Knowing that Mr Johnson had an infarct on 30 August means that his pain two weeks earlier was most probably ischaemic pain even though it was pain atypical of ischaemic pain. Most probably it was caused by some change in his plaque. The fact that he did not suffer any more pain might mean that his fissure had healed. Dr Dupuche agreed that Mr Johnson might or might not have suffered a fissure but there is no other reasonable explanation of what his pain might have been, he said. What happened on 30 August was a continuum of what had gone before. The continuum started two or three weeks before with the pain and continued with the pain on 30 August. Throughout all of this, Dr Dupuche understood that Mr Johnson was suffering from stress. The particular stressors came and went to some degree but not entirely.
67. Dr Dupuche said that he did not have an understanding of the duration of the pains that Mr Johnson's suffered on the morning of 30 August. He agreed that, if each pain lasted only one to two seconds, it was not particularly suggestive of ischaemic pain. It was more indicative of skeletal or muscular pain. If he were told of such a pain and there were no risk factors, Dr Dupuche said that he would not think it suggestive of angina. With the presence of risk factors, though, there is a need to be careful. In this case, he knew that Mr Johnson ultimately suffered an infarct and so there was the possibility of double pathology e.g. wind or infarct. He would not expect a thrombosis that developed to disappear in a second or two. For all that, it must be understood that a thrombosis sitting on plaque may break off and cause an occlusion. Therefore, a short pain is not specifically evocative of angina but angina cannot be ruled out.
68. In cross-examination, Dr Dupuche stated that myocardial infarction is a progressive development in the face of a lack of oxygen supply. He agreed that oxygen deficiency past a critical level will produce infarction after a period of about 30 minutes. If there is an established infarct in which heart muscle has died, it can be expected that there will be ECG changes. Dr Dupuche said that ST segment changes on ECG were indicative of injury rather than infarction. The criteria for infarction are T wave inversion and Q waves. Ischaemia gives ST segment elevation. It starts with ST elevation with progression to T wave inversion and the appearance of Q waves. From the time of occlusion to death of heart muscle takes only half an hour.
69. On examining the ECG records of the Katherine Hospital (Exhibit 2), Dr Dupuche observed that there were significant ST changes at 14:35 on 30 August. There was a change in the pattern of the T waves at the same time and this should be regarded as an indication of ischaemic disease. The T waves at the Katherine Hospital suggested myocardial damage, Dr Dupuche said, but he could not put it any higher than that. He could not say that Mr Johnson had suffered an infarction at the Base and could only say that there was something nasty going on. Dr Dupuche noted that there were some inconsistencies in the ECG taken at 14:35 and that they could be as a result of positional factors or a variation in the conductive gel. The later ECGs at the hospital are consistent and do not indicate myocardial infarction at that time. It followed, Dr Dupuche continued, that Mr Johnson underwent more dramatic changes in his coronary arteries after the time of the ECGs at the Katherine Hospital. In cross-examination, Dr Dupuche said that Mr Johnson's disability arises as a result of an infarct and it appears that he had not suffered an infarct at the time that he was admitted to the Katherine Hospital. In re-examination, Dr Dupuche said that he was unable to answer definitively a question whether Mr Johnson had suffered a minor infarct before the ECGs taken at the Katherine Hospital.. Given the accelerated process of his pain, though, it was very likely that he had and that it was beginning to have an impact on his heart.
70. Dr Dupuche agreed that the paper, "Triggering of acute myocardial infarction by heavy physical exertion: protection against triggering by regular exertion" by Mittleman MA, Maclure M, Tofler JB et al (N Engl J Med; 1993; 329 at 1677-1683) ("Mittleman paper") was a very good article. It was put to him that the paper concluded that the physical exertion required to trigger a myocardial infarct has to be significant and within an hour or less of infarction if a relationship is to be drawn between the two. Dr Dupuche replied that, while he would expect a fairly close relationship between the two, he would not rule out the relationship if two or three hours had elapsed. The statistics in the Mittleman paper are fairly useful he agreed. Those statistics showed that physical exertion at or above the level of six METS is recognised as triggering an infarction on occasion. The Mittleman paper described that level of exercise as representing quite a bit of exercise, such as speed walking and running, with panting and overheating. Dr Dupuche said that he found the description of the levels of exercise unhelpful as a trained marathon runner would find that level of work very easy. An overweight person with multiple risk factors should be measured by different rules, Dr Dupuche said. The same amount of work would have a much greater effect on such a person than on the marathon runner.
71. When asked whether the Mittleman paper shows that, if exertion triggers an infarct, it does so within one hour, Dr Dupuche agreed that this was so statistically. Statistics cannot govern the individual case, though. He also agreed that Mittleman's graph showed that myocardial infarction was much less likely after one hour but he remained certain that, in cases where more than an hour had elapsed since exercise, that exercise had put the process in train.
72. Dr Dupuche said that he did not know whether the work that Mr Johnson had undertaken on 30 August was any more difficult than the work he had done on other days but he did not think that mattered. A history of a little pain, thought to be indigestion, over a few weeks is a very common story given by patients. Looking back, it is possible to say that the pain was probably ischaemia that was not recognised as such. The opportunity to intervene before the infarct is lost. If a person stresses him or herself in that time, it would probably hasten the process. It was very hard to know whether exertion played a part in Mr Johnson's case. What mattered was that the plaque was fissuring and what he might have coped with on another day, he did not cope with on that day. He believed that the process started when Mr Johnson first got chest pain, it dribbled on and accelerated, that he became symptomatic because he had developed fissures in plaque and that it also accelerated towards the end. This commenced with sudden severe pain that morning on 30 August, 1998 and this was the first step and the second step was the change in the pain.
Professor Paul Nestel
73. Professor Nestel, who is a consultant physician, has conducted research into cardio vascular disorders focusing on the factors causing those disorders and the longer term management of those who suffer from them. He has prepared four reports relating to Mr Johnson.
74. In his first report dated 22 January, 2000, Professor Nestel referred to Mr Johnson's experiencing "severe crushing chest pain early on Sunday afternoon 30th August 1998 some 2 hours after returning home from work" (T documents, page 54). As to when Mr Johnson's infarct occurred, he continued:
"The issue of when his heart attack occurred or more importantly when it had probably begun. Heart attacks most commonly occur when the atheromatous plaque in a coronary artery ruptures leading to thrombosis over the plaque which, if sufficiently large, will obstruct the artery and damage the heart muscle. At angiography in Adelaide, the left anterior descending coronary artery was found to be blocked which is consistent with so much heart muscle having been infarcted within the territory supplied by that artery. Blockage of that artery and anteroseptal infarcts carry an adverse prognosis. Plaque rupture usually occurs over a period of time which may be of the order of hours or even a few days so that the total occlusion of the artery is not necessarily instantaneous. In fact it is more probable that the pathological process of plaque rupture had occurred prior to his return home than at home." (T documents, pages 54-55)
75. Professor Nestel said that he believed that Mr Johnson's "heart attack" occurred at work but then considered whether the events of that day, or of the preceding days, contributed to the rupture of the atheromatous plaque:
"... It is now recognised that two triggers that can initiate rupture are sudden excess physical exertion that places a high haemodynamic load on the arterial circulation and mental stress that by raising blood pressure and through other mechanisms can also distort the haemodynamics sufficiently to cause plaque rupture. ...In my opinion, the excess amount of physical work on the weekend of his heart attack, together with the background of considerable mental stress, in all probability contributed to the plaque rupture that lead to his heart attack. It is also possible that the anger he felt when admission to see a medical officer was unduly delayed had contributed to the extent of his eventual infarct." (T documents, page 55)
76. Professor Nestel acknowledged that Mr Johnson had several important factors for future heart disease; he had a family history of heart attack, he smoked and his cholesterol was raised. He dealt with those factors in this way:
"... Whereas it is correct that these factors would have contributed to the underlying coronary disease or atherosclerosis, and therefore predisposed him to a future heart attack, this is not directly relevant to the issue of why he had his heart attack on that particular day.
... In conclusion, I believe that the events during the weekend of his heart attack and the mental stress during the preceding month probably contributed to and accelerated the development of Johnson's heart attack." (T documents, page 55)
77. In his second report dated 7 May, 2000, Professor Nestel said that it was possible for Mr Johnson to develop a heart attack in view of his risk factors but even people with multiple risk factors have only a 50% chance of developing a heart attack. As to whether there is a relationship between the occlusion of the LAD and the number of plaque ruptures, he said that:
"... either is possible. Pathological examinations have shown that a single large rupture can cause thrombotic occlusion but equally it is common for several episodes of rupture in the one plaque to occur over days before occlusion eventuates. Regarding size, an occlusion can result from the rupture of a small fatty plaque that then initiates thrombosis. ... Small ruptures that do not block need not cause symptoms. The pathology of such plaques, showing repeated small ruptures followed by sealing, indicates that this is not unusual and cannot be related to a simultaneous clinical event. On the other hand, at times, transient anginal pain is experienced. It is often a question of whether the coronary artery spasms around the rupture and whether there is an adequate collateral circulation to supply the area of the myocardium that is temporarily threatened. ..." (T documents, page 67)
78. As to the role of psychological stress in giving rise to episodes of myocardial ischaemia, Professor Nestel said:
"... Mental stress is also a precipitating trigger for heart attack and well documented in recent cardiological journals. Taking into account the evidence that was available to me I believe that it is probable that the mental stress experienced by your member contributed to and accelerated his heart attack. The evidence linking mental stress to atherosclerosis and hence the pathology underlying coronary artery disease, is possibly but not probably supportive.
8. The mechanism for which mental or psychological stress causes a plaque to rupture and thus lead to heart attack, is by altering the haemodynamics around a vulnerable plaque ... This occurs through increased pressure and shear stress due to acute rises in blood pressure, increased thromobogenic factors through adverse hormonal responses and other factors.
9. The time factor can extend well beyond 2 hours. The pathology of plaque rupture is such that several episodes of rupture or a progressive increase in plaque and thrombus bulk result in a gradual blockage that extends over hours and even days. The syndrome of acute coronary syndrome is considered frequently to result from a plaque rupture that does not totally obstruct but that often progresses to a heart attack or infarction over several days if not treated. Therefore the 2-3 hours in this particular case between the time that he was still at work and the onset of clinical symptoms at home is well within the probability that the pathology causing his heart attack began at work." (T documents, page pages 67-68)
79. In a further report dated 20 November, 2001, Professor Nestel wrote:
"2. The issue of stress causing acute heart attacks and chronic coronary atherosclerosis has been fully reviewed in a publication by the Heart Foundation of Australia. It was published within the last few weeks and for the first time acknowledges linkage between mental stress and the above manifestations of coronary disease.
...
4. Plaque rupture due to acute unaccustomed physical stress is widely accepted, and the evidence that I am aware of includes the seminal Mittleman (1993) and Willich (1993) papers. ...
5. We all agree that this man had several important antecedent risk factors substantially raising the risk of a heart attack at its early age. That the underlying atherosclerosis was largely due to those factors bears little relevance to the acute complication of the disease induced as the relevant time by the stressful confrontations and substantial short-term physical exertion on the day in question." (Exhibit D)
80. In his final correspondence, Professor Nestel observed that the NHF Report was still not available but that:
"...the evidence on which they will base their position includes papers that I quoted in my original assessment relating to mental stress." (Exhibit F)
81. In cross-examination, Professor Nestel said that stress over time does not play an important role in the development of atherosclerosis. Stressful events such as depression, anger, hostility and panic disorders can be important stressful events affecting a person at or about the time of the rupture of a plaque. They do not necessarily produce an almost immediate infarct for, in the case of depression, for example, the NHF Report states that there is between six and eighteen months of depression before an infarction takes place. That finding is based on epidemiological studies. Epidemiologically, there is any amount of evidence of associations between repeated mental stressors due, for example, to anger and frustration and physical and social isolation. They do not precipitate a heart attack from one moment to the next but occur over a number of weeks.
82. In giving evidence, he said that Mr Johnson clearly related very adversely to stress. Stress led to an increase in blood pressure and that put extra strain on his heart. Mental stress can lead to an increase in the risk of blood clotting and so an increase in occlusion. A number of coagulant factors circulate in the blood and they increase under stress. Adrenalin is known to raise blood pressure which increases the pressure on vulnerable plaque.
83. When questioned about the contribution of physical effort to myocardial infarction and the findings of Mittleman, Professor Nestel said that the likelihood of suffering a myocardial infarction increased by about 7% after physical exertion. Mittleman did not claim that this is the inflexible position; only that it is possible. It is not an unusual occurrence for a person to suffer a myocardial infarction one or two days after physical exertion. A paper was published by Ojio S, Takatsu H, Tanaka T et al ("Considerable time from onset of plaque rupture and/or thrombi until the onset of acute myocardial infarction in humans" Circulation 2000; 102 at 2063-9) ("Ojio paper") some years after the Mittleman paper. It was based on observations of what happens in the arteries of those people who subsequently suffer a myocardial infarction. Those who had a coronary arteriogram at least a week before a myocardial infarction were studied. Twenty people were identified as having had a rupture up to a week before their myocardial infarctions. That is not surprising, Professor Nestel said, as it is known that there can be rumbling for a number of days before a myocardial infarction. That window of time can be used to try to salvage as much of the heart muscle as possible. Mittleman did the same study but in retrospect, Professor Nestel said.
84. Professor Nestel said that a paper by Willich SN, Lewis M, Lowel H et al entitled "Physical exertion as a trigger of acute myocardial infarction" (N Eng J Med 1993; 329 at 1684-90) ("Willich paper") does not give a time factor between physical exertion and a myocardial infarction. Instead, the Willich paper states that, in 7% of all infarcts, heavy physical exertion is a factor. He then conceded that the Mittleman paper states that no-one will dispute the connection between exercise and a myocardial infarction if they occurred within an hour of each other. Beyond that, Professor Nestel said, the greater the time, the less certainty there is that exercise is a causative factor.
85. Professor Nestel was shown the results of the ECGs at the Katherine Hospital. He observed that, at 15:34 hours, they showed a very large elevation in the ST segment, which is normally flat. This indicates that the heart was very short of blood supply and could be a manifestation of either an infarction or pre-infarction ischaemia. If the heart muscle has been damaged, there is an increase in certain enzymes known as CK enzymes. The height of the level of enzymes is an indication of damage. The reports from the Darwin Hospital showed the enzyme levels. It may be that they only become raised on the day after a myocardial infarction and then remain raised for some time. There is no question that Mr Johnson sustained substantial heart muscle damage. There is significant damage at a CK of 5,000 as shown in the report. There is also evidence that the enzyme, lactic dehydrogenase, was already elevated above normal at 10:15pm on 30 August. That indicated the beginning of a myocardial infarction.
86. With hindsight, Professor Nestel said, there was a 75% chance of a rupture of Mr Johnson's plaque taking place at any time in the preceding days or weeks. With regard to the earlier pains, he said, it is quite common for the initial manifestation to subside or not progress beyond recurrent angina from effort. Once coronary disease is manifest following a rupture, there can be a range of outcomes from sudden death to recurring angina or an event in between. That event is myocardial infarction.
87. The degree of exertion applied to rupture plaque depends not only on fitness and the level of exertion, Professor Nestel said, but also on the condition of the plaque. If the plaque is pre-disposed to being ruptured or is in the process of rupturing, the degree of physical exertion that is required is much less.
88. In cross-examination, Professor Nestel said that the opinions of Professor O'Rourke and Professor West were similar to his but with a different emphasis. He said that he had used the word "heart attack" in his reports intending to include the entire process and not just the myocardial infarction. A "heart attack" included plaque rupture, chest pain and the process which proceeds to myocardial infarction. "Acute coronary syndrome" is a much more serious manifestation of angina on effort. It includes the process where the infarction has not yet happened but there is already ischaemia as there is a reduced blood flow. Ischaemia occurs when the heart muscle is deprived of oxygen.
89. This is frequently accompanied by pain but there need not be pain, Professor Nestel said. Angina is accompanied by pain. That pain is experienced in the left chest, left arm and shoulder, the groin and, sometimes and atypically, in the right arm. Any pain in the chest is almost always investigated. Pain can also be felt over part of the back and the side of the chest. Rarely would it be encountered below the rib cage or in the side but the fact that it was experienced in that area did not exclude it from being such a pain. Professor Nestel agreed with Mr Gorton that it would be extraordinary if the pain were to last for only one to two seconds. He would expect it to be produced by exertion and the pain would be due to shortness of oxygen. The pain could last for one to two minutes but it would be unusual if it were to last one to two seconds. Once a person experiences pain, it does not necessarily recur each time he or she is put under stress. It is already a fairly late symptom in the process. During the initial stages, the onset of pain as a result of exertion is determined by a whole series of factors. It could last for three to five minutes on exertion but then only recur ever third to fifth day. Professor Nestel said that he would expect it to recur with greater degrees of exertion.
90. Plaque does not necessarily rupture at first instance. When it does rupture, it can do a number of things: heal and cause no further problems; grow in size and gradually occlude; and, if large enough, precipitate clotting with rapid occlusion. Pain is not suffered simply because there is a plaque rupture. Despite that, Professor Nestel said that it is possible to be reasonably certain when there was a plaque rupture when it is looked at retrospectively. If a person has an acute coronary syndrome and an angiogram is performed, then a major plaque rupture is seen in 75% of cases. "One knows with certainty that it has occurred", Professor Nestel said. An "acute coronary syndrome" is the sudden onset of major pain and is the manifestation of clinical coronary disease. It is not possible to tell when the plaque rupture occurred, he agreed.
91. Professor Nestel said his opinion was based on Mr Johnson's having experienced chest pain earlier on the Sunday, 30 August. His understanding was that the pain was of the same nature as the later crushing pain suffered at 2:30pm but not of the same severity. He said of the pain in Wagga two weeks before that he "... would put a question mark over that, as to its significance".. Chest pain of any duration that occurs within a few hours of a major heart attack and that is relieved when the exertion is removed is a matter that he "... would regard with considerable suspicion as having been part of the process". If it were part of the process leading to an infarction later in the day, it is possible that it would recur later in the day but not necessarily. It depends upon such matters as the speed with which he walked, whether there is constriction of the coronary arteries around the plaque and the nature of the collateral circulation. It is conceivable that Mr Johnson ruptured a plaque some time earlier. It takes hours for the plaque to reach dimensions that will occlude a vessel but, in its earlier stages, there is constriction around that lesion that can produce ischaemia. That ischaemia can resolve over a period of hours and then recur as the plaque rupture progresses. It is a very dynamic process and it is not possible to say that a fixed lesion and a fixed amount of exercise will bring on a fixed set of symptoms.
92. Despite the statistics in the Willich paper that indicate a relationship between exercise and myocardial infarction and despite the numbers of people who suffer a myocardial infarction without there being an exercise relationship, Professor Nestel said that Mr Johnson could be associated with the 7% who have a relationship with exercise. That is so, he said, "Because he is an individual as opposed to an epidemiological study which deals with a whole population".
93. As a clinician, Professor Nestel said, the history that a patient gives on his or her admission to hospital is probably the most accurate. He assumed that Dr Fenton properly asked the questions of Mr Johnson. Had he been given the history that Mr Johnson had suffered pain with exertion over the previous two weeks but that the pain was relieved with rest, Professor Nestel said that he would have been much more confident that he had experienced an acute coronary syndrome over two weeks. That would be so because it was the first onset of angina and that he was at risk of having an infarction if he did not receive appropriate treatment. When asked whether he was at risk of having the infarction whether or not he continued to work, Professor Nestel said that the risk was greater if he exerted himself.
94. With reference to the differences between the two week and two day history given on the day of admission, Professor Nestel said it did not change the process; only when it began.
NHF Report
95. An Expert Working Group of the National Heart Foundation of Australia undertook a review of systematic reviews of the evidence relating to major psychosocial risk factors to assess whether there are independent associations between any of the factors and the development and progression of coronary heart disease (CHD), or the occurrence of acute cardiac events.
"The expert group concluded that (i) there is strong and consistent evidence of an independent causal association between depression, social isolation and lack of quality social support and the causes and prognosis of CHD; and (ii) there is no strong or consistent evidence for a causal association between chronic life events, work-related stressors (job control, demands and strain), Type A behaviour patterns, hostility, anxiety disorders or panic disorders and CHD." (page 272)
Professor Michael O'Rourke
96. Professor Michael O'Rourke, who is a specialist in cardiology, prepared two reports. In his first report of 25 July, 2001 Professor O'Rourke set out a history of Mr Johnson's risk factors together with the statements and medical notes referring to chest pain leading up to and on 30 August. He has also noted that Mr Johnson was advised to alter his diet, reduce his blood lipids and had been advised of the ill effects of smoking. He was aware of Mr Johnson's exercising habits, that his aerobic power was average on testing and that he had no symptoms with exercise. Professor O'Rourke has recorded on page 2 of his report:
"It appears from the medical records of 30th August 1998 in Katherine, and from Mr. Johnson's second statement of 5th November 1999, that he had experienced angina pectoris with exertion for up to two weeks prior to his myocardial infarct on the 30th August." (Exhibit 3)
He was aware that Mr Johnson referred to similar pain carrying laundry on the morning of his myocardial infarct and observed:
"It appears that Mr. Johnson had no problems when he left work at 12.30pm, but that chest pain commenced at 2.30pm while he was in his home relaxing." (page 2)
97. Professor O'Rourke also observed that, in the Darwin Hospital, Mr Johnson's electrocardiogram had changed and showed acute evolving anterior myocardial infarct. He observed that the CK level rose to over 4,000 with MBCK index over 5 consistent with extensive myocardial infarction. In his opinion:
"Professor Nestel's theory on plaque rupture and time relationships appear to be speculative, ..." (page 3)
He stated:
"There are key literature articles describing triggers of myocardial infarction and the relationship between activity and onset of myocardial infarction. These references are enclosed ..." (page 3)
He referred to papers including the Mittleman paper and the Willich papers. He stated:
"The paper by Mittleman et al shows an increased risk of myocardial infarction during and up to one hour after engaging in heavy physical activity, but not beyond one hour. ... There is no increased likelihood of myocardial infarction beyond one hour after heavy physical exertion... The Mittleman studies showed a relationship between heavy physical exertion, with this defined as 6 mets or greater. The highest level of exertion achieved by Mr Johnson appears to correlate with approximately 6 mets. The Mittleman and other studies show that regular physical activity protects against development of myocardial infarction with heavy physical exertion.
...
The arguments presented by Professor Nestel do not fit with the article on mechanisms precipitating acute coronary events from NHLBI in 1997 ... nor with more recent studies which highlight the importance of plaque weakening through inflammatory changes (Libby P. Circulation 2001 ..." (Exhibit 3, page 4)
98. In his first report, Professor O'Rourke concluded that:
"Mr Johnson had established risk factors for coronary artery disease and appeared to develop angina pectoris in the latter part of August and then myocardial infarction with symptom onset at rest over two hours after returning from work. Mr Johnson had established risk factors for coronary artery disease. I believe that there was no relationship between Mr. Johnson's work on the day of infarction (30th August) and the development of acute myocardial infarction. I believe too that there was no relationship between any stress at work and the development of atherosclerosis. I believe that the development of atherosclerosis is attributable to familial predisposition, cigarette smoking, hyperlipidemia and glucose intolerance." (Exhibit 3, page 3)
It was inevitable, he wrote, that Mr Johnson would have suffered a heart attack at or around the time that he did so. He had severe uncontrolled risk factors and had experienced chest pain with exertion for several weeks prior to his infarct. That pain suggested the presence of extensive coronary artery disease and that was confirmed at cardiac catheterisation in Adelaide.
99. In answer to specific questions, Professor O'Rourke said that he could not, on the balance of probabilities, determine that the blockage of Mr Johnson's left anterior descending coronary artery occurred as a result of a single plaque rupture or of an accumulation of a number of small ruptures. The rupture of plaque does not necessarily amount to a sudden, dramatic physiological change because plaque rupture may be followed by healing. It does not necessarily result in coronary thrombosis and coronary occlusion. If a left anterior descending coronary artery had become blocked as a result of a single plaque rupture as it did with Mr Johnson, Professor O'Rourke said that, on the balance of probabilities, he would expect the symptoms to occur within a minute of the artery's being blocked. On the basis of the literature, and particularly on the basis of the Mittleman paper, Professor O'Rourke though it unlikely that any acute event related to exertion would have caused Mr Johnson's coronary thrombosis and resulting myocardial infarction some two hours after the discontinuance of accustomed physical exertion.
100. At the hearing, Professor O'Rourke described the process that concluded with Mr Johnson's myocardial infarction. It began as many years of atherosclerosis of the coronary arteries, inflammation in the artery and an acute event which coincided with the cardiac pain at home in the afternoon. He said the records showed some pain before 30 August, 1998. That pain was probably angina and that this was consistent with critical narrowing in those days in question before 30 August, 1998. He said plaque rupture was often the cause of narrowing and he compared it with a ruptured boil. Material can lead to clot formation and further narrowing. When asked about the time of the rupture, he said it was hard to say exactly. Something acute had happened in the afternoon. Professor O'Rourke said that it was possible that it had occurred in the days before with the first onset of pain. Equally, it might well have occurred immediately before the onset of the severe pain at 2:30pm with the earlier pain being narrowing due to inflammatory process. He observed that Mr Johnson was relatively fit and able to do quite a lot. He seemed not unaccustomed to activity.
101. Professor O'Rourke said that the modern theory was that fat in an artery undergoes oxidation. That leads to an inflammatory process, which is worsened by risk factors for atherosclerosis, such as high fat and cigarette smoking, and these factors are exacerbated if a person has a family history. Inflammation causes the swelling in the coronary artery to become greater and it weakens the surface lining of the artery. The surface lining is then predisposed to an erosion, or a small fissure, developing in the surface of the coronary artery. Professor O'Rourke considered that haemodynamic forces might play a role during unaccustomed exercise but otherwise do not. This is so because the coronary artery is made to have blood flowing very fast through the arteries and we know that increasing levels of exercise for people is very good for them. Consequently, haemodynamic forces by themselves are irrelevant in the development of coronary atherosclerosis.
102. In cross-examination, Professor O'Rourke said that he did not agree with Dr Dupuche's view that, without the plaque's being cracked, the obstruction to blood flow is a slow, incremental sort of process that would take a long period of time and be very predictable. Professor O'Rourke said that the process is not predictable and that there can be periods when the inflammation can cause the lesion of the artery to become bigger and less stable. Usually, it is a gradual process but there comes a certain critical narrowing of the artery and then the symptoms can come on very readily, if they did not appear before. He agreed that there can be a waxing and waning in the process of occlusion. Some people can have a 70% narrowing without any symptoms but develop them with a narrowing of 72%.
103. When asked how long it took to kill cardiac muscle, he replied that it was hard to be sure in Mr Johnson's case. That was because:
"... there was a stuttering process from the Sunday afternoon on and some of the first ECGs looked normal, or near normal, and the man's pain was coming and going and being relieved by glyceryl trinitrate. But, at some time there the artery muscle occludes completely because the changes in the electrocardiogram became characteristic of an occlusion of an artery and then he was - to the degree that he was considered to need, streptokinase. And that was given to dissolve the clot which was believed to be occluding the coronary artery. " (transcript, page 105)
104. Professor O'Rourke said that he probably did not agree with Dr Dupuche's proposition that the process of a little crack occurring and then healing itself waxed and waned over the preceding weeks until there was a sudden rupture. He thought that if the clot was coming and going, it would depend on the size of the clot that was formed and whether the size was sufficient to cause pain. By Sunday afternoon, there was a greater degree of clot and it occluded the artery. When he got the crushing pain, he probably obstructed completely at that stage and some clot was washed away so accounting for the disappearance of the pain. The occlusion occurred at 2:30pm on 30 August, 1998.
105. Enzymes, Professor O'Rourke said, are apparent after the infarct has occurred and after the decision to use streptokinase needs to be made. Professor O'Rourke believed that the process was evolutionary and said that the onset was the Sunday afternoon. The increase in LDH observed at 10:15 at night was consistent with infarction's having commenced. He agreed that if Mr Johnson had had angina two weeks before there was a possibility that there was an unstable plaque. He agreed that it was possible that unaccustomed stress could lead to rupture but emphasised that the exertion be unaccustomed. In Professor O'Rourke's view, the activities carried out by Mr Johnson "seemed a normal sort of job that a normal person would be able to do by himself". Professor O'Rourke did not consider that Mr Johnson's exertion in the morning of 30 August, 1998 was the cause of his severe pain later in the day and considered the proposition that it was to be speculation.
106. Whether a person is fit or not, he may still suffer a heart attack, Professor O'Rourke said. In a fit person, it probably occurs as often at rest as happens during exercise and could occur at anytime. Stress is not linked to the development of the underlying process but can be linked to an event. He gave as an example the increase in the number of heart attacks that occur during an earthquake and the reduced number in the period following it. The NHF paper attempted to quantify stress and the up shot was it could not find an association. He said it might bring on angina but he was not aware that it could bring on myocardial infarction. It was not a link accepted in "proper scientific cardiological circles".
Professor Malcolm West
107. Professor West is also a cardiologist. He prepared three reports. In his first report, dated 5 March, 2001, he set out Mr Johnson's history from the morning of 30 August, 1998 and answered specific questions. The cause of Mr Johnson's left ventricular failure was due to myocardial infarction. He said that, in view of Mr Johnson's risk factors, it was possible that a heart attack would occur in August, 1998. Without pathologically examining the artery, Professor West wrote that he did not believe that it was possible to say whether the blockage occurred as a result of a single plaque rupture or was the accumulative result of several small ruptures. As there is too much variation between different people, it is impossible to use a person's symptoms to determine the way in which an artery became blocked. As to whether the occurrence of plaque rupture or coronary artery block are two separate events or part of a spectrum in the disease process, Professor West wrote:
"The effect of coronary artery block is to reduce bloodflow to the heart muscle. This leads to myocardial ischaemia and may lead to infarction if bloodflow ceases. Symptoms are usually experienced if myocardial ischaemia occurs. Whether myocardial ischaemia occurs is dependent on the presence of collateral arteries, arteries which might also supply blood to the same area of tissue. If significant collateral supply is present, the effect of coronary artery block in one vessel may not be severe if a good collateral supply is present. Collaterals are more likely to develop when the blockage has been "stuttering" rather than sudden. In this respect the occurrence of plaque rupture and subsequent blockage and development of myocardial ischaemia is all part of one disease process. However, it is clear that the overall process is the sum total of a series of separate events, the most significant of which might be summarised as the development of the atherosclerotic plaque, the rupture of the plaque, the development of the overlying thrombosis which would partially or totally block the artery and the intrinsic capabilities of the blood to dissolve the clot. Each of these events are separate and determined by a range of different factors." (Exhibit 6)
108. Professor West wrote that it is possible that Mr Johnson's psychological stress contributed to his heart attack but he did not believe that it was probable. He believed that the myocardial infarction was inevitable at some time and that the factors that precipitated its occurrence on 30 August, 1998 could not be determined as the number of factors involved in causing a myocardial infarction at a given time are not fully understood. A number of mechanisms by which psychological stress may cause, aggravate or trigger a heart attack are unknown, he said. Most relate to the activation of neuro-hormonal levels in the blood stream and their possible adverse effects on atherosclerotic plaque. Such mechanisms have been postulated, Professor West observed, but not proven.
109. As to physical activity, Professor West wrote that he did not consider that Mr Johnson's physical activity had a material contribution to his heart attack. Mr Johnson had a moderate degree of fitness at the time of his heart attack. If it could be shown that he had a low level of fitness and that he had undertaken a significant additional level of activity on the day of the heart attack, there might be an argument to suggest that his fitness level was a factor. He did not, however, believe that it was a factor in his case. If physical exertion were to trigger a heart attack, the degree of physical exertion would have to be considerable and the onset of the myocardial infarction would be within one to two hours of the onset of the physical activity.
110. Prior to his giving oral evidence, Professor West had not been aware of Mr Johnson's suffering from any pain prior to 30 August, 1998. When told about the earlier pains, he said:
"Well, if you presume that the symptoms do reflect something happening with the heart, and that may not be the case, of course, but if we presume that that is the case, it would suggest that an event occurred to cause disruption of the plaque in the coronary artery to lead to some pathological process, particularly maybe the development of partial thrombosis developing over that period of time with the thrombosis being dissolved and then reappearing again over that two weeks. But that is conjecture" (transcript pages 124-125)
The only way to tell if that was the process was by an electrocardiogram which would have showed if there was any evidence of secondary myocardial ischaemia or limitation of blood flow to the heart muscle. Without it, historical grounds provide the only basis on which to form an opinion.
111. In his oral evidence, he said that he could not tell when the plaque was ruptured. It could have been days or minutes before 2:30pm. He was unable to determine if, at 2:30pm, the symptoms were more typical of myocardial ischaemia due to block or more typical of temporary block of one of the arteries. The ECG at the Medical Centre at Katherine was normal and so a diagnosis could not be made until later. He said it was more convincing that the cardiac event had occurred at this stage. Something happened at 2:30pm and, although the ECG was later normal, it could reflect a complete block at 2:30pm with dissolution shortly after. Dissolution can occur quite rapidly and it could be that something else happened later. The process could have been:
"Well, I think the abnormality of the plaque presents an adverse interface to the blood and if that interface is such that the clot was activated, well, then clotting occurs. Now it may be that there was a small rupture of the surface of the plaque - this is all speculation - there is a small rupture of the surface of the plaque or there was some bleeding into the plaque and this can - activates some thrombosis and then there are mechanisms within the arteries as well which lead to the secretion of substances which dissolve the clots. So I could imagine that maybe something small happened at 2.30 and then that that was able to be initially controlled by the body's defences, but as the afternoon wore on it wasn't able to be - the thrombosis wasn't able to be kept in check." (transcript page 127)
Once the thrombosis could not be kept in check, there was a shortage of blood supply and oxygen to the heart muscle and so pain developed. The integrity of the heart muscle is not immediately lost. The ECG showed ST segment elevation, which is regarded as a reversible feature. When Q waves are present, they are irreversible. When Mr Johnson's ST segment was elevated, that was the trigger to administer streptokinase.
112. In cross-examination, Professor West said that it is fair to say that the process of infarction started on 30 August, 1998. Initially, the problem was reversible but then it became irreversible. The whole thing was one process. He rejected a suggestion by Mr Moshinsky that it could be said, by virtue of the pain Mr Johnson experienced at 2:30pm, that a rupture was occurring as well as the occlusion. Some people have large heart attacks with minimal pain and others experience significant pain with minimal damage. There is no one to one correlation between pain and rupture. Professor West did not think that it was possible to say that the rupture occurred at any particular time. It was possible that something happened during the morning.
LEGISLATIVE FRAMEWORK
113. Section 14(1) of the SRC Act provides that:
"Subject to this Part, Comcare is liable to pay compensation in accordance with this Act in respect of an injury suffered by an employee if the injury results in death, incapacity for work, or impairment."
114. Unless the contrary intention appears, the word "injury" is defined in s. 4(1) to mean:
"(a) a disease suffered by an employee; or
(b) an injury (other than a disease) suffered by an employee, being a physical or mental injury arising out of, or in the course of, the employee's employment; or
(c) an aggravation of a physical or mental injury (other than a disease) suffered by an employee (whether or not that injury arose out of, or in the course of, the employee's employment), being an aggravation that arose out of, or in the course of, that employment;
but does not include any such disease, injury or aggravation suffered by an employee as a result of reasonable disciplinary action taken against the employee or failure by the employee to obtain a promotion, transfer or benefit in connection with his or her employment."
115. The word "disease" is, in turn, defined to mean:
"(a) any ailment suffered by an employee; or
(b) the aggravation of any such ailment;
being an ailment or an aggravation that was contributed to in a material degree by the employee's employment by the Commonwealth or a licensed corporation." (s. 4(1))
CONSIDERATION
116. There is no disagreement between the parties or amongst the medical witnesses who gave evidence, and we find, that Mr Johnson suffered an acute myocardial infarction on 30 August, 1998. He subsequently developed an abnormal rhythm, which is now controlled by a pacemaker. There was no disagreement, and we find, that, prior to that day, he was subject to three risk factors for heart disease: a family history of heart disease; he smoked; and his cholesterol was raised. What was not agreed between the parties was the course of events leading to his current condition and the application of the law to those events. In the following paragraphs, we have set out our understanding of the authorities followed by our consideration of the evidence in this case.
What was the course of events up to 2:30pm on Sunday, 30 August, 1998?
117. On or about Sunday, 30 August,1998, Mr Johnson underwent a very stressful event.. He is now asked to recall matters at or about that time and in the weeks and months preceding it. Some of those matters are matters that, at the time they occurred, may well not have occupied any place of importance in his mind at all and yet they now assume importance in the context of a claim that he could not be expected to have contemplated when they occurred. He is now asked to recall them and to recall them in detail. In view of what he has been through, it is understandable if he does not recall them or does not recall them accurately or, indeed, thinks that he recalls what he has not recalled in the past. Matters such as the work he carried out on the morning of Sunday, 30 August, 1998 and whether or not he suffered pain prior to that morning or even during the course of that morning are such matters. As a result of these sorts of factors, Mr Johnson's evidence has not been consistent in relation to a number of matters.
118. Mr Johnson's evidence as to his work history falls into this category. In that regard we do, however, have the advantage of Flying Officer Johns' report of 16 July, 1998 and that provides a marker in historical terms as well as Mr Johnson's statement of 15 February, 1999. In his statement, Mr Johnson marked his transfer as occurring on 11 July, 1998. It is clear from Flying Officer John's interview record that Mr Johnson transferred from the Catering Section to the Accommodation Section sometime before 16 July, 1998. Having regard to Mr Johnson's minute of 8 July, 1998 referring to his conversation of 7 July, 1998, it seems more likely, and we are satisfied, that his transfer had taken place by that time, rather than on the later date of 11 July, 1998. It is clear from his minute that he is speaking with some authority for the Accommodation Cell and signs himself as the Accommodation Cell's Senior Non-commissioned Officer in Charge. It is difficult to know just how long Mr Johnson had been in this position when he wrote the minute but it would have been at some time after he returned to work on 19 June, 1998 following his hernia operation. Given these events, we are satisfied that he probably took up the position at or about the beginning of July, 1998.
119. Prior to his transfer, we are satisfied in view of Mr Johnson's evidence as well as Flying Officer Johns minute that Mr Johnson felt that he was under pressure or stress from a variety of factors. We find that he felt stress, for example, over the events concerning his wife and the officer's wife. These events occurred over a period of time beginning, at the earliest, in January, 1998 when the officer's wife began work in the Catering Section. They had resolved themselves at least by the time that he moved to the Accommodation Section. He had also suffered ill health but, on the basis of his evidence, we find that he had built up his fitness and had achieved full fitness by the beginning of August, 1998. The only event that had caused him any upset before the weekend of 29 and 30 August, 1998 occurred on his return to work at the Base following his return from Wagga. That was on Monday, 24 August, 1998 and arose when he felt that a senior officer criticised him over inadequate entries that had been made in the booking system over the two weeks that he had been in Wagga. On the basis of Mr Johnson's evidence, we are also satisfied that he felt under stress during the Katherine floods in January, 1998.
120. Mr Johnson has always been clear that he suffered a pain at or about 2:30pm on Sunday, 30 August, 1998 and has always described it in terms of a crushing pain. There is no doubt that he suffered such a pain. He has been less clear about pains preceding that crushing pain. In his oral evidence, he described two pains of very short duration on the Sunday morning and another pain of very short duration at Wagga some two weeks before. By "very short", Mr Johnson meant one or two seconds. By contrast with his oral evidence, Mr Johnson made no mention of any such pains in his statement of 15 February, 1999 but he mentioned "some pains in my chest area" in his letter of 8 November, 1999. Given that those statements were made at a time much closer to the events of August, 1998, it could normally be expected that they might be more accurate than his oral evidence given some five years after the event. The fact that the earlier statement appears to be a comprehensive statement of significant events in Mr Johnson's work life from January to August, 1998 but makes no mention of any pain apart from the single pain on Sunday afternoon somewhat detracts somewhat from his noting pains in his later statement.
121. The notes taken on his admission to the various hospitals on 30 August, 1998 also need to be taken into account. Dr Fenton of the Katherine Hospital noted that Mr Johnson had suffered pain with exertion over the previous two weeks but that the pain had been relieved with rest. The notes at the Base before that recorded that he had been experiencing pain lasting two to three minutes over the previous one to two weeks. The In-Flight Patient Report of the Aerial Medical Service recorded on 30 August, 1998 noted that Mr Johnson had experienced increasing chest pain on exertion over the previous two weeks. Given the proximity of this note to the events, it seems to us that these are the records of events upon which we should rely even though they are not entirely consistent with each other. They are consistent in so far as they record, and we find, that Mr Johnson suffered episodes of pain over the two weeks leading up to 30 August, 1998. Beyond that, we find that the pain occurred only on three occasions for they are the only times on which Mr Johnson has recalled experiencing pain at any time.
122. The nature of that pain is more difficult to assess. As we have said, Mr Johnson said that it lasted only a second or two on the three occasions that he recalled its occurring. It felt like a "stitch" when it occurred. He described it extending from his left side just below his rib cage to an area forward and up to about the nipple area i.e. in the mid clavicular line. Professor Nestel and Dr Dupuche were of the view that the pain as described by Mr Johnson was quite unlike pain that is typical of anginal pain and we find that it was atypical of anginal pain. For all that, we are satisfied that anginal pain may present in an atypical way.
123. There was general agreement among the medical specialists as to the course of events leading to a myocardial infarction. In view of that general agreement, we find that pain is a clinical sign of insufficient oxygen to the heart muscle and so of insufficient blood flow to that muscle. Lack of oxygen to part of the heart muscle for approximately 30 minutes will cause that part of the heart muscle to die i.e. for there to be a myocardial infarction. If that occurs, there will be an increase in the levels of a person's CK enzymes. Insufficient blood flow may follow from an occlusion, or partial occlusion, of an artery. The description of the precise manner in which an occlusion occurs varied among the medical witnesses. Professor O'Rourke, for instance, described the fat in an artery as undergoing oxidation and thereby causing an inflammatory process in the artery. Inflammation causes swelling in the artery and this, in turn, weakens the surface lining of the artery wall. The surface lining is then predisposed to an erosion or a small fissure and a chemical reaction is set up leading to a thrombus. Dr Dupuche describes the process in slightly different terms. He speaks of there being a gradual deposit of plaque, which comprises scar tissue, calcium and fat cells, in the artery. There is a cap or fibrous tissue covering that plaque. The plaque grows incrementally over time and constricts blood flow as it does. A rupture of that cap may result in a thrombus or clot which may cause an occlusion. There may be multiple ruptures and multiple clots but not all will cause an occlusion.
124. Despite these differences in detail, we are satisfied that the evidence as to formation is generally consistent. Whether described in terms of inflammation or plaque rupture, the process may wax and wane with varying degrees of occlusion of the artery resulting. In the case of plaque, the rupture may repair itself and the clot dissolve. Whichever description is adopted, the process may be incremental. With regard to the process of inflammation, we prefer the evidence of Professor O'Rourke, who preferred this description, to that of Dr Dupuche, who preferred the description of ruptured plaque. On the basis of Professor O'Rourke's evidence, we find that the process of inflammation may be an incremental process on occasion but that, on others, there may be a sudden increase in the level of inflammation. Even on the occasions in which inflammation is a slowly incremental process, there may be a stage at which the occlusion of the artery becomes critical and symptoms occur.
Did Mr Johnson suffer an injury simpliciter?
125. We will now consider whether Mr Johnson suffered an "injury" or "disease".. On several occasions, the High Court has considered the meaning of the words "injury" and "disease", or one of them, together with their application in the context of workers' compensation legislation in Australia. Taking first The Darling Island Stevedoring and Lighterage Co Limited v Hankinson (1967) 117 CLR 19 (Barwick CJ, Kitto, Taylor, Menzies and Owen JJ). The facts were summarised in the headnote:
" Unknown to himself a worker had for some considerable time been suffering from an infection which had partially destroyed some of his spinal structures. Whilst lifting a heavy package at work, he felt an acute pain in his back. During the following fortnight his condition deteriorated until he became paralysed. Medical evidence accepted by the Worker's Compensation Commission was that the pain was caused by the collapse of one or two of the infected vertebral bodies and the consensus of medical opinion was that the infection, unless discovered and treated successfully, would in the ordinary course of events have progressed ultimately to produce a collapse of the vertebrae and incapacity. The Commission held that the worker had suffered at work an aggravation, acceleration, exacerbation and deterioration of a pre-existing disease, that the worker was totally incapacitated thereby ... " (page 19)
The word "injury" was defined in s. 6(1) of the Workers' Compensation Act 1926 (NSW) ("1926 NSW Act") to mean a "personal injury arising out of or in the course of employment" and included, among other matters, "the aggravation, acceleration, exacerbation or deterioration of any disease, where the employment was a contributing factor to such aggravation, acceleration, exacerbation, or deterioration". All of their Honours concluded that, in the words of Barwick CJ:
"...I do not think that the facts of the matter were rightly analysed as establishing an injury by aggravation, acceleration, exacerbation or deterioration of a pre-existing disease rather than an injury in the unextended sense of the statutory definition which itself led to incapacity. Regarded as the latter, the case presents no problem. Quite clearly, the circumstance that the injury would not have occurred but for the diseased state of the vertebrae or that its results were more extensive because of that condition would be irrelevant once incapacity was causally related to the injury. For my part, I am of opinion that the facts did establish such an injury and did not establish an injury by aggravation, acceleration, exacerbation or deterioration of an existing disease." (pages 23-24).
As explained by Owen J:
"... Dr. Paul's evidence was plainly capable of justifying the conclusion that the lifting strain had caused vertebrae to collapse, that this in turn had caused the back infection to spread and resulted ultimately in the injury to the spinal cord and paralysis." (page 35)
126. Had they considered the case under the extended meaning of "injury", Barwick CJ, Kitto J (who concurred with both Taylor and Owen JJ) and Taylor J concluded that they would have found in favour of the worker. As Taylor J said:
"...Whilst I agree that compensation in respect of incapacity resulting solely from the aggravation of an existing disease must be limited to the incapacity produced by the aggravation it by no means follows that the aggravation of a disease may not, itself, cause permanent incapacity. This could be said to have been the position in the present case for, if what happened on 3rd September 1964 was no more than an aggravation of the respondent's disease, it was the aggravation of that disease which directly resulted in the respondent's incapacity on and after that date. In that case, again, it is beside the point to say that if the aggravation had not occurred total incapacity or death would at some later time have resulted from the natural progress of the disease." (page 31)
127. In the case in which there is a sudden and distinct physiological change as the product of the inevitable development of a progressive disease from which a person suffers and where such a change can in no way be attributable to, or associated with, some incident of his employment, there is no personal injury by accident. This was the conclusion reached by the High Court in The Commonwealth v Ockenden (1958) 99 CLR 215, which considered the Commonwealth Employees' Compensation Act 1930 (Cth) ("1930 Act"). As a consequence of rheumatic fever, Mr Ockenden had developed incompetency of the aortic valve and aortic regurgitation. That condition was a consequence of rheumatic fever and the condition developed in the course of his employment. Dixon CJ, Fullagar and Taylor JJ said:
"... the traditional view must still prevail that a physiological change, sudden or otherwise, is not an injury by accident arising in the course of the employment unless it is associated with some incident of the employment. Indeed to hold otherwise would be to strip the work `accident' of all meaning by treating as such any distinct physiological change which is nothing more than the sole and inevitable result of the ravages of a disease. Such changes, even if they can be called accidents, occur not in the course of employment, but, it may, perhaps be said, in the course of the disease." (pages 223-224)
128. Of this case, Fullagar J was later to say that it should be regarded as a decision on the words "personal injury by accident" and not as a decision on the words "arising in the course of his employment" as they are used in s. 9 of the 1930 Act (Kavanagh v The Commonwealth (1959-1960) 103 CLR 547, Dixon CJ, Fullagar and Menzies JJ, Taylor and Windeyer JJ dissenting). The majority in Kavanagh considered that the rupture of Mr Kavanagh's oesophagus while vomiting at his place of employment was an accident. As Dixon CJ said:
"In my opinion it must be so considered. It is a sudden destruction of tissue by force or pressure. It is true that the force or pressure was not exerted from without the body, but that I think makes no difference nor does it make any difference if it occurred, as it may have done, as a consequence of another organ of the body, namely the stomach, responding to a virus infection ..." (page 553)
129. The issue confronting them was whether it was an accident that arose in the course of employment. There was no known connection between his employment and his vomiting and his vomiting might well have occurred at any other place and in any other circumstances. Having traced the history of provisions such as that in s. 9 and noting that they had originally provided that the injury must both arise out of and be in the course of employment rather than being expressed in the alternative as in s. 9, Dixon CJ continued:
"Few, if any, expressions had received so much judicial consideration and in so many jurisdictions as had the words `personal injury by accident arising out of and in the course of the employment'. Repeatedly the contrast had been made between the effect of the words `out of' and the effect of the words `in the course of'.. Whatever language was chosen to institute the contrast the first expression was treated as requiring a causal connexion between the employment or its incidents and the second as requiring that the pursuit of the employment should be an accompanying condition. I have seen nothing to suggest that within the expression `in the course of the employment' there had been discovered any element of causal relation with the employment and its incidents. To prescribe that element was considered to be the work of the words `arising out of'. It was thus natural for this Court to say after the word `or' had been substituted for `and' in the Western Australian provision that the result of English authority was `to show that the words "arising in the course of the employment" describe a condition which is satisfied if the accident happens while the workman is doing something in the exercise of his functions although it is no more than an adjunct to or an incident of his service'. That was said in Pearson v Fremantle Harbour Trust ((1929) 42 CLR 320 at pp. 329, 330)..." (page 556)
The majority held that Mr Kavanagh was entitled to compensation as the rupture of his oesophagus had occurred in the course of his employment. As Brennan CJ, Dawson and Gaudron JJ were to observe later in Zickar v MGH Plastic Industries Pty Ltd (1996) 140 ALR 156 (Brennan CJ, Dawson, Toohey, Gaudron, McHugh and Kirby JJ):
"... All the judgments distinguished the facts of that case - the onset of vomiting followed by the rupture - from the case where the relevant event was `nothing more than the sole and inevitable result of the ravages of a disease'. Windeyer J said:
It was quite unlike an episode that is an ordinary consequence of the progress of a disease, such as we have had to consider in other cases. It was not an accident arising out of the deceased's employment; but the Commonwealth Employees' Compensation Act, like some other Australian workers' compensation statutes, is satisfied when injury by accident arises either out of or in the course of employment." (pages 160-161)
130. Later in their judgement and after reviewing more recent authorities, their Honours summarised the relationship between a progressive disease and a provision that compensation was payable in respect of an "injury by accident':
"By judicial decision, the consequence of a progressive disease had been excluded from the cover of `injury by accident' if there was no cause of the consequence other than the progress of the disease. It did not matter that the consequence was gradual or was a sudden and distinct physiological change. If there was no underlying disease, however, a sudden and distinct physiological change could amount to `injury by accident' even though there were no external cause for the change. ..." (page 166)
131. The successor to the 1926 NSW Act, the Workers Compensation Act 1987 ("1987 NSW Act") was considered by the High Court in Zickar v MGH Plastic Industries Pty Ltd. An "injury" was defined in the same terms as in the 1926 NSW Act and not in terms of an injury by accident. Mr Zickar suffered a cerebral aneurism while at work. The Compensation Court of New South Wales had found that an injury had occurred in Mr Zickar's brain when the aneurism ruptured and that the rupture was not a disease. It awarded compensation to him without deciding whether or not there was any causal relationship between his employment and the rupture.
132. Brennan CJ and Dawson and Gaudron JJ analysed the definition of "injury" as it appeared in both the 1926 and the 1987 NSW Acts in the following terms:
"1. Diseases and their consequences are added to the categories of `injury' covered by para (a) where the particular disease is contracted `in the course of employment and to which the employment was a contributing factor' or `where the employment was a contributing factor' to the consequence.
2. Diseases and their consequences are not otherwise included in the definition.
3. Hence a consequence solely of a progressive autogenous disease is not an `injury'." (page 167)
133. They were, however, in the minority. Toohey, McHugh and Gummow JJ who, together with Kirby J, formed the majority, said in their joint judgement that:
" But the present case is not one of an autogenous disease. Or, to put it more accurately, it is not an autogenous disease upon which the appellant relies. It may be accepted that the aneurism was an autogenous disease but the appellant's claim to personal injury within para (a) is based on the rupture which occurred. From Dr Stening's evidence, it is clear that the rupture of the aneurism was not inevitable and further that the rupture may have been minor, allowing the appellant, after treatment, to return to his previous occupation. If there was no rupture there would be no event answering the description of personal injury and the appellant would be driven to rely upon para (b) of the definition. But there was such an event and the presence of a disease does not preclude reliance upon that event as personal injury.
The word `disease' has been considered by this court in a number of decisions, including Favelle Mort Ltd v Murray [(1976) 133 CLR 580 at 587] where Barwick CJ said:
The word `disease' is itself a word of some difficulty in this context, particularly in the expression `contraction of a disease'.. Properly used, disease denotes a morbid condition of the body. It may be initiated by some external cause or be idiopathic or autogenous.
But the word must be seen in the context in which it appears and be related to the circumstances of the case. To say that the aneurism was a disease does not answer the question whether the rupture itself can fairly be described as an injury.
Thus in Darling Island Stevedoring and Lighterage Co Ltd v Hankinson [(1967) 117 CLR 19] a worker suffered pain and later paralysis caused by the collapse of one or two infected vertebral bodies. The consensus of medical opinion was that the infection, unless discovered and treated successfully, would in the ordinary course of events have progressed ultimately to produce a collapse of the vertebrae and incapacity. The Workers' Compensation Commission treated the matter as an aggravation, acceleration, exacerbation and deterioration of a pre-existing disease. However, this court held that the collapse of the vertebrae was an `injury' in the ordinary sense without resort to the extended definition in s 6(1)(b) of the Workers' Compensation Act 1926 (NSW). The decision is mentioned in Hockey v Yelland [(1984) 157 CLR 124 at 137] ... without any doubt being cast on its correctness.
In O'Neill v Lumbey the respondent suffered a rupture of two aneurisms which occurred in his right cerebral artery, causing haemorrhaging into the intracranial space. The Court of Appeal (Priestley and Clarke JJA, Kirby P dissenting) held that the respondent had received an injury in accordance with the definition of injury in s 6(1) of the Workers' Compensation Act 1926 (NSW), that is, personal injury within the unextended meaning of that term. It is clear enough that Kirby P would have reached the same conclusion had he not felt constrained by authority, particularly Slazengers' Case.
In Accident Compensation Commission v McIntosh [[1991] 2 VR 253] the Appeal Division of the Supreme Court of Victoria held that it was open to the Accident Compensation Tribunal to find that the sudden rupture of blood vessels and consequent cerebral haemorrhage, arising from an arteriovenous malformation, was a `physical injury' under the relevant Victorian statute. Murphy J, with whom Crockett and Cummins JJ agreed, pointed out that there was general agreement that if some external agency precipitates a rupture, it is a physical injury. But, as his Honour observed:
If the rupture is due to blood pressure, arteriosclerosis, arteriovenous malformation, or any other congenital or diagnostic aetiology, it is nonetheless a rupture - something quite distinct from the defect, disorder or morbid condition, which enables it to occur.
We respectfully agree with this observation and, in our view, nothing in Hockey v Yelland or in any other decision of this Court precludes its acceptance." (pages 173-174)
134. Considering first the word "injury", it has been considered in the context of s. 6(1) of the Workers' Compensation Act 1951 (ACT) ("ACT Act") by the High Court in Kennedy Cleaning Services Pty Ltd v Petroska (2000) 200 CLR 286 (Gleeson CJ, Gaudron, McHugh, Gummow, Kirby and Hayne JJ, Callinan J dissenting). Mrs Petkoska was employed as a cleaner and was carrying out her duties as a cleaner when she collapsed and has been incapacitated since. Some years prior to her collapse, Mrs Petkoska had been diagnosed as suffering from rheumatic mitral valve disease. This is a condition of the heart that, in some cases, manifests itself with fibrillation that may lead to the release of an embolism into the bloodstream. At the time of her collapse, a blood clot had formed in Mrs Petkoska's left atrium and had broken off. It then passed to the temporo-parietal region of her brain. The medical evidence was that the process had been precipitated by her paroxysm of atrial fibrillation. Mrs Petkoska's employment was not a contributing factor to the contraction of her disease and it had not aggravated or accelerated her underlying condition.
135. In general terms, s. 7 provided that an employer was liable to pay compensation where a worker suffered personal injury arising out of or in the course of the worker's employment. While the term "personal injury" was not defined, the word "injury" was defined to mean any physical or mental injury and to include aggravation, acceleration or recurrence of a pre-existing injury. Section 9 of the ACT Act provided that a worker was entitled to be paid compensation for incapacity where a worker contracted a disease or suffered an aggravation, acceleration or recurrence of a disease and any "... employment of the worker ..... was a contributing factor to the contraction of the disease or the aggravation, acceleration or recurrence, as the case may be, whether or not the disease was contracted or the aggravation, acceleration or recurrence was suffered in the course of that employment". Furthermore, the contraction of the disease, or the aggravation, acceleration or recurrence of a disease, was deemed to be a personal injury to the worker. The word "disease" was defined to mean "any physical or mental ailment, disorder, defect or morbid condition, whether of sudden or gradual development, and also includes the aggravation, acceleration or recurrence of a pre-existing disease".
136. Gleeson CJ and Kirby J summarised the state of the authorities, including Kavanagh and Zickar:
"... All of those cases require that consideration be given to the precise evidence, on a fact by fact basis, concerning the nature and incidents of the physiological change accepted at trial. If this evidence amounts, relevantly, to something that can be described as a sudden and ascertainable or dramatic physiological change or disturbance of the normal physiological state, it may qualify as an `injury' in the primary sense of that word. If such an injury happens within the protected period of employment, it is ordinarily compensable without proof of a specific causal connection with the worker's employment [Higgins v Galibal Pty Ltd (1998) 45 SWLR 45 at 52, citing Mills, Workers Compensation (NSW), 2nd ed (1979), p 3."]. If the propounded `injury' is distinct from the underlying pathology that constitutes a `disease' that directly or indirectly caused the sudden event to occur, it is unnecessary to proceed to the alternative and additional basis whereby, in such cases, compensation may also be recovered for the disease process if the statutory preconditions are met [Zickar (1996) 187 CLR 310 at 335; Accident Compensation Commission v McIntosh [1991] 2 VR 253].
The foregoing approach does not rob the disease provisions of the Act of utility. They would apply in cases of a disease in the nature of dermatitis, lead poisoning, brucellosis and many others of a progressive type. The disease provisions remain as an alternative and additional heads of entitlement where a disease pathology exists with the appropriate employment connection, and does not manifest itself in the kind of physiological change or disturbance of the normal physiological state that will constitute an `injury' in the primary sense. There is no reason to read the word `injury' down because the alternative and additional definition of compensable disease conditions. On the contrary, considerations of the language and structure of the Act, of legislative history and of the proper approach to construing such legislation reinforce the conclusion to which the majority came in Zickar." (pages 300-301)
137. That brings us to consider what happened in the case of Mr Johnson. Dr Dupuche was of the opinion that Mr Johnson had suffered a rupture of the plaque cap during the morning of 30 August, 1998 but he based that opinion on his understanding that there was a substantial physical component to Mr Johnson's work and that he was stressed by his duties but that even a small amount of exercise, such as walking down the street in Wagga, might lead to a sudden rupture. Professor Nestel also based his opinion on Mr Johnson's suffering mental stress during the preceding month and upon Mr Johnson's suffering pain on the Sunday morning of the same nature as that which he suffered during the afternoon.
138. The facts that Dr Dupuche and Professor Nestel have assumed are not the facts that we find to have occurred at the relevant times. We have already found that Mr Johnson felt stressed by certain events that had happened in the past. There was some stress that he felt over the events that preceded his transferring to the Accommodation Cell but we are satisfied that they had resolved themselves by early July, 1998 when he was transferred. There was a change in the booking system before mid July. While he was in Wagga, there was nothing that upset him. He felt some stress on Monday, 24 August, 1998 when he was asked about bookings that had been lost from the computer but there is no evidence that his explanation was not accepted. Mr Johnson did not suggest that the enquiry upset him during the remainder of the week.
139. Mr Johnson said that he felt stressed by the work that he had to do on the Sunday but his evidence in this regard is somewhat at odds with his evidence that he chose to bag the laundry when it was not part of his duties to do so and he did so in order to get ahead for the week. That is not normally the action of a person who is feeling under pressure from performing his own duties. Nor is it normally the action of a person who is stressed by the amount of work he has to do to decline the assistance of another and yet that is what he did in relation to the cleaning of the toilets and showers. He acknowledged that he could have left the Army private to do that work but said that he preferred to do it himself. There is no suggestion that the Army private was not doing an adequate job of cleaning necessitating Mr Johnson's taking over from him and nor any suggestion that he had difficulty with delegating tasks. Warrant Officer Hyndman's evidence takes us no further.
140. As to the other tasks that he performed, we find that he had to carry sheets to and from, and to clean, no more than 30 rooms. Each room had one bed or bunk that had to be stripped and clean sheets left on it. On the basis of his own concession at the hearing, we find that Mr Johnson picked up approximately ten to fifteen sheets at a time, with each sheet weighing approximately a kilogramme, and carried them to the Accommodation Office. He completed that job in three or four trips. He also cleaned each of the thirty rooms by mopping them and cleaning under the lower bunks. Mr Johnson stated that he was not used to carrying weights but made no complaint about the physical exertion required when cleaning the toilets and showers or when performing additional duties in bagging the sheets.
141. We also note that Mr Johnson had passed his annual physical fitness test. In order to complete it, we find that he had walked 5 kilometres in 40 minutes, raised himself by his arms so that his chin was level with a bar and held the position for 20 seconds as well as performed 20 sit ups. On the basis of his own evidence, we find that he did not find it a strenuous test. In addition, we find that he regularly walked 2.4 kilometre each night, rode his bike 1.5 kilometres to and from work each weekday, played volleyball each week and also played soccer.
142. Taking all of these matters into account, we have concluded that Mr Johnson was not experiencing undue pressure, or stress, to complete his tasks on the Sunday morning. Given his level of fitness, his workload was not something that could be described as being a "substantial physical component" of his duties. Nor could Mr Johnson's chest pain of the Sunday morning be regarded as being of the same type as that in the afternoon even though a less intense version of that pain. None of Mr Johnson's statements supports our making a finding to that effect. His description of the Sunday afternoon pain was of one that he had never experienced before and of his earlier pain as more like a "stitch".
143. We have considered also whether we can form a view of what happened on the Sunday morning from what happened on the Sunday afternoon and evening but have concluded that we cannot. Given the manner in which plaque may rupture or the artery walls become inflamed and lead to a momentary occlusion and the way in which that condition may wax and wane together with the transient nature of the pain, atypical of angina, that Mr Johnson suffered that morning, what happened must remain a matter of conjecture. In particular, we are not satisfied that it is more probable than not that Mr Johnson suffered a rupture of plaque or even an increase in the level of his inflammation that could be regarded as, in the words of Gleeson CJ and Kirby J in Kennedy Cleaning Services Pty Ltd v Petroska as "a sudden and ascertainable or dramatic physiological change or disturbance of the normal physiological state...". He suffered two short pains that might, or might not, have resulted from an occlusion or might have been musculoskeletal pain. If they did result from an occlusion, whether they resulted from the rupture of plaque or from a sudden increase in the level of inflammation or from the previously existing level of occlusion is not a matter upon which we can conclude that one scenario was more probable than another.
144. It follows that we do not consider that Mr Johnson suffered an injury during his time on the Base on Sunday, 30 August, 2003. By 2:30pm on the Sunday afternoon, however, it is a different matter. There is no disagreement among the medical witnesses that Mr Johnson suffered an occlusion at or about that time. The crushing pain is indicative of such an occlusion and we are satisfied that it occurred as a result of "a sudden and ascertainable or dramatic physiological change or disturbance of the normal physiological state..." and so is an "injury" in its unextended meaning within the meaning of s. 4 of the SRC Act.
Did the injury on Sunday afternoon occur "in the course of employment"?
145. Several authorities have considered whether an injury arose out of, or in the course of, employment. They include: Charles R Davidson v M'Robb [1918] AC 304, Humphrey Earl Limited v Speechley (1951) 84 CLR 126, Commonwealth v Wright (1956) 96 CLR 536, Danvers v Commissioner of Railways (NSW) (1969) 122 CLR 529, Hatzimanolis v A.N.I. Corporation Ltd (1992) 173 CLR 473, Comcare v Mather and Mitchell (1995) 37 ALD 463, Gregory v Comcare (1997) 72 FCR 196, Comcare v O'Dea (1997) 26 AAR 252, Re Daykin and Department of Defence [1998] AATA 370 (Senior Member Handley) and Re Commonwealth Bank of Australia and Wark (1995) 37 ALD 697 (Senior Member Barbour).
146. The leading authority is Hatzimanolis in which the High Court considered, as we have said above, the definition of "injury" in the 1987 NSW Act. The majority of the High Court (Mason CJ, Deane, Dawson and McHugh JJ) traced the interpretation of the words "course of employment". They noted that:
"In Henderson v Commissioner of Railways (WA) ((1937) 58 CLR 281 at 294), Dixon J acknowledged that general expressions such as `incidental to the performance of the work' had not `proved very helpful' in determining whether an injury had occurred in the course of employment. His Honour suggested that, in cases which were not concerned with injuries sustained during actual work, the test of whether an injury had been sustained in the course of employment ultimately depended upon whether the workman was doing something which he was `reasonably required, expected or authorized to do in order to carry out his actual duties' ((1937) 58 CLR 281, at 294). Dixon J. also applied that principle in Humphrey Earl Ltd. v Speechley ((1951) 84 CLR 126, at p 133) although in that case he omitted the adjective `actual'." (page 479)
147. The majority traced the application of this test in various cases over the years and observed that:
"Given the flexible nature of the application of the test, it is not surprising that what is now perceived as required, authorized or expected to be done in order to enable an employee to carry out his or her duties covers many situations that were not contemplated when the test was first formulated in Henderson in 1937." (page 479)
148. They illustrated their point by reference to cases including Danvers. In that case, an employer had provided a van for his rail workers' accommodation. The van was moved from work site to work site. A railworker, who had finished work at 4:00pm, died when the van caught fire during the night. The majority in Hatzimanolis summarised the reasoning in Danvers as follows:
"Nevertheless, this Court, reversing the Court of Appeal of New South Wales, held that it was open to the Workers' Compensation Commission to find that the worker's death occurred in the course of his employment. Barwick C.J., with whose judgment Kitto and Windeyer JJ. agreed, adopted the statement of Dixon J. in Henderson ((1937) 58 CLR at p. 293) that doing what was reasonably required, expected or authorized to be done in order to carry out duties may include being at a place at which the workman's presence `is so consequential upon or incidental or ancillary to the employment that in being there he is doing something in virtue, or in pursuance, of his employment' (Danvers (1969), 122 CLR at p. 536). His Honour said that it was not enough to exclude the use of the employer-provided accommodation from the course of employment to establish that there was other accommodation available in the vicinity of the place of work. If alternative accommodation was available, the worker would be outside the course of his employment in choosing to use the employer's accommodation only if he had a real and meaningful choice to use the alternative accommodation. His Honour also said (ibid. at p.573) that, in determining the course of employment, regard had to be had: `to the general nature and circumstances of the employment and not merely to the circumstances of the particular occasion out of which the injury to the employee has arisen.' ..." (page 481)
149. The majority continued:
"Beneficial as the Henderson-Speechley test has proved to be in the law of workers' compensation, its formulation no longer accurately covers all cases of injury which occur between intervals of work and which are held to be within the course of employment. A finding that a worker was doing something `in order to carry out his duties' at the time he sustained injury is in many cases simply fictitious. Consequently, the rational development of this area of law requires a reformulation of the principles which determine whether an injury occurring between periods of actual work is within the course of the employment so that their application will accord with the current conception of the course of employment as demonstrated by the recent cases, particularly the decisions of this Court in Oliver and Danvers.
A striking feature of the recent cases which have held that an injury occurring in an interval between periods of actual work was within the course of employment is that in almost all of them the employer has authorized, encouraged or permitted the employee to spend his time during that interval at a particular place or in a particular way. However, it would be an unacceptable extension of the course of employment to hold that an employee was within the course of employment whenever the employer had authorized, encouraged or permitted the employee to spend the time during an interval between periods of actual work at a particular place or in a particular way. That formulation would cover not only the case of the `lunchtime' injury, as in Oliver, and the case of the railway worker, as in Danvers, but also many cases involving injuries occurring during intervals between daily periods of work which could not fairly be regarded as within the course of employment. Thus, an employee who is encouraged by his or her employer to see a doctor after working hours is not ordinarily within the course of employment if injured while visiting the doctor, although the case would come within such a formulation. The course of employment is ordinarily perceived as commencing when the employee starts work in accordance with his or her ordinary or overtime hours of work and as ending when the employee completes his or her ordinary or overtime hours of work.
The distinction between an injury sustained by a railway worker as in Danvers and a non-compensable injury sustained by an ordinary employee after the day's work has ceased lies not so much in the employer's attitude to the way the interval between the period of actual work was spent but in the characterization of the period or periods of work of those employees. For the purposes of workers' compensation law, an injury is more readily seen as occurring in the course of employment when it has been sustained in an interval or interlude occurring within an overall period or episode of work than when it has been sustained in the interval between two discrete periods of work. Where an employee performs his or her work at a permanent location or in a permanent locality, there is usually little difficulty in identifying the period between the daily starting and finishing points as a discrete working period. A tea break or lunch break within such a period occurs as an interlude or interval within an overall work period. Something done during such a break is more readily seen as done in the course of employment than something that is done after a daily period of work has been completed and the employee has returned to his or her home. On the other hand, there are cases where an employee is required to embark upon some undertaking for the purpose of his or her work in circumstances where, notwithstanding that it extends over a number of daily periods of actual work, the whole period of the undertaking constitutes an overall period or episode of work. Where, for example, as in Danvers, an employee is required to go to a remote place and live in accommodation provided by his or her employer for the limited time until a particular undertaking is completed, the correct conclusion is likely to be that the time spent in the new locality constitutes one overall period or episode of work rather than a series of discrete periods or episodes of work. An injury occurring during the interval between periods of actual work in such a case is more readily perceived as being within the current conception of the course of employment than an injury occurring after ordinary working hours to an employee who performs his or her work at a permanent location or in a permanent locality.
Moreover, Oliver and the cases which follow it show that an interval or interlude in an overall period or episode of work will ordinarily be seen as being part of the course of employment if the employer, expressly or impliedly, has induced or encouraged the employee to spend the interval or interlude at a particular place or in a particular way. Indeed, the modern cases show that, absent gross misconduct on the part of the employee, an injury occurring during such an interval or interlude will invariably result in a finding that the injury occurred in the course of employment. Accordingly, it should now be accepted that an interval or interlude within an overall period or episode of work occurs within the course of employment if, expressly or impliedly, the employer has induced or encouraged the employee to spend that interval or interlude at a particular place or in a particular way. Furthermore, an injury sustained in such an interval will be within the course of employment if it occurred at that place or while the employee was engaged in that activity unless the employee was guilty of gross misconduct taking him or her outside the course of employment. In determining whether the injury occurred in the course of employment, regard must always be had to the general nature, terms and circumstances of the employment and `not merely to the circumstances of the particular occasion out of which the injury to the employee has arisen'. (Danvers, (1969) 122 CLR at p. 537)." (pages 482-484)
150. In Mather and Mitchell, Kiefel J rejected a submission that the principles in Hatzimanolis required that an employee must be directed to a particular place or authority must be given for an identified activity before he or she could be said to have been in the course of his or her employment. Her Honour said that:
"The place at which or the activity undertaken at the time of the injury was not said in Hatzimanolis to have been previously expressed or identified by the employer. It happened that such an inference could be drawn there. An injury will, within the statement of principles, have occurred at a `particular' place if it can be found to fall within the ambit of the employer's encouragement or inducement which may, in its terms, leave some matters to the decision of the employee. The statement of principles read, with the preceding analysis of case law, discloses an attempt to provide a satisfactory connection between injury and employment by a temporal connection (and as to which see Inverell Shire Council v Lewis (1992) 8 NSWCCR 562) which is strengthened by connection via the employer, the `nexus' of which Lockhart J spoke in Comcare v McCallum (1994) 49 FCR 199 at 204." (page 468)
151. Section 45(1) of the Defence Act 1903 provides that:
"Members of the Australian Regular Army or of the Regular Army Supplement are bound to render continuous full time military service."
Mather and Mitchell concerned members of the Australian Army who were engaged in Kangaroo 92. Kangaroo 92 involved them in three months of simulated combat exercises in northern Australia. Only local leave was granted during the three month period. There is nothing in Kiefel J's judgement which suggests that the fact that a person is a member of the Australian Regular Army and so bound to render continuous full time service is relevant in considering whether he or she was in the course of his or her employment. Equally, there is nothing in her judgement to suggest that the fact that a person is at the place of her employment (i.e. Broadmeadows) necessarily resolves the question whether that person was injured "in the course of ... employment". Whether or not a person is required to "render full time continuous service", there remains the question whether there is the necessary connection between the injury and the person's employment. That connection is a temporal connection as Kiefel J explained it.
152. This was also the approach adopted by Cooper J in Gregory. Mr Gregory had been a member of the Fire Section in the RAAF. A farewell barbecue, catered for in part by RAAF cooks, was organised for him at the Airmen's Club on a RAAF base. The farewell was held during working hours and Mr Gregory's roster was altered so that he was not rostered for duty and could attend. Cooper J said:
"The judgment of the majority in Hatzimanolis did not, in my view, affect the proposition that for an injury to be said to arise in the course of employment the connection which must be established between the occurrence of the injury and the employment is a temporal connection (see Commonwealth of Australia v Lyon 24 ALR at 303-304). What their Honours did in Hatzimanolis was provide to tribunals of fact reasoned guidance, by way of a `unifying principle', in determining whether that temporal connection exists in circumstances where the injury in question is sustained during an interval between periods of actual work. Their Honours concluded that the distinction between a compensable and a non-compensable injury occurring in such an interval, where the employer had induced or encouraged the employee to spend the interval at a particular place or in a particular way and the injury was sustained at that place or while the employee was engaged in that activity, was to be drawn by a characterisation of the period or periods of work of the particular employee. That characterisation highlights the temporal nature of the connection between the place or activity at or during which the injury occurred and the employment.
The logical corollary of the approach adopted by the majority in Hatzimanolis is that, ordinarily, an injury which occurs in an interval between two discrete periods of work, even if the injury occurs at a place or in the course of an activity which the employer induced or encouraged the employee to spend the interval in or doing, will not be an injury which occurs in the course of employment. This is because, putting aside injuries suffered while travelling to and from work and the like which are specifically provided for under the Act (see s 6), the end of the discrete period of work breaks any temporal connection between the employment and the place at which or activity during which the injury is sustained.
The example given by the majority in Hatzimanolis of the employee who is encouraged by his or her employer to see a doctor after working hours illustrates the point. Whilst it might be said that an injury sustained by the employee while visiting the doctor is in some way causally connected to his or her employment, there can be no question of a temporal connection.
That is not to say that an injury occurring in an interval between two discrete periods of work can never be one occurring in the course of employment. In any given case, there may be a feature or features of the particular facts and circumstances which establishes a sufficient temporal connection between the place or the activity and the employment." (pages 201-202)
153. The principles established by the High Court and Federal Court have been applied by the Tribunal in Wark and Daykin. In Wark, the Tribunal considered the case of a bank officer, Ms Wark, who was a member of one of the Bank's ATM repair teams. In addition to her ordinary working hours, Ms Wark was required to hold herself in readiness to repair malfunctioning ATMs when she was rostered to do so. She was provided with a pager and paid an on-call allowance whether required to attend an ATM or not. If she was required to attend an ATM, she was required to repair it within the hour and paid attendance moneys and they were calculated on overtime rates on a minimum of four hours from the time of the first call-out. Only if she worked for more than four hours was she paid above the minimum amount. She was not required to remain at any particular place provided she could service the ATMs as required. While rostered to be on-call, Ms Wark injured her hand in the kitchen of her home when she attempted to remove a plastic strip from a tablet bottle. Senior Member Barbour decided that Ms Wark's injury occurred during an interval in an overall period of work while spending that interval at a particular place and in a particular way encouraged and induced by her employer. She was, therefore, acting in the course of her employment.
154. In Daykin, Senior Member Handley considered a case in which Mr Daykin, who was a member of the Royal Australian Air Force ("RAAF") walked into the side of an open tilt window and injured his eye. At the time, he lived on the Williamtown Base. As a storeman, it was possible that he might be called upon to issue a spare part between the hours of midnight and 6:00am. There was an informal roster whereby being "called-in" was shared around amongst the storemen. Senior Member Handley concluded that Mr Daykin was in an interval between his discrete periods of work when he was injured after the conclusion of his normal work day.
155. Applying the principles in these cases, did Mr Johnson's injury on Sunday afternoon arise in the course of his employment i.e. to adapt the words of Dixon CJ in Kavanagh v The Commonwealth, did the injury arise when the pursuit of his employment was an accompanying condition? There need be no causal connection between the employment and the injury provided that temporal connection was present. In Mr Johnson's case, we are satisfied that there was a roster for those who were "on call". He had, in fact, drawn it up himself but that does not detract from its being such a roster. We find that he did so in order to bring some order to the system that had previously existed so that it was clear who was on call and who was not. On the basis of Mr Johnson's own evidence, we find that he considered that his movements were limited when he was on call. He felt that he had to remain at the pool on the Base or at home. Others, however, did not feel similarly constrained and took themselves to Katherine, some 17 kilometres south of Tindal, or elsewhere. On the basis of Mr Johnson's evidence also, we find that it was a matter of personal choice whether a person stayed at home or in the close vicinity of, or on, the Base during periods of being on call. If a person was called out to attend to accommodation requirements on the Base, we find that he or she was given leave in lieu of that time spent attending to those duties. That leave was noted in a book kept for that purpose. There was no suggestion that leave was given in lieu of the time spent on call and we find that it was not. We also find that he was not given any additional allowance for the periods he was actually on duty or for the time spent on call but not actually called to perform any duties.
156. We can understand that Mr Johnson, as a conscientious member of the RAAF, wanted to remain on hand to answer the call to duty if it should come but his conscientious approach does not change the nature of the period that he was on call from what it was to what it was not. In our view, the RAAF did not induce or encourage him to be at one place rather than another and it did not recognise the periods between his performing his duties as time during which it could tailor his activities or for which it would pay him either in money or in kind. In view of this, we have concluded that, the time at which he suffered the crushing chest pain as he sat at home is not a time that can be regarded as being in the course of his employment. Therefore, his injury did not occur in the course of his employment and so is not compensable on that basis.
Did Mr Johnson's injury on Sunday afternoon arise out of his employment?
157. It is clear from the passage that we have set out from Dixon CJ's judgement in Kavanagh v The Commonwealth that the effect of the words "out of" as used in s. 4 of the SRC Act is to require a causal connexion between the employment and the injury. Professor Nestel and Professor West conceded that stress might be linked to a myocardial infarction. Professor West would not go any further than acknowledging a possibility but Professor Nestel was firmer in his evidence. It was Professor Nestel's view that stress can lead to an increase in the number of coagulant factors circulating in the blood as well as adrenalin that is known to raise blood pressure and so increase the pressure on vulnerable plaque. We understood Professor O'Rourke's evidence to mean that, epidemiologically speaking, there was an increase in myocardial infarctions when very stressful events, such as earthquakes, occur but that there is not scientific evidence linking the two. At most, he conceded that stress might produce anginal pain or that if it were unaccustomed stress, it could possibly lead to plaque rupture. Dr Dupuche attributed Mr Johnson's myocardial infarction in the afternoon to a continuum of events that had gone before. That continuum had commenced two or three weeks before 30 August, 1998 and had been accompanied by stress throughout.
158. We do not consider that we must resolve the divergence in the evidence for we have already found that we do not consider that Mr Johnson felt that he was under any stress on the Sunday morning or, indeed, at any time after Monday, 24 August, 1998. As for the two week period prior to that Monday, Mr Johnson had been attending a course at Wagga and we are satisfied that he has not complained of feeling any stress while on that course. Even if he was under stress on Monday, 24 August, 1998, the evidence of Professor Nestel given in this case does not support our finding that a single incident of stress five or six days before the injury would lead to an increase in blood pressure and so increase the risk of blood clotting and/or of an increase in the pressure on vulnerable plaque. Professor Nestel spoke in terms of the stressful events' having occurred over a number of months.
159. Physical stress is another matter. Each of the medical practitioners agreed that a myocardial infarction could be caused by physical exertion but it was not just any physical exertion. Professor O'Rourke insisted that it had to be unaccustomed physical exertion and he and Professor West adhered to the results of the Mittleman paper to the effect that, for there to be the probability of a causal link between a myocardial infarction and physical exertion, the two had to happen within an hour or two of each other. Professor Nestel conceded that the greater the time between the two, the less certainty there is that exercise is a causative factor of myocardial infarction. Dr Dupuche considered that exercise outside those time frames could be a causal factor but he acknowledged that it was very hard to know what the situation was in Mr Johnson's case.
160. We find that Mr Johnson was engaged in physical activity during the course of Sunday morning but, given his history of physical activity and physical fitness, we are not satisfied that his activity could be described as unaccustomed physical activity. Although he considered that he had worked hard when he looked back on events, it is apparent that he had finished moving the sheets by 10:30am. He had energy left to undertake the additional task of bagging the laundry when there was no need for him to do so and to do some work on the computer in order to get ahead for the next week. While the computer work might not be thought to tax him physically, it could be expected that he would not have done it had he felt tired from his physical work. His injury occurred over two hours after he had engaged in any bagging of sheets or any other physical work required by his employment. Taking into account the medical evidence that we have heard and Mr Johnson's particular circumstances, we consider that the causal link between his physical work and his myocardial infarction has not been established. It may be that at some time in the future, further studies will have been conducted as to the link between physical, as well as mental, stress and myocardial infarction but, for the moment, we do not have the advantage of that future research. We must reach our decision on the basis of probabilities and not possibilities.
Was Mr Johnson's disease "contributed to in a material degree" by his employment"?
161. There is no dispute between the parties, and we find, that Mr Johnson was suffering from atherosclerosis. This is a disease. What is meant by a disease's being "contributed to in a material degree by the employee's employment by the Commonwealth" in the context of the definition of "disease"? Davies J considered what was required to establish a contribution in a material degree in Australian Telecommunications Commission v Treloar (1989) 90 ALR 202 (Davies J). A similar concept appears in the Veterans' Entitlements Act 1986 and Davies J had considered that in Repatriation Commission v Bendy (1989) 18 ALD 144 (Davies J). He said in Treloar:
"... The test propounded by the 1971 Act, like the test propounded by the 1988 Act, requires that there be a contribution of a causal nature and therefore that the contribution be causally significant or, to use another term, material. A number of statutes are in this respect similar. In Bendy's case, I said:
`In Repatriation Commission v Law (1988) 36 ALR 411, 147 CLR 635 at 648, Aickin J, with whom Gibbs CJ, Stephen and Mason JJ agreed, when considering provisions of the Repatriation Act 1920 (Cth) accepted that it was sufficient if war service was one of a number of causes of a disease provided that it was a contributing cause. I have myself, on occasions, used the term "material contribution" in this context. The adjective "material" is not necessary but its use is familiar: see eg, Clover, Clayton & Co Ltd v Hughes [1910] AC 242, per Lord Loreburn at 247; Hetherington v Amalgamated Collieries of WA Ltd (1939) 62 CLR 317 per Latham CJ at 328; Adelaide Stevedoring Co Ltd v Forst; (1940) 64 CLR 538, per Rich ACJ, at 564; Dixon J at 567, 568; McTiernan J at 571, 572. The expression "contributed in any material degree" was used in the Workers' Compensation Act 1958 (Vic) and is used in s 9(1)(e) of the Veterans Entitlements Act and in s 7(3) of the Commonwealth Employees' Rehabilitation and Compensation Act 1988 (Cth). In each case, the reference to materiality serves to make it clear that the contribution required is a contribution of a causal nature, that a contribution which is de minimis, which did not influence the course of events or which is so tenuous as to be immaterial is to be ignored. The term "material" is here used not in the loose sense set out in definition 12 of the Macquarie Dictionary, namely, "of substantial import or much consequence" but rather in its legal sense of "pertinent" or "likely to influence".'
I remarked in Bendy's case, and have said on other occasions, eg Westgate v Australian Telecommunications Commission (1987) 17 FCR 235 at 240; that it is sufficient that the employment contribute to the contraction, aggravation, acceleration or recurrence of the disease. The contributing factor need do no more than contribute in a material way. The factor is not required to be the real, proximate or effective cause of the disease or of its development. When several separate factors together cause the contraction of a disease or its acceleration, aggravation or recurrence, all that is required is that one such factor exhibits the necessary connection with the worker's employment. The tribunal was, however, in error holding that a contribution brought about by the employment, however small, was sufficient. A contribution which is so small as to be immaterial, which has no causal significance, is not sufficient. A disease or an aggravation, acceleration or recurrence thereof is not attributable to employment unless it is causally connected therewith. As s 29 states, employment must be a contributing factor to the contraction of the disease or to the aggravation, acceleration or recurrence thereof." (pages 204-205)
162. What of employment as a contributing factor to the aggravation, acceleration or recurrence of a disease? The leading case in this area is Federal Broom Co Pty Ltd v Semlitch (1964) 110 CLR 626 (McTiernan, Kitto, Taylor, Windeyer and Owen JJ) in which the High Court considered the provisions of the 1926 NSW Act. In considering the words "aggravation" and "acceleration", Windeyer J said:
"The next question then is, was there in December 1960 `an aggravation, acceleration, exacerbation or deterioration' of the disease? The words have somewhat differing meanings: one may be more apt than another to describe the circumstances of a particular case: but their several meanings are not exclusive of one another. The question that each poses is, it seems to me, whether the disease has been made worse in the sense of more grave, more grievous or more serious in its effects upon the patient. To say that a man's sickness is worse or has deteriorated means in ordinary parlance, oddly enough, the same thing as saying that his health has deteriorated." (page 639)
163. The concept that the words are not mutually exclusive was taken up by Hill J in Casarotto v Australian Postal Commission (1989) 86 ALR 399 when he said at page 405:
"... the ordinary English meaning of the words `aggravation and acceleration', namely that `aggravation' connotes the disease becoming more severe and acceleration connotes the hastening of the normal underlying disease, which, if not invariably, will usually in any event be a progressive one. However, in the ordinary usage of the words it is clear that the two words are not mutually exclusive so that the consequence of hastening the development of an underlying progressive disease may be to increase or make worse the severity of that disease."
164. In Ogden Industries Pty Ltd v Lucas (1967) 116 CLR 537 (Barwick CJ, Kitto, Taylor, Windeyer and Owen JJ), Windeyer J had emphasised that the mere fact that the disease had become worse during a person's employment was not sufficient for it to be said that the disease had been "aggravated". It had to have been made worse and his or her employment had to be a contributing factor to its being made worse.
165. This aspect had also been addressed by the High Court in the earlier Federal Broom case. Windeyer J said at pages 641-642:
"I pass then to the next, and I think more difficult, question, was this aggravation or deterioration contributed to by her employment? This requirement of the Act is not satisfied by showing only that a worker suffering from some disease would or might have suffered less severely if he had not been employed at all. When the Act speaks of `the employment' as a contributing factor it refers not to the fact of being employed, but to what the worker in fact does in his employment. The contributing factor must in my opinion be either some event or occurrence in the course of the employment or some characteristic of the work performed or the conditions in which it was performed. In this case it was said that the employment was a contributing factor in the worsening of the disease, because the applicant focussed her delusions of pain and discomfort upon her right side which she believed she had hurt when lifting a tea chest in the course of her work. A minor physical strain she magnified in her irrational imagination into a serious and continuing derangement of her internal organs. The incident directed, or re-directed, her hypochondriacal attention to her abdominal muscles. But said the appellant, all that it did was to focus her existing delusional tendencies in a particular way: it was a cause of her condition only in the sense that it acted as a precipitant. That may be true: nevertheless, Doctor Ellard agreed that `something obviously happened in December to her to cause a change in her way of life'.
The question involved is difficult. Can the event to which a disordered mind irrationally attributes physical suffering, that is real to the patient but delusional, be properly called a contributing factor? Ordinary concepts of cause and consequence are perhaps not applicable. Yet it seems to me that the incident which precipitated or stimulated, however irrationally, the worsening of her condition could be regarded as a factor contributing to it. It was said that in any event she might have broken down sooner or later: that some other incident might have provided a focus for her delusions. But it was this event at work that in fact did so."
166. In Australian Telecommunications Commission v Tzikas (1985) 5 AAR 173 (Smithers, Sweeney and Woodward JJ), the Full Court of the Federal Court considered whether Mrs Tzikas' employment had contributed to the aggravation or acceleration of her mental disease. Sweeney and Woodward JJ said:
"... In our opinion, the resentment of a sick mind, directed towards former conditions of employment, if it aggravates or accelerates the disease, and thus contributes to incapacity, is capable of leading to a finding under s 29(1) of the Act that the employment is still contributing to the aggravation or acceleration. However we believe that resentment about lower earnings and delays in litigation cannot be said to have been contributed to by the employment. Such considerations are as remote from the employment as the other factors, such as relief at not having to work, dealt with earlier.
For those reasons the matter should, in our view, go back to the Tribunal to determine whether the continuing resentment of the respondent about the first aggravation and acceleration of her disease is in fact causally related to her former employment, and, if so, whether it is playing such a part in her present state of health that it can properly and fairly be said to be contributing to a current aggravation or acceleration of her disease and not merely providing a focus for that disease." (page 195)
167. In the same case, Smithers J said:
"If by his finding that the four specified sequelae played a part in the respondent's mental illness the Tribunal meant no more than that in the course of the respondent's natural illness the mind noted the situations described in the sequelae and, according to its naturally impaired mental process, developed a desire that the situation in items two and three should continue definitely or a desire to punish Telecom for the situations described in items one and four, then it could not be said that any of the sequelae were factors which contributed to cause an aggravation of the natural illness. They constituted a reason for action by the impaired mind but did not cause it." (page 186)
168. Provided that it is a person's employment, or some aspect of it, that has aggravated or accelerated his or her disease, there is no need to establish that the employment or any aspect of it was in any way out of the ordinary. That is to say, the person does not need to establish that the employer was at fault in some way. As Pincus J said in O'Neill v Commonwealth Banking Corporation (1987) 75 ALR 154 (Pincus J):
"It is, of course, not the law that mental conditions caused by employment are compensable only if there is unusual stress or extra stimulus, although no doubt the absence of such stress would make it more difficult to show a causal connection between a mental condition and the employment. Nor is it the law that only neurotic conditions arising in circumstances in which an ordinary man of normal personality would become neurotic (if there are such circumstances) are compensable." (page 159)
169. There is no question that Mr Johnson was subject to a number of risk factors: high cholesterol, smoking and a family history. We are also satisfied that Mr Johnson considered that he had worked under stress for some period of time for the reasons that we have given above. None of the medical witnesses, though, supported a finding that mental stress, whether long or short term, contributed to the development of atherosclerosis or to its aggravation. Therefore, we find that Mr Johnson does not suffer from a disease that has been contributed to in a material degree by his employment.
170. For the reasons we have given, we do not consider that Mr Johnson has suffered an injury that arose out of or in the course of his employment or a disease, or an aggravation of a disease, that was contributed to in a material degree by his employment with the RAAF. Therefore, we affirm the reviewable decision of the respondent dated 24 July, 2000.
Deputy President S A Forgie
Dr P D Fricker (Member)
Signed: ................................................................
P. Paczkowski Associate
Date/s of Hearing 14, 15, 20 and 21 May, 2003
Date of Decision 29 September, 2003
Counsel for the Applicant Mr N. Moshinsky QC
Solicitor for the Applicant KCI Lawyers
Counsel for the Respondent Mr R. Gorton QC with Ms A. McMahon
Solicitor for the Respondent Australian Government Solicitor
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