Tudor Capital Australia Pty Ltd v Christensen - [2016] NSWWCCPD 14

WORKERS COMPENSATION COMMISSION
DETERMINATION OF APPEAL AGAINST A DECISION OF THE COMMISSION CONSTITUTED BY AN ARBITRATOR
*Status: Appeal to the Court of Appeal allowed. Matter remitted to the Commission constituted by a Presidential member - Tudor Capital Australia Pty Ltd v Christensen* [2017] NSWCA 260**
CITATION:	Tudor Capital Australia Pty Ltd v Christensen [2016] NSWWCCPD 14
APPELLANT:	Tudor Capital Australia Pty Ltd
RESPONDENT:	Penelope Christensen
INSURER:	Allianz Australia Workers Compensation (NSW) Limited
FILE NUMBER:	A1-5286/13
ARBITRATOR:	Mr J Wynyard
DATE OF ARBITRATOR’S DECISION:	8 September 2015
DATE OF APPEAL DECISION:	25 February 2016
SUBJECT MATTER OF DECISION:	Section 25 of the Workers Compensation Act 1987; causation of death of worker; onus of proof; proof in the absence of scientific certainty; consideration of EMI (Australia) Ltd v Bes [1970] 2 NSWR 238 and Tubemakers of Australia v Fernandez (1976) 10 ALR 303; standard of proof; factual error; s 9A of the Workers Compensation Act 1987; need to engage with evidence and to state reasons for findings in circumstances when there is conflicting expert evidence
PRESIDENTIAL MEMBER:	Deputy President Kevin O'Grady
HEARING:	On the papers
REPRESENTATION:	Appellant:	HWL Ebsworth Lawyers
Respondent:	Edwards Michael Powell Lawyers
ORDERS MADE ON APPEAL:	1. The Arbitrator’s findings and orders found in the Certificate of Determination dated 8 September 2015 are confirmed. 2. The matter is remitted to Arbitrator Wynyard for further directions and hearing concerning the question of apportionment.

INTRODUCTION

The late Grant Andrew Christensen (the deceased) died at his home on 8 September 2008 suddenly and unexpectedly. These proceedings were commenced by the widow of the deceased, Ms Penelope Christensen (the respondent), against the deceased’s employer at the date of death, Tudor Capital Australia Pty Ltd (the appellant). The appellant had earlier declined liability following Mrs Christensen’s claim against it, seeking compensation benefits pursuant to s 25 of the Workers Compensation Act 1987 (the 1987 Act). Mrs Christensen and the two children of her marriage to the deceased, Dylan and Patrick, were at all material times dependent upon the deceased for support.
The deceased had been employed as a Portfolio Manager by the appellant, which is a corporate member of an internationally established hedge fund business founded in the United States of America. It was the respondent’s allegation that the deceased’s death resulted from an injury arising out of or in the course of that employment. Briefly stated, it was the respondent’s case that the prevailing conditions of employment experienced by the deceased in the months before his death were such that he was subjected to considerable stress, had been working very hard and was missing regular sleep. Those, and other circumstances, had given rise to a deterioration in the deceased’s state of health, he became run down and, as put by counsel, his immune system had become “debilitated”. As a consequence of his then state of health generally, he contracted a viral illness. It was the respondent’s case that, on the probabilities, that viral illness caused or aggravated ventricular fibrillation leading to cardiac arrest.
The appellant denied liability upon numerous grounds, which were particularised in a notice issued pursuant to s 74 of the Workplace Injury Management and Workers Compensation Act 1998 (the 1998 Act) which was served upon the respondent in July 2012. The fundamental assertion made in that notice was a denial of relevant injury. The facts and circumstances relied upon by the appellant were complex and are addressed in the course of discussion below. The appellant further relied upon the provisions of ss 9A and 11A of the 1987 Act in defence of the claim.
The dispute between the parties came before Arbitrator John Wynyard for conciliation and arbitration. The matter proceeded to hearing before the Arbitrator on 23 September 2014, 18 May 2015, 19 May 2015 and 16 June 2015. The Arbitrator reserved his decision and a Certificate of Determination, accompanied by a statement of the Arbitrator’s reasons for his decision, issued on 8 September 2015. The Arbitrator had, with the consent of the parties, addressed only the question of the appellant’s liability to pay compensation. It had been agreed that the question of apportionment should be deferred to permit appropriate submissions to be put on behalf of Dylan and Patrick, who were to be separately represented in respect of that aspect of the proceedings should liability be found in favour of the respondent. The Certificate of Determination recorded the following matters:
“The Commission determines:
1. I am satisfied that the respondent is liable pursuant to the terms of s.25 of the 1987 Act.
2. Noting the agreement of the parties as to the question of apportionment I make no order at this time but simply publish my reasons.
3. I set this matter down for further teleconference on 6 October 2015 at 10.30 am, or at such other time as the parties may request. I grant liberty to the parties to approach in that case upon telephone notice to each other.
4. I certify this matter as being complex, the reasons for which I trust are self explanatory. I also order that the resolutions of the hearing of 23 September 2014 be treated as a separate resolution to today’s determination for the purposes of the calculation or assessment of costs, pursuant to Schedule 6, Clause 9(2)(b) od [sic, of] the Workers Compensation Regulation 2010.” (emphasis in original)
A brief statement is attached to this determination setting out the Commission’s reasons for the determination.”
Following commencement by the appellant of this appeal, the Commission deferred determination of the question of apportionment pending the outcome of the appeal.

THRESHOLD MATTERS

There is no dispute between the parties that the threshold requirements as to quantum and time as found in the provisions of ss 352(3) and 352(4) of the 1998 Act have been met.

ON THE PAPERS

Section 354(6) of the 1998 Act provides:
“(6) If the Commission is satisfied that sufficient information has been supplied to it in connection with proceedings, the Commission may exercise functions under this Act without holding any conference or formal hearing.”
Having regard to Practice Directions Nos 1 and 6; the documents that are before me, and the submissions by the parties that the appeal can proceed to be determined on the basis of these documents, I am satisfied that I have sufficient information to proceed ‘on the papers’ without holding any conference or formal hearing and that this is the appropriate course in the circumstances.

ISSUES IN DISPUTE

The grounds of appeal relied upon are as follows:
Ground one:      The Arbitrator reversed the onus of proof: at [271] of Reasons.
Ground two:     The Arbitrator made a number of erroneous findings of fact:
(a)that the disarray present post mortem found on histological examination was caused by viral myocarditis: at [257] and [271] of Reasons;
(b)that T cell lymphocytes entered the myocardium: at [272] and [229] of Reasons;
(c)that emotional stress was the cause of the viral illness: at [245] of Reasons;
(d)that histological evidence of viral myocarditis was missed: at [262] of Reasons, and
(e)that stress induced ill health “allowed the introduction of a viral illness” into the body of the deceased: at [266] of Reasons.
Ground three:   The Arbitrator erred in finding that the ventricular fibrillation that caused the death of the deceased was caused by viral myocarditis: at [229], [254], [267] and [269] of Reasons.
Ground four: The Arbitrator failed to correctly apply s 9A of the 1987 Act to the facts: at [273] of Reasons.
Ground five:     The Arbitrator wrongly rejected the evidence of Professor Keogh: at [260] of Reasons.
I note that argument advanced in support of ground one suggests error on the part of the Arbitrator in two respects. As is stated in the ground, it is suggested that the Arbitrator had reversed the onus of proof. As argument is developed, the appellant further asserts that the reasoning of the Arbitrator demonstrated that he had had regard to the incorrect standard of proof concerning the medical question as to probable cause of death.
Grounds two and three suggest that the Arbitrator had erred in his conclusions of fact. Ground four asserts error concerning the Arbitrator’s application of the provisions of s 9A to the facts.
Ground five asserts error on the part of the Arbitrator in wrongly rejecting the evidence of the appellant’s principal expert medical witness, Professor Anne Margaret Keogh, senior heart transplant cardiologist at St Vincent’s Hospital. An examination of the submissions put in support of ground five reveals that the substance of the appellant’s complaint is that the Arbitrator had failed to abide relevant principles governing the obligation upon a fact finder to give reasons with respect to conflicting expert evidence. As argument is advanced it is suggested that factual error has been committed with respect to the Arbitrator’s conclusions concerning Professor Keogh’s evidence and further that error had come about by reason of the Arbitrator’s failure to engage with the evidence.
The relief sought on behalf of the appellant is that the decision of the Arbitrator be revoked and that a new decision, in its favour, be made in its place as is permitted by the terms of s 352(7) of the 1998 Act.

THE ARBITRAL PROCEEDINGS

As earlier noted, the hearing conducted by the Arbitrator took place over four separate days. A very large volume of documentary evidence was tendered by each party. Mrs Christensen was represented by Mr Wardell, solicitor, and the appellant was represented by Mr Grant of counsel. As was observed by the Arbitrator, the first day of hearing was dedicated to the identification of the relevant documentary evidence relied upon by the parties and, as stated by him, to “get some organisation into the evidence” (at T18, 23 September 2014).
The hearing proceeded on subsequent days at which time Mr Wardell called Associate Professor David Richards, consultant cardiologist. That evidence was adduced via telephone connection between the Commission and the witness. Associate Professor Richards was cross-examined by Mr Grant.
The appellant called Dr Stephen P Rainer, senior staff pathologist at St Vincent’s Hospital Sydney and Professor Keogh as witnesses. Both Dr Rainer and Professor Keogh were cross-examined.
The appellant tendered two written statements made by Mr Kevin Wulwik, Associate General Counsel to the appellant. Mr Wardell, who had unsuccessfully objected to the tender of the second of those two statements, was granted leave by the Arbitrator to cross-examine Mr Wulwik.
The balance of the evidence before the Arbitrator was tendered in documentary form and included a considerable volume of expert medical evidence and lay evidence, including that of the respondent as well as statements made by colleagues of the deceased. Also in evidence were articles and learned papers which were said to address the issues raised on the facts concerning the death of the deceased, as well as some documentary material relating to economic circumstances which prevailed at about the time of the deceased’s death. The respondent further tendered correspondence received by her from the appellant’s principal, Mr Paul Tudor Jones II. It is unnecessary to attempt a summary of all the documentary evidence or of the oral evidence adduced in the course of the hearing. That material, where relevant, will be referred to in the course of these reasons.

FACTUAL BACKGROUND

There is a wide variety of factual matters, some not in dispute before the Arbitrator, and others determined by him which are not challenged on this appeal, which may be noted at this point.
The deceased commenced employment with the appellant in Melbourne in February 1997, where he remained until July 2000. Following closure of the Melbourne office, the deceased relocated to London where he was employed by the appellant’s sister corporation Tudor Capital (UK) LP. He remained there working as a portfolio manager until, in late 2007, agreement was reached with the employer concerning relocation of the deceased’s family to Sydney, where he was to take on the position of portfolio manager with the appellant. That relocation was prompted by the deceased’s concern for the health of his father who resided in Sydney.
The deceased had no history of collapses, chest pain, exertional dyspnoea (other than as reported on the day of his death) or palpitation. There was no family history of sudden death. The brother and sisters of the deceased are alive and in good health. His cholesterol was elevated as recorded in the medical evidence. The deceased had been physically active, playing both cricket and football, and was a keen cyclist.
The matters considered by the Arbitrator concerning work conditions included difficulty and frustration experienced by the deceased with the existing technology in the Sydney office; difficulties establishing his algorithmic system, and the fact that the deceased had been placed on probation or on a “watch list” in June 2008, notice of which was not given, as found by the Arbitrator, until two months thereafter. The Arbitrator also considered it of significance that the deceased, and others concerned with the finance industry, were required to deal with the significant problems within world economies which were then developing rapidly, which subsequently led to the global financial crisis. The correspondence received by the respondent from Mr Jones following the death of the deceased was treated by the Arbitrator as constituting admissions of the following matters of fact (at [247] of Reasons):
“•     The deceased and others were experiencing heightened stress and anxiety that year
·        In the business of international hedge funds, it was not enough not to lose money
·        The deceased was placed on a watch list.
·        Advice that the deceased was on a watch list was not given to him until close to his untimely passing”.
The deceased commenced employment in the Sydney office on approximately 21 January 2008. At the hearing before the Arbitrator, there was significant dispute between the parties concerning the day to day working conditions and the relevance of such conditions to the deceased’s state of health. The Arbitrator, in the course of his reasons, determined a number of factual matters which were controversial concerning the deceased’s work conditions in the Sydney office. The relevant evidence was summarised by the Arbitrator between [27] and [96] of his Reasons. The Arbitrator’s reasoning as to those matters in dispute is to be found between [228] and [254] of his Reasons. The conclusion reached by the Arbitrator is to be found at [254] of his Reasons and is as follows:
“… The deceased was employed in an unforgiving and ruthless industry focussed on success at all costs. The move from the UK to Sydney proved to carry with it unforseen complications that impacted on the deceased’s performance. He was unable to perform at the level required from him, in circumstances that were not of his making. The difficulties with setting up the deceased’s system led to a drop in his trading results that brought him to the attention of the Capital Allocation Committee on 30 June 2008. At the same time he had also been required to produce a simulation of the results his system would have produced had he been trading from the time he closed his model down in December 2007. This, Mr Nicholson said, was brought to the Committee’s attention at the June 30 meeting. The time involved in the production of this simulation itself affected his ability to perform to an acceptable standard, notwithstanding that the simulation results were positive. It did no good. The deceased was placed on the watch list, a fact that he did not discover until around 20 August 2008, and about which he expressed some dismay. I infer that the positive results he was then beginning to achieve did not allay his frustration. Then his health began to fail him. He told Ms Easten around this time that he had been ill for some weeks, and that his wife was nagging him to go to the doctor. He developed a gastric problem which caused him diarrhoea which he could not shake off. He attended the surgery of Dr You on 4 September and was ill at home for the following two days at the end of the week. After the weekend on Monday 8 September he went to work against his wife’s wishes, saying that he’d had enough time off, and expressing concern about being on the watch list. He came home early that evening and was breathless when he dropped Ms Easten off. He helped put the children to bed and at about 11.30 that evening, whilst sitting on the sofa, he sighed and lost consciousness. He died of ventricular fibrillation causing cardiac arrest.”
It is important to note that, whilst the factual matters determined by the Arbitrator as to work conditions and the deceased’s state of health immediately before his death are generally not disputed on this appeal, there remains a dispute as to the relevance of those conditions to the question of injury leading to the deceased’s death. That dispute involves the question as to the relevance of the emotional and psychological distress suffered before his death to the illness as found by the Arbitrator, and the relevance of that illness to the occurrence of ventricular fibrillation leading to cardiac arrest causing death.
The autopsy report prepared by Dr B Elston, pathologist, addressed to the Coroner included, in part, the following summary :
“The toxicology results revealed no toxic drug levels.
Based on my examination, both with the naked eye and microscopically and on evaluation of the toxicology report, the cause of death in my opinion is unascertained.
No definitive cause of death was identified at autopsy. The right ventricle was dilated with a slightly thickened wall. There was also mild fibrosis of the pulmonary blood vessels, which could indicate early cor pulmonale (change in the right ventricle due to lung disease). It is however likely that the cause of death could have been a cardiac arrhythmia and the deceased was noted to be in ventricular fibrillation by ambulance officers. It is possible that a lesion occurred in the heart and death occurred so rapidly that no changes could be identified. The clinical history of kidney disease and recent high blood pressure would also contribute to heart disease.
Although there is circumstantial evidence suggesting myocardial infarction leading to ventricular fibrillation, the cause of death is unascertained.”
The respondent had received correspondence dated 17 December 2009 from Mr Paul West, Registrar of the State Coroner’s Court. Mr West advised in that correspondence that, following consideration of medical and other reports, the Coroner had dispensed with the holding of an inquest into the death of Mr Christensen. The Registrar also advised that the cause of death had been recorded as:
“DIRECT CAUSE Unascertained Natural Causes”.

THE MEDICAL DISPUTE

The medical experts relied upon by each party accepted that the deceased had suffered ventricular fibrillation which led to cardiac arrest causing death. The expert witnesses were in conflict as to the probable reason for the deceased’s experience of fibrillation immediately before his death.
The principal medical expert upon whom the respondent relied was Associate Professor Richards. In the first of six reports written by Associate Professor Richards, which had been tendered before the Arbitrator, he expressed the following opinion:
“Mode of death
The description by Dr. Elston suggests that Mr Christensen experienced cardiac arrest in ventricular fibrillation, and that this was the mode of death.
Cause of death
The cause of death was unascertained. Nevertheless, it is likely that cardiac disease of some sort predisposed Mr Christensen to ventricular fibrillation. The major possibilities include viral myocarditis, arrhythmogenic right ventricular dysplasia and atherosclerotic coronary arterial disease.
Stress at work
From the material you provided, it is clear that Mr. Christensen experienced considerable stress in his work in 2008, particularly related to, ‘…workability issues…’ in the Sydney office.
It is my view that stress at work likely predisposed and/or caused Mr. Christensen to have a viral illness during the week prior to his death. This viral illness probably affected his heart and caused ventricular fibrillation (perhaps on the basis of pre existing arrhythmogenic right ventricular dysplasia and coronary artery disease).
Viral illness during the week prior to death
Mr Christensen experienced a flu-like illness during the week prior to his death. Although there was not histologic evidence of myocarditis at post mortem, it is probable that ventricular fibrillation was a direct result of early myocarditis. It is my view that it is likely this viral illness caused or aggravated ventricular fibrillation, cardiac arrest and death.
The nonspecific symptom of fatigue was probably due in part or in total to a viral illness (to which he may have been partially susceptible due to stress at work). I accept that fatigue may have been partly due to myocardial ischaemia. However, it is my view that myocardial ischaemia was not the likely cause of death.
…
Conclusion
It is my view that it is more likely than not stress at work caused or aggravated a viral illness during the week prior to Mr. Christensen’s death, and that this viral illness likely caused or aggravated ventricular fibrillation and cardiac arrest from which Mr Christensen could not be resuscitated.”(emphasis in original)

The principal expert medical witness relied upon by the appellant before the Arbitrator was Professor Keogh, who had provided seven separate reports together with what appear to be photographs or “stills” of a PowerPoint presentation prepared by her. Professor Keogh first reported on 15 June 2012, in which a thorough summary of relevant facts and circumstances is to be found. When answering specific questions put to Professor Keogh by the appellant’s solicitors, the following was stated:
“In consideration as to the possible underlying conditions leading to his death, I am in agreement with Dr David Whalley as to the most likely cause being acute myocardial ischemia with primary arrhythmia. Less likely are atypical right ventricular arrhythmogenic dysplasia, atypical hypertrophic left ventricular cardiomyopathy or a mild right ventricular cardiomyopathy or a viral myocarditis.
That the specific type of cardiac disease is ‘not ascertainable’ does not diminish the strength of the findings on autopsy of strong structural pointers to underlying cardiac disease.
(2) It is not probable that G Christensen’s death resulted from an aggravation, acceleration, exacerbation or a deterioration of an injury arising out of or in the course of his employment.”
It should be noted at this point that there are two matters of importance concerning the statement as quoted immediately above. Firstly, it appears that Professor Keogh has misconstrued the views as expressed by Dr David Whalley. The likelihood of such misstatement or misconstruction is addressed below. The second matter to note is that, for reasons explained by Professor Keogh in the course of her oral evidence, she had occasion to review her opinions as to possible relevance of myocarditis and as to the question of diagnosis of the relevant condition leading to the deceased’s death.
In a report dated 13 March 2015, Dr Keogh recorded that “we have now obtained the autopsy slides relating to this matter” and that “we have now received the ECG reports from the night of the deceased’s death”. When providing her opinion concerning the matters demonstrated on the relevant slides, Professor Keogh stated as follows:
“The autopsy slides of Mr Christensen comprise hematoxylin and eosin stains of left and right ventricle, septum, and a coronary artery.
The heart shows autolysis of myocytes (muscle cells) – a snipped up appearance consistent with post mortem change. It also shows structural abnormalities which would have had to have been present during life and are of considerable duration (chronic months to years). These are the changes of a chronic cardiomyopathy.
anisonucleosis of ventricular myocytes
myocytolysis of ventricular myocytes
myocyte fibre disarray (myocytes disorientated with regard to one another)
fibrosis (mild to moderate degree) of ventricular myocytes
a total absence of any inflammatory cells ie no lymphocytes, neutrophils, eosinophils
macrophages not granolumas
endothelium of vessels normal (ie not increased in volume)
no valvulitis”.
In the course of cross-examination by Mr Wardell, Professor Keogh accepted that, following her viewing of the relevant slides, she had set aside her view concerning the existence of relevant coronary artery disease and had then preferred the diagnosis of hypertrophic cardiomyopathy as being the relevant abnormality leading to cardiac arrest and death.

SUBMISSIONS BEFORE THE ARBITRATOR

Submissions put at the hearing before the Arbitrator were, at times, interrupted by adjournments occasioned by reason of the effluxion of hearing time and by the interposition of the evidence of the expert witnesses. As a result, it appears that Mr Wardell commenced submissions on 18 May 2015, at which time attention was given to those authorities relevant to the standard of proof in circumstances where there is conflicting expert opinion and where, as stated in the course of argument (at T6, 18 May 2015), “neither of the propositions being propounded by either party can be approved [sic, proved] to a degree of absolute certainty.” The authorities relied upon included: the decision of the High Court in Tubemakers of Australia v Fernandez (1976) 10 ALR 303 (Fernandez); the decisions of the Court of Appeal in Seltsam Pty Ltd v McGuiness [2000] NSWCA 29; 19 NSWCCR 385; 49 NSWLR 262 (Seltsam) and the remarks of Herron CJ in EMI (Australia) Ltd v Bes [1970] WCR 114; 2 NSWR 238 at 242 (Bes). Those authorities are addressed in the course of discussion below.
Argument was then directed to the factual allegations concerning the deceased’s work conditions. It was also made clear in the course of argument that the respondent was not presenting a case of “psychological injury”. The following was put by Mr Wardell concerning the nature of the injury alleged:
“… we’re not saying this is a psychological injury case, simply that [the deceased] had a lot going on in his mind in relation to this work, he got run down and became, on the medical evidence which we’ll come to, susceptible to a viral illness which he contracted and which unfortunately at some point in time spread into his heart causing the arrhythmia which was the immediate cause of his death.” (T54, 18 May 2015)
The evidence of Associate Professor Richards was then taken, following which Mr Wardell completed his submissions concerning the allegations as to work conditions. Mr Grant responded to those matters raised and sought to characterise the claim as one concerning “psychological” injury.
It appears from the transcript of proceedings on 16 June 2015 that Mr Grant, at the direction of the Arbitrator, commenced and concluded his submissions in chief before Mr Wardell had completed those submissions which he had commenced on 18 May 2015. The appellant’s arguments again concentrated on the nature of the claim and it was put that the injury relied upon was that of a psychological injury and that the provisions of s 11A of the 1987 Act were relevant having regard to the deceased having been placed on a watch list. Those arguments provoked an intervention by Mr Wardell where he again sought to distinguish his client’s case from that which might concern psychological injury. Given the issues raised on appeal, it is unnecessary to attempt a summary of those matters.
The thrust of the appellant’s argument concerning causation of death was that:
“This is a case where there are two competing views and, at the end of the day, on the medical evidence you’re going to have to decide the case on the basis of which of the two you prefer…” (T54, 16 June 2015).
Counsel proceeded to analyse the medical evidence in considerable detail. Emphasis was placed upon the evidence as to the sampling taken by the pathologist at the autopsy and the absence of evidence of acute myocarditis. It was also stated that there “was a very persuasive basis for why [the deceased] might go into ventricular fibrillation, and that basis is pre-existing heart disease” (T76, 16 June 2015).
Mr Wardell resumed submissions (at T98, 16 June 2015) with the primary submission that there was a “simple causal chain” involving stress at work causing the deceased to be run down and affecting the immune system, which made him unable to fight off the virus. It was argued (at T100, 16 June 2015) that the Commission would be satisfied on the evidence that, in fact, the deceased had contracted the virus and that Professor Rawlinson’s evidence would support the proposition that stress increases the risk of viral illness. Reference was made in the course of argument to authority that was said to be relevant, however no particular portion of those authorities briefly referred to was expressly relied upon.
A number of submissions were put concerning the demeanour of Professor Keogh. Reference was also made to the apparent change of view expressed by Professor Keogh as to the likely cause of death. The reliability of Professor Keogh’s evidence was questioned in the course of argument. The focus of argument was the apparent change of view expressed concerning the relevance of the extent of coronary artery disease demonstrated at post mortem and the potential for that state of disease to “form the substrate for a malignant arrhythmia”.
In reply, Mr Grant made reference to the two “competing hypotheses” and placed reliance upon the expert’s opinions which were founded upon the appearance of the slides which were produced at post mortem.

THE ARBITRATOR’S DECISION

The documentary evidence tendered and the identity of those witnesses who gave oral evidence were noted at [12] and [13] of the Arbitrator’s Reasons.
The Arbitrator proceeded to identify the two principal issues raised by the parties as being:
“The case was fought on two fronts. The first related to the evidence regarding the temporal events. [Mrs Christensen] asserted that the nature of the deceased’s employment exerted such pressure on his health that it led to the contraction of a viral illness that in turn led to his death. This allegation was denied by [the employer].
The second dispute was as to the cause of the deceased’s fatal cardiac arrest, and concerned the conflicting expert medical evidence called in the case.
One of the issues raised by [the employer] concerned the nature of the stress the deceased was exposed to as a trader with an international hedge fund, particularly the unfolding of international events during 2008 which resulted in the Global Financial Crisis. Mr Grant submitted that [Mrs Christensen] had been unable to establish that the deceased was under such stress as to substantiate a plea that he had suffered a psychological injury within the terms of s.11A(3) of the 1987 Act.
As will be seen, I regard the issue of psychological injury as being something of a red herring in the case.” (Reasons [23]–[26])
The evidence concerning, as described by the Arbitrator, “the temporal events” was summarised by him between [27] and [38] of Reasons. Attention was given (between [39] and [48] of Reasons) to the evidence concerning the deceased’s state of health in the weeks prior to his death. At [47] and [48] of Reasons, the Arbitrator stated his impression of that evidence as follows:
“The evidence paints a picture of the deceased being ill for some weeks prior to the date of his death, being reluctant to seek medical attention until 4 September and being in some respiratory distress whilst he was with Ms Easten, only hours before he died.
There was support [sic] for [Mrs Christensen’s] evidence in other material lodged.”
The Arbitrator summarised and extracted portions of notes compiled by a Life Coach who had been made available to the deceased by the appellant. That life coach, Mr Scott, had been assisting and counselling the deceased in the months prior to his death. Those notes recorded the deceased’s state of mind and his circumstances at work, as well as the coach’s endeavours to encourage and counsel him. At [69] of Reasons the Arbitrator stated:
“The underlying theme discernible in all these notes is that the deceased was not coping with the disadvantage he had been placed in by the move. They are strong supportive evidence for [Mrs Christensen’s] assertions [of work related stress].”
The letter of condolence sent by Mr Jones to the respondent noted at [18] and [22] above was addressed by the Arbitrator and he recorded that he was “satisfied that the remarks [Mr Jones] made therein were heartfelt and his observations about the business were accurate”. As earlier noted (at [22] above), the Arbitrator, later in his Reasons (at [247]), concluded that admissions concerning relevant facts were to be found in that correspondence.
The lay evidence, that of Mr Nicholson, Mr Wulwik and Ms Easten, relied upon by the appellant, was summarised by the Arbitrator between [72] and [96] of Reasons. That evidence, later considered by the Arbitrator, concerned the working arrangements of the deceased when employed in the Sydney office in 2008. Whilst the Arbitrator had, up to this point, expressed his general impressions concerning the evidence, no conclusion as to the factual dispute was reached until he stated his evaluation of the evidence at [254], as noted above at [23]. I should here note that the opening sentence to that paragraph was as follows: “I am satisfied that the evidence establishes that the death of the deceased was brought about by the events of 2008, as described”. That generalised statement anticipates the Arbitrator’s later expressed conclusion concerning the “medical dispute”. No complaint is made on this appeal concerning any relevant error with respect to the Arbitrator making that statement before stating his reasons and conclusion concerning the “medical dispute”.
The Arbitrator commenced (at [97] of Reasons) his summary of the evidence concerning the “medical question” with a notation of the findings by Dr Bryan Elston, Pathologist at the Department of Forensic Medicine. I have earlier (at [25] above) quoted from Dr Elston’s report, however there were further findings made by that practitioner which were noted by the Arbitrator and which need to be noted here:
(a)     the heart appeared enlarged with dilation of the right ventricle. Dr Elston described the heart as being internally of normal size;
(b)     there was generalised atherosclerosis of the vessel supplying the heart, up to a maximum blockage of about 40 per cent. It was later noted that there was diffuse atherosclerotic disease with 30–40 per cent narrowing, but no significant stenosis were identified. Mild atherosclerotic disease was noted through the aorta;
(c)     the Arbitrator recorded Dr Elston’s microscopic examination as follows:
“Microscopic examination of the cardiovascular system Dr Elston reported showed the following:-

‘Sections from the heart show interstitial fibrosis with myocyte hypertrophy, which is more pronounced in the right ventricle than the left ventricle. There is some contraction band necrosis on the endocardial surface, likely agonal in nature. Some myocyte disarray is present in the right ventricle.’”

The evidence of Dr David Whalley, cardiologist, as found in correspondence from that practitioner to Dr Jennifer Sterrett, dated 11 February 2010, was noted by the Arbitrator. The respondent had, on referral by Dr Sterrett, consulted Dr Whalley concerning the circumstances and possible causes of her late husband’s death. It is convenient to note here the following extracts recorded by the Arbitrator from Dr Whalley’s correspondence:
“I discussed with Penny today possible causes for Grant’s sudden death. I pointed out that there are some inherited muscle diseases, which can cause sudden death, including arrhythmogenic right ventricular dysplasia and hypertrophic cardiomyopathy. From my reading of the post mortem, it does not appear that Grant had classical changes of either of these two conditions. His mild right ventricular dilation could have been secondary to his level of exercise. He could alternatively have had a mild right ventricular myopathy.
…
[The] post mortem was not reported to show an inflammatory infiltrate in the samples of myocardium, but this process can be patchy and may not show up depending on the timing of the post mortem relative to the onset of the viral illness. Certainly, there was a clear viral prodrome prior to his death.”
The Arbitrator noted (at [106] of Reasons) that Dr Whalley’s correspondence also contained the following expression of opinion. The passage appears at page 2 of Dr Whalley’s report as follows:
“Finally and what I suspect is the most likely cause of Grant’s death is a primary arrhythmia secondary to viral myocarditis. His postmortem was not reported to show an inflammatory infiltrate in the samples of myocardium, but this process can be patchy and may not show up depending on the timing of the postmortem relative to the onset of the viral illness. Certainly, there was a clear viral prodrome prior to his death.”
The Arbitrator proceeded to consider the evidence of Professor William Rawlinson who had been qualified by the respondent to provide an opinion for the purposes of these proceedings. Professor Rawlinson’s specialty is that of Medical Virologist and Infectious Diseases Physician. Professor Rawlinson provided a report dated 16 December 2012. The Arbitrator noted that, in response to questions put to him by the respondent’s solicitors, Professor Rawlinson expressed the view that: “on balance, it is likely that stress increases the risk of viral illness probability via an as yet undefined immunological mechanism”. Professor Rawlinson accepted that it was “very likely” that the deceased was suffering from a viral illness the week preceding his death. The Arbitrator further noted that Professor Rawlinson agreed that high levels of stress during the months preceding the deceased’s death would have tended to increase rather than reduce the deceased’s susceptibility to viral illness. The Arbitrator (at [114] of Reasons) recorded the following statements made by Professor Rawlinson in his report:
“… It is likely that stressful events in Mr Christensen’s life partly contributed to his susceptibility to viral illness in early September 2008. This is importantly on the background that there was no other cause found for Mr Christensen’s death at autopsy, that the genetic studies so far had been negative for known causes of arrhythmogenic left ventricular dysplasia, and that there was no family history of sudden death to suggest familial risk factors.”
The Arbitrator proceeded to consider the evidence relied upon by the appellant of Dr B J Hudson, Infectious Diseases Physician and Microbiologist. Dr Hudson had been qualified by the appellant to provide an opinion for the purposes of this litigation. The Arbitrator (at [117] of Reasons) recorded the following statement made by Dr Hudson in the first of his reports, dated 14 January 2014:
“The relationship between viral illness (increased risk of acquisition and increased risk of more severe illness) and psychological stress has mostly been explored for respiratory virus infections that have been induced in humans in an experimental or trial setting. Whilst there likely is a relationship as discussed by Professor Rawlinson, it is not well characterised, explained or understood.”
I note that there were minor errors or omissions in some quotations made by the Arbitrator.
The Arbitrator summarised the evidence of Dr Hudson and included reference to that practitioner’s expressed opinion that it was more likely than not that the deceased’s death was due to an arrhythmia relating to coronary artery disease in a patient who is suffering from an intercurrent virus infection. The Arbitrator expressed the view that Dr Hudson’s answers to questions put to him by the appellant’s solicitor “beg the question as to whether there was any causal link between the intercurrent viral infection and the stress the deceased was under at the time of his death” (at [120] of Reasons). The Arbitrator, at that point, foreshadowed his later finding that “coronary artery disease was not a relevant factor”.
The Arbitrator, between [124] and [135] of Reasons summarised the evidence of Associate Professor David Richards, which has been touched upon earlier in these reasons (at [28]). Particular attention was given by the Arbitrator, in the course of that summary, to the cross-examination of Associate Professor Richards by Mr Grant. Counsel had put that “[T]he way to diagnose whether or not [the deceased] suffered from myocarditis or not is a matter for [sic] looking at the pathology, that’s correct, isn’t it?”. In response, Associate Professor Richards stated, as recorded by the Arbitrator at [133] of Reasons:
“The diagnosis of a viral illness was a clinical diagnosis during life. In the absence of previous evidence of cardiomyopathy or atherosclerosis and in the presence of a viral illness seen before death and in the presence of … (not transcribable) … associated with a viral illness seen before death I think the inescapable conclusion is that he had viral myocarditis as the cause of death.”

The Arbitrator proceeded to consider the evidence of Dr Rainer, who had been qualified on behalf of the appellant, to provide an opinion for the purposes of this litigation. Dr Rainer produced two reports, the first dated 10 February 2014 and the second dated 12 March 2015. As earlier noted, Dr Rainer gave oral evidence before the Arbitrator. As recorded by the
Arbitrator, Dr Rainer declined to give an opinion as to any connection between psychological stress and the contraction of a virus. Dr Rainer, as noted by the Arbitrator, stated that in the case of acute myocarditis, the microscope would reveal some evidence of its presence. The relevance of the Dallas Criteria concerning diagnosis of myocarditis was addressed by Dr Rainer. When cross-examined as to there being a possibility that the myocarditis might have been overlooked on post mortem, Dr Rainer, as noted by the Arbitrator, said (at [145] of Reasons):
“I mean a short answer would be yes, but in terms of likelihood I think very unlikely because of the need to show damage.”
The Arbitrator proceeded to consider the evidence of Professor Keogh (between [147] and [211] of Reasons). It was noted that Professor Keogh had expressed the opinion that a ventricular fibrillation leading to cardiac arrest could have occurred at any stage of the deceased’s life irrespective of his employment. The initial opinion expressed by Professor Keogh was that death resulted from primary ventricular arrhythmia and that there were two structural causes for that phenomenon, first the interstitial fibrosis and the other being moderate coronary artery disease.
The Arbitrator further noted that Professor Keogh agreed with Professor Rawlinson that the relationship between psychological stress and viral illness was an unproven one. The Arbitrator noted that Professor Keogh did not take the discussion as to such relationship “any further”. Mention was made by the Arbitrator of the evidence of Professor Keogh found at [23] of her report dated 14 June 2013, where it was stated:
“The Coroner’s autopsy report found both premature coronary artery disease and features of hypertrophic cardiomyopathy. These pre-existing conditions were the cause of death. It is probable that these would have caused morbidity and/or mortality at some stage in the Deceased’s life irrespective of his employment with the Respondent.”
The Arbitrator, at [158] and [159] of Reasons, stated as follows:
“Professor Keogh at this stage was still maintaining that the probable cause was atherosclerotic coronary artery disease. She also considered that the presence of a lymphocytic thyroiditis should be considered as there was histopathological evidence for this. In considering differential diagnoses Professor Keogh said that the suggestion that there was viral illness in the week prior to the death was not supported as the soft tissues of the neck were normal and the larynx was ‘grossly’ normal so that the lymphadenomathy that would be expected in a viral pharyngitis was not present.
Professor Keogh also pointed out that no myocarditis was detected at autopsy, neither was any intermyocyte edema or myocyte necrosis seen, these matters being, Professor Keogh said, the histopathological hallmarks of a viral myocarditis.”
The oral evidence of Professor Keogh was summarised by the Arbitrator. It was noted that Professor Keogh placed emphasis upon the fact that, at autopsy, the deceased had evidence of coronary artery disease, myocyte disarray and fibrosis which, as stated by the witness, “are known substrates for VF. [The deceased] did not have changes of viral myocarditis.”
Professor Keogh’s evidence concerning the relevance of the pathology slides which had been viewed was summarised by the Arbitrator. The witness’s responses to questions put by Mr Grant were recorded by the Arbitrator and it was stated at [175] of Reasons that “… Professor Keogh abandoned her earlier opinion that the cause of death was coronary artery disease. Professor Keogh agreed with Mr Grant that a cardiomyopathy was in effect a pre-existing disorder of the heart muscle, in simple terms”.
The evidence of Professor Keogh when cross-examined was summarised by the Arbitrator, relevant detail of which is addressed in the course of discussion below.
Following a summary of submissions put on behalf of each party, the Arbitrator embarked upon the task of deciding the facts and the merits of argument advanced by each party. I have earlier (at [23] above) noted the Arbitrator’s factual conclusions concerning the deceased’s work conditions and his state of health immediately before his death.
The Arbitrator addressed the medical dispute between [255] and [272] of his Reasons. The evidence of Professor Keogh and Dr Rainer that the cause of death was the hypertrophic cardiomyopathy was rejected by the Arbitrator (at [263] of Reasons). Following consideration of relevant authority, the Arbitrator concluded as follows (at [272] of Reasons):
“It follows that I am satisfied that the death of the deceased resulted from an injury, and that the provisions of s.25 [of the] 1987 Act apply. The injury consisted of the entry of the T cell lymphocytes into the myocardium as a result of a viral illness the deceased had acquired following the breakdown of his health, which was due to the emotional stress and frustration he encountered with his employer after he had moved to Sydney in 2008.”
The Arbitrator determined that the provisions of s 9A of the 1987 Act had been satisfied and that the deceased’s employment was, as expressed by the Arbitrator, “the main substantial reason for the breakdown of the deceased’s health and subsequent death”. The Arbitrator expressly found that he was not satisfied “that the pre-existing condition of [the deceased’s] heart played any part in his death”.
Following a finding that Mrs Christensen’s evidence provided an explanation which constituted reasonable cause for her failure to make a claim within time, the Arbitrator made the finding and orders as noted at [4] above.

SUBMISSIONS, DISCUSSION AND FINDINGS

This appeal, being one against a decision made after the enactment of the Workers Compensation Legislation Amendment Act 2010, is governed by the provisions of s 352 of the 1998 Act: Sch 6, Pt 19G, cl 8 to the 1987 Act. The nature and scope of such an appeal is as provided by s 352(5):
“An appeal under this section is limited to a determination of whether the decision appealed against was or was not affected by any error of fact, law or discretion, and to the correction of any such error. The appeal is not a review or new hearing.”
The powers of the Commission upon conduct of such an appeal are defined by the provisions of s 352(7):
“On appeal, the decision may be confirmed or may be revoked and a new decision made in its place.
Alternatively, the matter may be remitted back to the Arbitrator concerned, or to another Arbitrator, for determination in accordance with any decision or directions of the Commission.”
The five grounds upon which the appellant relies are set out at [9] above.

Ground one

The matters raised in this ground are to be found in the Arbitrator’s Reasons (at [271]) where it was stated:
“I am satisfied that the facts as outlined cannot be simply ignored as being irrelevant. Whilst the cardiomyopathy was a pre-existing factor, there is no scientific evidence that establishes that the deceased must have co-incidentally have [sic] died at that precise moment. His pre-existing condition was described as a time bomb, and it was the sheer unpredictability of the cardiomyopathy which, combined with the disarray found on histological examination, was the basis of the respondent’s medical case. The disarray was also consistent with ventricular fibrillation caused by myocarditis, so the respondent’s case needed to demonstrate that medical science denied at least one of the two causal pre-conditions to the applicant’s case. This it has not been able to do. The possibility of a link between emotional stress and the risk of viral illness, and the possibility that the cause of the ventricular fibrillation was a viral myocarditis have both been accepted, as I have discussed.”
The appellant asserts that there are two errors demonstrated by the passage quoted immediately above, namely:
“(a) the Appellant did not carry any onus to demonstrate that the causal preconditions of [Mrs Christensen’s] case had not been made out; and
(b) the standard of proof adopted by the Arbitrator was less than the balance of probabilities” (at [25] of submissions).
The appellant correctly submits that the onus rested upon the respondent to establish before the Arbitrator that each aspect of her case had been made out on the balance of probabilities. The first question raised under this ground is whether the Arbitrator erred in reversing the onus, when stating at [271] “…the [employer’s] case needed to demonstrate that medical science denied at least one of the two causal pre-conditions to the [respondent’s] case. This it has not been able to do”.
The appellant submits, secondly, that the Arbitrator’s Reasons as stated at [271] demonstrate that he had adopted an incorrect standard of proof. It is argued that the Arbitrator’s statement made in the last sentence at [271] demonstrates that he erroneously contemplated a requirement merely to establish “possibility” of the two aspects of the respondent’s case there referred to.
The respondent, in written submissions put in opposition to this appeal, asserts that the Arbitrator’s reasoning demonstrates that he “clearly understood his task”. It is argued that the Arbitrator, between [225] and [226] of Reasons, “set out the principles he was required to apply in cases such as the present…”. Particular reference is made to the Arbitrator’s acknowledgment of the decision in Bes where Herron CJ, following a consideration of earlier authority, made the following statement:
“Much the same thesis is to be found in Ramsay v Watson in the High Court (108 CLR p 642) and I particularly refer to the passage in the joint judgement of their Honours at the foot of p 645. It seems to me that that bears out what I have concluded is the correct principle to apply, namely, that it is not incumbent upon the applicant, upon whom the onus rests, to produce evidence from medical witnesses which proves to demonstration that the applicant’s contention is correct. Medical science may say in individual cases that there is no possible connection between the events and the death, in which case, of course, if the facts stand outside an area in which common experience can be the touchstone, then the judge cannot act as if there were a connection. But if medical science is prepared to say that it is a possible view, then in my opinion the judge after examining the lay evidence may decide that it is probable. It is only when medical science denies that there is any such connection that the judge is not entitled in such a case to act on his own intuitive reasoning. It may be, and probably is, the case that medical science will find a possibility not good enough on which to base a scientific deduction, but courts are always concerned to reach a decision on probability and it is no answer, it seems to me, that no medical witness states with certainty the very issue which the judge himself has to try.”
The respondent further argues that there was “no reversal of the onus of proof” and that the Arbitrator was “simply setting out what the contest [was] between the parties”. It is also put that the Arbitrator applied the correct standard of proof.
The appellant asserts in argument that the reasons as expressed by the Arbitrator demonstrate that he “misunderstood” the import of what was said in cases such as Bes, Adelaide Stevedoring Co Ltd v Forst (1940) 64 CLR 538 (Forst) and St George Club Ltd v Hines (1961) 35 ALJR 106 (Hines). I note in passing that, at the hearing, neither the parties nor the Arbitrator made any reference to the two last mentioned authorities.
The appellant, correctly in my view, states that the authorities mentioned “are authority for the proposition that the whole of the evidence is to be considered in determining causation”. That point, it is argued, is made clear by Mason J in Fernandez, where his Honour said that an inference as to causation may be drawn from the medical evidence as to a possible causal link and other evidence. If such an inference is drawn, his Honour was of the view that such “involves no departure from the ordinary onus of proof which rests upon a plaintiff to establish on the probabilities that a medical condition or disability from which he suffers is ‘caused or materially contributed to’ by the defendant’s wrongful conduct” (at 310).
It must be said that the manner in which the Arbitrator structured his reasons causes difficulty when attempting to determine, with precision, the process of reasoning which he adopted. I make this statement given that, following his meticulous analysis of the evidence and of submissions, and his summary of relevant authority, the Arbitrator immediately (at [229] of Reasons) foreshadowed his ultimate findings in the following terms:
“The deceased’s death appears to have been caused by an unfortunate combination of events. As will be seen, I am satisfied that these events operated to weaken the deceased’s immune system so that he contracted his viral illness. I am also satisfied on the evidence that it was the viral illness that caused his eventual cardiac arrest.”
The Arbitrator’s statement quoted immediately above was made almost immediately following his summary of that stated by Herron CJ in Bes including his Honour’s observation that “if medical science is prepared to say that it is a possible view, then in my opinion the judge after examining the lay evidence may decide that it is probable.” (emphasis added)
Commencing at [230] of the Arbitrator’s Reasons, it appears that reference is being made to his acceptance of the respondent’s case concerning work conditions. The difficulty to which I have earlier referred (at [77] above) arises at [245] of Reasons where it was stated by the Arbitrator, before his final consideration of the conflicting medical evidence, as follows:
“I am satisfied that the temporal events described in these reasons caused emotional stress to the deceased of such a nature that he suffered a viral illness during at least the week before his death - probably, on the evidence before me, more in the nature of two weeks. That illness most likely caused T cell infiltration into the myocardium at the time that the deceased became breathless, a few hours before his death.”
The Commission is not, under this ground, dealing with a suggested failure on the part of the Arbitrator to provide sufficient or adequate reasons for his conclusions, but rather is required to ascertain whether the complaints concerning reversal of the onus and application of a wrong standard of proof are made out.
Before embarking upon that task, I make the observation that, upon examination of the nature of the issues raised before the Arbitrator, it is demonstrated, in my opinion, that the principles concerning the correct approach to the question of proof where medical science provides no certainty (as in Bes) are plainly relevant to the first issue, being the question of the existence or otherwise of a causal nexus between the deceased’s work conditions and his contraction of a virus. The second issue, which concerned the question as to the probable cause of death, was the subject of conflicting expert evidence and, notwithstanding the approach taken by the parties, raises an additional question to that addressed in Bes and the other authorities, which deal with postulation of a possibility rather than a certainty as to the existence of a relevant causal nexus. The appellant appears to acknowledge that additional question, which involves the requirements to address the evidence and the need to give reasons, in its argument advanced in support of ground five. There it is asserted that the Arbitrator wrongly rejected the evidence of Professor Keogh and reliance is placed upon the decision in Wiki v Atlantis Relocations (NSW) Pty Ltd [2004] NSWCA 174; 60 NSWLR 127 (Wiki) in which the Court addressed the need to engage with the evidence and to explain the basis of preference for one expert’s evidence over that of another.

Did the Arbitrator reverse the onus of proof?

I have earlier (at [71]) made reference to the appellant’s argument concerning reversal of the onus as being demonstrated by the Arbitrator’s statements at [271] of his Reasons.
I am not persuaded that, read in the context of the Arbitrator’s reasons as a whole, his statement concerning a “need to demonstrate” the matter of denial of possibility constitutes a reversal of the onus. I reach that conclusion given the state of the evidence before the Arbitrator.
The respondent had adduced evidence of the possibility of both a causal nexus between stress and contraction of viral infection, and causal nexus between viral infection and death. Whilst there is no shift of the onus of proof, there may arise, once evidence of possibility is before the Commission, a shift of the tactical burden, as discussed in the course of my reasons in Sydney’s Tune Pty Ltd v Scala [2014] NSWWCCPD 64 (between [99] and [102]). Such a circumstance is helpfully addressed in C R Williams, Burdens and Standards in Civil Litigation [2003] SydLawRw 9 where it was stated:
“Any case, whether civil or criminal, involves a finite number of potential issues; a number of elements comprise each cause of action and each criminal offence, and a number of potential defences are available to the defendant or the accused. In respect of each of these issues, rules of law determine upon which party the legal and the evidential burden lies. The only burden that does shift in the course of a trial is the tactical burden. A failure to distinguish between the evidential burden and the tactical burden would appear to be responsible for most of the suggestions that the burden of proof shifts. At any given point in time a party who has the legal burden in respect of a particular issue may appear more or less likely to be able to discharge that burden. If that party appears likely to be able to discharge the legal burden, then the tactical burden shifts to the other party; the other party must produce contradictory evidence or run the risk of losing on that issue. If that other party produces such evidence, then the tactical burden may shift back to the party bearing the legal burden. Such swings of the forensic pendulum as a case progresses involve, however, no shift in either the legal or the evidential burden.”
In the present case the words adopted by the Arbitrator, read in isolation were, regrettably, apt to mislead. It must be remembered that at [271] the Arbitrator was addressing the state of the evidence, in particular, that concerning “disarray found on histological examination”, which disarray was consistent with either competing hypothesis as to cause of death.
It seems to me that the statement made by the Arbitrator at [271] was intended as a statement of his view as to the state of the evidence that he had earlier summarised and which he stated could not “be simply ignored as being irrelevant”. That evidence, together with other evidence stated as having been accepted by the Arbitrator, was likely to discharge the legal burden upon the respondent. There was, in his view, an absence of acceptable contradictory evidence. Taking into account the entirety of the Arbitrator’s reasons, I conclude that the Arbitrator was making reference to an absence of a persuasive response by the appellant to a shift of the tactical burden as discussed by Williams as noted above. I am not persuaded that the appellant has made out the assertion in this ground that the Arbitrator had reversed the onus of proof.

Did the Arbitrator err as to the standard of proof?

As to the argument concerning the standard of proof, it is clear that the Arbitrator had made reference in his Reasons to authorities relevant to the question concerning the legal requirements of proof on the balance of probabilities when summarising submissions put by Mr Wardell (at [225]–[227]). However, the appellant argues that the Arbitrator has “misunderstood the import of what was said in cases such as [Bes, Forst and Hynes].”
In support of the assertion of the Arbitrator’s “misunderstanding”, the appellant points to the Arbitrator’s “paraphrase” (at [269] of Reasons) of that which was stated by Herron CJ in Bes. The appellant is correct in asserting that the Arbitrator’s “paraphrase” addressed only that portion of the Chief Justice’s reasoning which concerned the need, for the purposes of proof, for evidence of a possibility. No express reference was made by the Arbitrator to that which appears in the reasoning of Herron CJ concerning the need to examine the lay evidence, together with that evidence as to “possibility”.
Whilst the appellant’s submissions as to these matters have considerable force, it is apparent that they are founded upon statements by the Arbitrator which have been isolated from the text of the entirety of his Reasons. Those Reasons include an accurate and comprehensive consideration of the evidence and, importantly, that summary was accompanied by frequent evaluation by the Arbitrator of the evidence considered by him. As earlier noted, the Arbitrator’s summary of the evidence was followed by discrete passages in which each major issue was finally determined.
In Inghams Enterprises Pty Ltd v Sok [2014] NSWCA 217; 87 NSWLR 198 (Sok) the Court of Appeal addressed a submission as to error demonstrated, as argued, by the use of particular words or phrases by a Deputy President of the Commission. Whilst the present matter concerns an examination of a decision at first instance, I consider that the decision of the Court of Appeal affords guidance as to the correct approach to scrutiny of the Arbitrator’s reasoning. It was held in Sok (per Basten JA, Barrett JA and Sackville AJA agreeing) at [27]:
“If the approach adopted by Inghams in the present case were correct, references to ‘weight’ and to what was ‘properly open’ to the primary judge would have been indicative of an error on the part of the appellate court. That conclusion would, however, be false. The proper conclusion is that identification of error by the Deputy President in the exercise of his appellate function must depend upon a consideration of his reasons taken as a whole, and not be limited to the use of particular words or phrases. Errors of approach are not identified by reference to linguistic niceties, particularly where the language used has no precise meaning.”
It must be acknowledged at once that the language of the Arbitrator which is relied upon by the appellant, may not be said to have “no precise meaning” as stated in Sok. However, I am of the opinion that this complaint is not made out given that a fair reading of the Arbitrator’s Reasons as a whole demonstrates that he had regard to correct principle concerning standard of proof.
I reach that conclusion having regard to the following matters:
(a) the obligation upon the Arbitrator to take into account not only the evidence of “possibility” but the evidence as a whole was discharged, in my opinion, as is demonstrated by his evaluative statements made when summarising the evidence (for example at [47], [69], [121], [154], [155], [165], [189], [191], [197], [202] and [210]). Such is also demonstrated by the Arbitrator’s “discussion” concerning the “temporal events” which appears between [228] and [254] and where the medical question is addressed between [255] and [272], and
(b) the Arbitrator’s express acknowledgment, made at [255] of Reasons, that he had taken into account the decision of Murray v Shillingsworth [2006] NSWCA 367; 68 NSWLR 451; 4 DDCR 313 (Murray) and other authority when “assessing the medical evidence”. In Murray, Einstein J, with whom Hodgson JA and Santow JA agreed, addressed the legal requirements of proof on the balance of probabilities (between [30] and [38]). In the course of that discussion, his Honour cited, among other authorities, the decision of Spigelman CJ in Seltsam in which such requirements were closely examined by the Chief Justice. In the present case, the Arbitrator stated that the “approach to causation in assessing the medical evidence described in Murray … has been critical in the determination of this case.”
The appellant has failed to make out either complaint raised and this ground fails.

Ground two

As earlier noted, this ground asserts factual error on the part of the Arbitrator. There are five matters specified in this ground, however a difficulty arises by reason of the manner in which submissions in support have been presented. Those submissions take the form of generalised objection to the Arbitrator reaching his conclusions by reason of a suggested absence of evidence as to the “mechanism” which was said to have caused the ventricular fibrillation; that the findings were “essentially speculative”, and that there was, at best, a “tenuous” relationship between the deceased’s viral illness and the emotional stress or frustration encountered with his employer. The appellant accepts that it was common ground between the parties that “in the week or so prior to his death the Deceased had a viral infection”. Those submissions are not expressly directed to the individual findings which are particularised in this ground and some are not addressed at all.
In the circumstances, it is proposed to deal with the particular complaints of factual error as they appear in the ground seriatim:
(a)     That the disarray present post mortem found on histological examination was caused by viral myocarditis:
The finding made by the Arbitrator concerning that disarray is to be found, as noted in ground two, at [257] and [271] of his Reasons. Such disarray was found by the Arbitrator as being “equally consistent with a cardiac arrest being caused by a viral myocarditis [as being indicative of death by cardiomyopathy]”. I accept the respondent’s submission that the evidence established the presence of myocite disarray as found on post mortem and that such disarray was a key substrate for ventricular fibrillation. The Arbitrator had not found that the myocite disarray was caused by viral myocarditis. I note that no specific submission is put in relation to this suggested factual error. No error is made out.
(b)     That T cell lymphocytes entered the myocardium:
It seems to be suggested in submissions that the Arbitrator’s findings concerning entry into the myocardium by T cell lymphocytes were founded on speculation (submissions at [38]). The manner in which damage is caused to the heart in the case of myocarditis was addressed by Dr Rainer in his report dated 10 February 2014. Reference is there made to the Dallas Criteria which has been established concerning diagnosis of that condition. The first of the criteria, as stated by Dr Rainer, is that “there must be concordance of T cell infiltration and myocyte damage in the absence of fibrosis and myocyte hypertrophy.” Professor Keogh, when giving oral evidence, stated that a virus alone does not cause relevant damage, but that it employs as “its weapons” T lymphocytes and B lymphocytes and polymorphs and eosinophils. The Arbitrator had found, and it is not disputed, that the deceased had contracted a virus. It was open to the Arbitrator, as argued on behalf of the respondent, to draw an inference that the more probable cause of the fibrillation was his contraction of myocarditis, which, on the evidence, involves entry of T cell lymphocytes. The Arbitrator’s preference for the hypothesis advanced by the respondent’s expert medical witnesses was founded upon the clinical history. No error is made out.
(c)     That emotional stress was the cause of the viral illness:
It is submitted (at [37] of submissions) that “the evidence of the relationship between the Deceased’s viral illness and the emotional stress or frustration he encountered with his employer was tenuous at best and fell far short of supporting a finding that the viral illness was due to the emotional stress.” The difficulty with this submission is that the appellant appears to accept that there was evidence, albeit “tenuous”, of such a relationship. To succeed with respect to this assertion of error, the appellant must establish that the Arbitrator was wrong, that is, that material facts have been overlooked or given undue or too little weight in deciding the inference to be drawn, or that the available inference in the opposite sense to that chosen by the Arbitrator is so preponderant that the Arbitrator’s decision is demonstrated as being wrong: Whiteley Muir & Zwanenberg Ltd v Kerr (1966) 39 ALJR 505 per Barwick CJ at 506. As earlier noted, this appeal is not by way of review, however the appellant appears to be seeking to reiterate argument advanced before the Arbitrator. No relevant error is made out.
(d)     That histological evidence of viral myocarditis was missed:
The Arbitrator stated at [262] of Reasons that “the failure of the tissue samples to reveal any sign of a myocarditis is consistent with a recent attack, as the histological evidence may not have been diffuse, and was accordingly missed.” I accept the respondent’s submission (at [33.4] of submissions) that there was evidence before the Arbitrator which permitted the conclusion of which the appellant complains. That evidence includes that of Professor Keogh as to the possibility of a viral myocarditis, notwithstanding the absence of histological evidence. Whilst it is true that Professor Keogh subsequently attempted to retract her statements concerning the possibility of there being myocarditis, the Arbitrator, as argued on behalf of the respondent, was not persuaded by the evidence given by Professor Keogh in the course of cross-examination. The inference drawn by the Arbitrator was open on the evidence and no relevant error is identified.
(e)     That stress induced ill health “allowed the introduction of a viral illness” into the body of the deceased:
The Arbitrator’s finding concerning the nexus between work stress and ill health (a viral illness) was founded upon the opinions of Professor Rawlinson and, in some respects, upon the evidence of Dr Hudson. I accept the respondent’s submission that the expert medical evidence permitted the inference drawn by the Arbitrator concerning a causal link between the work related stress and development of the viral illness. Again no relevant error is identified.

Ground three

The nature of the medical dispute is addressed between [27] and [32] above. This ground asserts that the Arbitrator erred in finding that the ventricular fibrillation, which the parties agree caused death, was caused by viral myocarditis. The substance of the complaint is that the respondent’s expert evidence was, erroneously, accepted by the Arbitrator.
The appellant’s submissions, again, seek to emphasise the fact that no evidence of myocarditis was found on post mortem. The difficulty with the argument advanced is that there was abundant evidence as to myocarditis being the likely cause of the ventricular fibrillation leading to death.
That evidence includes that of Dr Whalley as found in his correspondence noted at [49] and [50] above, in which, notwithstanding the absence of histological evidence, Dr Whalley considered myocarditis the “most likely cause of [the deceased’s] death”. It is important to note that Dr Whalley, who had been consulted by the respondent by reason of a need to exclude familial or inherited factors that might affect the deceased’s children, had expressed the view that the post mortem findings did not suggest changes indicating “arrhythmogenic right ventricular dysplasia” or, significantly in my view, “hypertrophic cardiomyopathy”.
It was that last condition that Professor Keogh ultimately preferred as the likely cause of the fatal ventricular fibrillation. That view was expressed following abandonment of her earlier preferred view that “the most likely cause being acute myocardial ischemia with primary arrhythmia” (report of Professor Keogh, 15 June 2012 at [19]). I note that Professor Keogh had, in that report, clearly misstated the view of Dr Whalley where it was asserted that a similar view to that of Professor Keogh was held by Dr Whalley.
It is important to note that, when evaluating the evidence, the Arbitrator noted that, in her first report noted above, Professor Keogh included the following summary of other matters that may have been relevant “underlying conditions leading to [the deceased’s] death”:
“Less likely [than acute myocardial ischemia with primary arrhythmia] are atypical right ventricular arrhythmogenic dysplasia, atypical hypertrophic left ventricular cardiomyopathy or a mild right ventricular cardiomyopathy or a viral myocarditis.”
The evidence of Associate Professor Richards, when cross-examined (at T44–45, 18 May 2015), is a further statement by that witness that affords a basis for the finding made by the Arbitrator which is challenged under this ground. When questioned concerning the relevance to diagnosis of pathological studies, Associate Professor Richards stated (I note the context is not entirely clear given the failure to transcribe an earlier response of Associate Professor Richards):
“Q. In what way, Professor?
A.     The diagnosis of a viral illness was a clinical diagnosis during life. In the absence of previous evidence of cardiomyopathy or atherosclerosis and in the presence of a viral illness soon before death and in the presence of ..(not transcribable).. (1:43:51) associated with a viral illness soon before death I think the inescapable conclusion is that he had viral myocarditis as the cause of death.
Q.     Well, rather, Professor, isn’t it this way? The inescapable conclusion is that he had either a virus or a bacterial disorder but not necessarily myocarditis, isn’t that so?
A.     Except that he had shortness of breath associated with a viral illness in the day or days prior to his death indicated to me that it’s highly likely that it’s the viral illness that caused the shortness of breath which has not been present previously.
Q.     Although you accept that it may well be a sign of cardiac ischemia?
A.     ..(not transcribable).. (1:44:44) who have myocardial ischemia, yes. This man did not have narrowing of the arteries to cause myocardial ischemia, nor did he have thrombosis in an artery to cause myocardial ischemia.”
The weight to be attached to the evidence considered by the Arbitrator was a matter to be determined by him. The state of the evidence summarised above and as touched upon in the course of these Reasons permitted, in my view, the Arbitrator’s finding as to probable cause of death. That finding does not, as argued by the appellant, constitute “conjecture” as addressed by Kitto J in Jones v Dunkel (1959) 101 CLR 298 (at 305) (Jones), which is noted at [55] of submissions. I consider that the facts proved formed a reasonable basis for the Arbitrator’s conclusion as discussed by Dixon CJ in Jones (noted at [56] of submissions). This ground fails.

Ground four

An assertion is made in this ground that the Arbitrator failed to correctly apply the provisions of s 9A of the 1987 Act to the facts. The terms of s 9A(1), as it stood at the time of the alleged injury, was as follows (I note in passing that the respondent in its submissions has incorrectly cited the terms of the subsection as it presently stands following amendment in 2012):
“9A No compensation payable unless employment substantial contributing factor to injury
(1)No compensation is payable under this Act in respect of an injury unless the employment concerned was a substantial contributing factor to the injury.”
Submissions in support of this ground commence with an assertion that the Arbitrator erred in concluding “that the pre-existing condition [of the deceased’s heart] did not play any part in the death of the deceased”. That error, it is argued, is to be found in the following statement made by the Arbitrator (at [273] of his Reasons):
“I am satisfied that the provisions of s.9A [of the] 1987 Act apply. The employment was the main substantial reason for the breakdown of the deceased’s health and subsequent death, for the reasons given above. I am not satisfied that the pre-existing condition of his heart played any part in his death. There was insufficient evidence before me to raise that proposition. The argument was that it was either the pre-existing condition or the viral illness that was responsible for causing the ventricular fibrillation. I have preferred the latter view.”
Whilst it is not expressly stated in the appellant’s submissions, it seems to be asserted that the Arbitrator has committed factual error concerning the relevance of the “pre-existing condition” of the deceased’s heart. It is argued that the Arbitrator’s conclusion is contradicted “not merely by the appellant’s experts but by Associate Professor Richards…”. The following extract from Associate Professor Richards’ report of 2 September 2013 is included in the appellant’s submissions:
“I accept it is possible that ventricular fibrillation would not have occurred in this case in the absence of underlying myocardial pathology. However it is my view that it is not likely ventricular fibrillation would have occurred in the absence of the recent viral illness (associated with dyspnoea and lethargy and probable myocardial involvement).”
It is clear that the Arbitrator at [273] had disregarded the deceased’s pre-existing cardiac condition as being a factor that “played any part in his death”. Such conclusion was reached by the Arbitrator without regard to the statement by Associate Professor Richards, however it must be noted that the Arbitrator’s adoption of the term “pre-existing condition” appears to be a reference to the preferred hypothesis put forward by Professor Keogh that the ventricular fibrillation was caused by underlying hypertrophic cardiomyopathy. That is, the Arbitrator at [273] was addressing the nature of the two distinct and conflicting hypotheses, being the presence of relevant myocarditis or relevant hypertrophic cardiomyopathy.
Upon an acceptance that the Arbitrator has erred in disregarding the evidence highlighted in the course of the appellant’s submissions, I am nevertheless of the opinion that such error has not affected the Arbitrator’s decision. The Arbitrator’s conclusion was that employment “was the main substantial reason for the breakdown of the deceased’s health and subsequent death”. The terms of s 9A(1) employ the indefinite article and, as found in Department of Education & Training v Sinclair [2005] NSWCA 465; 4 DDCR 206 at [49], “these words, particularly the use of the indefinite article, admit the possibility of other, possibly non-employment related, substantial contributing factors…”. Whilst it follows that there may be more than one substantial contributing factor to injury, the evidence, in my view, left it open to the Arbitrator to conclude as he did. The Arbitrator’s finding concerning the requirements of s 9A is not vitiated by his apparent disregard of the suggested concession made by Associate Professor Richards. It should be noted that Associate Professor Richards’ acceptance of the possibility that ventricular fibrillation would not have occurred in the absence of underlying myocardial pathology was qualified in the second statement found in the paragraph earlier quoted, where it was said that it was “not likely ventricular fibrillation would have occurred in the absence of the recent viral illness (associated with dyspnoea and lethargy and probable myocardial involvement)”. The Arbitrator had earlier stated his reasons for his acceptance of the ventricular fibrillation having been caused by myocarditis and it was open for him to conclude that employment, given the causal nexus discussed in the course of his Reasons, was a substantial contributing factor to the injury leading to the deceased’s death.

The appellant’s submissions proceed to, again, challenge the Arbitrator’s factual conclusion concerning the causal connection between employment and his contraction of an infective virus. As earlier discussed in relation to ground two, those factual conclusions were open on the evidence and have not been successfully challenged. The question raised under the present ground must be whether, upon the assumption that those factual conclusions were correctly reached by the Arbitrator, the terms of s 9A have been met.
At [89] of submissions, the appellant purports to respond to those matters raised for consideration by the terms of s 9A(2). A difficulty arises with that submission having regard to the assertion made that “the injury occurred at 11.30 pm at the Deceased’s home when he was having a cup of tea”. The injury is not, and cannot, be the death of the deceased but rather his experience of stress which, as found by the Arbitrator, made him susceptible to the contraction of an infective virus. Another difficulty with that submission is that the appellant seeks to, again, raise the question as to which of the hypotheses as to cause of death was the probable cause of death.
The facts as found by the Arbitrator included a finding as to the existence of stressful conditions experienced in the course of the deceased’s employment. The stress as found constitutes the relevant injury and that injury has been found to have rendered the deceased more susceptible to contraction of the virus. That conclusion has not been successfully challenged on this appeal. The strength of the causal linkage between employment and injury has been found to be substantial. That conclusion followed an evaluation by the Arbitrator and, as discussed in Haider v J P Morgan Holdings Aust Ltd t/as JP Morgan Operations Australia Ltd [2007] NSWCA 158; 4 DDCR 634, that exercise raised matters of impression and degree. Such a finding as to relative contributing factors is a finding of fact. I am not satisfied that the appellant has made out any error on the part of the Arbitrator in his evaluation of relevant contribution nor as to the strength of the causal linkage between the employment and the injury. This ground fails.

Ground five

It is asserted under this ground that the Arbitrator “wrongly rejected the evidence of Professor Keogh”. In submissions, the appellant argues that the Arbitrator “did not make a finding that he disbelieved Professor Keogh” nor, it is put, did he find Professor Keogh’s evidence had been “tainted by dishonesty, was misleading, the product of advocacy for a party or was inherently unreliable” (at [95] of submissions). The thrust of that argument appears to be an assertion that the Arbitrator did not have regard to the demeanour of Professor Keogh when her evidence had been considered by him.
Argument is then developed by reference to the decision of Wiki in which Ipp JA (with whom Bryson and Stein JJA agreed) examined the correct approach required of a fact finder to the determination of issues which are the subject of conflicting expert evidence. There it was stated by his Honour (at [60]–[61]):
“In some disputes between experts, demeanour will be crucial. This may occur where a witness has given dishonest or misleading evidence, or has become an advocate for a party, or where the evidence given is inherently unreliable for other reasons. Demeanour may also be crucial in other cases where the evidence is not so tainted. Situations may arise where, after due consideration of the reasoning of the differing views of the expert witnesses, the judge is simply unable to decide the issue otherwise than by impression and demeanour. Demeanour may also be crucial in situations of the kind described by Mahoney JA in Public Trustee v Commonwealth of Australia (Court of Appeal, 20 December 1995, unreported) at 24 when making the following remarks:
‘[N]ot infrequently, the court may not be in a position to decide whether the facts on which the witness relies are true and may not be able to judge the scientific or professional accuracy of the principles ... And where experts state different conclusions and rely for them upon facts which differ and principles which do not agree, it may not be able to form its conclusion by reference to those facts or those conclusions alone. When a judgment must be made between the facts and the principles advocated at the trial, the court may not be in a position to give objectively convincing reasons for its choice. It may, in the end, have to depend upon the impression which the witness has made...’
Demeanour also often plays a partial role in a decision whether to prefer one expert over another. A judge may be persuaded by a combination of the material force of an expert’s views together with the way in which the evidence was given.
But, where the issue in dispute involves differences between expert witnesses that are capable of being resolved rationally by examination and analysis, and where the experts are properly qualified and none has been found to be dishonest, or misleading, or unduly partisan, or otherwise unreliable, a decision based solely on demeanour will not provide the losing party with a satisfactory explanation for his or her lack of success. A justifiable grievance as to the way in which justice was administered will then arise.” (emphasis in original)
It is thus made clear, having regard to the reasoning expressed by Ipp JA in Wiki, that there is an obligation upon a fact finder, in circumstances such as the present, to engage with the evidence; and when a choice is made between conflicting evidence of experts, reasons should be provided for such choice. A determination founded upon demeanour alone is not a sufficient discharge of the duty to give reasons where rational examination and analysis is possible.
The appellant argues that the Arbitrator’s rejection of Professor Keogh’s evidence was made on an “unacceptable basis namely that she changed her opinion for what [the Arbitrator] regarded as unconvincing reasons” (at [96] of submissions).
It is the appellant’s contention that demeanour played no part in the Arbitrator’s reasoning and that he failed, as he was obliged, to engage with the evidence. His choice or preference for the evidence relied upon by the respondent, it is put, was not explained and it seems to be argued that such failure constitutes relevant error. The evidence is, yet again, traversed in submissions and it is argued that the error as to such choice should be corrected on appeal.
The respondent, in submissions, asserts that it is clear from the Arbitrator’s reasoning that, in fact, he had taken into account the demeanour of Professor Keogh and that there had been a “painstaking and comprehensive analysis” of all evidence before him, including that of Professor Keogh.
As was noted by the Arbitrator, Professor Keogh retracted, in terms that failed to satisfy the Arbitrator, her express view found in her first report that viral myocarditis was one explanation for the deceased’s death, although less likely than acute myocardial ischemia with primary arrhythmia. Her opinion concerning suggested myocardial ischemia was also retracted. Such retractions, I note, were not to be found expressly stated in the reports of Professor Keogh, but were unequivocally elicited in the course of her cross-examination concerning the content of her report dated 13 March 2015 (at T70–72, 19 May 2015). Such evidence explains, in my view, the Arbitrator’s hesitance in accepting the witness’s delayed explanation for her change of view. Whilst no submission has been made concerning the requirements of the Expert’s code of conduct, it remains a fact that the relevant changes of opinion were not expressly brought to the notice of the Commission as is required by cl 5(4) of that code.
The Arbitrator stated (at [191] of Reasons) that he found Professor Keogh’s evidence concerning the slides being a “game changer” to be “not particularly helpful” and that her answer concerning the subject of the histological material was “discursive” and was one “critical of the coroner’s pathologist”. There are other observations concerning Professor Keogh’s evidence which are noted by the respondent at [59] of submissions which confirm, in my view, that the Arbitrator had taken into account the witness’s demeanour when evaluating her evidence. I reject the appellant’s submission that suggests otherwise and am of the opinion that the Arbitrator was entitled to take such matters into account.
As stated in Wiki, there is the further obligation to engage with the evidence. That the Arbitrator did so is beyond dispute. I note that I have earlier attempted to identify the Arbitrator’s approach to evaluation of the evidence (at [92] above). The Arbitrator’s reasons for his preference for the evidence of the respondent’s experts are plainly stated and, in my opinion, his statements discharged his obligation, in the present circumstances, to provide reasons for his conclusion. This ground fails.

CONCLUSION

Each of the grounds relied upon by the appellant have been rejected and the appeal fails. In the circumstances, the Arbitrator’s decision should be confirmed. Appropriate orders appear below.

ORDERS

The Arbitrator’s findings and orders found in the Certificate of Determination dated 8 September 2015 are confirmed.
The matter is remitted to Arbitrator Wynyard for further directions and hearing concerning the question of apportionment.

Kevin O'Grady
Deputy President

25 February 2016

I, STEVEN HAMPSON, CERTIFY THAT THIS IS A TRUE AND ACCURATE RECORD OF THE REASONS FOR DECISION OF KEVIN O'GRADY, DEPUTY PRESIDENT OF THE WORKERS COMPENSATION COMMISSION.

ASSOCIATE