Casey, J. Appeal from a decision of the Workers’ Compensation Board, filed May 12, 1989, which ruled that claimant sustained an accidental injury in the course of his employment and restored the case to the trial calendar.
At issue on this appeal is whether the Workers’ Compensation Board can reject the unanimous conclusion of the only two medical experts to offer an opinion as to the causal relationship between claimant’s employment and the myocardial infarction which disabled him, and conclude that the constant high stress associated with claimant’s employment aggravated his preexisting heart condition over time and, therefore, constituted repeated trauma which created a causal relationship between claimant’s employment and the disability. Since the end result is a decision which lacks the support of substantial evidence in the record, we answer this question in the negative and reverse the Board’s decision.
Claimant began working for his employer as an investigator in 1973 and was chief welfare fraud investigator from 1978 until November 26, 1982, when he sustained a myocardial infarction at his home that left him totally and permanently *935disabled. It is undisputed that claimant’s job was generally stressful and that he occasionally was confronted by specific circumstances that were particularly stressful. It is also undisputed that claimant’s hypertension, which began at an early age, and his obesity, heavy smoking and family history were risk factors that predisposed claimant to the early development of coronary artery disease, which first manifested itself in the form of angina chest pain no later than 1977 and perhaps as early as 1970.
The attending physician, who treated claimant for his heart condition beginning in 1977, noted that claimant had expressed concern that the stress of his job was contributing to his heart condition, but the attending physician was never asked for, and never volunteered, his opinion as to whether the stress of claimant’s job had any causal relationship to claimant’s myocardial infarction or the underlying heart condition. The employer’s medical expert and the impartial specialist appointed at the Board’s direction were both of the opinion that the stress of claimant’s employment was not a contributing factor in either the underlying coronary artery disease or the myocardial infarction. Nevertheless, as noted above, the Board found that claimant’s disability was causally related to his employment.
In its brief on appeal the Board cites a number of cases in support of the argument that the decision must be affirmed since the question of whether claimant’s heart attack was an accident causally related to his employment presented a factual issue for the Board to resolve. The bulk of the cited cases are, however, irrelevant since the question of causal relationship in those cases either was not in dispute (see, e.g., Matter of Klimas v Trans Caribbean Airways, 10 NY2d 209) or was resolved by the Board in a manner which was consistent with the opinion evidence in the record presented by at least one medical expert (see, e.g., Matter of Currie v Town of Davenport, 37 NY2d 472). Here, in contrast, the question of causal relationship is the only issue in dispute and the Board’s resolution of that issue is in direct conflict with the conclusion of the only medical experts who expressed their opinions on that issue.
In reviewing a Board decision concerning the medical question of causality, we will look to the record to determine whether, read as a totality, it contains substantial and adequate opinion evidence to support the Board’s finding (see, Matter of Ernest v Boggs Lake Estates, 12 NY2d 414, 415). We have said that "[iln a case of this nature causal relationship *936can only be established by medical opinion” and where the opinions of the medical experts are in conflict “[t]he choice * * * as to which opinion is to be accepted, lies with the board” (Matter of Miller v Dimon & Son, 45 AD2d 788). We have also held that in resolving medical questions, the Board’s fact-finding authority includes the power to selectively adopt a portion of the unanimous opinion of the experts and, based upon that adopted portion of the opinion and other evidence in the record, resolve the medical question in a manner which is not wholly consistent with the experts’ opinion (Matter of Moore v RPM Indus., 144 AD2d 135, 136). In contrast, however, we have said that the Board cannot entirely reject the unanimous opinion of the experts on the issue of causation and draw its own conclusion as to causation, as such a conclusion would not be supported by substantial evidence (Matter of Smith v Bell Aerospace, 125 AD2d 140, 142-143). It is our view that the Board’s finding herein falls into this latter category.
The Board’s decision, as amplified by its brief on appeal, purports to base its finding of causal relationship on the undisputed evidence that claimant’s heart condition deteriorated significantly during the period that claimant was employed in a stressful job. According to the Board, this evidence, coupled with the attending physician’s testimony that stress has been suspected of causing coronary artery disease or myocardial infarction and the impartial specialist’s concession that a minority of the medical community is of the view that constant stress over time could lead to coronary artery disease and myocardial infarction, provided the necessary substantial evidence to support the Board’s finding of causal relationship between claimant’s stressful employment and his disability. We disagree. Although the evidence is weak at best, there may be substantial medical opinion evidence in the record to support a finding that stress over time can cause coronary artery disease and myocardial infarction. The medical question presented in this case, however, was not a general hypothetical one, but a specific factual one: was the stress encountered by claimant during his employment a contributing factor in claimant’s coronary artery disease and myocardial infarction. On this issue, the record contains no medical expert opinion evidence of a causal relationship. The only opinion that such a causal relationship exists is that of the Board. Although the Board’s repeated exposure to cases involving medical questions, medical reports and medical witnesses may have led to the development of a certain expertise *937in such matters (see, Matter of Currie v Town of Davenport, supra, at 476), that expertise is to “be employed in weighing and balancing evidence with appropriate regard for its probative character” (supra, at 476), not in the fashioning of the Board’s own medical opinion in direct and total conflict with the unanimous conclusion of the only experts to offer an opinion on the particular medical question (see, Matter of Smith v Bell Aerospace, supra).
Decision reversed, and claim dismissed, with costs against the Workers’ Compensation Board. Mahoney, P. J., Casey and Mercure, JJ., concur.