Appeal from a decision and award of the Workmen’s Compensation Board. The issues raised are of accident and causal relationship. Claimant was employed as a fruit clerk in a fruit and vegetable market. The evidence upon which the board relied was that on August 1, 1953 while lifting boxes of merchandise, he sustained accidental injury in the nature of acute posterior myocardial infarction with pains in the chest. After consulting a doctor and receiving treatment he stayed in *914bed for a day, then resumed his employment. On August 4, 1953 he collapsed and was sent home. The award involved here covered various periods of total and partial disability between August 4, 1953 and November 7, 1954. The board has found that he suffered an aggravation due to the unusual exertion and strain in moving boxes of merchandise, unassisted, during the course of his regular employment and that this occurrence was an accidental injury as contemplated by the statute. On the question of causal relationship, there was a sharp dispute between the medical experts, which presented a question of fact. This factual dispute has been resolved by the board in favor of the claimant. We feel that there was a substantial basis for the findings of the board. Certainly wé may not say as a matter of law that such is not the case. Decision and award affirmed, with costs to the Workmen’s Compensation Board. Bergan, J. P., Gibson, Herlihy and Reynolds, JJ., concur.