Appeal from a decision of the Workers’ Compensation Board, filed December 28, 1976, which affirmed a referee’s decision and held that claimant sustained an accidental injury on July 13, 1974 which arose out of and in the course of his employment. The board found that the claimant’s work activities on July 13, 1974, including the walking up of 25 to 30 steps while carrying a briefcase, were stressful for the claimant and that superimposed upon his three-vessel coronary artery disease precipitated his subendocardial infarction and that this constituted an accidental injury arising out of and in the course of his employment. The board further found that the claimant’s disability was causally related to such accidental injury. There is, in our view, substantial evidence to sustain the determination of the board. Decision affirmed, with costs to the Workers’ Compensation Board against the employer and its insurance carrier. Mahoney, P. J., Greenblott, Sweeney, Main and Larkin, JJ., concur.