Appeal from a decision of the Workmen’s Compensation Board, filed October 30, 1975, which awarded death benefits. Claimant’s decedent, a 44-year-old mechanic, suffered a heart attack while at work and died of a coronary occlusion. From our review of the record we are of the view that substantial evidence supports the factual findings of the board that decedent, on the night of his death, was engaged in work involving significant physical exertion and mental pressures arising from the need to complete his tasks hurriedly so that other employees could resume their duties. We similarly conclude that the opinion of Dr. Sherwin that there was a causal relationship between decedent’s work and his death is properly founded upon the facts as to the nature of claimant’s work, and, therefore, constitutes substantial evidence to support the finding of causal relationship. Decision affirmed, with costs to the Workmen’s Compensation Board against the employer and its insurance carrier. Greenblott, J. P., Sweeney, Main, Larkin and Herlihy, JJ., concur.