In this worker’s compensation case the deceased, who had a prior history of chest pains, suffered an attack of angina while at work. A medical examination which followed revealed that he was suffering from a long-standing condition requiring open-heart surgery. We agree with the Workers’ Compensation Board and the circuit court that the claimant has not shown by a preponderance of the evidence that the on-the-job attack of angina contributed materially to the underlying condition which necessitated the surgery.

Affirmed.