CORONARY embolization is an infrequent cause of myocardial infarction. Oakley and his associates1were able to collect only 90 cases from the literature, to which they added five cases of their own. Wenger and Bauer2found 11 cases of coronaryartery embolism in 17,469 consecutive autopsy cases at Mount Sinai Hospital, New York, for a general necropsy incidence of 0.06%. The actual incidence of coronary occlusion due to embolism is unknown. Although 50% of cases of coronary embolism are associated with bacterial endocarditis, several other sources of emboli have been less commonly reported. In addition to paradoxical embolization, emboli may arise from any one of a number of sites in the left side of the heart and its immediate tributaries. The advent of open-heart surgery, and particularly valve prosthesis, has introduced a new source for thrombus formation and subsequent embolization, namely thrombosis on the prosthetic valve. This paper presents the