Coronary artery embolism and myocardial infarction.

Although coronary artery embolism is a recognized entity, there is little morphologic information indicating it is a cause of myocardial infarction. We studied patients with coronary artery embolic infarcts, which comprised 13% of our autopsy-studied infarcts. Underlying diseases predisposing to coronary emboli included valvular heart disease (40%), myocardiopathy (29%), coronary atherosclerosis (16%), and chronic atrial fibrillation (24%). Mural thrombi were present in 18 (33%). Myocardial infaction, clinically diagnosed in 15 (27%) patients, caused death in 11 (20%). Most emboli involved the left coronary artery and lodged distally, causing infarcts that were usually transmural. Because of their distal location and recanalization, coronary emboli may be a cause of infarcts with angiographically normal coronaries. Thus, coronary emboli are not rare, may produce signs and symptoms indistinguishable from altherosclerotic coronary disease, and by lodging distally in coronary arteries that are usually previously normal, they most often cause small but transmural myocardial infarction.