Despite great strides made in the field of cardiovascular surgery during the past decade, the problems posed by peripheral arterial emboli remain largely unsolved, since the emboli tend to be multiple and are often fatal. Bull has classified five possible sites of origin of peripheral arterial emboli: (1) a central artery, such as the aorta, (2) the left side of the heart, (3) pulmonary veins, (4) the right side of the heart, and (5) systemic veins. The last two sites of origin postulate the presence of a patent foramen ovale. Although emboli may originate from any of these five locations, the most frequent site of origin is the left side of the heart.
The location of mural thrombi and the incidence of arterial embolization vary with the type of heart disease present. Garvin 2 has reported a 67% incidence of mural thrombi in patients with coronary thrombosis and myo- cardial