Subepicardial myocardial lesions.

Subepicardial myocardial lesions are rarely seen at necropsy, and a description of them and their causes has not been reported. Over the last 13 years we have studied 22 patients with subepicardial myocardial lesions. They ranged in age from 14 to 73 years (mean 47), and 20 were men. The lesions were associated with atherosclerotic coronary artery disease in six patients, sarcoidosis in five, idiopathic dilated cardiomyopathy in four, lymphocytic myocarditis in two, and hypoplastic right and left circumflex coronary arteries in one. In four patients the cause was unclear. In the patients with atherosclerotic coronary artery disease, the subepicardial myocardial lesions were small, few in number, and located in the left ventricular posterior wall. In patients with sarcoidosis or myocarditis, the subepicardial lesions were extensive and commonly associated with transmural left and right ventricular lesions. The right ventricular half of the ventricular septum also was frequently affected. In the remaining nine patients, the subepicardial lesions were small and unassociated with transmural left ventricular lesions. Thus subepicardial myocardial lesions occur in a variety of cardiac diseases.