Anomalous origin of the left main coronary artery from the main pulmonary artery in a young adult.

A23-year-old man who had had cardiac murmurs since childhood experienced heart arrest during exercise. Cardiac resuscitation and cardioversion of ventricular fibrillation rescued the patient. Subsequent work-up showed that the patient’s left coronary artery arose from the main pulmonary artery. Transesophageal echocardiography showed aneurysmal dilatation of the left coronary artery, which arose from the posterior aspect of the main pulmonary artery (Figures 1–3). Under hypothermic cardiopulmonary bypass and cardioplegic arrest, the cuff of the left coronary artery orifice was excised and reimplanted into the ascending aorta. The patient was discharged 6 days after the operation.