Myocardial infarction in the distribution of a patent anomalous left circumflex coronary artery.

Anomalous origin of the left circumflex coronary artery is the most common congenital coronary artery anomaly. Myocardial infarction has been seen in the distribution of this anomalous vessel. This has been noted most typically when the vessel is atherosclerotic. Sudden death and myocardial infarction, however, also have been seen in a case without atherosclerotic involvement. This is a case report of a 45-year-old man who suffered a myocardial infarction after strenuous and sustained physical effort and who was found to have nonatherosclerotic coronary arteries with an anomalous left circumflex coronary artery arising from the right sinus of Valsalva.