Epicardial fibrosis mimicking a myocardial bridge.

Coronary artery compression during left ventricular systole is usually the result of a segment of coronary artery tunnelling within the myocardium, termed a 'myocardial bridge'. A 49-year-old man presented with acute anterior wall myocardial infarction thought to be secondary to a myocardial bridge seen during coronary arteriography; however, in the operating room the entire left anterior descending artery had a normal epicardial course without evidence of an intramyocardial segment, and coronary artery compression was the result of overlying fibrotic tissue, which was successfully excised. Overlying epicardial coronary artery fibrosis should be in the differential diagnosis of coronary artery compression.