Impending acute myocardial infarction during severe exercise associated with a myocardial bridge.

A young man had an impending acute myocardial infarction while playing soccer. Chest pain and anterior ST-segment elevation lasted 3 hours despite anti-ischemic medication, including streptokinase thrombolysis. An electrocardiogram recorded after the symptoms had passed was normal. There was a minimal increase in cardiac enzyme levels, and a pyrophosphate scan and echocardiogram were normal. Coronary cineangiography showed normal coronary arteries except for systolic compression of the left anterior descending coronary artery. An exercise stress test, while the patient was on atenolol, showed absence of myocardial ischemia. This impending acute myocardial infarction could have been caused by an acute thrombus with lysis prior to catheterization or by a deep muscle bridge that kinked or twisted the coronary artery due to myocardial forceful muscular contraction during the sympathetic stimulation of exercise. In conclusion, an impending acute myocardial infarction may occur in young patients having myocardial bridges, and a beta-blocker must be administered, especially when this condition appears during severe exercise.