Exercise-induced plaque rupture producing myocardial infarction

A 37-year-old man with unstable angina was subjected to coronary angiography. The right coronary artery showed a minor proximal stenosis, but there were no obstructive lesions in the left coronary artery. He developed a small inferior infarction. He was asymptomatic until re-admission 1 month later, 1 hour after a normal exercise test, with anterior myocardial infarction. Acute coronary angiography showed sub-total occlusion of the left anterior descending artery. The occlusion was partially relieved after intracoronary injection of nitroglycerin. Intracoronary infusion of streptokinase had no further effect. Balloon angioplasty was then successfully performed. It is suggested that stress-induced plaque rupture with intimal hemorrhage and secondary spasm resulted in sub-total occlusion of the left anterior descending artery producing the second myocardial infarction.