Hyperthyroidism has been reported to be associated with cardiac complication, such as heart
failure, atrial fibrillation, heart block and acute coronary syndrome. Acute coronary syndrome in
hyperthyroidism has been known mainly due to coronary spasm, but plaque rupture of atherosclerotic
lesion has been rare. We reported a case of acute myocardial infarction associated with hyperthyroidism
which had been confirmed plaque rupture by intravascular ultrasound.