Acute myocardial infarction and the five-chambered heart.

The case of a patient presenting with acute inferior ST-elevation myocardial infarction is described. Emergent coronary angiography of the right coronary artery revealed what appeared to be the abrupt drainage of contrast into a large, peculiar cavity or chamber. Echocardiography and cardiac computed tomography demonstrated a giant right coronary aneurysm in the right coronary artery that gave the impression of a "fifth heart chamber." The patient underwent successful surgical resection of the aneurysm. Diagnostic and treatment approaches to giant coronary aneurysms are discussed.