A 73-year-old woman with a past medical history of hypertension suffered a cardiac arrest. After successful resuscitation, she was hypotensive and tachycardic and the ECG showed ST elevation in the inferior and lateral precordial leads. Coronary angiography did not show evidence of obstructive coronary artery disease. A bedside echocardiogram demonstrated a large pericardial effusion with signs of cardiac tamponade. The echocardiogram and subsequent aortic root angiography did not reveal evidence of dissection. Pericardiocentesis removed 700 cc of bloody fluid with relief of tamponade. A few minutes later the patient again arrested. Fluid was again drained but she suffered recurrent hemodynamic collapse and could not be resuscitated. Autopsy revealed a small transmural myocardial infarction with external rupture and hemopericardium. There was only mild coronary artery disease without evidence of plaque rupture. This case illustrates that mild coronary artery disease and a small myocardial infarction can lead to catastrophic mechanical complications.