Delair Gardi M.D.              University of Missouri-- Columbia
A case of aortic dissection which mimics an inferior myocardial infarction   
         
 

A 72 year old hypertensive male came to the ER by ambulance after blacking out. He was confused, diaphoretic, and nauseated but did not complain of chest pain. His BP was 60/0 mm Hb in both arms. No cardiac murmurs were noted. An ECG showed 2mm ST segment elevation in the inferior leads. Right precordial ECG leads showed no RV infarction. An emergency cardiac catheterization study showed a 60% lesion in the right coronary artery (RCA) which was cannulated with difficulty. Minor lesions were noted in the left anterior descending and circumflex arteries. He received pressors and an intraaortic balloon pump but remained hypotensive. A right heart catheterization showed equilibration of diastolic pressures. An echocardiogram showed pericardial fluid with RV collapse consistent with pericardial tamponade. Despite resuscitative efforts the patient died. An autopsy demonstrated a proximal aortic dissection with a hematoma which compressed the ostium of the right coronary artery; blood was found in the pericardium.

Proximal aortic dissection rarely involves the ostium of the coronary arteries. When it does, the RCA is more often affected than the left coronary artery and signs of an inferior MI can obscure the diagnosis of aortic dissection. Angiographic findings include coronary artery dissection, or in this case, external compression of the coronary which can be missed if the catheter enters the ostium of the coronary artery. In this case the diagnosis was made by the finding of blood in the pericardium, the result of dissection from the aortic wall to the pericardium. Administration of thrombolytic therapy for an apparent acute MI in this situation would be disastrous