In order to determine the effect of right atrial dysfunction on clinical outcome, six patients with inferior myocardial infarction with extension to right ventricle and right atrium involving only obstructions of the right coronary artery were examined with transesophageal echocardiography (TEE) at the time of the event. Five of the patients were reexamined 15 to 55 months later. Two patients underwent thrombolysis and maintained ratios of right-to-left ventricular diameters of less than 1, as well as normal convexity of the interatrial septum. One patient had spontaneous reperfusion of the right coronary artery, reduction in right ventricular diameter, and normalization of interatrial septum. Another patient underwent delayed angioplasty and manifested a diminished wall movement score (WMS) in the follow-up echocardiogram. One patient died during his first hospitalization with significant right ventricular dilatation, inverted convexity of the interatrial septum, and right atrial thrombosis. The last patient died during follow-up with right ventricular dilatation, increased WMS, right atrial akinesis, and inverted interatrial convexity. Serial TEE examination of patients with infarction of the left ventricular inferior wall is a safe technique for determining the degree of the extension of the ischemic process to the right chambers.