Ventricular septal defect is a serious complication of acute myocardial infarction with a high mortality rate. Right ventricular dysfunction, which frequently accompanies septal defect, can be due to several etiologies. We describe two cases of septal defect following infarction, with sequential studies of right and left ventricular function. Right ventricular infarction was found in both patients. Postoperatively, the right ventricular ejection fraction improved significantly. The pathophysiology and expectation for recovery are discussed.