In the patient in cardiogenic shock with or without a mechanical complication after acute myocardial infarction, medical treatment alone is often inadequate. Occasionally, early mechanical circulatory support by means of intraaortic balloon pumping (IABP) may be successful; in such patients, however, operation is usually required later. In most instances, IABP alone is insufficient, but it is an effective stabilizing measure that allows many patients to safely undergo cardiac catheterization, coronary arteriography, and surgical treatment. In selected patients with anterior myocardial infarction, early IABP can interrupt injury. Patients with severe cardiogenic shock due to massive infarction with extensive ventricular dysfunction are best managed with myocardial revascularization and, frequently, infarctectomy. Patients with an interventricular defect who survive to undergo defect repair usually do not undergo concomitant revascularization, but we frequently perform infarctectomy in this situation. Other patients with mechanical complications of myocardial infarction, such as mitral regurgitation due to papillary muscle rupture or dysfunction, ruptured chordae tendineae, or annular or ventricular dilatation, are usually best treated with both coronary artery bypass grafting and mitral valve repair or replacement with or without infarctectomy. In some patients with a malignant ventricular arrhythmia, wide excision of the infarct may be helpful, with or without revascularization. The likelihood of a good result after operation for any of the complications of myocardial infarction improves if the surgical procedure can be safely postponed until the patient is not in an acute state of illness. However, post-