In patients with acute myocardial infarction, percutaneous transluminal coronary angioplasty (PTCA) may be used (I)to restore antegrade flow in the infarct artery (so called ''primary'' PTCA) instead of thrombolytic therapy, (2) to establish antegrade coronary flow after unsuccessful thrombolytic therapy (so called ''rescue'' or ''salvage'' PTCA), and (3) to reduce the residual infarct artery stenosis after successful thrombolysis. This review examines the prospective, randomized studies that have addressed the use of PTCA for each of these purposes. In selected circumstances, PTCA is a reasonable alternative to thrombolytic therapy in patients with evolving or recent Q-wave myocardial infarction. In those patients with acute myocardial infarction complicated by cardiogenic shock, PTCA may be the preferred treatment. After thrombolytic therapy, the use of PTCA in the absence of spontaneous or provocable ischemia offers no benefit with regard to left ventricular function or survival. In this circumstance, its use is associated with an excessive risk of bleeding, transfusions, and emergent coronary artery bypass surgery when performed within hours of infarction.