Thrombolytic therapy has been found to improve the prognosis of selected patients with acute myocardial infarction. Many investigators advocate that combined emergency coronary angiography and percutaneous transluminal coronary angioplasty be performed immediately after thrombolytic therapy. Emergency angiography documents the anatomic extent of coronary artery disease, shows whether reperfusion has occurred, and indicates whether emergency angioplasty is necessary. In this setting, emergency catheterization without angioplasty is associated with relatively little additional risk. However, a number of prospective trials have compared emergency angioplasty to more conservative treatment strategies, and emergency angioplasty has been not found to offer any advantage in terms of improved prognosis or preservation of left ventricular function. Therefore, it is probable that most patients with evolving Q-wave myocardial infarction are best treated with conservative strategies after initial thrombolytic therapy, although there may still be a role for emergency angioplasty in a relatively small subset who present with evolving myocardial infarction and severely depressed left ventricular function.