A substantial proportion of patients receiving fibrinolytic therapy for myocardial infarction with ST-segment elevation have inadequate reperfusion or reocclusion of the infarct-related artery, leading to an increased risk of complications and death. methods We enrolled 3491 patients, 18 to 75 years of age, who presented within 12 hours after the onset of an ST-elevation myocardial infarction and randomly assigned them to receive clopidogrel (300-mg loading dose, followed by 75 mg once daily) or placebo. Patients received a fibrinolytic agent, aspirin, and when appropriate, heparin (dispensed according to body weight) and were scheduled to undergo angiography 48 to 192 hours after the start of study medication