 This is a prospective, open label, randomized trial of 100 patients who present to the cardiac catheterization laboratory with an ST Elevation Myocardial Infarction for primary PCI. Patients may receive up-front unfractionated heparin or low molecular weight heparin, but not glycoprotein IIbIIIa inhibitors or thrombolytics. Patients will be consented prior to the diagnostic catheterization and will be randomized once the patient is deemed amenable to PCI to receive eptifibatide or no eptifibatide just prior to or at the time of primary angioplasty. Patients will be randomized in a 1:1 fashion. All patients will be assessed for the primary endpoint of ST resolution at 60 minutes post PCI and followed throughout the duration of the hospitalization and up to 30 days for secondary endpoint evaluation. 