In patients with acute myocardial infarction who are managed in the prehospital setting, and who will treated with primary angioplasty, we evaluate the benefit of an early administration of tirofiban, a powerful GPIIbIIIa inhibitors. Patients are randomised to early administration in the ambulance or administration in the cathlab. The primary endpoint is TIMI 2-3 flow in the first coronary opacification of the culprit artery.

Inclusion Criteria:

• Age > 18 years
• Information given to the patient and consent obtained
• Thoracic pain or symptoms of infarction
• Symptoms < 12 hours
• ST deviation identified by electrocardiography (ECG) in at least 2 contiguous leads
• Transfer time to angioplasty room evaluated by the coordinating doctor as less than 90 minutes (from ECG diagnosis to arrival in angioplasty room)

Exclusion criteria

• Physiological or pathological conditions not compatible with a revascularisation procedure (in the acute phase of myocardial infarction (MI)
• Administration of fibrinolytics or another antiGPIIBIIIa in the previous seven days
• Contraindications to aspirin or tirofiban or heparin
• Diagnosed severe kidney failure (dialysis, creatinin > 350µmol/l
• Pregnancy
• Time for transfer to the angioplasty room evaluated by coordinating doctor as more than 90 minutes
• Subject participating in another trial
• Subject with high hemorrhagic risk.