 Mechanical recanalization of the culprit artery in acute myocardial infarction using stents provides in 2003, TIMI 3 flow restoration in more than 90 of patients. However, the prognosis of this condition remains poor, to a large degree because of microcirculatory dysfunction that is observed, in near than 20 to 40 of patients, during or following primary percutaneous intervention. The lack of ST-segment elevation resolution after angioplasty with stenting is a marker of microcirculatory dysfunction and is associated with a poor prognosis. Routine administration with primary stenting of the platelet glycoprotein IIbIIIa inhibitor Abciximab in acute myocardial infarction is still a matter of debate with conflicting results emerging from two major clinical studies ADMIRAL and CADILLAC. However, evidences are in favour of a benefit of this treatment especially when administrated early in a pre-hospital manner before percutaneous coronary intervention.Our primary purpose is to investigate the benefit of an early i.e. pre-hospital vs. a conventional i.e. per-angiography administration of Abciximab on ST-segment elevation regression at one hour after primary percutaneous angioplasty. 