Myocardial infarction will be assessed with Contrast enhanced cardiac magnetic resonance at 2 days and at 2 months. Microvascular obstruction (MO) may be assessed by first- pass perfusion (FPP) and delayed hyper enhancement (DHE) MO is defined as regional hypoperfusion on first-pass perfusion as previously described . The investigators have recently demonstrated that MO as verified by CMR following MI may allow early identification of patients with a high risk of LV remodeling likely to benefit from pharmacological therapy .