Transthoracic echocardiography will be performed at 2-5 days post-MI and 28 days after MI in standard apical and parasternal views using a commercial ultrasound system either Phillips 7500 or IE33 ultrasound imaging system with an S3 transducer. The transducer will be placed on the apical and/or parasternal location on the chest and ECG-gated images will be obtained during a breath hold. Each acquisition will be performed in zoom mode at 40 Hz, over the entire LV in 4 cardiac cycles with 40 frames per cardiac cycle. Image data will be captured in digital form and will be backed up on DVDs. NOTE: No patient HIPPA data will be saved on the DVD. Left ventricular ejection fraction (LVEF), end-diastolic volume (LVEDV), and end-systolic volume (LVESV) will be measured. The echocardiograms will be used to determine LV mass, LV cavity size and regional thickening. Patients will undergo MRI with gadolinium contrast in the GE Signa 1.5 tesla magnetic resonance image scanner located in the Yale-New Haven Hospital MRI Center, using standard ECG-gated cine gradient echo, and echo-planar, phase contrast and MR tagged imaging sequences.