Prochymal® (Human Adult Stem Cells) Intravenous Infusion Following Acute Myocardial Infarction (AMI)

Inclusion Criteria: * Male or female between 21 and 85 years old, inclusive * First heart attack within 7 days prior to randomization and drug infusion * Baseline left ventricular ejection fraction (LVEF) 20-45% * Hemodynamically stable within 24 hours prior to randomization * Adequate pulmonary function Exclusion Criteria: * Previous medical history of heart attack, heart failure, significant valvular heart disease, aortic dissection * Pacemaker or other device * Pregnant, breast-feeding, or intends to become pregnant during the study * Allergy to cow or pig derived products * Evidence of active malignancy or prior history of active malignancy * Major surgical procedure or major trauma within the past 14 days * Autoimmune disease (e.g., Lupus, Multiple Sclerosis) * Any medical condition, which in the opinion of the Investigator, renders participation unsuitable * Undergone pharmacologic cardioversion or external defibrillation within 24 hours of randomization. * Experienced cardiac arrest more than 36 hours after presentation to site or within 24 hours of randomization.