The PreSERVE-AMI Study is a phase II study sponsored by Amorcyte, LLC. The research is focused on patients who have received a stent to open the blocked artery after a specific heart attack called an ST-Segment Elevation Myocardial Infarction, or STEMI. A STEMI a critical type of heart attack caused by a prolonged period of blocked blood supply, affecting a large area of the heart muscle. The study evaluates the effectiveness and safety of infusing stem cells collected from a patient's bone marrow into the artery in the heart that may have caused the heart attack. Because stem cells are immature cells they have the potential to develop into new blood vessels and preserve cardiac muscle cells. By infusing certain stem cells into the area of the heart muscle that has been damaged from a heart attack, tissue can be preserved and heart function restored.