A recent trial shows benefits: "treating heart attack patients with an infusion of their own heart-derived cells helps damaged hearts re-grow healthy muscle. Patients who underwent the stem cell procedure demonstrated a significant reduction in the size of the scar left on the heart muscle by a heart attack. Patients also experienced a sizable increase in healthy heart muscle following the experimental stem cell treatments. One year after receiving the stem cell treatment, scar size was reduced from 24 percent to 12 percent of the heart in patients treated with cells (an average drop of about 50 percent). Patients in the control group, who did not receive stem cells, did not experience a reduction in their heart attack scars. ... While the primary goal of our study was to verify safety, we also looked for evidence that the treatment might dissolve scar and regrow lost heart muscle. This has never been accomplished before, despite a decade of cell therapy trials for patients with heart attacks. Now we have done it. The effects are substantial, and surprisingly larger in humans than they were in animal tests. ... In the past, all we could do was to try to minimize heart damage by promptly opening up an occluded artery. Now, this study shows there is a regenerative therapy that may actually reverse the damage caused by a heart attack."