Implantation of bone-marrow stem cells in the heart might be a new method to restore tissue viability after myocardial infarction. We injected up to 1.5x10(6) autologous AC133+ bone-marrow cells into the infarct border zone in six patients who had had a myocardial infarction and undergone coronary artery bypass grafting. 3-9 months after surgery, all patients were alive and well, global left-ventricular function was enhanced in four patients, and infarct tissue perfusion had improved strikingly in five patients. We believe that implantation of AC133+ stem cells to the heart is safe and might induce angiogenesis, thus improving perfusion of the infarcted myocardium. See Commentary page 11