Cardiac PET studies may have a role in the early detection of coronary artery disease. The early prediction of the ultimate fate of reperfused myocardium with cardiac PET imaging remains elusive. At present the predominant clinical use of PET scans lies in the identification of ischemic but viable tissue. Cardiac PET imaging with a combination of perfusion and metabolic tracers can distinguish those patients with a history of previous infarctions and severe heart failure who will benefit from therapeutic revascularization. Conversely, the group that is not expected to improve will be spared needless and risky attempts at revascularization and will become candidates for cardiac transplantation at an earlier stage.