Long-chain free fatty acids and glucose account for the vast majority of ATP production in the heart. An alteration of fatty acid oxidation is considered to be a sensitive marker of ischemia and myocardial damage. Recently, several radiolabeled fatty acid analogs have been introduced to assess myocardial cellular function. The use of such analogs has enabled the analysis of cardiac metabolism and led to the identification of prior ischemic events, termed 'ischemic memory'. Such advances will find use in the clinical setting for the diagnosis and treatment of subclinical or progressive cardiovascular disorders, as in acute coronary syndrome, that often remain elusive with traditional imaging approaches.