Metabolic intervention for the ischemic and post-ischemic heart.

There is increasing evidence that the availability of different metabolic substrates can influence post-ischemic functional recovery of the heart and the damage incurred during episodes of myocardial ischemia. Here we present the rationale for metabolic interventions, describe their mechanisms of action and suggest potential clinical applications. In cardiac surgery, basic research, studies of human myocardial metabolism after cardiac operations, and available experience with metabolic interventions provide a rationale for metabolic support with glutamate and/or high-dose glucose-insulin-potassium (GIK) in postoperative cardiac failure. In the treatment of acute myocardial infarction GIK deserves serious evaluation as recent randomized studies in diabetics with myocardial infarction and in patients undergoing reperfusion strategies demonstrate significant reductions in mortality. However, before large scale prospective randomized studies are undertaken, further studies of myocardial metabolism in acute myocardial infarction and the impact of different GIK regimes may be advisable in order to determine appropriate doses. A brief overview of metabolic modulation with pharmacological measures is given as it eventually may prove that we have to await the introduction of pharmacological agents which enhance full glucose oxidation at the expense of free fatty acids to create the commercial interest necessary to achieve widespread use of metabolic therapies.