Metabolic Effects of Glucose-Insulin-Potassium in the Ischemic Myocardium

This investigation was designed to explore the metabolic, hemodynamic, and electrocardiographic effects of glucose-insulin-potassium (GIK) solution in a model of segmental myocardial ischemia with significant but incomplete restriction of coronary blood flow. An open-chest anesthetized canine model was utilized including 11 GIK and 6 saline control experiments. The anterior descending coronary artery (LAD) was partially occluded causing an average 71% reduction in its blood flow. Thirty min following occlusion GIK or saline was infused for 30 min at 3 ml/min into a femoral vein. Statistically significant effects of GIK included: increased glucose uptake by the ischemic myocardium, reduced arterial free fatty acid (FFA) concentration, reduced myocardial FFA uptake, decreased coronary arterio-venous oxygen content difference, increased myocardial lactate extraction, decreased myocardial potassium egress, and reduced epicardial ST segment elevation. Heart rate, aortic and left ventricular end-diastolic pressures, and developed force in the ischemic area were unchanged. The results indicate a potentially favorable effect of GIK on the metabolism of the ischemic myocardium which may be due to the shift of substrate utilization from free fatty acids to glucose.