Response of hypertrophic heart myocardial glycogen to GIK and hypovolemic shock

Glucose-insulin-potassium (GIK) given during myocardial ischemia or anoxemia results in improved myocardial function and augments energy reserves of myocardial glycogen (MG). Because many patients with heart disease also have myocardial hypertrophy, our purpose was to examine whether similar elevations in MG can occur in hypertrophic hearts with GIK administration and to study the effect of hypovolemic shock on those MG levels. Mongrel dogs (n = 5) with myocardial hypertrophy underwent serial myocardial biopsies of the left (LV) and right (RV) ventricles, and blood samples were followed by GIK infusion (14.5 ml/kg/hr) for 2 hr. after which the dogs were subjected to 2 hr of hypovolemic shock (mean arterial pressure = 40 mmHg). It was found that after GIK infusion MG was consistently elevated in both RV (.43 +/- .02 to .60 +/- .04 g%) and LV (.63 +/- .07 to .71 +/- .01 g%) and FFA declined (.20 +/- .05 to .05-.01 mEq/liter). The MG responded to hypovolemia by further significant elevations (RV 1.16 +/- .33; LV .82 +/- .17), as did FFA (.38 +/- .21). These results indicate that hypertrophic hearts can indeed respond to GIK infusion by increasing MG in both the RV and LV, as do normal hearts. These hearts then submitted to hypovolemic shock showed a further elevation of MG. The elevated insulin levels post-GIK resulted in suppression of FFA. Thus GIK administration may have a sparing effect on energy stores of the heart during hypovolemic shock, which could have clinical implications in the treatment of patients with hypertrophic myocardia.