Original Article

The Effect of Substrate Enhanced Cardioplegia on Postbypass Electrical and Hemodynamic Recovery

University of Michigan Medical Center, Department of Thoracic Surgery, Ann Arbor, Michigan, and Medical University of South Carolina, Department of Extracorporeal Technology, Charleston, SC

^* Address correspondence to: Alfred H. Stammers, BS, CCP Medical University of South Carolina, Department of Extracorporeal Technology, 171 Ashley Avenue, Charleston, sc 29425-2701.

Abstract

Substrate enhanced terminal cardioplegia increases metabolic activity which may enhance recovery in the post cardiotomy patient. Twenty-eight consecutive low risk patients requiring coronary artery bypass grafting were randomly assigned to receive either a dose of warm aspartate glutamate enriched terminal cardioplegia or reperfusion with unmodified pump blood. There were no significant differences between patient groups in prebypass parameters. Bypass indices did not vary between groups other than total cardioplegia volume administered (2364±578 cc mean±SD in the non-aspartate glutamate group, vs 2828±579 cc in the aspartate glutamate group, p<.05). Patients in the aspartate glutamate group received less defibrillatory shocks with lower total Joule wattage, and were paced less than the non-aspartate glutamate hearts. There were no significant differences in the use of inotropes or antiarrhythmics, nor did cardiac index or systemic vascular resistance differ between groups over the first several postoperative days. Therefore, in low risk patients undergoing coronary artery bypass grafting, the routine use of substrate enriched terminal cardioplegia resulted in a more rapid return to electrical activity, but failed to improve immediate postoperative hemodynamic recovery.