A canine model to assess the electrical stability of the transplanted heart

The electrophysiological stability of the transplanted heart under conditions of myocardial ischemia is largely unknown. This problem was studied using a canine model of total cardiac denervation as a substitute for transplantation. Group 1 (N = 3) served as control with placement of ventricular pacing wires only. Group 2 (N = 3) underwent total cardiac denervation with placement of ventricular wires. Group 3 (N = 8) underwent total cardiac denervation with subsequent ligation of the left anterior descending coronary artery and collaterals to the apex. Group 4 (N = 9) underwent coronary artery ligation only. Chronic electrophysiological studies were conducted in all groups in the conscious state. Electrophysiological variables were determined from continuous Holter monitoring of the ECG, determination of strength-interval curves, and assessment of the inducibility of ventricular tachycardia by premature programmed pacing. In general, the denervated, infarcted group (Group 3) consistently demonstrated a greater level of electrical stability than the infarcted animals with normal innervation (Group 4).