Coronary artery surgery with induced temporary asystole and intermittent ventricular pacing: an experimental study

Coronary artery bypass grafting performed without cardiopulmonary bypass presents a difficulty in performing coronary anastomoses on a beating heart. A non-cardiopulmonary bypass technique in sheep by which individual sutures can be placed on a still heart is described. Epicardial pacing wires were placed and a curved needle passed between the aorta and pulmonary artery into the muscular interventricular septum and directed caudally and to the right. The tip of the needle now lay in the vicinity of the outflow of the bundle of His. No cardiac chamber or vital structures were traversed. Injection of lignocaine here resulted in immediate ventricular asystole. Ventricular pacing restored cardiac output. After establishing local control of the vessel coronary anastomosis was performed stopping ventricular pacing for the few seconds required to place a single suture and reinstating it between the passage of sutures. Reversion to sinus rhythm occurred spontaneously.