Left atrial isolation. New technique for the treatment of supraventricular arrhythmias

Surgical management of refractory ectopic supraventricular tachycardia arising in the left atrium requires cryoablation of the bundle of His and insertion of a permanent ventricular pacemaker. This study was designed to develop a technique to isolate the left atrium electrically from the remainder of the heart, so that an artificial pacemaking system would be unnecessary. Ten adult dogs were subjected to cardiopulmonary bypass and a standard left atriotomy was extended anteriorly across the mitral valve anulus between the right and left fibrous trigones. Posteriorly, the atriotomy was extended across the mitral valve annulus just to the left of the posterior crux and interatrial septum. The muscular interatrial fibers accompanying the coronary sinus were cryoblated at -60°C for 2 minutes. Postoperatively, all animals remained in normal sinus rhythm. Rapid left atrial pacing did not affect the rate or rhythm of the remainder of the heart. Preliminary hemodynamic measurements suggest that loss of the synchronous left atrial 'kick' does not significantly affect left ventricular preload, afterload, or cardiac output. This technique offers an alternative to the current surgical approach for management of refractory ectopic supraventricular tachycardia arising in the left atrium.