A method for localization of the cardiac conduction system during open-heart surgery

INJURY to the invisible subendocardial conduction system during surgical closure of congenital defects in the ventricular septum is an uncommon but extremely grave complication.1 , 2 Impalement of these delicate fibers with a needle or enclosure by a silk suture invariably results in complete, irreversible heart block. Recent anatomic and histologic studies indicate that in the presence of a high defect, the bundle of His arises from a normally placed atrioventricular node and penetrates the membranous septum adjacent to the margin of the defect. From this position, the right bundle branch proceeds downward in an arc along the posteroinferior rim at varying . . .