Is right bundle branch block aviodable in surgical correction of tetralogy of Fallot?

Right bundle branch block (RBBB) is usually considered almost unaviodable after repair of teralogy of Fallot (TOF). By modifications of the standard technique, its frequency has been decreased to 32% in a series of 1000 consecutive patients. These modifications are: (1) a very short right ventricular incision avoiding the ventriculotomy-induced RBBB pattern; (2) an infundibular resection limited to the septal attachment of the infundibular septum; and (3) closure of the ventricular septal defect with a patch sutured to the very edge of the muscular septum, avoiding injury to the right bundle along the right aspect of the septum. No patient in this series sustained permanent complete atrioventricular heart block. Among patients with RBBB, five had a left anterior hemiblock. Postoperative intraventricular conduction was related to age at operation: The incidence of RBBB was significatively higher in infants. The beneficial effects of a low incidence of postoperative RBBB after repair of TOF are not known.