Late recovery of atrioventricular conduction after pacemaker implantation for complete heart block associated with surgery for congenital heart disease.

OBJECTIVES: Pacemaker implantation is a standard recommendation for patients with persistent complete heart block following surgery for congenital heart disease. This study was performed to determine the incidence and clinical significance of late recovery of atrioventricular conduction following pacemaker implantation.
METHODS: Between 1990 and 2001, 5662 open cardiac procedures for congenital heart defects were performed at our institution. The postoperative course of all patients with complete heart block in whom a permanent pacemaker was implanted was followed on a monthly basis, by either clinical or transtelephonic follow-up.
RESULTS: A total of 72 patients with persistent postoperative complete heart block underwent pacemaker implantation. After insertion of the pacemaker, recovery of atrioventricular conduction was recognized in 7 of 72 patients (9.6%) at a median of 41 days (18-113 days) after the initial cardiac operation. These included 3 patients with ventricular septal defect, 2 with ventricular inversion or single ventricle, and 1 each with left ventricular outflow tract obstruction and atrioventricular septal defect. During a mean follow-up of 4.4 +/- 2.6 years, there was no late recurrence of heart block. Three patients had residual right bundle branch block and 1 had first-degree atrioventricular block.
CONCLUSIONS: Atrioventricular conduction may return in a small but significant percentage of patients following pacemaker implantation for complete heart block associated with congenital heart surgery. When recovery of atrioventricular conduction occurs within the first months after surgery it appears reliable, which suggests that lifelong cardiac pacing may not be necessary in these individuals.