Late Outcomes of Postoperative Complete Heart Block After Congenital Heart Surgery: Recovery or Recurrent Heart Block?

BACKGROUND: Postoperative complete heart block (CHB) constitutes a complication of congenital heart surgery, requiring a permanent pacemaker (PPM). This study aimed to determine the incidence of postdischarge recovery from CHB after PPM implantation and the incidence of recurrent CHB after initial recovery. METHODS: The cumulative incidences of recovery from CHB and postdischarge recurrent CHB after 9892 congenital cardiac operations between 2001 and 2024 were analyzed. A Cox regression model was used to identify predictors of recovery from CHB and recurrent CHB. RESULTS: Of 327 patients with CHB, 193 (59.0%) required a PPM within the same hospital stay, and 134 (41.0%) were discharged without a PPM because of complete recovery. Postdischarge recovery of atrioventricular conduction was observed in 32 of 193 (16.6%) patients with a PPM (median period of 3.8 [0.3-6.3] years). The type of recovery included 22 sinus rhythms, 8 first-degree, and 2 second-degree atrioventricular blocks. Postdischarge recurrent CHB requiring PPM was observed in 11 of 134 (8.2%) patients with a median period of 0.6 (0.2-4.7) years. The cumulative incidence of recovery and late PPM implantation at 10 years was 24.2% and 9.5%, respectively. Neonatal operation (hazard ratio [HR], 4.491; P = .018), longer recovery time with an 8-day threshold (HR, 1.107; P = .022), and catheter intervention (HR, 4.587; P = .025) were risk factors for postdischarge recurrent CHB. CONCLUSIONS: Our findings support the current class 1 guidelines for pacemaker implantation after 7 days of CHB. Postdischarge recurrent CHB is difficult to predict in individual patients and can be manifested many years postoperatively, supporting lifelong follow-up after congenital heart surgery.