Incidence and Risk Factors of Complete Atrioventricular Block after Operative Ventricular Septal Defect Repair

Background. Complete atrioventricular block (AVB) is a recognized complication of ventricular septal defect (VSD) repair. The objective of this study was to examine incidence and risk factors. Methods. This is a single-center, retrospective study. All pediatric patients (age <18 years) who underwent VSD repair between November 2001 and August 2009 with concordant atrioventricular and ventriculoarterial connections were included. Patients were classified as having no AVB or transient AVB, and outcomes of early pacemaker placement (before hospital discharge) or late pacemaker placement (after hospital discharge) were recorded. Results. Eight hundred twenty-eight patients (48.6% female) underwent VSD repair during the study period. Mean age at repair was 14 +/- 29.4 months. A total of 64 patients (7.7%) developed surgical AVB. Among those patients who developed AVB, 48 (75%) had transient AVB. Sixteen patients (1.9%) required a pacemaker, 14 early (88%) and 2 late (12%). Patients <4 kg (4.2% vs. 1%, P <= .01) and those with inlet VSDs (11.6% vs. 1.4%, P <= .01) were more likely to develop surgical AVB. Surgical AVB was not influenced by the presence of chromosomal abnormalities or other congenital heart disease. Conclusion. The overall incidence of surgical AVB is consistent with previous reports. Weight <4 kg and presence of an inlet VSD were significant risk factors.