Risk factors for atrioventricular block after occlusion for perimembranous ventricular septal defect

Background: The risk factors for complete atrioventricular block (CAVB) after device closure of perimembranous ventricular septal defect (pmVSD) remain unclear.

Objective: The purpose of this study was to analyze the incidence and risk factors for CAVB after device closure for pmVSD.

Methods: We reviewed 1884 patients with pmVSD who had undergone successful device occlusion between June 2005 and January 2020. Permanent CAVB was defined as CAVB requiring implantation of a permanent pacemaker (PPM) or extraction of the occluder.

Results: In total, 14 patients (0.7%) developed permanent CAVB. Of these patients, 10 (0.5%) required PPM implantation. Four permanent CAVB occurred within 7 days after the procedure (acute), 2 between 7 and 30 days (subacute), 3 between 30 days and 1 year (late), and 5 more than 1 year (very late). None of the subacute, late, and very late CAVB recovered normal conduction with medication and eventually required device removal or PPM implantation. Four patients with acute CAVB and 1 with subacute CAVB underwent device removal, and 4 (80%) recovered normal conduction. Multivariate regression revealed that the ratio of device to defect size was the only independent risk factor for permanent CAVB (odds ratio 3.027; 95% confidence interval 1.476-6.209; P = .003).

Conclusion: The incidences of permanent CAVB after occlusion for pmVSD and PPM implantation were 0.7% and 0.5%, respectively. The ratio of device to defect size was the only independent risk factor for permanent CAVB. Device removal is an effective therapeutic modality for recovering normal conduction in acute and subacute CAVB patients.