Atrioventricular Block During Catheter Ablation for Ventricular Arrhythmias

OBJECTIVES This study sought to evaluate the incidence and significance of atrioventricular (AV) block associated with ventricular arrhythmia (VA) ablation. BACKGROUND Attempted ablation of VAs that arise from the septum carries a risk of AV block. METHODS Data from 1,418 patients who had catheter ablation for drug-refractory VAs were evaluated. Two analyses were conducted. The first analysis assessed the patient and procedure characteristics associated with ablation-induced AV block. The second analysis investigated outcome differences between patients with and without AV block. For the second analysis, patients with AV block (Group I) were compared with a 1:2 propensity score-matched control group (Group II) and with patients with pre-existing AV block before ablation (Group III). RESULTS Twenty-one (1.6%) patients developed AV block. In multivariable analysis, nonischemic cardiomyopathy (odds ratio: 3.33; 95% confidence interval: 1.32 to 8.40; p = 0.011) and transcoronary ethanol ablation (odds ratio: 46.50; 95% confidence interval: 14.10 to 153.00; p < 0.001) were independently associated with AV block. Subsequent to the AV block, 9 patients were upgraded from an implantable cardioverter-defibrillator to cardiac resynchronization therapy with defibrillator (CRT-D), 2 had de novo CRT-D implantation, 5 had pre-existing CRT-D, and 5 had pacing without CRT. VAs recurred in 33% of patients in Group I, 17% in Group II (log-rank p = 0.842), and 35% in Group III (p = 0.636). The composite outcome of heart failure hospitalization, heart transplantation, or death occurred in 29% of patients in Group I, 17% in Group II (p = 0.723), and 45% in Group III (p = 0.303). CONCLUSIONS Complete AV block occurs in fewer than 2% of patients undergoing VA ablation and does not appear to be associated with the worse outcome of heart failure hospitalization, heart transplantation, or death. (C) 2019 by the American College of Cardiology Foundation.