His Bundle Pacing and Atrioventricular Nodal Ablation in the Management of Refractory Atrial Fibrillation, a Systematic Review and Meta-Analysis

Introduction: Ventricular rate control is critical in management of atrial fibrillation (AF). When pharmacologic therapy fails in controlling the ventricular rate, atrioventricular nodal ablation (AVNA) and pacing is considered an effective therapy for symptomatic management. His bundle pacing (HBP) is considered a physiologic mode of pacing with AVNA ensuring synchronized activation of right and left ventricles preserving ventricular functioning. Hypothesis: HBP and AVNA are feasible, safe, and effective for management of refractory AF. Methods: We identified 218 studies after literature review of EMBASE, Medline, and Cochrane databases. Our analysis was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines. Results: Six studies (two randomized controlled trials, four observational cohorts) were included in the final meta-analyses. A total of 275 patients underwent attempted permanent HBP and AVNA. The mean age of patients was 70.74 (SD 4.38; 95% CI 62.15-79.32). Mean implant success rate for acute HBP was 94.5% (SD 10.12; 95% CI 74.70, 100.00). Selective HBP was noted in 44.7% (95% CI 12.5-76.9), while Non-selective-HBP was noted at rate of 42.2% (95% CI 10.2-74.2). The mean follow-up duration was 21.71 months (SD 3.77; 95% CI 14.32-29.11). All-cause mortality had a pooled proportion of 0.107 (SD 0.110, 95% CI -0.109-0.323); hospitalization proportion was 0.078 (SD 0.072; 95% CI -0.063-0.219). We noted a significant improvement in left ventricular ejection fraction (LVEF) (Baseline [BL] 41.84%, Follow-up [FU] 53.63%, Standardized mean difference [SMD] 0.646, p 0.028), NYHA class (BL 2.77, FU 1.55, SMD -2.542, p <0.001) and LV end diastolic volume (SMD -0.495, 95% CI -0.721, -0.269, p <0.001). We found a significant rise of threshold potential (BL 1.12 V, FU 1.49 V, SMD 0.393, p <0.001 and an increase between baseline and follow up QRS duration (BL 102.21 ms, FU 106.90 ms, SMD 0.646, p 0.028). Conclusion: HBP and AVNA are feasible, safe, effective and has high success rate for management of refractory AF. Further studies are needed to evaluate its role in comparison to left bundle branch area pacing and cardiac resynchronization therapy to evaluate comparative efficacy in refractory AF.