Feasibility and clinical outcomes of left bundle branch area pacing as an alternative to right ventricular conventional pacing in patients with permanent atrial fibrillation
T Pereira Dos Santos, A L Silva, D Martinez, M J Primo, R Ventura, I Cruz, M Simoes, A L Rocha, D Fernandes, C Saleiro, P Alves, P Sousa, J A Ferreira, N Antonio, L GoncalvesAbstract
Introduction
Left bundle branch area pacing (LBBAP) is an emerging physiological pacing strategy associated with better clinical outcomes than conventional right ventricular (RV) pacing. Evidence in patients with permanent atrial fibrillation (AF), however, remains limited.
Purpose
To compare outcomes between LBBAP and conventional RV pacing in patients with permanent AF.
Methods
This single-center retrospective study included patients who underwent LBBAP between September 2022 and June 2024. Baseline pacing indication, procedural characteristics, and LVEF were collected. The primary endpoint was a composite of emergency visits for acute heart failure (HF) and HF hospitalization. Median follow-up was 873 days (IQR 355.5).
Results
The analysis included 165 patients with permanent atrial fibrillation who underwent permanent pacemaker implantation, of whom 72.1% were male, with a mean age of 81.9 ± 0.56 years. Among these patients, 46 (27.9%) received left bundle branch area pacing (LBBAP) and 119 (72.1%) received right ventricular pacing (RV). There were no significant differences in baseline cardiovascular risk factors between the two groups. The pacing indication was complete heart block in 58 patients (35.2%) and bradycardia in 106 patients (64.2%), with one patient (0.6%) presenting with alternating bundle branch block. Median left ventricular ejection fraction (LVEF) for the entire cohort was 57% (IQR = 11.5). The LBBAP group had a slightly lower baseline LVEF, with a median of 55% (IQR = 10), which was statistically significant (p = 0.044). Procedure duration was similar between groups (p>0.05) with a mean of 57.59±2,54 min. The mean intrinsic QRS duration for the entire cohort was 129.3 ± 2.37ms. Among paced complexes, LBBAP produced a narrower QRS (122.0 ± 3.0ms) compared with RV pacing (159.9 ± 2.39ms, p < 0.001). Capture thresholds (0.53 V) and sensed R-wave amplitudes (12.86 mV) were similar between groups. Median ventricular pacing during follow-up was 79.5%, with no difference by pacing modality (p = 0.372). In Cox regression adjusted for confounders, RV pacing was associated with a 4.02-fold higher risk of heart failure events versus LBBAP (HR 4.02, 95% CI 1.1–14.5, p = 0.033).
Conclusion
In patients with permanent atrial fibrillation, LBBAP was feasible, achieved pacing parameters comparable to RV pacing, and produced narrower paced QRS complexes. LBBAP was associated with fewer adverse clinical outcomes, while RV pacing conveyed a 4-fold higher risk of heart failure events. These results support LBBAP as a more physiological and clinically favorable pacing strategy in this population.