Feasibility and safety of left bundle branch area pacing in patients with septal hypertrophy

Left bundle branch area pacing (LBBAP) aims to provide physiological ventricular activation during pacing. Left ventricular septal hypertrophy (LVSH) might be challenging for LBBAP due to the thickness of the interventricular septum and potential presence of septal scar. This study assesses the feasibility, safety, and outcome of LBBAP in patients with LVSH using primarily stylet-driven leads (SDL).

Adult patients with LVSH who underwent LBBAP between March 2019 and November 2022 were enrolled. Baseline patient characteristics, procedural data and postprocedural results were collected. The feasibility of LBBAP in LVSH patients was compared to a cohort of LBBAP patients with normal septal wall thickness (NST).

Seventeen LVSH and 133 NST patients underwent LBBAP with successful implantation achieved in 15 LVSH patients (88%). Mean implant depth was 17.2 ± 1.9 mm, with 53% proven left bundle branch (LBB) capture. Paced QRS duration (146 ± 14 ms) and V6 R-wave peak time (V6 RWPT; 79 ± 20 ms) were comparable between patients with and without septal hypertrophy, although patients with NST had higher rates of proven LBB capture (71% vs. 53%). In LVSH pacing thresholds (0.6 ± 0.3 V at 0.4 ms) and R-wave amplitude (13.9 ± 5.6 mV) were favorable and remained stable at follow-up. At 12 months, 87% of patients had stable or improved left ventricular ejection fraction.

The results of the study indicate that LBBAP in patients with LVSH is safe and feasible and no lead-related complications were observed despite a mean implant depth exceeding 15 mm. LBBAP using SDL results in favorable pacing and electrocardiographic characteristics in LVSH patients, comparable to patients with NST.