Comparison of Left Bundle Branch and His Bundle Pacing in Bradycardia Patients

Objective: The aim of this study was to assess pacing and electrophysiological parameters, as well as short-term outcomes, among patients undergoing left bundle branch pacing (LBBP) or His bundle pacing (HBP).

Background: There are limited data directly comparing different conduction system pacing modalities.

Methods: Consecutive patients undergoing de novo conduction system pacing for bradycardia indications were evaluated. Procedural and fluoroscopic times and pacing characteristics were compared between groups at implantation and at 3-month follow-up.

Results: This study included 251 subjects. HBP was successful in 109 (87.2%) of 125 patients, compared with 115 (91.3%) of 126 for LBBP. The mean procedure time (78 ± 36 min vs. 54 ± 24 min, p < 0.001) and fluoroscopy duration (12 ± 5 min vs. 5 ± 2.8 min, p < 0.001) were significantly longer for HBP compared with LBBP. The paced QRS duration (113.7 ± 24.4 ms vs. 114.1 ± 11.2 ms) were similar between groups (p = 0.87). Capture threshold was significantly lower (1.3 ± 0.6 V/1.0 ms vs. 0.6 ± 0.2 V/0.4 ms, p < 0.001), whereas R-wave amplitude was significantly higher (2.8 ± 3.0 mV vs. 12.5 ± 9.0 mV, p < 0.001) with LBBP compared with HBP at implantation. During follow-up, a capture threshold >3.0 V occurred in 8 HBP patients versus 0 LBBP patients (p = 0.003).

Conclusions: LBBP has similar paced QRS durations and success rates, but shorter procedure and fluoroscopy durations, as well as better pacing parameters compared with HBP. Further prospective study is needed to compare long-term outcomes, safety, and pacing stability with these 2 conduction system pacing modalities.