Electrophysiologic Assessment of the Successful Left Bundle Branch Pacing Using the Standardized Criteria

Left bundle branch area pacing (LBBAP) is an emerging physiological pacing method that preserves ventricular synchrony. Achieving true LBB capture remains challenging, and the reported success rates vary considerably due to nonuniform definitions. Most previous studies have assessed LBBAP without distinguishing successful left bundle branch pacing (LBBP) from other septal capture patterns. The lack of standardized criteria limits the comparability across studies.

A retrospective cohort study included 407 adult patients undergoing LBBAP implantation between 2019 and 2025. Successful LBBP was defined according to the European Heart Rhythm Association (EHRA) consensus criteria. The success rate of achieving LBBP, electrophysiologic parameters, lead performance over time, and complications were analyzed descriptively, and factors associated with success were analyzed using regression models.

The overall success rate of achieving LBBP was 85.5%. Diagnostic confirmation primarily relied on QRS morphology transition during threshold testing (87.4%) and shortened V6-LVAT (74.1%). V6-V1 interpeak > 44 ms and potential-stim to V6-LVAT equality was observed in 39.9% and 37.1%, respectively. V6-LVAT and QRS duration were significantly shorter in the successful group (p < 0.001). Lead parameters remained stable in the long term, with low complication rates.

The high success rate of achieving LBBP using EHRA criteria highlights the feasibility, safety, and durable performance of LBBAP implantation in routine clinical practice.