Left bundle branch area pacing: baseline characteristics and echocardiographic response: trends in patients with atrial fibrillation
A Phelan, R M Evans, A Duncan, R Bourke, B Gaffney, R Sheahan, Z I SharifAbstract
Introduction
Left bundle branch area pacing (LBBAp) is a physiologic pacing technique that directly stimulates the left bundle branch or its fascicles which aims to restore ventricular synchrony. The method was developed due to limitations recognised in traditional right ventricular pacing, the technical challenges with His-bundle pacing, and non-responders to Biventricular Pacing (CRT)(1). Criteria identifying super responders to LBBAp has not been fully delineated. Patients with both atrial fibrillation & heart failure have poor outcomes(2). The role of LBBAp and persistent atrial fibrillation remains underexplored.
Purpose
To review patient characteristics, implant measures and effects on echocardiographic (Echo) parameters in our cohort who had an early response or super-response to LBBAp in order to optimize patient selection in the future and also access the response in patients with persistent atrial fibrillation.
Methods
We reviewed data of patients who underwent LBBAp in 2 centres between 2022 and 2025. Baseline demographics, comorbidities and echo parameters and intra-procedural measurements prior to implantation were recorded. Left ventricular ejection fraction (LVEF) was reassessed at least 3 months post implantation. Echo response was defined as non-responders (LVEF improvement <0%), non-progressors (0-5%), responders (6-15%) and super-responders (>15%).
Results
A total of 102 patients were included. Baseline characteristics are available in table 1. Baseline Echo parameters included mean LVEF 42%, LVIDD of 5.51cm and LVEDV of 151.9ml. 59% of patients had atrial fibrillation. The most common indication was atrioventricular block (34%) and left ventricular dysfunction (26.5%). 30 patients with implant indication for resynchronisation had follow-up Echo at the time of review (median time to follow up Echo was 154 days). 20% were non-responders, 20% were non-progressors, 23% were responders, 37% were super-responders. Patients with atrial fibrillation trended towards improved response compared with those without (p=0.092). The outcomes were equivocal across gender and age groups. Lower LVAT, higher V1/V6 interval and the presence of fixation beats and R prime during implantation did not result in improved outcomes. One patient required lead revision seven days post procedure. No other procedure related complications were observed.
Conclusion
In our cohort of patients, LBBAp was demonstrated to be feasible with a high success rate and low rates of complications. Patients receiving LBBAp for resynchronisation in the setting of heart failure had excellent response rates. Patients with preexisting atrial fibrillation had an improved Echo response. Interestingly, intraprocedural parameters did not seem to influence or predict response, although this must be interpreted in the setting of low overall numbers. Further studies to identify optimal patient profiles for LBBAp selection and in those with atrial fibrillation is required.Table 1For image description, please refer to the figure legend and surrounding text.