Echocardiographic outcomes across different capture types in left bundle branch area pacing: a real-world cohort analysis
D Martinez, M Primo, I Cruz, J Ferreira, E Jorge, L GoncalvesAbstract
Background/Introduction
Left bundle branch area pacing (LBBAP) is increasingly used as a physiological pacing strategy, yet the impact of different capture phenotypes on ventricular function and clinical outcomes remains insufficiently defined. Prospective evidence characterizing echocardiographic response and event-free survival across capture types is still limited.
Purpose
To prospectively evaluate echocardiographic and clinical outcomes after LBBAP and to identify electrical and procedural predictors of left ventricular functional improvement.
Methods
A total of 655 patients receiving LBBAP were prospectively analysed. Echocardiography at baseline and follow-up assessed LVEF (Left ventricular ejection fraction) and post-implant LVEF, allowing calculation of ΔLVEF. Capture was classified as confirmed, probable, left septal, or deep septal, and paced QRS morphology as anterior, septal, or posterior. Paired t-tests compared LVEF pre and post-implantation; χ² tests analysed categorical distributions. Logistic regression assessed predictors of echocardiographic response (ΔLVEF > 10%). Kaplan–Meier curves with log-rank tests evaluated time-to-event outcomes (all-cause death, HF hospitalization, composite endpoint). Cox proportional hazards models adjusted for age, sex and baseline LVEF identified independent predictors of adverse outcomes. ROC analysis quantified the discriminative performance of capture confirmation and paced QRS morphology.
Results
Median age was 75 years (IQR 69–82), 67.5% were male, and mean procedure duration was 74.7 ± 24.5 minutes. Baseline LVEF was 50.2 ± 12.7%, increasing to 52.7 ± 11.6% (paired t-test p < 0.001), with a mean ΔLVEF of +4.7 ± 8.9; responders (>10 pp) represented 4.1% and LVEF loss occurred in 5.3%. Capture was confirmed in 75.8%, probable in 12.3%, left septal in 6.8% and deep septal in 5.1%. Paced QRS morphology was septal in 48.1%, posterior in 29.5% and anterior in 22.4%. Clinical events were infrequent: mortality 6.6%, HF hospitalization 1.7% and composite endpoint 8.4%. ΔLVEF correlated significantly with confirmed/probable capture (ANOVA p < 0.05) (Figure 1). ROC analysis showed moderate discrimination for response: AUC 0.74 for capture, 0.69 for QRS morphology and 0.66 for bundle potential (Figure 2). In Cox models, age independently predicted composite events (HR 1.07 per year, p = 0.04), while capture category was not significant after adjustment.
Conclusions
LBBAP resulted in modest but consistent improvement in systolic function, with the greatest benefit in confirmed or probable capture. Event rates were low, and electrical parameters, particularly capture confirmation and paced QRS morphology, demonstrated relevant ability to discriminate echocardiographic responders. These findings support LBBAP as a dependable physiological pacing strategy and underscore the importance of refined electrical characterization during implantation.Delta LVEF by type of CaptureROC curves of Capture and QRS morfology