Impact of Left Bundle Branch Area Pacing on Echocardiographic Parameters and Symptoms: Data From the Conduction System Pacing Italian Network Group (C-SING) Study.

INTRODUCTION

Left bundle branch area pacing (LBBAP) has emerged as a physiologic alternative to conventional right ventricular and biventricular pacing, yet large real-world evidence remains limited. We aimed to assess changes in ventricular function and symptoms after LBBAP in patients with different clinical indications.

METHODS AND

RESULTS

Consecutive patients discharged with confirmed LBBAP across 29 Italian centers underwent evaluation of echocardiographic parameters and New York Heart Association (NYHA) functional class at follow-up. A total of 697 patients were included: 532 with a bradycardia indication and 165 with a heart failure (HF) indication, assessed at a median follow-up of 12.4 months. In the bradycardia group, left ventricular ejection fraction (LVEF) showed a slight improvement from 55% (interquartile range, 50-60) to 56% (52-60) (p = 0.027). Paced-induced cardiomyopathy (PICM), defined as a ≥ 10% absolute LVEF reduction to < 50%, occurred in 3% of patients. Loss of LBBAP capture (p = 0.025) and lower LBBAP percentage (p = 0.024) were independent predictors of PICM. In the HF group, LVEF improved from 35% (30-41) to 45% (36-52) (p < 0.001). Overall, 61.8% were classified as responders (LVEF increase ≥ 5%), rising to 73.8% among patients with ≥ 12 months of follow-up. Higher LBBAP pacing percentage and absence of coronary artery disease independently predicted response. NYHA functional class improved significantly in both groups.

CONCLUSIONS

In this large real-world cohort, LBBAP was associated with meaningful improvements in ventricular function and symptoms in both bradycardia and HF populations. A high percentage of effective LBBAP capture is essential for optimizing outcomes, supporting its role as an effective physiologic pacing strategy.