Left bundle branch area pacing versus biventricular pacing for cardiac resynchronisation therapy

Abstract Funding Acknowledgements Type of funding sources: None. Background Conventional right ventricular pacing induces dyssynchrony and 20% of patients may need upgrade for resynchronisation therapy (CRT). Currently, left bundle branch area pacing (LBBAP) is growing as an alternative for conventional pacing, preserving left ventricular function. Purpose We aimed to describe procedural characteristics of a group of consecutive patients submitted to LBBAP, and to compare the final QRS duration to a group of consecutive idiopathic LBB patients submitted to conventional CRT. Methods Single-centre cohort including consecutive patients submitted to LBBAP or CRT since November 2021. Feasibility, procedure and fluoroscopy times, final QRS duration during pacing immediately after implantation, and periprocedural complications were assessed. Successful implantation of LBBA pacing was defined as a left ventricular activation time (LVAT) < 90ms plus right bundle branch block pattern in V1. Results A total of 91 patients (mean age 75±11 years, 70.3% male, and 43 [47.3%] with LBBAP) were included. Total procedure (63min [50-76] vs. 91min [71-131], p<0.001) and fluoroscopy times (4.1min [2.4-6.4] vs. 13.4min [8.3-23.1], p<0.001) were significantly lower in the LBBAP vs. CRT group, respectively. In the LBBA pacing group, median LVAT was 86ms (IQR 81-94) and no cases of electrode dislocation or perforation at discharge were reported. Final QRS duration was 112ms (IQR 105-125) vs 127ms (IQR 115-143) in the LBBAP vs CRT groups respectively (p<0.001). Conclusion When compared to a group of idiopathic LBB block patients submitted to CRT, LBBAP was faster, required less fluoroscopy time and was associated with final narrower QRS. Further studies are necessary to understand its role in patients with LV dysfunction and indication for resynchronisation therapy.