Left bundle branch pacing: efficacy and safety compared to right ventricular outflow tract pacing

Abstract

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Patients with preserved left ventricular ejection fraction (LVEF) and atrioventricular block (AVB) who are anticipated for high-burden of right ventricular (RV) pacing possess a risk to develop pacing-induced cardiomyopathy and adverse clinical outcomes. Left bundle branch pacing (LBBP) has recently emerged as a mode of conduction system pacing in the quest for physiological pacing. Purpose The aim of our study was to assess LBBP feasibility and safety compared to right ventricular outflow tract pacing (RVOTP). Methods Single centre randomized clinical trial to investigate acute success, feasibility and safety of LBBP versus RVOTP. May to October 2020. Patients with pacemaker indication and preserved LVEF were randomized 1:1 and followed up 3 months. Success was defined in LBBP group as a paced ECG < 120ms or with a 20% length reduction from the basal ECG. Results 120 patients were randomized, 60 in each group, 61% males. The mean age was 77,9 ± 9 years and third-degree AVB was the main pacing indication. The procedure was successful in 95% of the cases in both groups (p = 1). The paced QRS interval was narrower in the LBBP group compared to the RVOT group (99 ± 2 ms vs 113,6 ± 11,7 ms, p < 0,001). Lower fluoroscopy times were achieved in LBBP group (3.1 ± 2.1 min vs 4.3 ± 3.4, p = 0,035) and also longer procedure times in LBBP group (68,9 ± 36,9 min vs 44,3 ± 18,7 min, p < 0,001). No complications were achieved and no difference in ventricular lead dislocation was found between both groups (1.6% vs 1.6%)(p = 1). Conclusions LBBP is feasible, safe and provides a narrower paced QRS compared to RVOTP. LBBP required lower fluoroscopy times but longer procedure times compared to RVOTP. LBBP (n = 60) RVOTP (n = 60) p Age (mean ± SD) 76,7 ± 9 79,7 ± 8 0,067 Male gender 62 (37) 60 (36) 1 Successful procedure 95 (57) 95 (57) 1 Basal left bundle branch block 15 (9) 13 (8) Basal QRS duration (mean ± SD) 112,6 ± 29,6 109,9 ± 25,8 0,59 Pacing QRS duration (min)(mean ± SD) 99 ± 2 139,6 ± 11,7 < 0,001 Procedure time (min) (mean ± SD) 68,9 ± 36,9 44,3 ± 18,7 < 0,001 Fuoroscopy time (min)(mean ± SD) 3.1 ± 2.1 4.3 ± 3.4 0,035 R wave (mV)(mean ± SD) 9,9 ± 5,7 9,9 ± 5 0,98 Right ventricle pacing threshold (V)(mean ± SD) 0,67 ± 0,3 0,58 ± 0,24 0,08 Ventricular lead dislocation 1.6 (1) 1.6 (1) 1