Intraprocedural Transthoracic EChocardiography To Facilitate Left Bundle Branch Pacing: EC-LBBP

Background: Left bundle branch (LBB) pacing (P) has gained rapid adoption. Evidence for direct LBB capture has varied from 30-95% depending on the criteria.

Objective: The aim of the study was to assess the feasibility and efficacy of intraprocedural transthoracic echo guidance to achieve LBB capture.

Methods: This was a prospective, nonrandomized, case-control study (NCT05646251). The pectoral region including echocardiographic windows were sterile-draped using Ioban^R. The lead was placed in the RV septum and sheath orientation adjusted under echo. The lead was advanced under echo visualization until the tip reaches the LV subendocardium. LBB capture was strictly defined: Transition from nonselective to selective/LV septal capture; LBB potential with injury current; Delta (HBP-LBBP) V6RWPT of ≥10.

Results: Thirty patients underwent Echocardiography guided (EC)-LBBP and compared with 30 patients (standard approach). Mean age 74.4±10; female 45%; hypertension 92%; cardiomyopathy 43%; AV block/AV node ablation 75%. Total procedural and fluoroscopy duration were similar. Left bundle branch area pacing (LBBP or LV septal pacing) was successful in all patients in both groups. EC-LBBP was 97% successful in achieving LBB capture (vs 70%, P=0.02) with LBB potentials (LB-V 23±6ms) in 95% (vs 77%, 22±6ms). Morphology transition confirming LBB capture was seen in 87% vs 67% (P=0.02). Lead-tip was visualized at LV subendocardium in 100% of patients in EC-LBBP.

Conclusions: EC-LBBP was 97% successful in achieving LBB capture using strict criteria. LBBP lead was subendocardial in all patients. EC-LBBP is practical, feasible, safe and highly effective in achieving LBB capture.