MAgnetic resonance imaging based DUal lead cardiac Resynchronization therapy: A prospectIve Left Bundle Branch Pacing study (MADURAI LBBP study)

Abstract

Cardiac resynchronization therapy(CRT) is a class-I indication for LVEF≤35%, and heart failure(HF). LBBB associated nonischemic-cardiomyopathy (LB-NICM) with minimal or no scar by cardiac-magnetic-resonance(CMR) imaging may be associated with excellent prognosis following CRT. Left-bundle-branch-pacing(LBBP) can achieve excellent resynchronization in LBBB patients. Aim of our study was to prospectively assess feasibility and efficacy of LBBP with or without a defibrillator in patients with LB-NICM and LVEF ≤35%, risk stratified by CMR. Pts with LB-NICM, LVEF≤35% and HF were prospectively enrolled from 2019 to 2022. If the scar burden<10% by CMR, LBBP only (Group-I) and if ≥10%, LBBP+ICD(Group-II) was performed. Primary endpoints-1.Echocardiographic-response(ER)- ΔLVEF ≥15% at 6 months; 2.Composite of time to death, HFH or sustained VT/VF. Secondary endpoints-1.Echocardiographic-hyper-response(EHR-LVEF≥50%orΔLVEF ≥20%) at 6 and 12 months; 2.Indication for ICD-upgradation(persistent LVEF<35% at 12 months or sustained VT/VF) RESULTS: 120 patients were enrolled. CMR showed <10% scar-burden in 109 patients(90.8%). 4 patients opted for LBBP+ICD and withdrew. LBBP optimized-dual-chamber-pacemaker(LOT-DDD-P) was done in 101 patients and LOT-CRT-P in 4 patients(Group-I,n=105). Scar-burden ≥10% in 11 pts who underwent LBBP+ICD(Group-II). During mean-follow-up 21±12 months, primary endpoint of ER observed in 80%(68/85 pts) in Group-I vs 27%(3/11 pts) in Group-II(p-0.0001). Primary composite-endpoint of death,HFH or VT/VF occurred in 3.8% in group-I vs 33.3% in Group-II(p<0.0001). Secondary endpoint of EHR(LVEF≥50%) observed in 39.5%vs0%, 61.2%vs9.1% and 80%vs33.3% at 3, 6 and 12 months in group-I and group-II respectively. CMR guided CRT using LOT-DDD-P appears to be a safe and feasible approach in LB-NICM and has the potential to reduce healthcare cost.