Comparing Left Bundle Branch Area vs Right-Ventricular Septal Pacing in High-Degree Conduction Disease After Transcatheter Aortic Valve Replacement: Randomized Trial Study Protocol.

Left bundle branch area pacing (LBBAP) is a novel method of conduction-system pacing in the muscular interventricular septum. Although LBBAP has been shown to produce physiologic electrical and mechanical intraventricular synchrony, superiority of LBBAP, compared to right ventricular septal pacing (RVSP) at preserving normal left-ventricular (LV) systolic function after transcatheter aortic valve replacement (TAVR) has not been demonstrated. Left Bundle BRAVE is an investigator-initiated, multicentre, prospective, double-blinded, randomized, crossover study investigating the superiority of LBBAP, compared to RVSP, with respect to preservation of systolic function in patients with high-degree conduction disease after TAVR. Adults with severe aortic stenosis and normal systolic function who sustain high-grade atrioventricular block within 4 weeks of TAVR are eligible. All subjects receive a biventricular pacemaker generator with RVSP, and LBBAP leads. Participants are randomly assigned to 9 months of each pacing mode, in series. The primary endpoint is change in global longitudinal strain, tested in series with change in LV ejection fraction, comparing RVSP to LBBAP. Secondary endpoints include the following: echocardiographic markers of interventricular synchrony and right ventricular performance; heart failure functional status and symptom classification; 6-minute walk test results; pacemaker and lead performance; and brain natriuretic peptide concentration. The Left Bundle BRAVE study is designed to identify an upstream and clinically relevant marker of superiority in LBBAP, compared to RVSP, at preventing deterioration of LV function in patients with a high ventricular pacing burden after TAVR. ClinicalTrialsgov identifier: NCT05541679.