Permanent LEft ventricular septAl Pacing vs. right ventricular pacing in patients with atrioventricular conduction disorders—a randomized trial: rationale and design of the LEAP trial

Permanent cardiac pacing is the only available therapy in patients with atrioventricular (AV) conduction disorders and can be lifesaving. However, conventional right ventricular pacing (RVP) causes dyssynchronous electrical and mechanical activation of the ventricles, possibly resulting in pacing-induced cardiomyopathy and heart failure. Left bundle branch area pacing (LBBAP) might overcome these adverse effects of RVP, but evidence to support this assumption is lacking. The LEAP trial is a multi-centre investigator-initiated, prospective, randomized controlled, open-label, blinded endpoint evaluation (PROBE) study, designed to test the hypothesis that in patients with an indication for pacemaker implantation due to AV conduction disorders with an expected ventricular pacing percentage ≥20%. LBBAP is superior to RVP in preventing the composite primary endpoint of (1) all-cause mortality, (2) hospitalization for heart failure, and (3) a more than 10% point decrease in left ventricular ejection fraction (LVEF) leading to an LVEF below 50%. The LEAP trial randomizes 470 patients 1:1 to the index LBBAP or RVP control arm. The primary endpoint will be determined at 1-year follow-up. This article describes the design and analytic plan for the trial.