Left Bundle-Branch Area Pacing vs Right Ventricular Pacing for Atrioventricular Block and Preserved Left Ventricular Function

Importance: For patients with atrioventricular block requiring high-burden ventricular pacing, the optimal pacing strategy to reduce heart failure (HF) and all-cause mortality remains uncertain. Robust comparative evidence on the clinical outcomes of left bundle-branch area pacing (LBBAP) vs right ventricular pacing (RVP) in this population is needed. Objective: To compare 24-month clinical outcomes of LBBAP vs RVP in patients with atrioventricular block and preserved left ventricular ejection fraction (LVEF; ≥50%). Design, Setting, and Participants: The LEAP-Block study was a prospective, multicenter, randomized, controlled, superiority trial conducted across 14 Chinese hospitals from January 2021 to August 2025, with last follow-up on June 3, 2025. Of 551 patients with LVEF 50% or greater requiring ventricular pacing who underwent eligibility assessment, 499 with anticipated ventricular pacing greater than 40% were randomized. Interventions: Patients were randomized in a 1:1 ratio to LBBAP (n = 249) or RVP (n = 250). Main Outcomes and Measures: The primary end point was a composite of all-cause death, HF events, or upgrade to biventricular pacing at 24 months. Secondary end points included pacing-induced cardiomyopathy and device-related complications. Results: The primary analysis included 482 patients (LBBAP, n = 242; RVP, n = 240; mean age, 67 years; 46% female). Acute procedure success was comparable between the 2 groups (LBBAP, 237/242 [97.9%] vs RVP, 239/240 [99.6%]; P = .22), with left bundle-branch capture confirmed in 188 of 236 patients (79.7%). LBBAP significantly reduced the primary end point vs RVP (2.4% vs 12.5%, respectively; absolute risk difference, -10.1% [95% CI, -16.8% to -3.4%]; P = .003). Among secondary outcomes, the LBBAP group had fewer HF events (3.4% vs 11.3%; -7.9% [95% CI, -13.0% to -2.8%]). No significant differences were observed in all-cause death, biventricular pacing upgrade, device-related complications, or pacing-induced cardiomyopathy. The 24-month Kaplan-Meier estimated cumulative incidence of the primary end point was 5.0% for LBBAP vs 13.2% for RVP (hazard ratio, 0.37 [95% CI, 0.19 to 0.73]; P = .004). LBBAP superiority was consistent across all prespecified subgroups. Conclusions and Relevance: Among patients with atrioventricular block and preserved LVEF requiring high-burden ventricular pacing, LBBAP was superior to RVP in reducing the risk of the composite end point of all-cause death, HF events, or upgrade to biventricular pacing at 24 months. Trial Registration: ClinicalTrials.gov Identifier: NCT04730921.