Clinical outcomes of left bundle branch area pacing versus right ventricular pacing in patients with preserved ejection fraction

Abstract Purpose Chronic right ventricular pacing (RVP) can exacerbate heart failure, whereas data on left bundle branch area pacing (LBBAP) remain limited. This study aimed to compare the clinical outcomes of LBBAP and RVP in patients undergoing permanent pacemaker (PPM) implantation with preserved ejection fraction. Methods This prospective registry at a University Hospital (South Korea) included de novo patients with left ventricular ejection fraction >50% who underwent transvenous PPM implantation between 2020 and 2024. Patients with an expected ventricular pacing burden >20% were analyzed. The composite endpoint comprised all-cause mortality, heart failure hospitalization (HHF), pacing-induced cardiomyopathy (PICM), and upgrades to biventricular pacing (BVP). Results A total of 242 patients (mean age, 76.0 ± 10.2 years; 45.5% male) were included: 125 received RVP and 117 received LBBAP. Baseline characteristics were comparable between groups. Paced QRS duration was significantly shorter in the LBBAP group than in the RVP group (129.1 ± 18.0 ms vs. 157.5 ± 17.7 ms; p < 0.001). Over a median follow-up of three years, 46 composite events occurred (36 deaths, 10 HHF, 13 PICM, and 4 BVP upgrades). While the overall composite outcome did not differ between groups, the incidence of PICM was significantly lower in the LBBAP group (1.7% vs. 8.8%; p = 0.003). In multivariate analysis, reduced global longitudinal strain (HR 1.55; 95% CI 1.31–1.82; p < 0.001) and longer paced QRS duration (HR 1.04; 95% CI 1.00–1.08; p = 0.043) were independent predictors of adverse outcomes. Conclusions In patients with preserved ejection fraction requiring PPM implantation, LBBAP achieved narrower paced QRS duration and significantly reduced the risk of pacing-induced cardiomyopathy compared with RVP, without differences in composite clinical outcomes.