Comparative clinical outcomes of stylet-driven left bundle branch area pacing versus right ventricular pacing in patients with preserved ejection fraction: A 3-year follow-up study

Purpose Chronic right ventricular pacing (RVP) can exacerbate heart failure, but the clinical impact of left bundle branch area pacing (LBBAP) in patients with preserved left ventricular ejection fraction (LVEF) remains unclear. Because LBBAP has been performed almost exclusively with stylet-driven leads (SDLs) in Korea, we compared 3-year clinical outcomes between SDL-based LBBAP and conventional RVP in patients with preserved LVEF and a high anticipated pacing burden. Methods This prospective registry enrolled de novo patients with preserved LVEF (≥ 50%) and an expected ventricular pacing burden > 20% who underwent transvenous permanent pacemaker implantation between 2020 and 2023. LBBAP was performed using stylet-driven leads (Tendril MRI, Abbott). The composite outcome comprised all-cause mortality, heart failure hospitalization (HHF), pacing-induced cardiomyopathy (PICM), and upgrade to biventricular pacing. Results Of 242 patients, 125 received RVP and 117 LBBAP. Clinical characteristics were comparable between groups, except that post-implant GLS was less impaired in the LBBAP group (-15.3 ± 3.6% vs. -17.6 ± 3.5%; p < 0.001). Paced QRS duration (pQRSd) was shorter with LBBAP (157.5 ± 17.7 ms vs. 129.1 ± 18.0 ms; p < 0.001). LBB capture was achieved in 103 patients (88.1%) and LVSP in 14 (11.9%). Over a median 3-year follow-up, the primary composite outcome occurred in 33 patients (26.4%) in the RVP group and 12 (10.3%) in the LBBAP group (p = 0.003), driven by HHF (7.2% vs. 0.9%; p = 0.016) and PICM (8.8% vs. 1.7%; p = 0.016); all-cause mortality did not differ significantly (16.0% vs. 8.5%; p = 0.096). In multivariable Cox analysis, early post-implant GLS (HR 1.361; 95% CI 1.009–1.834; p = 0.043) and pQRSd (HR 1.124; 95% CI 1.057–1.196; p < 0.001) were independently associated with PICM. Conclusions In patients with preserved LVEF and a high pacing burden, LBBAP using stylet-driven leads was feasible and safe and was associated with better 3-year clinical outcomes than RVP, in parallel with a narrower paced QRS duration and better-preserved early post-implant GLS.