Performance and safety of a fixed-helix stylet-driven lead for left bundle branch area pacing: a multicenter registry

Background Stylet-driven leads (SDLs) may facilitate septal penetration during left bundle branch area pacing (LBBAP), but concerns remain regarding fixation stability and long-term performance. The FINELINE™ lead is the thinnest available SDL and features a fixed helix that advances synchronously with the lead body to enhance fixation. We aimed to evaluate handling characteristics, safety, and electrical performance of the FINELINE lead in patients undergoing LBBAP. Methods This multicenter registry included consecutive patients undergoing LBBAP using the FINELINE™ lead at two German centers. Data were collected retrospectively and prospectively. Prespecified safety and effectiveness performance goals were adopted from prior LBBAP registries: (1) lead-related complication (LRC)–free rate >90% at last follow-up; (2) pacing capture threshold (PCT) ≤2.0 V at 0.4 ms and R-wave amplitude ≥5 mV in ≥80% of patients. Outcomes were benchmarked against published results of the INGEVITY lead from the INSIGHT-LBBP registry. Results A total of 435 patients were included (mean age 77 ± 9 years, 37% female). Indications were atrioventricular block, bradycardia, pace-and-ablate strategies and heart failure. Median follow-up was 10 months The LRC-free rate was 97.0% (95% CI 95.0–98.4%), exceeding the prespecified safety performance goal of 90%. At 10 months, 99.5% of patients had PCT ≤2.0 V, and 94.7% had R-wave amplitudes ≥5 mV. Electrical parameters remained stable throughout follow-up. Observed outcomes were consistent with previously reported performance of the INGEVITY lead in LBBAP. Conclusion In this multicenter registry, the fixed-helix, stylet-driven FINELINE™ lead met all prespecified safety and performance goals for LBBAP. These findings support the use of thin SDL technology as a viable alternative for LBBAP.