Long-Term Outcomes and Safety of His-Purkinje Conduction System Pacing in China: The ChiCSP Study

Conduction system pacing (CSP), including His bundle pacing (HBP) and left bundle branch area pacing (LBBAP), offers a physiological alternative to conventional pacing. However, current evidence is limited by small sample sizes, short follow-up, and inconsistent LBBAP definitions.

This study evaluated the long-term outcomes, safety, and lead performance of CSP in a large multicenter cohort, and provided a precise LBBAP classification for investigating its impact on clinical outcomes.

This prospective registry-based study included patients receiving CSP at 5 Chinese centers from 2019 to 2021. LBBAP was classified as left bundle branch pacing (LBBP), left ventricular septal pacing (LVSP), or unclassified LBBAP based on the presence, absence, or uncertainty of left bundle branch capture. Pacing and clinical outcomes were analyzed.

Of 3,336 enrolled patients, 3,167 successfully received CSP (557 HBP, 2,610 LBBAP), with a mean follow-up of 41.3 ± 14.0 months. LBBAP comprised LBBP (84.2%), unclassified (12.5%), and LVSP (3.3%). In patients with LBBB and heart failure with reduced ejection fraction, LBBP and HBP achieved the greatest LVEF improvements (+20.7% and +21.9%), while LVSP showed the least (+12.1%). LVSP was associated with higher mortality or heart failure hospitalization (33.3%) compared with LBBP (8.6%) and unclassified LBBAP (15.4%). Threshold increases ≥1 V/0.5 ms occurred in 5.03% HBP vs 1.80% LBBAP (P < 0.001). Procedural complications (excluding threshold rise) occurred in 1.3% of both groups.

CSP demonstrated long-term safety and stability. Subclassification of LBBAP enhances clinical precision, with LBBP capture yielding a higher positive clinical outcomes and LVSP with inferior outcomes, especially in cardiac resynchronization therapy patients.