Procedural Success, Predictors of Failure, and Clinical Outcomes of Conduction System Pacing in Korea: The Korean Conduction System Pacing (K-CSP) Registry.

BACKGROUND

Conduction system pacing (CSP), particularly left bundle branch area pacing (LBBAP), is a promising physiologic pacing strategy, but large-scale Asian data are lacking.

OBJECTIVE

To evaluate the feasibility, predictors of failure, and clinical outcomes of CSP in a nationwide Korean multicenter registry.

METHODS

This observational registry included 2,215 consecutive patients undergoing attempted CSP at 35 Korean centers between January 2021 and June 2025. Capture types were classified using EHRA criteria.

RESULTS

Stylet-driven leads were used in 87.0%. CSP succeeded in 87.4% (1,932/2,211). Among 1,922 LBBAP patients, left bundle branch pacing (LBBP) was achieved in 35.1%, left fascicular pacing (LFP) in 31.3%, and left ventricular septal pacing (LVSP) in 17.2%. Independent predictors of CSP failure included prior open-heart surgery involving septal manipulation, right-sided approach, and male sex. Pacing parameters were stable over 17.0±10.8 months. CSP failure was associated with worse composite outcomes on unadjusted analysis, but these associations were attenuated and no longer significant after adjustment. Among LBBAP patients, LVSP was associated with a higher adjusted risk of heart-failure hospitalization (adjusted HR 3.04, 95% CI 1.05-8.73, p=0.039) than LBBP+LFP; however, this association was based on few events with wide confidence intervals and was not significant on unadjusted analysis.

CONCLUSION

In this large-scale Asian CSP registry, LBBAP was feasible and safe, performed predominantly with stylet-driven leads. Direct conduction system capture (LBBP+LFP) was associated with a lower adjusted risk of heart-failure hospitalization than LVSP, although this was based on few events; these findings are hypothesis-generating and warrant confirmation in randomized trials.