Real-World Effectiveness of Adaptive Left Ventricular-Only Pacing for Cardiac Resynchronization Therapy in Asian Population: Insights From the K-Adaptive CRT Study

Background and Objectives: Conflicting results have been reported regarding the efficacy of left ventricular-only pacing (LVP) synchronized with intrinsic right ventricular conduction (adaptive LVP) for cardiac resynchronization therapy (CRT) in Western heart failure (HF) populations. We compared adaptive LVP with conventional biventricular pacing (BVP) in Asian HF patients. Methods: The K-adaptive CRT study, the largest adaptive CRT study to date in Asian HF patients, evaluated 368 HF patients who received CRT devices with an adaptive pacing algorithm between September 2013 and March 2020 from 25 tertiary hospitals in Korea. Patients were classified into 3 groups according to their pacing configuration: adaptive LVP (n=160), adaptive BVP (n=86), and conventional BVP groups (n=122). Primary outcome was the composite of all-cause death, HF hospitalization, and appropriate implantable cardioverter-defibrillator therapy. Results: During the mean 3.7-year follow-up period, incidence of the primary outcome was significantly lower in the adaptive LVP group than the conventional BVP group (hazard ratio [HR], 0.56; 95% confidence interval [CI], 0.36–0.85; p=0.007), while outcomes in the adaptive and conventional BVP groups were comparable. Patients with higher LVP% (≥65%) showed a further reduction in relative risk of the primary outcome (HR, 0.41; 95% CI, 0.22–0.76; p=0.005). Adaptive LVP was consistently associated with a lower risk of clinical outcomes in various subgroup analyses, and was identified as an independent factor for favorable long-term outcomes. Conclusions: The K-adaptive CRT study suggests that adaptive LVP is associated with better clinical outcomes than conventional BVP in Asian HF patients.