Catheter ablation is associated with reduced cardiovascular events in atrial fibrillation patients with atrial functional mitral regurgitation

BACKGROUND Atrial functional mitral regurgitation (AFMR) frequently occurs secondary to atrial fibrillation (AF). Although prior studies reported improvement in AFMR severity after catheter ablation (CA), the long-term cardiovascular benefit remains uncertain. OBJECTIVE To evaluate the association between CA and cardiovascular outcomes in AF patients with moderate or severe AFMR. METHODS AF patients with moderate or greater AFMR were consecutively recruited from the China-AF registry and assigned to CA or medical therapy (MT) based on baseline treatment, following the intention-to-treat principle. This study explicitly emulated a parallel-group, randomized target trial, with follow-up aligned to treatment initiation. Baseline covariates were balanced using stabilized inverse probability of treatment weighting. RESULTS Among 873 patients (484 CA, 389 MT) with median follow-up of 1,509 days, 22 primary outcome events occurred in CA and 42 in MT (incidence per 100 person-years: 1.76 vs 3.30; absolute risk difference -1.54%; weighted HR 0.55 [95% CI 0.32-0.94]). CA was associated with lower weighted hazards for AF recurrence (HR 0.31; 95% CI, 0.25-0.37), cardiovascular death (HR 0.48; 95% CI, 0.24-0.96), and all-cause death (HR 0.49; 95% CI, 0.27-0.89). No significant differences were observed for ischemic stroke/systemic embolism, major bleeding, or cardiovascular hospitalization. Sensitivity analyses and exploratory subgroups showed consistent directional trends. CONCLUSION In AF patients with moderate or severe AFMR, CA was associated with fewer cardiovascular events in this observational study explicitly emulating a target trial, and these findings require confirmation in randomized controlled trials.