Kaplan–Meier curves of A) HFH, B) cardiovascular death or HFH, and C) cardiovascular death according to median baseline RVol/LAV ratio and treatment. Interaction testing was performed using a Cox regression model including treatment assignment, binary RVol/LAV ratio (stratified by the median), and the interaction term (treatment assignment ∗ binary RVol/LAV ratio) to access the differences in treatment effect of MitraClip vs. GDMT according to the RVol/LAV groups. GDMT, guideline-directed medical therapy; HFH, heart failure hospitalization; LAV, left atrial volume; RVol, regurgitant volume; TEER, transcatheter edge-to-edge repair.