Influence of catheter ablation for atrial fibrillation on atrial and ventricular functional mitral regurgitation

Aims: The purpose of this study was to compare the impact of catheter ablation on cardiac structural reverse remodelling and atrial (AFMR) and ventricular (VFMR) functional mitral regurgitation (MR), and the long-term prognosis of patients with AFMR and VFMR. Methods and results: The retrospective study included persistent AF patients who had AFMR (n = 136, left atrial (LA) volume index >30 mL/m(2) and left ventricular (LV) ejection fraction >= 40%) or VFMR (n = 31, LV ejection fraction <40% or LV regional asynergy) and had undergone the initial AF ablation from April 2015 to December 2019. Baseline and 6 month follow-up echocardiography were performed to assess MR, LA, and LV sizes. MR improvement after ablation was comparable in the AFMR (64%) and VFMR groups (52%, P = 0.20). Patients with AFMR improvement showed a greater decrease in left atrial volume after ablation than those without (amount of change: -11.4 +/- 15.1 vs. -2.3 +/- 21.1 mL/m(2), P = 0.01). Patients with VFMR improvement showed a greater increase in LV ejection fraction than those without (amount of change: 28.5 +/- 13.6% vs. 9.0 +/- 14.8%, P = 0.001). The composite endpoint of all-cause death and heart failure hospitalization during the 2 year follow-up period was more frequently observed in the VFMR than in the AFMR group (22.6% vs. 3.7%, P < 0.0001). Patients with MR improvement after catheter ablation less frequently demonstrated the composite endpoint than those without (1.9% vs. 15.6%, P < 0.0001). Conclusions: Atrial functional mitral regurgitation and VFMR improvement after ablation were associated with atrial and ventricular reverse remodelling, respectively. It is possible that long-term prognosis is better in patients with AFMR than with VFMR, and in those with MR improvement than in those without.