The impact of substrate and trigger ablation for reduction of functional mitral regurgitation in patients with persistent atrial fibrillation

Abstract Background Functional mitral regurgitation (FMR) is not uncommon in atrial fibrillation (AF) patients. Left atrial (LA) substrate remodeling and corresponding mitral valve annulus dilation has been reported as the most possible cause of FMR. Percutaneous catheter ablation (CA) is an effective treatment for AF. Although significant FMR could be improved by sinus restoration, patients with mitral regurgitation were more likely to experience recurrent AF post ablation, especially those with significant mitral regurgitation. There is no information available on the efficacy of CA for persistent AF in patients with FMR. Purpose The purpose of this study is to investigate the predictors of FMR improvement by CA and to determine the efficacy of substrate and trigger CA for persistent AF in patients with FMR. Methods We prospectively studied 512 consecutive patients admitted for persistent AF ablation from the EARNEST-PVI (Prospective Multicenter Randomized Study of Effect of Extensive Ablation on Recurrence in Patients with Persistent Atrial Fibrillation Treated with Pulmonary Vein Isolation) trial. On admission, enrolled patients were randomly assigned in a 1:1 ratio to pulmonary vein isolation (PVI) or PVI-plus additional ablation (linear ablation or/and CFAE ablation). Of the 512 patients, we studied 94 patients with preoperative echocardiography showing moderate or greater baseline FMR. FMR grades were classified into 5 grades (0/1/2/3/4). The FMR improvement group (FMRI(+)) was defined as a case in which the FMR was improved by two or more grades compared the preoperative echocardiography and the one year follow-up examination. Results Of the 94 patients, 42 were in the PVI group and 52 were in the PVI-plus additional ablation group. There were 30 cases in the FMRI(+) group and 64 cases in the FMRI(−) group. There were no significant baseline differences in age, sinus rhythm maintenance, plasma B-type natriuretic peptide (BNP) level, left ventricular diastolic dimension, or left atrium dimension between the FMRI(+) and FMRI(−) groups. AF duration was significantly shorter in the FMRI(+) group than FMRI(−) groups (5.8±9.4 months vs 12.4±15.4 months, p<0.0001). In addition, significantly more additional ablation cases were observed in the FMRI(+) group than in the FMRI(−) group (73.3% vs 46.8%, p=0.016). In multivariate analyses, only additional ablation was an independent predictor of FMRI (odds ratio 0.226 95% CI 0.081–0.626; p=0.004). Conclusions Catheter ablation is a valid option for the treatment of AF in patients with functional MR and additional substrate and trigger ablation were the only independent predictor of FMR improvement. Funding Acknowledgement Type of funding sources: None.