B-PO03-081 CLINICAL SIGNIFICANCE OF POST-PROCEDURAL FUNCTIONAL MITRAL REGURGITATION AFTER ATRIAL FIBRILLATION ABLATION IN PATIENTS WITH LEFT VENTRICULAR SYSTOLIC DYSFUNCTION

Abstract

Functional mitral regurgitation (FMR) is a common finding in patients with atrial fibrillation (AF) and reduced left ventricular (LV) ejection fraction (LVEF). Although association between FMR severity and prognosis is reported in heart failure patients, structural reverse remodeling after AF ablation can reduce the FMR severity, and the clinical significance of this change is still unclear. The purpose of the present study was as follows: (1) to examine the change of FMR severity before and after AF ablation in patients with reduced LVEF, (2) to evaluate the contribution of left atrial (LA) and LV reverse remodeling to the FMR improvement, and (3) to investigate the impact of pre- and post-procedural FMR on long-term clinical outcomes. A total of 407 patients with baseline LVEF of <50% who underwent first-time AF ablation were retrospectively evaluated. Patients were divided into 4 groups according to the pre- and post-procedural FMR severity: no or mild FMR at baseline which remained unchanged at 6 months after AF ablation (group 1), moderate to severe FMR which improved to no or mild (group 2), no or mild FMR which worsened to moderate to severe (group 3), and moderate to severe FMR which remained unchanged (group 4). The endpoint was composite of heart failure hospitalization and cardiovascular death. The number of patients with group 1, 2, 3, and 4 were 283 (69%), 74 (18%), 11 (3%), and 39 (10%), respectively. Reduction in LA volume (47±25ml vs. 30±23 ml, p <0.001) and LV end-systolic volume (37±30 ml vs. 23±21 ml, p <0.001) was significantly larger in patients with group 2 compared to the other patients. Over a median follow-up of 3 months, 28 patients experienced the endpoint. The event rate was 2.8%, 8.1%, 27.3%, and 25.6% in patients with group 1, 2, 3, and 4, respectively (log-rank p <0.001). Age-adjusted multivariate cox regression analysis including pre- and post-procedural FMR severity revealed that moderate to severe FMR at 6 months (hazard ratio, 3.28; 95% confidence interval 1.26-8.54) was significantly associated with the unfavorable events. AF ablation modified the FMR severity. Moderate to severe FMR at 6 months after AF ablation was strongly associated with unfavorable events in patients with reduced LVEF.