Prognostic significance of residual functional mitral regurgitation in hospitalized heart failure patients with chronic atrial fibrillation and preserved ejection fraction after medical therapies

Background: Functional mitral regurgitation (MR) can be seen in patients with atrial fibrillation (AF), even without left-ventricular (LV) systolic dysfunction, as a result of left atrial enlargement. The purpose of this study was to evaluate the prognostic significance of residual functional MR in hospitalized heart failure patients with chronic AF and preserved LV ejection fraction (pEF) after medical therapies. Methods: In this retrospective multi-center study, the determinants of post-discharge prognosis (cardiac death and re-hospitalization for worsening heart failure) were examined in 54 hospitalized heart failure patients with chronic AF and pEF at discharge. Results: Of the 54 patients, 53 (98%) had mild or higher degrees of functional MR at hospitalization.At discharge, 47 (87%) still had functional MR, even after medical therapies [mild in 27 (50%), moderate in 16 (30%), and severe in 4 (7%)]. During the follow-up period (20 ± 16 months) after discharge, 16 (30%) patients met the composite end points. The grading of residual functional MR at discharge was the significant predictor of the end point (hazard ratio per one grade increase: 2.4, 95% confidence interval 1.1–5.5, p = 0.035). The greater the residual functional MR was, the lower the event-free rate from the end point was in the Kaplan–Meier curve analysis (p = 0.0069 for trend). Conclusions: A substantial proportion of patients hospitalized due to heart failure with chronic AF have residual functional MR at discharge, even with pEF after medical therapies, and the MR is related to future heart failure events.