Impact of Sinus Rhythm Restoration on Mitral Regurgitation in Patients With Atrial Fibrillation: A Comparative Echocardiographic Study.

Introduction: Mitral regurgitation (MR) is a common valvular abnormality that can be exacerbated by atrial fibrillation (AF). Mitral regurgitation is classified based on mitral leaflet motion and can be either primary (organic) or secondary (functional). This study investigates the relationship between AF and functional MR, specifically assessing whether cardioversion to sinus rhythm influences MR severity and echocardiographic indices.

Methods: This retrospective cohort study included 417 patients with AF and significant MR (Grade III or IV) who were hospitalized for cardioversion. Patients underwent echocardiography during AF and again within six months after successful cardioversion. The primary outcome was the change in MR severity post cardioversion. Secondary outcomes included changes in left atrial size, left ventricular ejection fraction, and mitral valve anatomy. Statistical analysis involved chi-square tests for categorical variables, Student's t-tests for continuous variables, and multivariate logistic regression to assess the impact of sinus rhythm restoration on MR severity.

Results: Of the 417 patients, 61% (n = 254) returned to sinus rhythm after cardioversion. Among these, 28.4% (n = 72) showed a two-grade or greater improvement in MR severity. Patients who returned to sinus rhythm also exhibited significant reductions in left ventricular and left atrial dimensions and improved transvalvular gradients. The multivariate analysis indicated that conversion to sinus rhythm was independently associated with MR improvement.

Conclusions: Restoration of sinus rhythm is associated with significant improvement in functional MR, potentially reducing the need for surgical intervention. These findings suggest that rhythm control should be considered in managing patients with AF and significant MR, as it may lead to improved cardiac function and better clinical outcomes. Further large-scale prospective studies are needed to determine the most effective management strategy for functional MR in the context of AF.