Transcatheter Approaches to Atrial Functional Mitral Regurgitation: How Far Have We Come?

Functional mitral regurgitation (MR) is associated with increased cardiovascular morbidity and mortality and over the past decade, the diagnosis of atrial functional mitral regurgitation (aFMR) has been increasingly observed in the elderly, especially in those with atrial fibrillation (AF) and heart failure with preserved ejection fraction (HFpEF). Annular enlargement, perturbations of annular contraction, and atriogenic leaflet tethering distinguish the pathophysiology of aFMR from the one of ventricular origin. However, no consensus provides recommendations regarding the differential diagnosis and the subsequent management of aFMR. The advent of transcatheter mitral valve repair has paved the way for various treatments including edge-to-edge repair (TEER), mitral annuloplasty, and replacement, with optimistic results on short-medium-term outcome provided by preliminary studies. In parallel, rhythm control of AF for paroxysmal and persistent types, should be pursued to induce reverse remodeling and restoring the normal leaflet coaptation. In this setting, catheter ablation aiming for electrical isolation of the pulmonary veins is the most widely recognized and effective strategy for maintaining sinus rhythm. Nevertheless, arrhythmia-free survival is lower in patients with persistent and long-term persistent AF, leading to the adoption of hybrid strategies combining transcatheter endocardial ablation and thoracoscopic epicardial surgical ablation. This review provides an update on the diagnosis and treatment of aFMR, focusing on available transcatheter approaches that can be performed in the catheterization lab and electrophysiology lab.