The 2026 American Association for Thoracic Surgery Expert Consensus Document: Management of atrial functional mitral regurgitation

Atrial functional mitral regurgitation (AFMR) represents a distinct pathophysiologic entity characterized by MR secondary to left atrial dilation and annular remodeling, in the absence of significant left ventricular disease. With the increasing prevalence of atrial fibrillation and heart failure with preserved ejection fraction, AFMR has emerged as an important and potentially underrecognized etiology of MR. This expert consensus statement provides an evidence- and experience-based framework for the evaluation and management of AFMR, encompassing diagnosis, medical and rhythm therapy, surgical and transcatheter interventions, and postoperative management.