ObjectiveTo determine the durability of mitral valve repair (MVr) with complete ring or flexible band annuloplasty in patients with atrial functional mitral regurgitation (AFMR) due to atrial fibrillation (AF) and identify risk factors associated with postoperative recurrence of mitral regurgitation. MethodsBetween January 1, 2000, and January 1, 2023, 194 adults with a history of AF underwent MVr with annuloplasty alone for moderate/severe AFMR. Exclusion criteria were prior cardiac surgery, additional repair techniques, ejection fraction <45%, ischemic heart disease, aortic valve disease, mitral annular calcification, and concomitant procedures other than surgical ablation or tricuspid repair/replacement. The durability of annuloplasty was assessed using longitudinal analysis of postoperative echocardiographic data. ResultsComplete ring annuloplasty was performed in 126 of 194 patients (65%); partial ring (posterior band) in the other 68 (35%). Concomitantly, 124 of the 194 patients underwent tricuspid valve surgery, and 173 (89%) had a procedure for AF, including biatrial Cox-Maze III/IV lesion set in 152 (88%) and pulmonary vein isolation in 21 (12%). All patients were discharged with no/trace MR. Freedom from moderate/severe MR after repair with annuloplasty alone was 89% at 10 years, and no significant differences were noted between complete and partial ring annuloplasty (early, P = .41; late, P = .92). Forty-eight percent of patients developed AF at 3 months or longer after surgery, and the presence of postoperative AF was not associated with a greater likelihood of recurrence of MR (P = .15). Freedom from mitral reintervention was 96% at 10 years. ConclusionsIn appropriate patients with AFMR, the long-term durability of annuloplasty is excellent with complete ring and posterior band annuloplasty techniques.