In this retrospective analysis of patients who had mitral valve annuloplasty (MVA) to treat atrial secondary mitral regurgitation (ASMR) or ventricular secondary mitral regurgitation (MR) (VSMR) in an academic centre, researchers analyzed surgical outcomes as well as repair durability in ASMR group vs a contemporary group of patients with VSMR. Typically women, with a history of atrial fibrillation, paralleling a larger left atrial size, comprised the ASMR group. Findings showed that a better prognosis, as reflected by lower all-cause mortality and MR recurrence, was achieved post-MVA to treat ASMR vs VSMR. Thus, there are essential therapeutic implications of early distinction of secondary MR towards underlying ventricular vs atrial disease.