Left atrial function and not volume predicts mid-to-late atrial fibrillation after mitral valve repair

OBJECTIVES: Patients undergoing surgical mitral valve repair (MVr) for degenerative mitral regurgitation are at risk of even late postoperative atrial fibrillation (AF). Left atrial (LA) function has been shown superior to LA volume in evaluating the risk of AF in diverse cardiac conditions. We therefore investigated the prognostic value of LA function and volume in predicting mid-to-late postoperative AF after MVr (>30 days postoperatively). METHODS: We retrospectively identified all patients who underwent MVr for degenerative mitral regurgitation between 2012 and 2019 at our institution. Exclusion criteria were preoperative AF, concomitant procedures, re-operations, missing or insufficiently processable preoperative echocardiograms and missing follow-up. LA function and volume measurements were conducted using speckle-tracking strain echocardiographic analysis. Postoperative LA function was measured in a subgroup with sufficient postoperative echocardiograms. RESULTS: We included 251 patients, of whom 39 (15.5%) experienced AF in the mid-to-late postoperative period. Reduced LA strain parameters and more than mild preoperative tricuspid regurgitation were independently associated with mid-to-late postoperative AF. LA volume index had no association with mid-to-late postoperative AF in univariable analysis and did not improve the performance of multivariable models. Patients with mid-to-late AF exhibited diminished improvement in LA function after surgery. CONCLUSIONS: In MVr patients, LA function (but not volume) showed independent predictive value for mid-to-late postoperative AF. Including LA function into surgical decision-making and approach may identify patients who will benefit from earlier intervention with the aim to prevent irreversible LA damage with consequent risk of postoperative AF.