Post-Operative Atrial Fibrillation: Novel Predictive Value of CT-Derived Adipose Tissue Density in Minimally Invasive Mitral Surgery.

Postoperative atrial fibrillation (POAF) remains a significant complication following minimally invasive thoracoscopic mitral valve surgery (MITMVS), yet current risk prediction models inadequately capture the underlying metabolic determinants of arrhythmogenesis. We investigated whether computed tomography (CT)-derived body composition parameters, as markers of metabolic status, could predict POAF risk in patients undergoing mitral valve repair. We retrospectively studied 104 consecutive MITMVS patients (2014-2023). Preoperative CT scans quantified skeletal muscle index, muscle density, and visceral/subcutaneous adipose tissue. Patients were grouped by preexisting atrial fibrillation (AF) with concurrent Maze (n=48) vs. no AF history (n=56). The primary outcome was POAF development. Higher visceral (VAT) and subcutaneous (SAT) adipose tissue density showed associations with increased POAF odds in multivariable analysis (VAT: OR 1.075, 95 % CI: 1.010;1.149, p=0.026; SAT: OR 1.073, 95 % CI: 1.011;1.146, p=0.025). Quartile analysis revealed a striking 5.5-fold increased POAF risk in the highest VAT density quartile compared to the lowest (42.3 % vs. 7.7 %). Notably, the relationship between intramuscular adipose tissue (IMAT) density and POAF differed between groups (interaction p=0.029), with a positive association in patients without prior AF (OR 1.167, 95 % CI: 1.011;1.377, p=0.047), but no significant relationship in those with preexisting AF (p=0.175). CT-derived tissue quality parameters, particularly VAT density, demonstrate robust associations with POAF risk following MITMVS. These findings establish preoperative CT-based metabolic assessment as a promising tool for perioperative risk stratification without additional testing burden. Key words Postoperative atrial fibrillation " Body composition " Computed tomography " Mitral valve surgery " Metabolic risk factors.