Incidence and predictors of postoperative atrial fibrillation in patients with preoperative sinus rhythm undergoing cardiac or aortic surgery.

Postoperative atrial fibrillation (POAF) is frequent after cardiac or aortic surgery and is linked to adverse outcomes. We evaluated the incidence and independent predictors of POAF in patients with preoperative sinus rhythm. We conducted a single-center retrospective cohort study of 78 patients undergoing cardiac or aortic surgery (May 2022-December 2024). POAF during the index hospitalization was modeled using multivariable logistic regression with three prespecified predictors: transmitral early (E) to late (A) diastolic filling velocity ratio (E/A)(per + 1.0), CHADS₂ ≥ 2, and abnormal body mass index (BMI) (< 18.5 or ≥ 25.0 kg/m²). Model performance was summarized by AUC (DeLong 95% CI), Brier score, calibration metrics, and Akaike information criterion (AIC). POAF occurred in 49/78 patients (62.8%). Higher E/A independently predicted POAF (adjusted OR 19.38; 95% CI 3.92-141.87; p = 0.001), as did CHADS₂ ≥ 2 (adjusted OR 4.39; 95% CI 1.31-17.50; p = 0.024) and abnormal BMI (adjusted OR 5.08; 95% CI 1.51-20.44; p = 0.011). The model showed good discrimination (AUC 0.806; 95% CI 0.709-0.904) and acceptable calibration (Brier 0.168; Hosmer-Lemeshow p = 0.530 with g = 10; calibration slope 1.00; intercept 0.00). AIC was 93.50. In patients with preoperative sinus rhythm, higher E/A (continuous), CHADS₂ ≥ 2, and abnormal BMI independently predict POAF, with good model discrimination and calibration. Routine preoperative echocardiography combined with simple clinical indices may aid perioperative risk stratification.