Impact of Upper Lobe Resection and Potassium on AF After Lung Surgery.

OBJECTIVE: This study aimed to investigate the relationship between postoperative atrial fibrillation (POAF) following lung resection and surgical factors, particularly the extent and location of resection, alongside preoperative electrolyte levels. We also sought to develop and internally validate a composite risk model for identifying high-risk patients. METHODS: In this single-center retrospective cohort study, 422 patients who underwent lung resection (sublobar, lobar, or major resection) between December 2024 and April 2025 were analyzed. Patients with pre-existing atrial substrate, heart failure, or left atrial dilatation (≥40 mm) were excluded. Independent predictors were identified using multivariable logistic regression. To further address potential confounding, inverse probability of treatment weighting (IPTW) analysis was performed. RESULTS: POAF developed in 66 patients (15.6%). In multivariable analysis, lower preoperative potassium levels (OR 0.40; 95% CI 0.21-0.79; p=0.008), major resection (OR 4.10; 95% CI 1.98-8.49; p<0.001), and upper lobe resection (OR 4.23; 95% CI 2.22-8.05; p<0.001) were independent predictors of POAF. In the IPTW-adjusted analysis, upper lobe resection remained significantly associated with POAF (OR 2.08; 95% CI 1.16-3.75; p=0.013). The composite model demonstrated moderate discrimination (AUC 0.716; 95% CI 0.641-0.777), which remained stable after bootstrap validation. POAF was associated with longer ICU stay and higher in-hospital mortality (16.7% vs. 1.4%, p<0.001). CONCLUSION: POAF after lung resection is a predictable complication associated with the extent of surgery, upper lobe involvement, and preoperative potassium levels. These findings highlight the importance of closer rhythm surveillance and perioperative electrolyte optimization in high-risk patients.