ObjectiveTo establish and validate a nomogram model for predicting the risk of new-onset postoperative atrial fibrillation (POAF) after isolated aortic valve replacement (AVR). MethodsThe clinical data of patients without atrial fibrillation (AF) who underwent isolated AVR in the General Hospital of the Northern Theater of the Chinese People's Liberation Army from June 2020 to June 2022 were retrospectively collected. Patients with AVR were divided into a POAF group and a non-POAF group according to whether POAF occurred within 7 days after surgery. The preoperative baseline data, preoperative blood indexes, preoperative color Doppler echocardiography and the heart rate variability (HRV) in 7-days Holter monitoring before surgery were analyzed. Logistic regression was used to analyze the preoperative risk factors for POAF and R language was used to construct a nomogram to predict POAF. The results were compared with the established AF model (POAF-AF score). ResultsA total of 191 patients were enrolled in this study, and 66 (34.55%) of them developed POAF within 7 days after the surgery. The age of the patients in the POAF group was 60.97±8.41 years and 16 (24%) were female, while the age of the patients in the non-POAF group was 54.65±11.85 years and 59 (47%) were female. Univariate and multivariate logistic regression analysis showed that age, sex, drinking history, chronic obstructive pulmonary disease, platelet accumulation and high frequency power were independently associated with POAF after the AVR. The nomogram of POAF was constructed by combining the above independent risk factors. We predicted the area under ROC curve (AUC =0.812) in the nomogram of POAF after simple aortic valve replacement. The model was internally verified by a 10-fold cross-validation resampling (AUC=0.757, Kappa=0.438). Compared with the POAF-AF score, the nomogram had a superior discrimination performance. ConclusionAge, sex, drinking history, chronic obstructive pulmonary disease, plateletocrit, and high frequency power are independent predictors for POAF after isolated AVR. The nomogram can be used as a practical tool to help clinicians predict the probability of individual POAF occurrence and take necessary preventive measures.