Objective:The objective of this study was to assess the predictive value of N-terminal pro-brain natriuretic peptide (NT-pro-BNP) levels on admission and new-onset atrial fibrillation (AF) in patients with acute myocardial infarction (AMI). Methods:In this study, a retrospective cohort study design scheme was used to include a total of 291 consecutive patients who were hospitalized for AMI from July 2019 to May 2020, of whom 36 (12.4%) developed new-onset atrial fibrillation (AF) during their hospitalization, which was classified as the AF group, and the rest of the patients were in the non-AF group. The impact of NT-pro-BNP on new-onset atrial fibrillation was investigated using the general data, laboratory tests, cardiac ultrasonography, and coronary angiography results of the two groups. Logistic regression analysis was employed to investigate the effect of NT-pro-BNP on new-onset atrial fibrillation. Additionally, we analyzed the significance of NT-pro-BNP in predicting new-onset AF in AMI patients using the the area under the AUC. Results:Univariate analysis indicated that patients in the AF group had significantly higher (P < .05) age, leukocyte count on admission, high-sensitivity C-reactive protein (hs-CRP), blood creatinine, uric acid, NT-pro-BNP, and left ventricular end-diastolic internal diameter (LVED) than those in the non-AF group. Patients in the AF group had lower blood pressure and left ventricular ejection fraction compared with the non-AF group. Logistic multifactorial regression analysis indicated that NT-pro-BNP was an independent risk factor for new-onset AF in patients with AMI (OR=2.752, 95% CI 1.352-5.602, P = .005). The area under the AUC was 0.747 (95% CI 0.655-0.84; P = .001), with a sensitivity of 64%, a specificity of 78%, and a Jordon's index of 0.458. This corresponds to an optimal cutoff value of 5374 pg/ml, suggesting that NT-pro-BNP performs well in predicting new-onset atrial fibrillation. Conclusion:NT-pro-BNP on admission can be a useful predictor of whether new-onset atrial fibrillation occurs in patients with AMI, with good predictive value. This finding helps better to meet patients' diagnostic and therapeutic needs and provides useful clinical guidance to improve the management and prognosis of AMI patients.