<h4>Background</h4>This study aimed to investigate the association between the B-type natriuretic peptide (BNP)/ left ventricular ejection fraction (LVEF) and atrial fibrillation (AF) and to evaluate its discriminative performance in a real-world hospitalized population.<h4>Methods</h4>We conducted a hospital-based observational study that included 270 consecutive patients hospitalized at the Second Affiliated Hospital of Wannan Medical University between August 2023 and December 2025. This evidence concerns the gene NPPB and atrial fibrillation.