In acute ST-segment elevation myocardial infarction (ASTEMI), new-onset atrial fibrillation (NOAF) was not only associated with worse short-term outcomes but also with higher long-term mortality. This study aimed to evaluate the effect of dyslipidemia on the incidence of NOAF. Among the 985 patients (2014 to 2017) with ASTEMI consecutively enrolled and followed-up for 31 months in this study, 81 patients (8.2%) developed NOAF during hospitalization. Fasting levels of total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) were measured using standard procedures. The study population was categorized into 3 groups based on tertiles of lipid profile. Multivariate regression analysis was adjusted for baseline characteristics, laboratory values, angiography findings, and medication. Inverse associations of TC (hazard ratio [HR] 0.54, 95% confidence interval [CI] 0.32 to 0.90) and LDL-C (hazard ratio 0.56, 95% confidence interval 0.31 to 1.00) with NOAF was observed in this study. In contrast, the levels of TG and HDL-C were not associated with NOAF in patients with ASTEMI. Moreover, the all-cause mortality in the NOAF group (19.8%) was apparently higher than that in sinus rhythm goup (6.1%) after a long term follow-up. In conclusion, plasma LDL-C and TC concentrations but neither TG nor HDL-C were inversely correlated to NOAF during hospitalization, which indicated a bad prognosis even after discharge. (C) 2019 Elsevier Inc. All rights reserved.