RESUMO
BACKGROUND: The development of atrial fibrillation (AF) during the course of acute coronary syndrome (ACS) is related to poor prognosis. Possible predictors of new-onset AF (NOAF) have not been adequately investigated in elderly patients with ACS undergoing percutaneous coronary intervention (PCI). We aimed to identify the factors associated with NOAF in such patients. METHODS: A total of 308 elderly patients with ACS undergoing PCI were enrolled in the study. Patients were divided into two groups: without NOAF [254 patients, 64.6% men, age: 73.5 (69.0-79.0) years] and with NOAF [54 patients, 70.4% men, age: 75.0 (68.7-81.2) years]. Clinical, angiographic, and laboratory features including neutrophil-to-lymphocyte ratio (NLR) and monocyte-to-high-density lipoprotein ratio (MHR) were compared between the groups. RESULTS: The percentages of prior myocardial infarction (MI) (20.4 vs. 5.9%) and Killip III/ IV (24.1 vs. 7.1%), NLR [4.5 (2.6-7.2) vs. 3.2 (2.0-6.0)], and MHR [19.4 (15.7-26.5) vs. 12.9 (9.9-18.5)] were higher in patients with NOAF compared to the others (p = 0.020, < 0.001, 0.030, and < 0.001, respectively). In multivariate regression analysis, prior MI (OR 4.509, 95% CI 1.679-12.106, p = 0.003) and MHR (OR 1.102, 95% CI 1.054-1.152, p < 0.001) independently predicted NOAF. In addition, Killip III/IV was found to be an independent predictor of 6-month overall mortality (HR 2.949, 95% CI 1.218-7.136, p = 0.016). CONCLUSIONS: Prior MI and MHR are independent predictors of NOAF in elderly patients with ACS undergoing PCI. Killip III/IV predicts 6-month overall mortality in such patients.