Age-Stratified Mortality Impact of Atrial Fibrillation in Elderly NSTEMI Patients

Objectives: Non-ST-segment elevation myocardial infarction (NSTEMI) in the elderly is frequently complicated by multiple comorbidities, which influence clinical outcomes. However, the prognostic significance of atrial fibrillation (AF) in this context remains uncertain. This study aimed to evaluate the impact of AF on short- and long-term mortality in elderly patients (≥65 years) with NSTEMI. Methods: This cross-sectional observational study included 474 NSTEMI patients aged 65 years and older. Participants were stratified into four groups based on age (65–74 vs. ≥75 years) and the presence or absence of AF. One-month and one-year all-cause mortality were assessed as the primary and secondary endpoints, respectively. Results: AF was detected in 23 (11.6%) of 199 patients aged 65–74 and in 80 (29.1%) of 275 patients aged ≥75. While one-month mortality did not differ significantly among the four groups (p = 0.514), one-year mortality showed a statistically significant difference (p < 0.001). Univariate analysis revealed that AF was not predictive of one-month mortality. In multivariate Cox regression analysis, AF, reduced creatinine clearance, and left ventricular ejection fraction