Troponin is associated with mortality and significant coronary artery disease in patients treated for atrial fibrillation in the emergency department

Troponin is a crucial biomarker in the emergency department (ED). Current evidence does not support differentiation between an uncomplicated tachyarrhythmia and significant coronary artery disease (CAD). The aim of the present study was to assess the use of troponins to predict CAD and mortality in patients with acute atrial fibrillation/flutter (AF/AFL). This cohort study included 3,425 consecutive episodes with AF/AFL treated at the ED of the Medical University of Vienna between 2012 and 2024. Coronary angiography was performed in 251 cases. Patients were grouped according to the troponin levels (ng/L): 0-4; 5-14; 15-28; 29-51 and ≥ 52. Outcomes were significant CAD and mortality. Of all cases (n = 3,425), coronary angiography was performed within 30 days in 251 (7%); 115 (46%) had significant CAD. The rate increased with rising troponin levels: baseline troponin, ng/L, %: 5-14: 32, 15-28: 38, 29-51: 47, ≥ 52: 57; p = 0.028; serial troponin, ng/L, %: 5-14: 15, 15-28: 19; 29-51: 54; ≥ 52: 66; p < 0.001. Sensitivity for significant CAD at 5 ng/L was 99%; specificity at ≥ 52 ng/L was 77% and increased to > 92% at ≥ 92 ng/L. 713 patients (21%) died in an observation time of 13,771 years. A troponin value ≥ 15 ng/L was significantly associated with all-cause mortality. Prevalence of significant CAD increases with rising and dynamic troponin levels. Troponin thresholds for further diagnostics or interventions may be different in AF/AFL than in the general population. Elevated troponin levels at baseline and in subsequent measurements as well as significant changes are associated with an increased all-cause mortality.