Clinical profiles and in-hospital outcomes of pre-existing versus newly diagnosed atrial fibrillation in coronary care units: insights from the MORCOR-TURK national registry

Abstract

Objective: To compare demographic, clinical, and laboratory profiles and short-term outcomes between pre-existing (chronic) atrial fibrillation (AF) and newly diagnosed AF among patients admitted to coronary care units (CCUs) in Turkey, and to identify factors associated with in-hospital mortality within AF subtypes. Methods: This multicenter, prospective national registry analysis included 540 consecutive AF patients from 50 CCU centers across seven geographic regions in Turkey (MORCOR-TURK National Registry; September 1–30, 2022). Patients were categorized as pre-existing AF (documented AF prior to or at admission) or newly diagnosed AF (first detected during hospitalization). Demographics, comorbidities, admission diagnoses, laboratory biomarkers (including NT-proBNP and hs-troponin I), management, and outcomes were recorded. Multivariable logistic regression identified independent predictors of in-hospital mortality. Results: Pre-existing AF (n = 324) had higher prevalences of diabetes mellitus (42.3% vs. 31.5%; p = 0.012) and acute coronary syndromes (58.6% vs. 34.7%; p < 0.001). Newly diagnosed AF (n = 216) more frequently presented with heart failure (45.8% vs. 28.4%; p < 0.001) and dyspnea (67.1% vs. 48.5%; p < 0.001). Newly diagnosed AF exhibited higher inflammatory burden (CRP median 28.4 vs. 12.6 mg/L; p < 0.001) and lower hemoglobin (11.8 ± 2.1 vs. 12.9 ± 1.8 g/dL; p < 0.001). NT-proBNP was elevated in both groups and higher in newly diagnosed AF (median 4850 vs. 3240 pg/mL; p = 0.003). In-hospital mortality was greater with newly diagnosed AF (12.0% vs. 6.8%; p = 0.042). Independent mortality predictors included age, chronic kidney disease, cardiogenic shock, and log-transformed NT-proBNP, hs-troponin I, and CRP. Conclusion: In Turkish CCUs, pre-existing and newly diagnosed AF constitute distinct clinical phenotypes with differing presentations, biomarker profiles, and short-term risk. Newly diagnosed AF is associated with greater inflammatory and hemodynamic stress and higher in-hospital mortality. Biomarker-enriched risk stratification may refine prognostication and guide targeted management within AF subtypes.