ABSTRACT NUMBER: ESOC2026A1909 ATRIAL FIBRILLATION DETECTED AFTER STROKE: COMPARING ECG-DETECTED, MONITORING-DETECTED, AND KNOWN ATRIAL FIBRILLATION

Abstract Background and aims Atrial fibrillation (AF) detected after ischemic stroke (AFDAS) is heterogenous. We hypothesized that AFDAS identified on admission ECG (ECG-AFDAS) represents an intermediate stage on the AF disease continuum between AFDAS detected only during prolonged cardiac monitoring on stroke unit (PCM-AFDAS) and AF known before the stroke (KAF). Methods We compared clinical, electrophysiological and neuroimaging features of consecutive patients with AF and MRI-confirmed ischemic stroke admitted to a comprehensive stroke center (10/2020–01/2023). AF subtype was treated as an ordered factor reflecting the suspected AF disease progression (PCM-AFDAS <ECG-AFDAS <KAF). P for trend values from Jonckheere–Terpstra (continuous variables) and Cochran–Armitage tests (binary variables) were used to test for monotonic increases or decreases across this order. Results Among 409 ischemic stroke patients with AF (median age 81 years, 272 had KAF (66.5%), 56 ECG-AFDAS (13.7%), and 81 PCM-AFDAS (19.8%). Monotonic increases (i.e., lowest in PCM-AFDAS and highest in KAF) were observed for rate of diabetes and prior stroke, CHA₂DS₂-VASc score and AF burden. Monotonic decreases (i.e., highest in PCM-AFDAS and lowest in KAF) were observed for stroke lesion volume, rate of insular involvement, heart rate during AF, and LDL cholesterol (all P for trend <0.05). Across these variables, ECG-AFDAS consistently maintained an intermediate position relative to PCM-AFDAS and KAF. Conclusions Across many domains, ECG-AFDAS represents an intermediate AF phenotype between PCM-AFDAS and KAF. These findings support a continuum model of AFDAS and could inform future risk stratification strategies. Conflict of interest Markus G. Klammer, MD: nothing to disclose; Laura Reimann: nothing to disclose; Simone Lieschke, MD: nothing to disclose; Helena Stengl, MD: nothing to disclose; Maximilian Schoels, MD: nothing to disclose; Alexander Nelde, MSc: nothing to disclose; Kersten Villringer, MD: nothing to disclose; Christian Meisel, MD: nothing to disclose; Matthias Endres, MD: nothing to disclose; Jan F. Scheitz, MD: nothing to disclose