ABSTRACT NUMBER: ESOC2026A1442 PROLONGED CARDIAC MONITORING OPTIMIZES REAL-TIME ATRIAL FIBRILLATION DETECTION AND MANAGEMENT IN EMBOLIC STROKE OF UNDETERMINED SOURCE

Abstract Background and aims Prolonged cardiac monitoring (PCM) is essential after embolic stroke of undetermined source (ESUS) to detect subclinical atrial fibrillation (AF), but its clinical impact remains uncertain. We evaluate the efficacy of 30-day PCM for real-time AF detection and management after ESUS. Methods This retrospective cohort study enrolled ESUS patients with normal 24-hour-Holter results (March 2023-July 2025) and compared the efficacy of 30-day QOCA ecg103-K1 (PCM group) with usual care (non-PCM group, event-driven ECG, at least once during follow-up) within one month after ESUS diagnosis. The primary outcome was the efficacy of real-time AF detection using time-to-event analysis. The secondary outcomes included time-to-initiation of direct oral anticoagulant (DOAC) and recurrent ischemic stroke. Results Among 283 ESUS patients (mean age: 62.7 years), 129 underwent PCM (45.6%). Baseline characteristics were comparable between groups. During a mean follow-up of 1.7 years, PCM significantly increased AF detection (27 [20.9%] vs. 6 [3.9%], HR 5.95, 95% CI 2.46–14.41; p<0.001) and shortened the time-to-detection (11.3±8.3 vs. 49.3±41.4 days, p=0.03). Notably, 51.9% of AF was detected between days 15 and 30 in the PCM group. Furthermore, the time-to-DOAC initiation was markedly shorter (1.4±0.7 vs. 42.0±15.3 days, p<0.001), and the recurrent stroke rate was lower during follow-up (5 [3.7%] vs. 16 [10.4%], OR 0.35, 95% CI 0.12-0.98, p=0.045). However, time-to-event analyses for recurrent stroke were limited by the small number of events. Conclusions Real-time PCM enhances AF detection and management in ESUS and likely reduces stroke recurrence. Further studies are warranted to identify a cost-effective preventive recommendation. Conflict of interest Chi-Sheng Wang, Jin-An Huang, Yu-Cheng Hsieh, Po-Lin Chen, Yi-Ju Chen, Chiann-Yi Hsu, Tze-Fan Chao, I-Hui Lee, Jiunn-Cherng Lin: nothing to disclose.