Abstract Number: Esoc2026a1396 Evaluating the Diagnostic Yield of R-Test Monitoring for Atrial Fibrillation After Stroke and Transient Ischaemic Attack

Abstract Background and aims Undiagnosed atrial fibrillation (AF) is a major contributor to recurrent ischaemic stroke and transient ischaemic attack (TIA). Ambulatory cardiac rhythm monitoring is increasingly used to improve AF detection following cryptogenic or suspected cardioembolic events. This study aimed to assess the diagnostic yield and clinical utility of R-Test monitoring following stroke or TIA. Methods We conducted a retrospective review of consecutive patients with ischaemic stroke or TIA who underwent R-Test monitoring over a 12-month period (January–December 2024). Patients were selected based on clinical suspicion of a cardioembolic source. R-Test monitors were applied in a secondary prevention clinic by Stroke Clinical Nurse Specialists with cardiology expertise, and all recordings were reviewed by a stroke consultant and specialist nurse. Results 99 patients were included. Atrial fibrillation was detected in 21 patients (21.2%). Patients with AF were significantly older than those without AF (mean age 76.0 ± 7.1 vs 71.0 ± 12.0 years; p = 0.019). R-Test monitoring demonstrated a specificity of 91% for AF detection. Left atrial enlargement was significantly more prevalent in patients with AF compared with those without AF (38% vs 9%; relative risk ≈ 4; p = 0.004). Detection of AF resulted in initiation of direct oral anticoagulation in 18 patients (86%). Conclusions R-Test monitoring identified a substantial burden of previously unrecognised atrial fibrillation. The strong association between atrial fibrillation and left atrial enlargement highlights the value of integrating structural cardiac markers with ambulatory rhythm monitoring to better target patients at highest cardioembolic risk. Conflict of interest John Drought. Nothing to disclose