Abstract Number: Esoc2026ot94 Smartwatches for Detection of Atrial Fibrillation in Secondary Prevention of Cryptogenic Stroke – Watch Afib

Background and aims Detection of atrial fibrillation (AFib) and subsequent anticoagulation reduces the risk of stroke recurrence, while prolonged rhythm monitoring significantly increases AFib detection. Smartwatch-based prolonged rhythm monitoring after cryptogenic ischemic stroke or transient ischemic attack (TIA) may constitute a cost-effective, non-invasive, and broadly available alternative to current standards. Methods WATCH AFib investigates the accuracy of smartwatches for AFib detection compared to an implantable event recorder. Results WATCH AFib is an investigator-initiated, prospective, intraindividual-controlled, multicentre clinical study in patients with cryptogenic ischemic stroke or TIA. ECG-data from smartwatches and event recorders are continuously centrally monitored by two independent cardiologists for a follow-up period of six months. If AFib is detected, therapeutic options are discussed at the including centre. WATCH AFib is an event-driven trial, and the primary analysis will be performed after 40 cases of AFib (or after a total of 400 patients are recruited). Conclusions Sensitivity and specificity of AFib detection per patient after six months are the primary outcomes. Subgroup analysis will be performed for patients with residual deficits and severely affected patients. Further outcomes include positive /negative predictive values, detection based on PPG signal, sensitivity for AFib episodes >1h, time to confirmed AFib diagnosis and AFib burden. Conflict of interest Figure 1 - belongs to Results Figure 2 - belongs to Conclusions