Smartwatches for Detection of Atrial Fibrillation (AFib) in Secondary Prevention of Cryptogenic Stroke

Scientific Background: In secondary prevention of ischemic stroke, detection of atrial fibrillation (AFib) and subsequent anticoagulation therapy reduce the risk of recurrent stroke by approximately 60%. Prolonged electrocardiogram (ECG) monitoring up to 6 months significantly increases detection of AFib in cryptogenic stroke. Wearables like smartwatches have recently been shown to adequately detect AFib in the general population. Thus, prolonged ECG monitoring after cryptogenic ischemic stroke or transient ischemic attack (TIA) using a smartwatch could lead to a reduction of recurrent stroke by prompting adequate anticoagulation therapy and may constitute a cost-effective, non-invasive, and broadly-available alternative to the current standard of care. Hypothesis: The investigators hypothesize that AFib detection via smartwatch in patients with cryptogenic TIA or ischemic stroke is accurate compared to an implantable event recorder. Methods: The investigators introduce a prospective, intraindividual-controlled, multicentre clinical study in patients with cryptogenic ischemic stroke or TIA. In addition to an implanted event recorder as indicated by clinical standard, included patients receive a smartwatch for detection of AFib. ECG-data from smartwatches will be continuously monitored by two independent cardiologists. As soon as AFib is confirmed, a doctoral appointment is set to evaluate start of anticoagulation. The follow-up period will be six months. The study consists of four study visits: a baseline visit, two phone visits at one and three months, and an end of trial visit at six months. Primary Objective: To compare smartwatch and event recorder based analysis for sensitivity and specificity of AFib detection per patient after six months