Ischemic stroke is worldwide the second most frequent cause of death and disability and
has a lifetime risk of approximately 25%. In the secondary prevention of ischemic stroke,
detection of atrial fibrillation (AFib) and subsequent anticoagulation therapy reduce the
risk of recurrent stroke by approximately 60%. Cryptogenic stroke is defined as ischemic
stroke for which no probable cause is found despite a full standard evaluation and
comprises 25% of all ischemic strokes. Prolonged electrocardiogram (ECG) monitoring for
30 days to 6 months significantly increases the detection of occult paroxysmal AFib in
cryptogenic stroke, which is present in 9 - 16%. Thus, prolonged ECG monitoring is likely
to lead to a reduction of recurrent stroke by prompting adequate anticoagulation therapy.
Still, prolonged AFib screening after stroke is currently suboptimal due to a limitation
of resources, loss to follow-up, invasiveness of procedures, and costs. Wearables like
smartwatches have recently been shown to adequately detect AFib in the general
population. Sensitivity and specificity of AFib detection compared to ECG-based diagnosis
is high (93-98% and 90-98%, respectively). Compared to implantable Event Recorders,
smartwatch based AFib diagnosis in the general population exhibits a sensitivity of 97.5%
for AFib episodes >1h and a sensitivity of 100% for AFib detection per patient.
The investigators hypothesize that AFib detection via smartwatch in patients suffering
from cryptogenic transient ischemic attack (TIA) or ischemic stroke is accurate for AFib
detection compared to an implantable Event Recorder and might therefore be a
non-invasive, cost-effective, widely available alternative, which could potentially
change the current standard of post-stroke care.
The primary objective is to assess whether AFib detection via smartwatch in patients
suffering from cryptogenic TIA/ ischemic stroke is accurate in comparison to implantable
Event Recorders. This will be assessed by sensitivity and specificity of AFib detection
per patient after six months. The investigators aim on a comparison of smartwatch based,
continuous, automated, cardiologist supervised rhythm analysis of photoplethysmography
(PPG)- signal and patient activated 1-lead ECG with Event Recorder based, continuous,
automated ECG rhythm analysis.
This is a prospective, intraindividual-controlled, multicenter clinical study.
The study population includes patients with cryptogenic TIA or ischemic stroke and known
risk factors for the presence of paroxysmal AFib (see inclusion criteria; CHA2DS2VASc
score ≥4, Atrial runs, Left atrial size > 45mm, Left atrial appendage flow ≤ 0.2m/s).
In addition to an implanted Event Recorder according to clinical standard, patients
receive a smartwatch. Smartwatch- and Event Recorder-derived heart rhythm are daily
uploaded and ana-lyzed by the cardiologists at the Cardiology Core Lab at the Department
of Internal Medicine I, Klinikum rechts der Isar, Munich. The obtained data on cardiac
arrhythmia will be assessable for each study site in consultation with the Cardiology
Core Lab. In case of an arrhythmic event, the obtained data on duration, source of
information (e.g., smartwatch PPG signal, smartwatch 1-lead ECG, Event Recorder) will be
implemented in the eCRF by the Cardiology Core Lab.
In parallel, the study consists of a total of four visits. The baseline visit (Visit 0)
may take place within the clinical setting of the acute stroke work up. A table
containing a detailed plan of the data to be collected will be provided. Furtherly, the
implementation and set-up of the smart-watch will take place within the baseline visit. A
manual will be provided for each study center and patient to correctly set up and
instruct on the usage of the smartwatch. The second and third visit (Visit 1, Visit 2)
constitute phone-visits at one and three months with a tolerated time deviation of one
week. The last visit at the end of the study (Visit 3) will be performed at six months
with a tolerated time deviation of three weeks. This visit will take place at each
pa-tient's study center. A table containing a detailed plan of the data to be collected
will be pro-vided for each study center.
The first patient is planned to be included approximately in the third quarter of 2023
and the last patient approximately in the first quarter of 2025. Accordingly, the last
patient will exit the study ('last patient last visit') approximately by the end of 2025.
The clinical study will be carried out in accordance with the study protocol and the
principles of the Declaration of Helsinki by the World Medical Association and specific
applicable national ethical and regulatory requirements.
All patients included in the clinical study will receive standard of care for cryptogenic
TIA/ is-chemic stroke. The clinical study protocol does not interfere with generally
accepted standards in post stroke care and local SOPs .The applied smartwatch is
CE-certified as a medical device for AFib detection. As the study intervention consists
in simply wearing a smartwatch (and phone visits are implemented at one and three
months), we expect no safety risk for study partici-pants.
