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Improving AF Detection in Cryptogenic Stroke

A Non-invasive, Prolonged Surveillance Strategy Using Apple Watch for Atrial Fibrillation Detection in Cryptogenic Stroke

Status
Completed
Phases
NA
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT05007847
Acronym
CSAF-AW
Enrollment
27
Registered
2021-08-16
Start date
2022-02-04
Completion date
2025-02-28
Last updated
2025-03-25

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Atrial Fibrillation, Cryptogenic Stroke

Keywords

cryptogenic stroke, atrial fibrillation, wearable

Brief summary

No cause for stroke is found in up to 30% of cases despite extensive investigations. These are called cryptogenic strokes (CS). 1 in 4 stroke survivors will suffer another in 5 years and this is a leading cause of fear and anxiety. A common reason for CS is an undetected heart rhythm disorder called atrial fibrillation (AF). AF occurs intermittently, so it may not be detected during the mandated 24-96 hours of rhythm monitoring that is performed as part of the standard post-stroke investigation strategy. A randomised controlled study in 2014 showed that whereas this standard monitoring strategy picks up AF in 2% of CS patients, longer-term, continuous monitoring for 12 months can pick up AF in 13% of patients. This suggests the standard strategy may miss AF in a proportion of CS patients and thus also the opportunity to mitigate against further strokes with anticoagulation therapy. Prolonged monitoring has traditionally required a minimally-invasive surgical procedure to implant a recording device under the skin at a specialist centre. A specifically trained team is also required to interpret the large number of recordings this strategy yields. The Apple Watch (AW) is a wristwatch able to monitor a wearer's heart rate and rhythm regularity and facilitates real- time, single-lead ECG recordings. This over-the-counter, non-invasive device has demonstrated feasibility and has a Certification (CE) Mark for detecting AF. It may offer a potential non-invasive alternative long-term rhythm surveillance strategy to diagnose AF in these patients. The investigators propose a study in which CS patients will be randomised in a 1:1 ratio to receive additional AW monitoring on top of standard care versus standard care alone. The investigators shall then explore the incidence of AF in the two groups at 1 year and how it impacts clinical outcomes too.

Interventions

For the duration of the study, participants in the active arm will be asked to make ECG recordings in three circumstances: Routinely once per day from the day of randomisation till the 12-month visit after AF Catheter Ablation (they will be encouraged to do so at the same time each day with the option to set a reminder on the watch). If the AW requests them to do so (the automatic AF-notification algorithm will be active throughout the study period and if AF is suspected based on the tachogram, it will trigger notification for the participant to make an ECG recording). This will be till the 12-month time point. If the patient has symptoms of palpitations, pre-syncope or syncope. This will be till the 12-month time point. Monitoring should continue even if AF has been diagnosed to characterise arrhythmia burden and profile. Participants will be given the contact details of a dedicated email inbox to which to send ECGs recorded through the AW.

Sponsors

Barts & The London NHS Trust
Lead SponsorOTHER

Study design

Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
DIAGNOSTIC
Masking
NONE

Intervention model description

The investigators propose a prospective, randomised controlled study to determine our hypothesis. This single-centre, investigator-initiated trial will be performed at Barts Health NHS Trust which provides tertiary cardiac electrophysiology services to 4 stroke units part of the London Stroke Care Network (SCN). Participants will be randomised on day 0 to either the active or control study arm. Participants randomised to the active arm will be provided with an AW Series 4 on Day 0 for the duration of the study. All participants will be followed up for 12 months after enrolment.

Eligibility

Sex/Gender
ALL
Age
30 Years to No maximum
Healthy volunteers
No

Inclusion criteria

* Recent stroke or TIA event (\<90 days) that is supported by consistency between symptoms and findings on brain magnetic resonance imaging (MRI) or computed tomography (CT). Patients with TIA will be enrolled only if symptoms at presentation were speech problems, limb weakness, or hemianopsia. Diagnosis shall be made by a Consultant Stroke physician. * Stroke classified as cryptogenic following extensive investigations to rule out a cause as per local protocol, but to include at least: * Trans-thoracic echocardiogram * A period of at least 24-hour rhythm monitoring with no evidence of AF. * MRI or CT-angiography of the brain * Sufficient mobility and dexterity to perform an ECG recording on the AW by touching the dial on the watch when worn with the contralateral hand for 30 seconds. * Access to a smartphone with Apple-operating system (OS) within their household for syncing with their watch. * Participants must be able and willing to provide written informed consent to participate in the study.

Exclusion criteria

* Documented history of AF or atrial flutter. * Expected to undergo heart surgery in the 1 year following the stroke event. * Any episode of myocardial infarction, coronary intervention or coronary artery bypass grafting \<1 month prior to the stroke event * Any other indication for oral anti-coagulation. * Patient has a cardiac implantable electronic device in-situ already or is expected to undergo implantation in the 1 year following the stroke event (excluding implantable loop recorder for the investigation of the CS). * Previous left atrial (LA) ablation or LA surgery * Life expectancy less than 1 year

Design outcomes

Primary

MeasureTime frame
Atrial fibrillation detection rate12 months

Secondary

MeasureTime frame
Incidence of non-elective, hospital admissions.12 months
Incidence of recurrent stroke or TIA.12 months

Other

MeasureTime frameDescription
Exploratory study of correlation between participant activity and AF12 monthsAccelerometer, activity and heart rate data \[Active arm only\]

Countries

United Kingdom

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026