# WATCH AFib: smartwatches for detection of atrial fibrillation in secondary prevention of cryptogenic stroke—protocol for a prospective, intraindividual-controlled, multicentre clinical study

## TL;DR

This study will compare smartwatches and implantable devices for detecting heart rhythm issues in stroke patients to see if smartwatches can help prevent future strokes.

## Contribution

The study introduces a novel clinical protocol to evaluate smartwatches as a non-invasive alternative for AFib detection in secondary stroke prevention.

## Key findings

- Smartwatches may offer a non-invasive alternative for prolonged AFib monitoring after cryptogenic stroke.
- The study aims to enroll 400 patients to assess smartwatch accuracy compared to implantable event recorders.
- AFib detection could improve anticoagulation therapy decisions and reduce stroke recurrence.

## Abstract

Detection of atrial fibrillation (AFib) and subsequent anticoagulation therapy reduce the risk of recurrent stroke, while prolonged rhythm monitoring significantly increases AFib detection. Thus, prolonged smartwatch-based ECG monitoring after cryptogenic ischemic stroke or transient ischemic attack (TIA) could lead to a reduction of recurrent stroke by prompting adequate anticoagulation therapy.

WATCH AFib investigates the accuracy of smartwatches for AFib detection in patients with cryptogenic TIA or ischemic stroke compared to an implantable event recorder.

40 cases of AFib are required to estimate the sensitivity for AFib detection per patient with a precision of about 10%. As AFib is observed in 9%−16% of cryptogenic strokes, we intend to enroll 400 patients.

WATCH AFib is a prospective, intraindividual-controlled, multicentre clinical study in patients with cryptogenic ischemic stroke or TIA. ECG-data from smartwatches and event recorders is continuously monitored by two independent cardiologists for a follow-up period of 6 months. If AFib is detected, therapeutic options are discussed at the including center.

To compare smartwatch- and event recorder- based sensitivity and specificity of AFib detection per patient after 6 months.

Prolonged AFib screening after stroke is currently suboptimal. Smartwatches might be a non-invasive, cost-effective, widely available alternative for prolonged rhythm monitoring. Usability in severely affected patients and patients with persisting neurological deficits might be limited.

The study is registered on clinicaltrials.gov. Registration number: 20230726.