The search for a device that can reliably monitor for Atrial Fibrillation (AFib) has driven a rapid expansion in wearable technology. AFib, a common type of irregular heart rhythm, increases the risk of stroke, making early detection a significant health priority. For the average person, AFib monitoring in a consumer wearable means the device can track heart rhythm continuously and alert the user to irregularities suggestive of the condition. This capability transforms a simple timepiece into a non-invasive screening tool, offering a practical way for individuals to track their heart health outside of a clinical setting.
How Smartwatches Detect Irregular Heart Rhythms
Smartwatches primarily employ two distinct sensor technologies to monitor for irregular heart rhythms. The most common method for continuous, background monitoring is Photoplethysmography (PPG), which uses optical sensors. This technology shines a green light onto the skin and measures changes in light absorption caused by blood flow, tracking volumetric changes in blood vessels. The PPG sensor can detect when the time between heartbeats becomes highly irregular, which is a key indicator of potential AFib activity.
PPG sensors are ideal for passive, long-term monitoring, offering high sensitivity for detecting AFib throughout the day and night. However, the reading is not a direct measurement of the heart’s electrical activity; it only suggests an irregularity rather than providing diagnostic confirmation. The second technology, the Electrocardiogram (ECG), captures the actual electrical signals generated by the heart, similar to a single-lead clinical test. This function requires the user to actively place a finger on the watch’s crown or bezel to complete an electrical circuit with the sensor on the wrist.
An ECG reading provides a more clinical assessment of the heart’s rhythm at that specific moment, classifying the rhythm as normal or suggestive of AFib. Although the ECG offers a definitive reading, it is an on-demand process, making it unsuitable for continuous monitoring of intermittent or asymptomatic AFib episodes. Most leading devices combine both technologies, using the PPG for continuous screening and the ECG for immediate, user-initiated confirmation when an alert is received.
Critical Features for Reliable AFib Tracking
The most important feature for a reliable AFib monitoring device is regulatory clearance from health authorities, such as the U.S. Food and Drug Administration (FDA). This clearance confirms that the device’s AFib detection feature has been clinically validated and proven to be accurate and safe for its intended use as a screening tool. Without this official authorization, irregularity notifications should be viewed with skepticism, as the device has not met necessary accuracy benchmarks.
Reliable devices must also offer practical data sharing capabilities, enabling the user to export the recorded ECG tracing or the history of irregular rhythm notifications. Generating a PDF report is important for sharing data with a physician, who can use it to inform further diagnostic testing. Furthermore, a device must possess sufficient battery life to support the continuous, background monitoring performed by the PPG sensor over multiple days. Since AFib occurs intermittently (paroxysmal), consistent, uninterrupted tracking is necessary to avoid missing episodes.
The Leading Wearables for AFib Monitoring
Several major manufacturers have received regulatory clearance for their AFib detection features, establishing them as leaders in this segment.
Apple Watch
The Apple Watch utilizes both PPG and ECG technology. It uses the PPG sensor for background detection of irregular heart rhythms, prompting the user to take an on-demand ECG to confirm the finding. This system provides continuous screening and a clinical snapshot, allowing users to share a detailed AFib History report with their healthcare providers.
Samsung Galaxy Watch
The Samsung Galaxy Watch series also features a dual-technology approach with an FDA-cleared Irregular Heart Rhythm Notification (IHRN) and an on-demand ECG. The IHRN uses the watch’s BioActive Sensor for proactive, background monitoring. If multiple irregular rhythms are detected, the device advises the user to take a manual ECG reading for immediate verification.
Withings ScanWatch
The Withings ScanWatch is a hybrid smartwatch designed with a traditional aesthetic but includes medical-grade monitoring capabilities. It has received regulatory clearance for its ability to take a single-lead ECG reading on demand. The device is clinically validated to detect signs of AFib, focusing on providing a high-quality electrical reading.
When to Consult a Physician Based on Watch Data
A smartwatch functions as a screening tool, not a diagnostic device. If the watch provides a persistent alert for an irregular rhythm or if an on-demand ECG suggests AFib, the user should contact a primary care physician or cardiologist. Watch data, such as an ECG tracing or a history of irregular rhythm notifications, should be viewed as a prompt for professional medical evaluation.
The physician will use this information to decide whether to prescribe a more extended, clinical-grade monitor, such as a Holter or patch monitor, to confirm the diagnosis. Users should also seek medical attention even without a watch notification if they experience symptoms like palpitations, dizziness, or a rapid, fluttering heartbeat. It is crucial never to self-diagnose or alter a prescribed treatment plan based solely on a consumer wearable device reading.