If you have been told you have atrial fibrillation, or you simply have a family history and a racing pulse now and then, a smartwatch can feel like a cheap safety net. It is a useful one, with limits. A watch can notice an irregular rhythm you would never feel, and it can record a 30-second ECG on demand. It can also miss episodes, and it cannot diagnose anything on its own.
This guide to the best smartwatch for AFib in 2026 explains how the detection actually works, what the big studies found, which brands carry FDA-cleared features, and how to choose between them. The figures come from published studies and manufacturer documentation. Study results differ a lot depending on who was tested, so treat any single number as a rough guide, not a promise.
Quick answer
For iPhone users, an Apple Watch is the best-studied choice, with an on-demand ECG, background irregular rhythm alerts and an AFib History feature. For Android, a Samsung Galaxy Watch offers FDA-cleared irregular heart rhythm notifications plus ECG through the Samsung Health Monitor app. A Fitbit or Pixel Watch is a reasonable third option, tuned to avoid false alarms. Whichever you pick, a watch is a screening tool. Talk to your doctor about any alert.
How a Smartwatch Detects AFib
Atrial fibrillation is an irregular, often fast heartbeat caused by disorganized signals in the upper chambers of the heart. Many people feel nothing, which is why it often goes unnoticed until a stroke or a routine checkup. Smartwatches use two different methods to look for it.
- Background pulse analysis (optical sensor). The green lights on the back of the watch measure blood flow through your wrist. The software looks for a pulse pattern that stays irregular over time and sends an alert. It runs passively, so it works while you sleep or go about your day, mostly when you are still.
- On-demand ECG (electrical sensor). You touch the crown, a button or a bezel for about 30 seconds, and the watch records a single-lead ECG. The result is usually labeled as sinus rhythm, AFib or inconclusive.
The two methods complement each other. The background feature has a chance to catch something you did not notice. The ECG gives you something concrete to show a clinician if you feel symptoms.
Good to know
Apple’s irregular rhythm feature is meant for people with no known AFib diagnosis. If you already have AFib, the Apple Watch AFib History feature estimates how much time you spend in AFib each week, which can help track your burden between appointments.
What the Studies Found
The largest real-world test came from the Apple Heart Study, published in the New England Journal of Medicine. It enrolled 419,297 people, and 2,161 of them (0.52%) received an irregular pulse notification over a median of about 117 days. Of the notified participants who returned an analyzable ECG patch, 34% had AFib during patch wear. The study also found that 84% of the time, a notification that arrived while a patch was being worn matched AFib on the patch. Those two numbers use different groups of people, so they should not be compared directly.
Newer research looks at how well watches catch AFib that is already known. In a study of people after an ablation procedure, researchers compared wearables against continuous implanted monitoring. Apple Watch AF Burden caught about 82% of AFib, Apple’s irregular rhythm notification about 71%, and Fitbit’s irregular rhythm detection about 64%. Sensitivity dropped when patients were more active. In the Fitbit Heart Study, the algorithm had 67.6% sensitivity and 98.4% specificity against a one-week ECG patch, which fits its design to avoid false alarms.
Pooled analyses of smartwatch ECGs are more encouraging. A 2025 meta-analysis in JACC: Advances reported about 94% sensitivity and 97% specificity for the Apple Watch ECG. The authors flagged high variation between studies, so real-world results can be lower.
Best Smartwatches for AFib by Brand
| Brand | Background alerts | On-demand ECG | Works with |
|---|---|---|---|
| Apple Watch | Irregular rhythm notifications, AFib History | Yes, 30-second ECG app | iPhone only |
| Samsung Galaxy Watch | Irregular heart rhythm notification (FDA-cleared, ages 22 and up) | Yes, via Samsung Health Monitor | Android, Samsung phone recommended |
| Fitbit and Pixel Watch | Irregular rhythm notifications, tuned for few false alarms | Yes, on supported models | Android and iPhone |
| Withings ScanWatch | ECG-based AFib detection | Yes, FDA-cleared ECG | Android and iPhone |
Features vary by model, region and software version, so check the manufacturer’s page for your exact watch before you buy. Several makers also add features through updates, which is another reason to read the current spec sheet.
Apple Watch: the best-studied option
Apple was the first to get FDA clearance for smartwatch AFib detection, and it has the deepest research behind it. Alongside the irregular rhythm alerts and the ECG app, AFib History gives people with a diagnosis a weekly percentage of time spent in AFib. In 2024 the FDA qualified AFib History as a medical device development tool, which says something about how seriously it is taken in research. The main limit is that you need an iPhone. If you are weighing the models, our best Apple Watch 2026 comparison breaks down which one fits.
Samsung Galaxy Watch: the strongest Android pick
Samsung received FDA clearance in 2023 for its Irregular Heart Rhythm Notification, which runs in the background and works alongside the on-demand ECG. The feature is meant for adults age 22 and up, and Samsung says it is not designed to notify you about every episode. The ECG function relies on the Samsung Health Monitor app, which pairs best with Galaxy phones. Our guide to the best Android smartwatches compares them with other Wear OS options.
Fitbit and Pixel Watch: low false alarms, lower sensitivity
Fitbit’s irregular rhythm feature is conservative on purpose. It rarely cries wolf, which is good for avoiding anxiety, but it can miss shorter episodes. That trade-off makes sense for casual screening and less so if you want to catch every event. The ECG app on supported models fills part of that gap.
Withings ScanWatch: a hybrid for long battery life
The ScanWatch has an analog face with a small digital display and a battery that lasts weeks, and its ECG is cleared for AFib detection. It is a good fit if you dislike charging a smartwatch every night. For a wider look at what ECG-capable watches offer, see our roundup of the best smartwatch with ECG.
What a Smartwatch Cannot Do
- It cannot diagnose AFib. Only a clinician reviewing a medical-grade ECG can confirm it.
- It can miss paroxysmal AFib. Short episodes that come and go may not trigger a background alert. A Holter or patch monitor remains the standard for people with symptoms.
- It reads poorly during movement. Background detection works best when you are still, so an active day lowers the chance of catching an episode.
- It can raise false alarms. Skin tone, a loose fit, tattoos and cold hands can all affect the optical sensor.
- It does not replace treatment. If you take blood thinners or other medicine, do not change anything because of a watch reading.
How to Choose the Right One
- Start with your phone. Apple Watch needs an iPhone. Samsung’s ECG works best with a Galaxy phone. That decision removes half the options right away.
- Decide if you want ECG or only alerts. If you often feel palpitations, an on-demand ECG is worth paying for.
- Check how you wear it. A snug fit, worn through the night, gives the optical sensor more clean readings.
- Look at battery life. A dead watch records nothing. Our guide to smartwatches with the longest battery life helps if you hate daily charging.
- Save and share your ECGs. Export the PDF and bring it to your appointment.
- Treat every alert seriously, and every all-clear carefully. A normal reading does not rule out AFib at another time.
When to See a Doctor
Call a doctor if
you get repeated irregular rhythm alerts, an ECG labeled AFib, or symptoms such as a pounding heartbeat, shortness of breath, dizziness or chest discomfort. Call emergency services right away for chest pain, fainting or signs of stroke such as face drooping, arm weakness or trouble speaking.
Frequently Asked Questions
What is the best smartwatch for AFib?
For iPhone users, the Apple Watch has the most research and features, including AFib History. For Android, the Samsung Galaxy Watch is the strongest option, with FDA-cleared irregular rhythm notifications and an ECG app.
Can a smartwatch detect AFib accurately?
It can flag likely AFib with good accuracy in studies, especially the ECG on the Apple Watch. Background alerts catch only part of all episodes, and results drop with movement. It is a screening tool, not a diagnosis.
Can a smartwatch tell you have AFib while you sleep?
Background detection can run while you sleep, since you are still and the signal is cleaner. It only works if you wear the watch to bed and keep it charged.
Is a smartwatch ECG the same as a hospital ECG?
No. A watch records a single-lead ECG, while a hospital uses 12 leads. It is good for rhythm, not for spotting issues like a heart attack.
Do I need a prescription for a smartwatch with AFib detection?
No, you can buy these watches directly. A doctor can help interpret the results and decide whether you need more testing.
Can I rely on a smartwatch if I already have AFib?
Use it as a supplement. Features like Apple’s AFib History can show trends, but your cardiology team should guide treatment and monitoring.
Final Verdict
The Bottom Line
The best smartwatch for AFib is the one that pairs with your phone, has an on-demand ECG and that you will actually wear day and night. Apple Watch leads on evidence, Samsung Galaxy Watch is the top Android choice, and Fitbit, Pixel Watch and Withings are solid alternatives. Use alerts as a nudge to see a doctor, never as a diagnosis.
This article is for general information and is not medical advice. Talk to your doctor about symptoms, test results and treatment.
Sources and Further Reading
- NEJM: Large-Scale Assessment of a Smartwatch to Identify Atrial Fibrillation
- Circulation: Detection of Atrial Fibrillation in a Large Population Using Wearable Devices, the Fitbit Heart Study
- Europace: Wearable smartwatches for atrial fibrillation detection and burden estimation after ablation
- JACC: Advances: Accuracy of Smartwatches in the Detection of Atrial Fibrillation
- Samsung Newsroom: FDA-cleared irregular heart rhythm notification for Galaxy Watch
- Medical News Today: How to use an Apple Watch for AFib
Featured image: Pexels.
About this article: GeekBlog covers U.S. technology news, AI, phones, smartwatches and gaming. Every story is written and checked under our Editorial Policy. Spotted a mistake or have a story tip? Contact our editors.
