Set up your Apple Watch to check for AFib
To turn on AFib detection, open the Health app on your iPhone. Tap Browse, then Heart, then Irregular Rhythm Notifications, then Set Up. If a doctor has already told you that you have AFib, set up AFib History on the same screen instead. A few settings can switch these off without telling you, so this guide also shows how to keep them working.
From Dr. Kenneth Civello, MD, MPH, cardiologist and electrophysiologist
The heart features live in the Health app on your iPhone. You turn them on there, and the watch does the checking. Which ones you turn on depends on one question: has a doctor told you that you have AFib?
Your watch
The ECG app needs Series 4 or later, or any Apple Watch Ultra. It is not on Apple Watch SE.
Your age
These features are for adults 22 and older. Your birth date in the Health app should be correct.
Your software
Update your iPhone and your watch first. Some features are not offered in every country.
The three features, in one line each
Irregular rhythm notifications check your pulse in the background and alert you if it looks irregular. They are for people without AFib. The ECG app records your heart's electrical signal for 30 seconds when you ask it to. It is for everyone. AFib History estimates how much time you spend in AFib each week. It is for people already diagnosed. More in Irregular rhythm notifications, explained.
Your setup
Answer one question, then work through the list on your iPhone. Check off each step as you go. Apple renames menus with updates. These steps match iOS 26 and 27. If a label looks a little different, pick the closest match.
Has a doctor told you that you have AFib?
See it on screen
These are the screens you will see on your iPhone. They are from iOS 26. The menu names are the same in iOS 27.
Pick the right wrist
In the Watch app on your iPhone, tap My Watch, then General, then Watch Orientation. Choose the wrist you wear it on. Apple notes this is needed to record an accurate ECG.
Keep Wrist Detection on
In the Watch app, tap My Watch, then Passcode, and scroll to Wrist Detection. The switch should be on.
Keep Heart Rate on
In the Watch app, tap Privacy. Heart Rate should be on. The watch needs it for heart rate alerts and to record an ECG.
Turn on irregular rhythm alerts, if you do not have AFib
In the Watch app, tap Heart. Turn on Irregular Rhythm. The same screen sets your High Heart Rate and Low Heart Rate alerts.
Find the heart features in Health
In the Health app, tap Browse, then Heart. AFib History, Irregular Rhythm Notifications, and your ECGs all live here. A feature you have not used yet sits under No Data Available.
Set up AFib History, if you have AFib
In Health, tap Browse, then Heart, then AFib History, then Set Up. Follow the screens. This turns off irregular rhythm alerts, which is expected.
Save an ECG for your visit
In Health, tap Browse, then Heart, then Electrocardiograms (ECG). Tap a recording, then Export PDF. Share it or save it to bring to your visit.
Check that everything is on
In Health, tap Summary, then your picture in the top corner, then Health Checklist. Under Active, the ECG App should say it is set up, and Irregular Rhythm Notifications should say they are on.
What quietly turns it off
Your watch will not warn you about most of these. If you stop seeing heart data, check here first.
Low Power Mode
It stops background heart checks. You will get no irregular rhythm or heart rate alerts, and AFib History may have no estimate that week.
Wrist Detection is off
The watch stops tracking your heart rate. In the Watch app on your iPhone, tap My Watch, then Passcode, and keep Wrist Detection on.
Heart Rate is off
In the Watch app on your iPhone, tap Privacy and keep Heart Rate on.
A loose band
The light sensor needs to sit flat on your skin. Wear the watch snug on top of your wrist.
AFib History is on
Turning on AFib History turns off irregular rhythm notifications. That is by design, since one is for people with AFib and the other is for people without it.
Not wearing it enough
AFib History needs the watch on at least 12 hours a day, 5 days a week, to give you a weekly estimate.
Record and share an ECG
Record one when you get an alert, and any time you feel your heart racing, pounding, or skipping.
Sit and rest your arms
Rest your arms on a table or in your lap. The watch should be snug, on the wrist you chose under My Watch, General, Watch Orientation.
Open the ECG app on the watch
Hold a finger from your other hand on the Digital Crown. You do not need to press it. Stay still for 30 seconds.
Add how you felt
When it finishes, tap Add Symptoms if you felt something, then Save.
Make a PDF for us
On your iPhone, open Health, tap Browse, then Heart, then Electrocardiograms (ECG). Tap the recording, then Export PDF, and share it or save it to bring to your visit.
If the ECG app is missing from your watch
Open the Watch app on your iPhone, tap Heart, and tap Install next to the ECG app. If it is still missing, your watch model or country may not support it. See My watch ECG says inconclusive for help getting a clean recording.
Check that it is on
Apple keeps one screen that shows every health feature and whether it is on.
Open the Health Checklist
In the Health app, tap Summary, tap your picture in the top corner, then tap Health Checklist.
Look for the heart features
Irregular rhythm notifications or AFib History should be on, along with the ECG app. Tap any feature that is off to set it up.
Check again after updates
A new phone, a new watch, or a big software update is a good time to look again.
If you have fainting, chest pain, shortness of breath, or any other symptom that worries you, call 911. Do not wait for your watch.
Common questions
I set it up and never get alerts. Is it working?
Probably. No alert usually means the watch has not seen a pattern that looks like AFib. But it only checks now and then, mostly when you are still, so it can miss short episodes. If you feel symptoms, record an ECG right then.
Which Apple Watch models detect AFib?
Every Apple Watch sold today can send irregular rhythm notifications. That includes Apple Watch SE, the Series models, and Apple Watch Ultra, including Ultra 4. The ECG app needs Series 4 or later, or any Apple Watch Ultra. Apple Watch SE has no ECG app. To see what your own watch supports in your country, open the Health Checklist. See Best smartwatch for catching AFib if you are choosing a new one.
AFib History or irregular rhythm notifications: which do I need?
It depends on whether you have been diagnosed with AFib. Irregular rhythm notifications are for people without AFib. They alert you when your pulse looks irregular. AFib History is for people who already have AFib. It does not alert you. It gives you a weekly estimate of how much time you spent in AFib. You use one or the other. Setting up AFib History turns irregular rhythm notifications off.
Will Apple Watch call 911 if I fall or stop responding?
Only after a hard fall, and only if Fall Detection is on. If the watch senses a hard fall and you do not move for about a minute, it starts a 30 second countdown. If you do not cancel it, the watch calls emergency services and messages your emergency contacts. It needs a way to place a call, through the watch itself or your nearby iPhone. Wrist Detection must be on. Fall Detection turns on by itself if you are 55 or older. Anyone 18 or older can turn it on in the Watch app on your iPhone under My Watch, then Emergency SOS. The watch does not check your breathing, and it does not call 911 because your heart rhythm changed. It also cannot catch every fall.
I have an Apple Watch SE. What can I use?
SE does not have the ECG app. Open the Health Checklist to see which heart features your watch and country support. If you need ECG recordings, a personal ECG device is an option. See Best personal ECG without a smartwatch.
Where do I see my weekly AFib History?
Your watch sends a summary every Monday. For the full view, open Health, tap Browse, then Heart, then AFib History. Bring a screenshot to your visits. It shows us how much AFib you are having between appointments.
Should I also turn on heart rate alerts?
Yes. In the Watch app on your iPhone, tap My Watch, then Heart, and set High Heart Rate and Low Heart Rate. See My watch says my heart rate is high or low for what the alerts mean.
I use a Fitbit or Pixel Watch instead.
I got an alert. What now?
Record an ECG, save it, and tell us. My watch says I have AFib walks through the next steps.
This page is general education for my patients. It does not replace advice from your own doctor. Watch alerts and ECG apps are not a diagnosis. Apple Watch is a trademark of Apple Inc. This page is not affiliated with Apple. Steps checked against Apple Support and an iPhone in October 2026. Screenshots are from the author’s own iPhone, with personal details blurred.
Based on: Joglar JA, et al. 2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Atrial Fibrillation. Circulation. 2024. Apple Support: Irregular rhythm notifications, ECG app, AFib History, and Health Checklist.