How to Check for Afib on Apple Watch | ECG Setup & Results

Guide

A compatible Apple Watch records a 30-second ECG when you open the app, rest your arm, and hold one finger on the Digital Crown.

Water is the fastest way to wreck an Apple Watch ECG.

The mechanics of how to check for AFib on an Apple Watch are simple enough — open the ECG app, rest your arm, hold a finger on the crown — but the reading only helps if you understand what each label means and where its limits sit.

Which Apple Watch Models Support The ECG App?

ECG recording works on Apple Watch Series 4 and later and on every Apple Watch Ultra model. Apple Watch SE does not have the ECG app, and neither does a watch set up with Apple Watch For Your Kids.

Apple’s documentation pairs the feature with a reasonably current iPhone running the latest iOS, and the watch on the latest watchOS. Availability varies by country, so confirm regional support before you lean on it while traveling.

  • Age: intended for users 22 and older.
  • Cost: no subscription — ECG is included on supported models.

Checking For AFib On Your Apple Watch: Setup And The 30-Second Recording

Setup is a one-time job in the iPhone Health app. Every reading after that takes 30 seconds on the watch and works best with your forearm supported.

Setting Up ECG On iPhone

  1. Update the iPhone to the latest iOS and the watch to the latest watchOS.
  2. Open Health on the iPhone. If the ECG setup card is waiting, tap it; otherwise tap Browse > Heart > Electrocardiogram (ECG).
  3. Answer the age and setup prompts.
  4. Check the fit and the wrist setting in Watch app > My Watch > General > Watch Orientation. The band needs to sit snugly on the wrist you actually wear it on.

Once those prompts are finished, the ECG app stops sending you back to the iPhone and opens on the watch itself.

Recording A Clean 30 Seconds

  1. Open ECG on the watch.
  2. Rest the arm wearing the watch on a table or in your lap.
  3. Touch and hold the Digital Crown with a finger from the opposite hand. Rest on it; don’t press.
  4. Hold still for the full 30 seconds.
  5. Add any symptoms you felt, tap Save, then Done.

A finished recording ends with a label on screen and a matching entry saved in Health > Browse > Heart > Electrocardiograms (ECG).

The app only classifies heart rates inside a set window: 50–120 beats per minute on ECG app version 1, and 50–150 on version 2. Above that you get High Heart Rate instead of a rhythm answer. Sweat and water push you toward a failed recording, so dry the watch and your skin first. Apple Support’s instructions for taking an ECG walk through the same sequence.

What Each ECG Result Means After You Save It

Apple Watch sorts every recording into one of five labels, and each one points at a different next step.

Result What It Means What To Do Next
Sinus Rhythm The heartbeat looks regular during this strip. Nothing to fix — it covers one moment, not the whole day.
Atrial Fibrillation The rhythm is irregular in a way that suggests AFib. Show the strip to a doctor; this is not a diagnosis.
High Heart Rate The rate is above the range the app can classify. Sit and rest a few minutes, then record again.
Inconclusive The app can’t classify the recording. Rest, check the fit, keep the finger still, retry.
Poor Recording Signal quality was too low to read. Dry the watch and skin, clean the crown, try later.

A recording covers 30 seconds. It cannot clear you for the other 23 hours and 59 minutes, and Apple is explicit that the result is not a medical diagnosis.

Irregular Rhythm Notifications And AFib History

These two background features are not interchangeable. Irregular Rhythm Notifications check periodically for a pattern suggesting AFib and set up under Health > Browse > Heart > Irregular Rhythm Notifications, and Apple does not design them for people already diagnosed with AFib. Those users get pointed to AFib History instead, which requires a physician diagnosis, needs Heart Rate and Wrist Detection turned on, works best with 12 or more hours of wear on 5 days a week, and posts weekly estimates on Mondays. Its display floor is 2% or less rather than 0%, and it stays silent during an episode. If you want a watch that follows AFib burden across weeks instead of one short strip, these best watches for AFib tracking are worth comparing.

When To Get Medical Care

Chest pain or pressure, fainting, or severe trouble breathing means emergency care — get help and don’t wait on a watch reading. Apple’s own materials say an ECG result should never delay treatment.

The order never changes: support the arm, hold the crown, stay still for 30 seconds, save, then read the label. Rerun an inconclusive or poor recording once you’re dry and settled, and take any AFib label to a clinician.

Common Questions

Why does my ECG keep coming back inconclusive?

Inconclusive results usually trace back to signal quality rather than your heart. A loose band, movement, a finger tapping instead of resting, dry skin contact, or a heart rate above the app’s classification range can all block a reading. Dry the watch and your wrist, sit down, support your forearm, and hold the crown lightly for the full 30 seconds before trying again.

Do I need a subscription for the ECG app?

No. Apple’s documentation lists no separate fee, plan, or cellular requirement for ECG recording. The only real gate is hardware: an Apple Watch Series 4 or later, or any Apple Watch Ultra model, paired with a compatible iPhone on current software. Apple Watch SE owners don’t get the feature at any price.

Does a sinus rhythm result mean I don’t have AFib?

It doesn’t. A sinus rhythm label means the 30-second strip looked regular, and AFib can come and go between recordings. Someone with paroxysmal AFib may record normal strips all week and still have episodes. Treat a normal reading as one clean data point, not a clean bill of health, and keep a symptom log for your doctor.

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