Atrial fibrillation is a health condition that often goes undiagnosed, so ECG app and heart rhythm alerts on Apple Watch are highly useful for detecting early signs of disease. ECG readings also normally require a full ECG machine and a visit to the doctor, which is far less convenient than a reading taken with the Apple Watch.
apple watch ecg

The irregular rhythm notification feature intermittently checks heart rhythm in the background and sends a notification if an irregular heart rhythm is identified that could potentially be atrial fibrillation (AFib). Upon receiving a notification, users in territories where the feature is approved can immediately launch the ECG app and perform a more comprehensive test in just 30 seconds by placing their finger on the Digital Crown to generate an ECG waveform.

Apple has designed two algorithms that Apple Watch uses to measure electrocardiogram (ECG) waves. The second algorithm improves upon the first, by allowing the ECG app to check for atrial fibrillation (AFib) at higher heart rates - during exercise, for example. However, because of regulations in your country or region, version 2 might not be available to you. You can verify which version of the irregular rhythm notification feature you have on your Apple Watch or iPhone by following these steps.

On Apple Watch

  1. On your Apple Watch, press the Digital Crown and select the Settings app.
  2. Scroll down and select Heart.
    watch

  3. Tap Irregular Rhythm Notifications.
  4. Scroll down to view the version number.
    watch

On iPhone

  1. On your ‌iPhone‌, open the Health app.
  2. Tap the Browse tab.
  3. Scroll down and tap Heart.
  4. Tap Irregular Rhythm Notifications.
  5. Scroll down to Options, then tap About.

The version number of the irregular rhythm notification is listed next to Feature Version.

Related Roundup: Apple Watch 11
Buyer's Guide: Apple Watch (Neutral)

Popular Stories

Aston Martin CarPlay Ultra Screen

Apple's CarPlay Ultra to Expand to These Vehicle Brands Later This Year

Sunday February 1, 2026 10:08 am PST by
Last year, Apple launched CarPlay Ultra, the long-awaited next-generation version of its CarPlay software system for vehicles. Nearly nine months later, CarPlay Ultra is still limited to Aston Martin's latest luxury vehicles, but that should change fairly soon. In May 2025, Apple said many other vehicle brands planned to offer CarPlay Ultra, including Hyundai, Kia, and Genesis. In his Powe...
Apple Logo Black

Apple's Next Launch is 'Imminent'

Sunday February 1, 2026 12:31 pm PST by
The calendar has turned to February, and a new report indicates that Apple's next product launch is "imminent," in the form of new MacBook Pro models. "All signs point to an imminent launch of next-generation MacBook Pros that retain the current form factor but deliver faster chips," Bloomberg's Mark Gurman said on Sunday. "I'm told the new models — code-named J714 and J716 — are slated...
Apple MacBook Pro M4 hero

New MacBook Pros Reportedly Launching Alongside macOS 26.3

Sunday February 1, 2026 5:42 am PST by
Apple is planning to launch new MacBook Pro models with M5 Pro and M5 Max chips alongside macOS 26.3, according to Bloomberg's Mark Gurman. "Apple's faster MacBook Pros are planned for the macOS 26.3 release cycle," wrote Gurman, in his Power On newsletter today. "I'm told the new models — code-named J714 and J716 — are slated for the macOS 26.3 software cycle, which runs from...
iOS 26

iOS 26.3 and iOS 26.4 Will Add These New Features to Your iPhone

Tuesday February 3, 2026 7:47 am PST by
We are still waiting for the iOS 26.3 Release Candidate to come out, so the first iOS 26.4 beta is likely still at least a week or two away. Following beta testing, iOS 26.4 will likely be released to the general public in March or April. Below, we have recapped known or rumored iOS 26.3 and iOS 26.4 features so far. iOS 26.3 iPhone to Android Transfer Tool iOS 26.3 makes it easier...
14 inch MacBook Pro Keyboard

Apple Changes How You Order a Mac

Saturday January 31, 2026 10:51 am PST by
Apple recently updated its online store with a new ordering process for Macs, including the MacBook Air, MacBook Pro, iMac, Mac mini, Mac Studio, and Mac Pro. There used to be a handful of standard configurations available for each Mac, but now you must configure a Mac entirely from scratch on a feature-by-feature basis. In other words, ordering a new Mac now works much like ordering an...