After the announcement that the all new Apple Watch Series 4 would be the commercially available device to provide ECG readings, Apple finally released the app with the latest WatchOS 5.1.2. The new electrocardiogram (ECG) and irregular heart rhythm notifications are now live within the U.S.

It’s worth noting that Apple has only activated the app to watches bought from the U.S only, so changing the region won’t actually work unless your Apple Watch was purchased with the U.S.
ECG App
Here’s how to take an ECG (electrocardiogram) on Apple Watch series 4:
- Update your Apple Watch Series 4 to watchOS 5.1.2 and iPhone to iOS 12.1.1
- Open the Watch app on your iPhone and tap on the Heart icon to set Set up the ECG app in Health app and follow the instructions.
- Once done, the ECG app will be amiable on your Apple Watch.
To take an ECG:
- Launch the ECG app
- With your arms relaxed on a surface or your lap, hold the Digital Crown with your finger for 30 seconds without pressing, and keep your finger still until the countdown is over.

Once that is done, the Apple Watch will display your results.

Irregular Rhythm Notification
Using the optical heart sensor, the irregular rhythm notification feature will occasionally check the user’s heart rhythm in the background for signs of an irregular heart rhythm that appears to be AFib and alerts the user with a notification if an irregular rhythm is detected on five rhythm checks over a minimum of 65 minutes.

