Here’s what’s changing with ECG Version 2 on your Apple Watch

Person using Apple Watch ECG app.

Apple yesterday released new firmware upgrades for all of its devices including the Apple Watch. watchOS 7.2 brings along a bunch of new health-related improvements such as VO2 measurement, Cardio Fitness measurements, support for Fitness+, and more.

However, Apple also pushed one more update that seemingly went under the radar—ECG Version 2. It’s the next iteration of Apple’s famous Electrocardiogram feature on the Apple Watch.

Now, Apple has updated its ECG support document to reveal what’s new. As per the document, supported Apple Watch models can now check for AFib for heart rates between 50 and 150 bpm as opposed to the 120 bpm limit before. This means that a heart rate below 50 and above 150 bpm can return inconclusive results.

Apple says that “The ECG app version 2 was also tested in a clinical trial with approximately 546 subjects, and demonstrated 99.3% specificity with respect to sinus rhythm classification, and 98.5% sensitivity for AFib classification for the classifiable results.”

Furthermore, ECG Version 2 also improves the accuracy with which it measures ECG. Not resting your hands on the table while conducting a test now won’t return an inconclusive result. However, there’s a new classification within ECG Version 2 called Poor Recording. If you get a Poor Recording message, it means that the result can’t be classified.

Apple says that you still need to rest your hands on either a table or your lap to get the best results. But doing that is no longer explicitly necessary.

Lastly, according to the support document, not everyone might receive the Version 2 update as it is ultimately dependent on the regulations of the country you reside in. In order to check which version of ECG you have, head over to the Health app on your iPhone, navigate to the Browse tab and tap on the Heart icon. Then tap ECG, and About.

On your Apple Watch, head over to Settings, tap on the Heart icon, and the ECG version number will be listed there.

Note that you’ll need to make sure your Apple Watch and iPhone are upgraded to watchOS 7.2 and iOS 14.3 respectively in order to take advantage of ECG Version 2.

Currently, ECG is only available in selected countries and Apple Watch models. You need to have an Apple Watch Series 4, 5, or 6 in order to measure ECG. The Apple Watch SE is not supported as well.