New Apple Watch ECG Algorithm Version Included in iOS 14.3 and watchOS 7.2

Apple has designed a new algorithm that Apple Watch uses to measure electrocardiogram (ECG) waves, according to developer documentation for the iOS 14.3 and watchOS 7.2 betas.

apple watch ecg
In the official documentation, a new "version 2 algorithm" declaration has been added. No other information is included.

The ECG feature includes irregular heart rhythm detection, which intermittently measures the user's heart rate in the background and sends a notification if it detects an anomaly it categorizes as atrial fibrillation, which can be a serious heart arrhythmia condition.

Based on beta code uncovered by MacRumors, it's likely that the new algorithm will allow the ECG app to check for atrial fibrillation (AFib) at higher heart rates - during exercise, for example.

ecg algorithm version 2
iOS 14.3 will introduce support for Apple Fitness+, Apple's upcoming fitness service that will work with the Apple Watch, plus it brings a new Cardio Fitness feature that lets you know if your VO2Max levels are low. VO2Max is a useful measurement of overall fitness and heart health.

iOS 14.3 is set to be released on Monday, December 14, which is also the day that Apple Fitness+ is coming out.

(Thanks, Simon!)

Top Rated Comments

jambon Avatar
19 weeks ago
In the Health app on the phone, it now states that ECG is available/better at higher/lower HRs
Score: 8 Votes (Like | Disagree)
hellosil Avatar
19 weeks ago
I love how tech like this can make our health better.
Score: 7 Votes (Like | Disagree)
tx368 Avatar
19 weeks ago
And ECG is finally rolling out to Taiwan in this update!
Score: 5 Votes (Like | Disagree)
neuropsychguy Avatar
19 weeks ago

Wait what? The ECG only works when your finger is on the Digital Crown. It can’t work in the background.
The background irregular heart rhythm detection does not use the ECG but it is grouped with the ECG features (which is technically inaccurate but they are related features, just different technologies). It's been around as long as the ECG: "Using the optical heart sensor in Apple Watch Series 1 or later, 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." (https://www.apple.com/newsroom/2018/12/ecg-app-and-irregular-heart-rhythm-notification-available-today-on-apple-watch/)
Score: 3 Votes (Like | Disagree)
tx368 Avatar
19 weeks ago

Still waiting for ECG in Japan!
Any news about it?
Since ECG received final medical approval in Japan this September, I guess maybe iOS 14.3 will cover ECG functionality also Japan as well? *finger-crossed*
Score: 2 Votes (Like | Disagree)
smbutton Avatar
6 weeks ago
Well it appears the TGA has approved this for Australia. Can't wait for the update to include this function.
Score: 2 Votes (Like | Disagree)

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