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.
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.
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.
Thursday August 28, 2025 4:08 am PDT by Tim Hardwick
An iPhone 17 announcement is a dead cert for September 2025 – Apple has already sent out invites for an "Awe dropping" event on Tuesday, September 9 at the Apple Park campus in Cupertino, California. The timing follows Apple's trend of introducing new iPhone models annually in the fall.
At the event, Apple is expected to unveil its new-generation iPhone 17, an all-new ultra-thin iPhone 17...
Apple is expected to unveil the iPhone 17 series on Tuesday, September 9, and last-minute rumors about the devices continue to surface.
The latest info comes from a leaker known as Majin Bu, who has shared alleged images of Apple's Clear Case for the iPhone 17 Pro and Pro Max, or at least replicas.
Image Credit: @MajinBuOfficial
The images show three alleged changes compared to Apple's iP...
Friday August 29, 2025 4:54 am PDT by Tim Hardwick
Apple and Samsung have reportedly issued cease-and-desist notices to Xiaomi in India for an ad campaign that directly compares the rivals' devices to Xiaomi's products. The two companies have threatened the Chinese vendor with legal action, calling the ads "disparaging."
Ads have appeared in local print media and on social media that take pot shots at the competitors' premium offerings. One...
Apple is preparing to release iOS 18.7 for compatible iPhone models, according to evidence of the update in the MacRumors visitor logs.
We expect iOS 18.7 to be released in September, alongside iOS 26. The update will likely include fixes for security vulnerabilities, but little else.
iOS 18.7 will be one of the final updates ever released for the iPhone XS, iPhone XS Max, and iPhone XR,...
Monday September 1, 2025 4:35 am PDT by Tim Hardwick
Apple will launch its new iPhone 17 series this month, and the iPhone 17 Pro models are expected to get a new design for the rear casing and the camera area. But more significant changes to the lineup are not expected until next year, when the iPhone 18 models arrive.
If you're thinking of trading in your iPhone for this year's latest, consider the following features rumored to be coming to...
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/)
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*
Biggest design overhaul since iOS 7 with Liquid Glass, plus new Apple Intelligence features and improvements to Messages, Phone, Safari, Shortcuts, and more. Developer beta available now ahead of public beta in July.
