Hands-On With the ECG Feature for Apple Watch Series 4

Apple today released the watchOS 5.1.2 update to the public, and the update implements a much-anticipated ECG feature for all Apple Watch Series 4 users in the United States.

Following the launch of the new update, we installed the software and went hands-on with the ECG function to see just how it works.


An ECG, or electrocardiogram, is designed to measure the electrical activity of the heart to detect abnormal rhythms and diagnose serious heart conditions.

The Apple Watch Series 4 allows users to take a single-lead electrocardiogram to keep an eye on heart health. This isn't as informative or as sensitive as the multi-lead ECGs you might get in a doctor's office or hospital, which use several points of contact, but it provides valuable information for those who might not even be aware of a heart condition.

The ECG feature in the Apple Watch uses electrodes built into the sapphire crystal of the Apple Watch (where the heart rate sensor is located) and the Digital Crown that work together to detect the electrical impulses from your heartbeat and route the data to the S4 processor in the device, where it is converted into a signal for Apple's algorithms.

ecg1
You can take an ECG using the built-in ECG app on the Apple Watch, which walks you through the steps. You'll need to place a finger on the Digital Crown of the Apple Watch and wait for approximately 30 seconds while the measurement is taken.

ecg2
You'll see a countdown on your wrist, which is designed to let you know just how long your finger needs to stay in place before you can move it.

ecg 3
Following the conclusion of the ECG, Apple will provide a heart rhythm classification that can be shared with your doctor. If your heart is beating in a normal rhythm, Apple will let you know that a standard sinus rhythm has been detected. If your heart is not beating normally, however, the app will let you know that atrial fibrillation has been detected.

If atrial fibrillation is detected, Apple will suggest that you get in touch with your doctor for further testing.

All ECG results captured with the Apple Watch Series 4 are stored in the Health app in a format that's easy to export and share with your doctor.

ecg 4
Apple has received de novo FDA clearance for the ECG feature in the Apple Watch Series 4, but FDA clearance is not the same as full FDA approval. The FDA does not recommend that the ECG feature be used by those under 22 or those who have already been diagnosed with atrial fibrillation.

The Apple Watch Series 4's ECG function is not designed to replace traditional methods of diagnosis or treatment, and Apple intends for it to be used for informational purposes.

At the current time, Apple Watch Series 4 owners in the United States are the only Apple Watch customers who can take an ECG because the feature needs regulatory approval to be made available in other countries. Apple is working to expand the feature to additional countries.

While the ability to take an ECG is limited to Apple Watch Series 4 users, Apple is implementing a secondary feature designed to send Apple Watch Series 1, 2, 3, and 4 users a notification if an irregular heartbeat is detected via the normal heart rate sensor in the device.

What do you think of the ECG option in the Apple Watch? Let us know in the comments.

Related Roundup: Apple Watch Series 9
Buyer's Guide: Apple Watch (Neutral)

Top Rated Comments

ericgtr12 Avatar
69 months ago
I predict a 200% rise in calls to the doctor by tomorrow.
Score: 31 Votes (Like | Disagree)
mariusignorello Avatar
69 months ago
Why is it America only, exactly? I mean, it's clear some in America have different hearts, but how different is this?
The backhanded comment was absolutely unnecessary.

Edit: I made this comment in the morning. Not actually offended. But leave us Americans alone.
Score: 26 Votes (Like | Disagree)
now i see it Avatar
69 months ago
I can tell you right now... this is going to create a lot of unnecessary anxiety for countless users who see an occasional heart jump on the display. Admittedly, it might help a few people too.
This is gong to be one of those devices that people either obsess on, (100x worse than your iPhone battery capacity meter) or learn to ignore and not use after a few panicked visits to the Dr, reveal nothing can be done about occasional irregular heartbeats.

It's going to be helpful and harmful. The few it helps will come at the expense of the many who develop anxiety disorders staring at it incessantly.
Score: 11 Votes (Like | Disagree)
iamgalt Avatar
69 months ago
Why is it America only, exactly? I mean, it's clear some in America have different hearts, but how different is this?
Read the full article. It clearly states that Apple has to get regulatory approval from other counties before it can be made available. Just like they had to get FDA Clearance here in the US.
Score: 10 Votes (Like | Disagree)
Baymowe335 Avatar
69 months ago
If that 98bpm is accurate, Dan might need to talk to his doctor about exercise.
Score: 10 Votes (Like | Disagree)
Moof1904 Avatar
69 months ago
It seems a bit absurd that the FDA states this should not be used by those who already have been diagnosed with a-fib. Wouldn't such people want to know if their a-fib is being well controlled by whatever anti-a-fib-whatever their doctor has them on?
Score: 9 Votes (Like | Disagree)

Popular Stories

reset password request iphone

Warning: Apple Users Targeted in Phishing Attack Involving Rapid Password Reset Requests

Tuesday March 26, 2024 4:34 pm PDT by
Phishing attacks taking advantage of Apple's password reset feature have become increasingly common, according to a report from KrebsOnSecurity. Multiple Apple users have been targeted in an attack that bombards them with an endless stream of notifications or multi-factor authentication (MFA) messages in an attempt to cause panic so they'll respond favorably to social engineering. An...
maxresdefault

Apple to Launch New iPad Pro and iPad Air Models in May

Thursday March 28, 2024 11:07 am PDT by
Apple will introduce new iPad Pro and iPad Air models in early May, according to Bloomberg's Mark Gurman. Gurman previously suggested the new iPads would come out in March, and then April, but the timeline has been pushed back once again. Subscribe to the MacRumors YouTube channel for more videos. Apple is working on updates to both the iPad Pro and iPad Air models. The iPad Pro models will...
Generic iOS 18 Feature Purple

iOS 18: What to Expect From 'Biggest' Update in iPhone's History

Wednesday March 27, 2024 11:10 am PDT by
At least some Apple software engineers continue to believe that iOS 18 will be the "biggest" update in the iPhone's history, according to Bloomberg's Mark Gurman. Below, we recap rumored features and changes for the iPhone. "The iOS 18 update is expected to be the most ambitious overhaul of the iPhone's software in its history, according to people working on the upgrade," wrote Gurman, in a r...
maxresdefault

Apple Announces WWDC 2024 Event for June 10 to 14

Tuesday March 26, 2024 10:02 am PDT by
Apple today announced that its 35th annual Worldwide Developers Conference is set to take place from Monday, June 10 to Friday, June 14. As with WWDC events since 2020, WWDC 2024 will be an online event that is open to all developers at no cost. Subscribe to the MacRumors YouTube channel for more videos. WWDC 2024 will include online sessions and labs so that developers can learn about new...
apple maps 3d feature

Apple Maps May Gain Custom Routes With iOS 18

Tuesday March 26, 2024 3:10 pm PDT by
Apple may be planning to add support for "custom routes" in Apple Maps in iOS 18, according to code reviewed by MacRumors. Apple Maps does not currently offer a way to input self-selected routes, with Maps users limited to Apple's pre-selected options, but that may change in iOS 18. Apple has pushed an iOS 18 file to its maps backend labeled "CustomRouteCreation." While not much is revealed...
General iOS 17 Feature Orange Purple

Apple Releases Revised Versions of iOS 17.4.1 and iPadOS 17.4.1 With Updated Build Number

Wednesday March 27, 2024 5:59 am PDT by
Apple on late Tuesday released revised versions of iOS 17.4.1 and iPadOS 17.4.1 with an updated build number of 21E237, according to MacRumors contributor Aaron Perris. The updates previously had a build number of 21E236. The revised updates are available for all iPhone and iPad models that are compatible with iOS 17 and iPadOS 17, but they can only be installed via the Finder app on macOS...
applephilschiller

Apple's Phil Schiller Works 80 Hours a Week Overseeing App Store

Wednesday March 27, 2024 2:03 pm PDT by
With the App Store and app ecosystem undergoing major changes in the European Union, The Wall Street Journal today shared a profile on App Store chief Phil Schiller, who is responsible for the App Store. Though Schiller transitioned from marketing chief to "Apple Fellow" in 2020 to take a step back from Apple and spend more time on personal projects and friends, he is reportedly working...