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

Popular Stories

Generic iOS 18 Feature Real Mock

iOS 18 Coming Later This Month With These 8 New Features

Tuesday September 3, 2024 12:07 pm PDT by
iOS 18 has been in beta testing for nearly three months, and the software update will finally be released for all compatible iPhones soon. Apple should reveal iOS 18's exact release date during its September 9 event, with the most likely possibility being Monday, September 16. Below, we have highlighted eight key new features included in iOS 18. Note that Apple Intelligence is not coming...
iPhone 16 Side New Action Button Emphasis Bump

iPhone 16 Apple Silicone Cases Have No Cutout for New Capture Button

Wednesday September 4, 2024 3:19 am PDT by
Apple is introducing a new camera-based "Capture" button on at least some iPhone 16 models this year, and a new rumor claims that Apple's own silicone cases will have a design that is specially made so as not to impede the use of the capacitive button's multiple functions. Several rumors have suggested that the iPhone 16 models are going to have an all-new button that's designed to make it...
iOS 18 CarPlay Feature

iOS 18 Adds These 6 New Features to CarPlay

Tuesday September 3, 2024 12:59 pm PDT by
Apple did not mention CarPlay when it unveiled iOS 18 in June, but the update includes a handful of new features for the in-car iPhone system. iOS 18 includes some changes to the Messages app, Settings app, and Siri on CarPlay. The update should be widely released later in September. Below, we recap CarPlay's key new features on iOS 18. 1. Contact Photos in Messages App iOS 18 adds...
sonny iphone 16 pro colors

New iPhone 16 and iPhone 16 Pro Colors Revealed Ahead of Apple Event

Friday September 6, 2024 5:01 am PDT by
Apple is "shaking up its color palette" for its iPhone 16 lineup this year, according to well-connected Bloomberg reporter Mark Gurman. Early iPhone 16 Pro dummy models via Sonny Dickson According to Gurman, the iPhone 16 Pro models will come in a Gold Titanium to replace Blue Titanium, while the Black, White, and Natural Titanium options that debuted with the iPhone 15 Pro will remain...
iPhone 16 Pro Mock Article

iPhone 16 Launch Month Is Here: Everything We Know

Sunday September 1, 2024 4:30 am PDT by
Apple has announced that on Monday, September 9 it will hold its annual fall event, which means we are just days away from the launch of the iPhone 16. Like the iPhone 15 series, this year's lineup is expected to stick with four models – iPhone 16, iPhone 16 Plus, iPhone 16 Pro, and iPhone 16 Pro Max – although there are plenty of design differences and new features to take into account. ...
its glowtime event youtube

Report Details Last-Minute Apple Event Rumors About New iPhones, Apple Watches, and AirPods

Friday September 6, 2024 4:40 am PDT by
Bloomberg's Mark Gurman today shared his final expectations for Apple's "It's Glowtime" event, providing some new tidbits and clarifications about the new devices set to be announced on Monday. iPhone 16 Pro Along with larger 6.3- and 6.9-inch display sizes, the iPhone 16 Pro and iPhone 16 Pro Max will have bezels that are "now about a third slimmer" for a "sleeker overall look." The...
Generic iOS 18 Feature Real Mock

When to Expect iOS 18 on Your iPhone as Beta Testing Wraps Up

Wednesday September 4, 2024 10:50 am PDT by
iOS 18 has been in beta testing for nearly three months, and the software update should finally be widely released later this month. Below, we outline when to expect iOS 18 to be available on all compatible iPhones. iOS 18: Beta Testing Wraps Up In his Power On newsletter last weekend, Bloomberg's Mark Gurman said iOS 18 beta 8 will likely be the final developer beta version for the...

Top Rated Comments

ericgtr12 Avatar
75 months ago
I predict a 200% rise in calls to the doctor by tomorrow.
Score: 31 Votes (Like | Disagree)
mariusignorello Avatar
75 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
75 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
75 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
75 months ago
If that 98bpm is accurate, Dan might need to talk to his doctor about exercise.
Score: 10 Votes (Like | Disagree)
Moof1904 Avatar
75 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)