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macrumors bot
Original poster
Apr 12, 2001

Apple Watch Series 4 models include an electrical heart rate sensor that's designed to take an electrocardiogram (ECG) using an ECG app, the built-in sensor, and the electrodes included in the Digital Crown, but the ECG functionality won't be coming until later this year.

According to Apple's Apple Watch Series 4 website, the ECG app that will enable the electrocardiogram feature will be available later in 2018. That means at launch, the ECG feature won't be functional.


As several MacRumors readers have pointed out, it appears ECG readings are going to be limited to Apple Watch models sold in the United States. Apple Watch Series 4 pages for countries like the UK and Canada contain no mention of the feature, and Apple's press release for Series 4 models says ECG functionality is U.S. only.

To take an ECG reading from the Apple Watch, users will need to place a finger on the Digital Crown while wearing the watch. The reading is completed in just 30 seconds, allowing users to determine whether their hearts are beating in a regular pattern or if there are signs of atrial fibrillation, which can be an indicator of serious health problems.

Atrial fibrillation is a health condition that often goes undiagnosed, so the ECG feature in the Apple Watch will be highly useful for detecting early signs of disease. ECG readings also normally require a full ECG machine and a visit to the doctor, which is far less convenient than a reading taken with the Apple Watch.

Apple says that the ECG feature in the Apple Watch has been granted a De Novo classification by the FDA as outlined on the FDA's website [PDF], and the need for regulatory approval is likely why the ECG feature is not available in other countries.

De Novo FDA approval is a preliminary approval process granted to new devices that are not likely to cause harm. According to the FDA, the Apple Watch's ECG feature should be used only for informational purposes, should only be used by those over 22 years of age, and is not recommended for people with known arrhythmias.
The ECG app is a software-only mobile medical application intended for use with the Apple Watch to create, record, store, transfer, and display a single channel electrocardiogram (ECG) similar to a Lead I ECG. The ECG app determines the presence of atrial fibrillation (AFib) or sinus rhythm on a classifiable waveform. The ECG app is not recommended for users with other known arrhythmias.

The ECG app is intended for over-the-counter (OTC) use. The ECG data displayed by the ECG app is intended for informational use only. The user is not intended to interpret or take clinical action based on the device output without consultation of a qualified healthcare professional. The ECG waveform is meant to supplement rhythm classification for the purposes of discriminating AFib from normal sinus rhythm and not intended to replace traditional methods of diagnosis or treatment.

The ECG app is not intended for use by people under 22 years old.
Apple has also obtained FDA approval for the feature in the Apple Watch Series 4 models that sends notifications when an irregular heart rhythm is detected through the ECG feature or through standard Apple Watch heart rate monitoring.

All ECG data gathered by Apple Watch Series 4 models is stored in the Health app in a PDF format that can easily be shared with physicians.

Article Link: Electrocardiogram Functionality in New Apple Watch Series 4 Models Limited to US, Coming Later This Year


macrumors newbie
Jan 9, 2007
I hope everyone knows this is pretty much worthless for 99% of users. Why don't we ALL get EKGs every day or every time we go to the doctor? because there's no reason to and it would lead to false positive diagnoses with harm caused to patients. "Should not be used for patients with known arrythmias." So this is basically for an extremely small subset of buyers who have some kind of coronary artery disease or heart pathology that makes them susceptible to possibly developing A-fib.


macrumors regular
Mar 31, 2005
Needs more approvals in the EU and elsewhere.
Yeah, someone correct me if I'm wrong, but I think the FDA's approach regarding approvals is more along the lines of "go ahead, but we'll go after you if it turns out to be unsafe or completely unfit for its purpose", whereas most other health authorities will require more data regarding safety and effects before they approve a product.

Bascially: Reactive vs proactive action. Both have their pros and cons – one allows for a quicker time-to-market with less red tape, while the other is usually better at weeding out bad or dangerous products before they do harm.
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macrumors newbie
Aug 13, 2014
According to Apple AU, a quick search did have the keyword ECG in the post. I'd say its coming, just after it gets necessary approvals.
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Staff member
Dec 7, 2012
Oddly enough, while it doesn't mention the ECG on the compare page for versions in Canada, the actual product purchase page does mention it

Do you have a link? I didn't see it on the purchase page in Canada.

Edit: Just to update, Apple's announcement page for Series 4 says US only for ECG. Missed that earlier.
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macrumors 65816
Oct 30, 2015
Jeff said in the presentation that they were “working hard” to bring it to other countries.
Does anybody know if the 4 will measure blood pressure?
That’s more of a watchband feature.


macrumors member
Jan 14, 2017
My wallet breathed a sigh of relief at the lack of any selling points over the series 2 here in Norway. No LTE here, no ECG here, and battery doesn’t seem to offer a sufficient improvement to switch. Also nothing but a spec bump to the X, and a feature cut on the merely-premium cost device. Fall detection came too late for the four people I’ve wanted it for.

Most cost-effective keynote ever.

Will be interesting to see if the EU/EEC get feature parity at some point. Those cut features are the two I’d spring for. That, or double the battery, or the charge speed, would be a “take my money” situation.

Wonder if apps get access to the sensor?


macrumors 6502a
Nov 7, 2013
Seattle, WA
I have a feeling it will be available on the same day as a new Mac Mini and AirPower.. which is when god knows when it will ever happen!


macrumors 6502
Jul 5, 2008
I think this restriction is probably going to be easy to defeat by changing the country, much like with those US-only workout achievements. But then when you want to use the Apple Pay, you have to switch the country back to wherever you really are.

It’s true though, for most people this will not be too useful. But then again, neither is the constant heartbeat measuring. But, it will find something for someone, and be very useful.

Do you have a link? I didn't see it on the purchase page in Canada.
They mention the new electrical heart sensor, but nothing about ECG on the Canadian page. On the US page, in the guardian section, they do make note of it, prominently.
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macrumors newbie
Aug 24, 2016
Crap. That sucks. Needs to come to Australia also.
I already have A Fib so probably not that useful for me, but it would be cool to have more than just the heart rate checked. Very tempted by an s4 watch none the less for the slightly bigger display.


macrumors 6502
Jul 5, 2008
Hypochondriacs, rejoice!

Though I question the wisdom of giving an advanced diagnostic tool like that to regular people. Non-doctors tend to diagnose themselves with the worst things possible.
My guess is that it works well enough that when it tells you something is wrong, that something probably is wrong. Think of a blood pressure measuring at home - it’s useful because you can do it in various situations, when you’re relaxed, stressed, etc. where at the doctors office you only do it in that window of a few minutes. And with BP, it’s also a measuring that’s as precise as anything a doctor would use. This probably won’t be at that level, but maybe it’s just close enough.


macrumors 6502a
May 6, 2003

Apple says that the ECG feature in the Apple Watch has been granted a De Novo
According to the FDA, the Apple Watch's ECG feature should be used only for informational purposes, should only be used by those over 22 years of age

“The ECG app is not intended for use by people under 22 years old.”

What about those who are 22?

Classic off-by-one error there.
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