Over 2,000 Participants Received Irregular Heart Rhythm Notification in Apple Watch Study

Stanford Medicine researchers presented their findings of the Apple Heart Study at the American College of Cardiology's 68th Annual Scientific Session and Expo in New Orleans today, as noted by Apple in a press release.

apple heart study
Apple and Stanford created the study to evaluate the Apple Watch's irregular heart rhythm notification feature, which occasionally checks the wearer's heart rhythm in the background and sends a notification if an irregular heart rhythm appears to be suggestive of atrial fibrillation.

419,093 people across the United States participated in the study. As part of the study, if an irregular heart rhythm was identified, participants received a notification on their Apple Watch and iPhone, a phone consultation with a doctor, and an ECG patch for additional monitoring.

Study results showed 0.5 percent of participants - approximately 2,095 people - received an irregular heart rhythm notification. Apple says "many participants sought medical advice following their irregular rhythm notification."

Apple COO Jeff Williams:

We are proud to work with Stanford Medicine as they conduct this important research and look forward to learning more about the impact of Apple Watch alongside the medical community. We hope consumers will continue to gain useful and actionable information about their heart health through Apple Watch.

Apple announced the Heart Study in collaboration with Stanford back in November 2017 and stopped accepting new participants in August 2018.

Related Roundup: Apple Watch 10
Buyer's Guide: Apple Watch (Neutral)

Popular Stories

Apple iPhone 16e Feature

Apple Announces iPhone 16e With A18 Chip and Apple Intelligence, Pricing Starts at $599

Wednesday February 19, 2025 8:02 am PST by
Apple today introduced the iPhone 16e, its newest entry-level smartphone. The device succeeds the third-generation iPhone SE, which has now been discontinued. The iPhone 16e features a larger 6.1-inch OLED display, up from a 4.7-inch LCD on the iPhone SE. The display has a notch for Face ID, and this means that Apple no longer sells any iPhones with a Touch ID fingerprint button, marking the ...
iphone 17 pro asherdipps

iPhone 17 Pro Models Rumored to Feature Aluminum Frame Instead of Titanium Frame

Tuesday February 18, 2025 12:02 pm PST by
Over the years, Apple has switched from an aluminum frame to a stainless steel frame to a titanium frame for its highest-end iPhones. And now, it has been rumored that Apple will go back to using aluminum for three out of four iPhone 17 models. In an investor note with research firm GF Securities, obtained by MacRumors this week, Apple supply chain analyst Jeff Pu said the iPhone 17, iPhone...
apple launch feb 2025 alt

Here Are the New Apple Products We're Still Expecting This Spring

Thursday February 20, 2025 5:06 am PST by
Now that Apple has announced its new more affordable iPhone 16e, our thoughts turn to what else we are expecting from the company this spring. There are three product categories that we are definitely expecting to get upgraded before spring has ended. Keep reading to learn what they are. If we're lucky, Apple might make a surprise announcement about a completely new product category. M4...
Generic iOS 18

Here's When Apple Will Release iOS 18.4

Wednesday February 19, 2025 11:38 am PST by
Following the launch of the iPhone 16e, Apple updated its iOS 18, iPadOS 18, and macOS Sequoia pages to give a narrower timeline on when the next updates are set to launch. All three pages now state that new Apple Intelligence features and languages will launch in early April, an update from the more broader April timeframe that Apple provided before. The next major point updates will be iOS ...
apple launch feb 2025

Tim Cook Teases an 'Apple Launch' Next Wednesday

Thursday February 13, 2025 8:07 am PST by
In a social media post today, Apple CEO Tim Cook teased an upcoming "launch" of some kind scheduled for Wednesday, February 19. "Get ready to meet the newest member of the family," he said, with an #AppleLaunch hashtag. The post includes a short video with an animated Apple logo inside a circle. Cook did not provide an exact time for the launch, or share any other specific details, so...
apple c1

Apple Unveils 'C1' as First Custom Cellular Modem

Wednesday February 19, 2025 8:08 am PST by
Apple today announced its first custom cellular modem with the name "C1," debuting in the all-new iPhone 16e. The new modem contributes to the iPhone 16e's power efficiency, giving it the longest battery life of any iPhone with a 6.1-inch display, such as the iPhone 15 and iPhone 16. Expanding the benefits of Apple silicon, C1 is the first modem designed by Apple and the most...
Apple Northbrook

Apple Store Permanently Closing at Struggling Mall in Chicago Area

Tuesday February 18, 2025 8:46 pm PST by
Apple is permanently closing its retail store at the Northbrook Court shopping mall in the Chicago area. The company confirmed the upcoming closure today in a statement, but it has yet to provide a closing date for the location. Apple Northbrook opened in 2005, and the store moved to a larger space in the mall in 2017. Apple confirmed that affected employees will continue to work for the...

Top Rated Comments

GubbyMan Avatar
78 months ago
So what did this lead to? 0.5% got the notification and then what? Did they all really have irregular heart rhythm or were there false positives?
Score: 31 Votes (Like | Disagree)
ThunderSkunk Avatar
78 months ago
A couple times a month I get a few dropped heartbeats and some fluttering around for a bit while I wonder if this is finally it. But every time, it ends in disappointment. I still have to get up the next day and go to work to prop up this barbaric culture for absolutely no good reason.
Score: 18 Votes (Like | Disagree)
DoctorTech Avatar
78 months ago
No medical screening test is 100% accurate. Early pregnancy tests are about 99% accurate. Even mammogram screening for breast cancer is only 87% accurate https://ww5.komen.org/BreastCancer/AccuracyofMammograms.html

Most people in the medical community agree it is better to have a false positive than a false negative because a false negative would discourage someone from seeking medical treatment and could ultimately lead to worse effects than someone seeking medical treatment for a condition they do not have.

For such a new, low cost, and non-intrusive device, I think the results of this study are actually pretty amazing.
Score: 12 Votes (Like | Disagree)
KPandian1 Avatar
78 months ago
Irregular rhythm happens everyday, even by narrow medical definition; there is variation even with breathing.

The irregularity detected here is reported "if an irregular heart rhythm appears to be suggestive of atrial fibrillation." The software is setup by a medical team with oversight to eliminate the daily variations - A Fib is characteristically different. Even on a 12-lead ECG with Holter monitoring, the interpretation is physician based, preferably a cardiologist.

So, if 200-20 or even 2 of these detected were found with real atrial fibrillation rhythm, it is a win; these are from people with no known heart problems.

The worst a false positive does is send someone for further rhythm monitoring by a pro - worth the hassle.

The first post is sarcasm.
Score: 11 Votes (Like | Disagree)
Khedron Avatar
78 months ago
So what did this lead to? 0.5% got the notification and then what? Did they all really have irregular heart rhythm or were there false positives?
34% were confirmed to have atrial fibrillation with a follow-up.

Not all the other 66% would be false positive since it's an intermittent condition.
Score: 9 Votes (Like | Disagree)
kpeex Avatar
78 months ago
So what did this lead to? 0.5% got the notification and then what? Did they all really have irregular heart rhythm or were there false positives?
I enrolled on the first day that the AHS app was available to the public. From the app, I had 3,144 data contributions in 459 days. As info, I cycled about 6,000 miles during that period, probably about half those days. My heart rate normally goes way up when cycling. RHR tends to be kind of low. I received an "Irregular Heart Rhythm Observed" notification about 45 days into the study:

* I initiated an in-app video call to an AHS cardiologist using the direct link on the notification that popped up. She interviewed me for about 30 minutes. During the interview, she discussed the study as having flagged me for single digit number of SVT events during five different 60-second measurement periods. (Supra-ventricular Tachycardia)
* They overnighted a 7-day ambulatory ECG monitor that I returned at the end of the week.
* When the results were ready, they notified me and sent another in-app video call link.
* A second video conference explained the results -- a few more instances of SVT detected. She recommended that I follow-up with a cardiologist, who was provided the monitor results. I also got pdfs of all records.
* I went to a locally recommended cardiologist, who discussed the SVT events that the watch and monitor picked up.
* He recommended I have an echocardiogram done to establish a baseline, which I did.
* There was a follow-up to discuss the results.

I guess it wasn't a false positive and it wasn't A-fib. The cardiologist seemed surprised that a fitness tracker caught it.
Score: 9 Votes (Like | Disagree)