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

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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 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.

Article Link: Over 2,000 Participants Received Irregular Heart Rhythm Notification in Apple Watch Study
 
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ThunderSkunk

macrumors 68040
Dec 31, 2007
3,016
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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.
 
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KPandian1

macrumors 65816
Oct 22, 2013
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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.
 
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I7guy

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Nov 30, 2013
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Gotta be in it to win it
Like the fitness motivate people to stay healthy through positive reinforcement of goals, the Apple Watch EKG feature encourages people to stay healthy (or healthier) by seeking medical help as warranted.
 
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I7guy

macrumors Penryn
Nov 30, 2013
24,226
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Gotta be in it to win it
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 id send someone for further rhythm monitoring by a pro - worth the hassle.

The first post is sarcasm.
Key findings....very interesting as it shows the AW EKG can have a positive impact on health by predicting potential medical events.

  • Overall, only 0.5 percent of participants received irregular pulse notifications, an important finding given concerns about potential over-notification.
  • Comparisons between irregular pulse-detection on Apple Watch and simultaneous electrocardiography patch recordings showed the pulse detection algorithm (indicating a positive tachogram reading) has a 71 percent positive predictive value. Eighty-four percent of the time, participants who received irregular pulse notifications were found to be in atrial fibrillation at the time of the notification.
  • One-third (34 percent) of the participants who received irregular pulse notifications and followed up by using an ECG patch over a week later were found to have atrial fibrillation. Since atrial fibrillation is an intermittent condition, it’s not surprising for it to go undetected in subsequent ECG patch monitoring.
  • Fifty-seven percent of those who received irregular pulse notifications sought medical attention.
 
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DoctorTech

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Jan 6, 2014
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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.
 
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Crowbot

macrumors 6502a
May 29, 2018
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Without having the entire study group have an EKG afterwards there’s no way to measure the actual effectiveness of the watch. Of course if even just one life is saved it’s great but I feel Apple is being a little disingenuous here.

I disagree that Apple is being disingenuous. The study was of patient's heart rate, not ECG, and how it relates to AFib. The sensor sees normal heart rhythm as something like this drawing. If the rate or wave shape changes in specific ways it can point to a problem. This is screening at the lowest level. The participants were offered follow-up for any alerts. And it helps Apple make the sensors better. They could easily read O2 levels with a minor change to the sensors on the back. If they can figure out to do sugar levels they'd sell a billion.
 

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Not-Sure

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The only thing you have to worry about in your body is erectile dysfunction.
Just avoid eating fast food, always work out, have sex (not porn) and you are all set.
 
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Relentless Power

macrumors Nehalem
Jul 12, 2016
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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.

Great points. And you said something really true, being that it is [non-intrusive and low-cost] for a device that provides relevant results with this Apple Watch study. If anything, I commend conducting these types of studies to understand irregular heart rhythm and anomalies as it is.
 
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rdcsw

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May 5, 2010
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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?
In a Reuters article on this : "Some 84 percent of the irregular pulse notifications were later confirmed to have been AF episodes, data showed."
 
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I7guy

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neliason

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When my niece was born she had a low heart rate and the doctors were very concerned. She was sent to be seen by a pediatric heart specialist. Then her parents tell them that our family has very low resting heart rates. Suddenly the big health worry is nothing.

The point of that is that what is regular or average is somewhat subjective. Unnecessary doctors visits are expensive. Worse they can lead you down a terrible path where doctors do more harm than good.

So I can see doctors pushing this technology very hard. You can never be too careful they’ll say. Saving just one life is worth it. Of course if anyone paid attention to the statistic that doctors are the third leading cause of death in the US then more people would realize being careful means avoiding doctors. This isn’t to say the technology can’t be great for some people. We just need to realize that we each individually value our own life and health far more than anyone else.
 
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I7guy

macrumors Penryn
Nov 30, 2013
24,226
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Gotta be in it to win it
When my niece was born she had a low heart rate and the doctors were very concerned. She was sent to be seen by a pediatric heart specialist. Then her parents tell them that our family has very low resting heart rates. Suddenly the big health worry is nothing.

The point of that is that what is regular or average is somewhat subjective. Unnecessary doctors visits are expensive. Worse they can lead you down a terrible path where doctors do more harm than good.

So I can see doctors pushing this technology very hard. You can never be too careful they’ll say. Saving just one life is worth it. Of course if anyone paid attention to the statistic that doctors are the third leading cause of death in the US then more people would realize being careful means avoiding doctors. This isn’t to say the technology can’t be great for some people. We just need to realize that we each individually value our own life and health far more than anyone else.
Ignoring the medical community when you are the one with a critical health issue as in the above, is far worse than going to the doctor to find out you are okay, when you think there is an issue. The definition of "unnecessary" is a personal definition and one that I don't share. YMMV though.
 
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Marekul

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The name of the article is "First Opinion" that should tell one the entire story. There is no critical analysis in that op-ed blog and the AW is not a medical device. If yours if the life that is saved by the the AW you might feel differently. However the cat is already out of the bag.
Yeah true. It basically says even if the Apple Watch is super accurate, it would be a questionable success.
The study itself from what I understand Shows mediocre accuracy.
In any way the Apple Watch is clearly intended to be used as a medical device and therefore should be held to higher Standards than some gadget..
 
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kpeex

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Oct 22, 2013
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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.
 
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neliason

macrumors 6502
Oct 1, 2015
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Ignoring the medical community when you are the one with a critical health issue as in the above, is far worse than going to the doctor to find out you are okay, when you think there is an issue. The definition of "unnecessary" is a personal definition and one that I don't share. YMMV though.

It’s like you missed entirely the point that doctors are the third leading cause of death in the US. That isn’t to say one should never go to the doctor. But to say one should always go ignores the restated fact.
 
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