The new Apple Watch Series 4 adds heart-monitoring features, letting users track their heart rhythms and detect signs of atrial fibrillation, which is the most common type of irregular heartbeat and can lead to heart problems and stroke.
The U.S. Food and Drug cleared the new heart features, and the American Heart Association’s president even came onstage as part of an Apple product-launch event on Wednesday in Cupertino, Calif.
But doctors, and particularly cardiologists, are questioning whether the features — which include the ability to take an electrocardiogram (ECG), which measures the heart’s electrical activity — will actually help users.
There are scenarios in which information recorded by the watch could be helpful for medical professionals, experts said. But they also voiced serious concerns about whether the watch could correctly point to atrial fibrillation, something that can be tricky to diagnose, and that users would have trouble knowing what to do with the data the watch gathers, since the heart isn’t a subject that’s well understood by most people.
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The new features could spur unnecessary doctor’s-office or even emergency-room visits by those doctors term “the worried well,” they said, since young, healthy Apple Watch users are also the least likely to be at risk for atrial fibrillation, a disease tied to aging. The experts also worried about the inevitable false positives and negatives once the watch is let loose on potentially millions of people.
“What would we be talking about if Apple AAPL, +2.42% came up with something where women could do their own mammograms at home? Would everybody think that’s a great thing?” said Dr. David Brown, a cardiologist and professor at Washington University School of Medicine in St. Louis, referring to the X-ray procedure used to detect breast cancer early.
“And really, when you think about it, what’s the difference? They’re treating healthy people as potential patients; they’re monitoring something where there’s no evidence of potential benefit.”
I can’t figure out whether today is the best day in the history of Cardiology or the worst
— Ethan Weiss (@ethanjweiss) September 12, 2018
The new heart-health features on the Apple Watch Series 4 and the new operating system, watchOS 5, which is for all Apple Watch models, not just the new ones, are particularly centered on detecting atrial fibrillation. Consisting of a quivering or irregular heartbeat, atrial fibrillation can lead to blood clots, heart failure and other complications, and at least 2.7 million Americans have it, according to the American Heart Association.
The Apple Watch Series 4, which starts at $399 for the non-cellular version and costs $499 with the cellular option, allows users to take an ECG thanks to both built-in electrodes and an electrical heart-rate sensor at the back of the watch. The watch will indicate whether there are signs of atrial fibrillation, and readings will be stored in a PDF that can be sent to a medical professional, according to Apple.
Read more: Apple introduces three new iPhones and Apple Watch Series 4: Live blog recap
The watch uses one electrode to measure heart rhythm; by contrast a medical-grade ECG typically uses 12, which are placed on a patient’s arm, chest and legs, said Dr. John Mandrola, a Louisville, Ky., cardiologist who specializes in diagnosing and treating heart-rhythm disorders.
The new Apple Watch operating system will also “intermittently” track heart rhythms and let users know if atrial fibrillation, or another irregular rhythm, is detected. There’s also the capability in the OS to be alerted if one’s heart rate goes above or below certain levels.
These features could be helpful for individuals with atrial fibrillation, with watch readings potentially helping their doctors make diagnoses, Dr. James Brophy, a professor of medicine and epidemiology at McGill University in Montreal, told MarketWatch in an e-mail.
Separately, the devices could aid those who are having symptoms that could be caused by an irregular heart rhythm, or who have undiagnosed heart-rhythm problems, Mandrola said.
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Most individuals with atrial fibrillation first find out once they’ve had a stroke, Washington University’s Brown said, and “that’s what we want to prevent.”
But, importantly, there are other risk factors for a stroke, including high blood pressure and diabetes; for individuals with those risks, doctors might put them on medications like blood thinners.
Atrial fibrillation “in general doesn’t kill anybody. It’s the strokes that are caused by them that kill people,” Brown said. “There aren’t a lot of 25-year-olds who have undiagnosed [atrial fibrillation] walking around there, and those are going to be the people wearing Apple Watches, for the most part.”
See: People want a smart watch that doesn’t make them feel dumb
Still, for other, “asymptomatic” patients, doctors don’t know if the same medications are as helpful — it hasn’t been studied — and the medications could have serious side effects, Brophy and other physicians said.
Another key consideration is that people’s normal heart rhythms range widely. Many individuals have irregular heartbeats that are “totally benign,” said Mandrola, the Louisville cardiologist. Healthy Apple Watch users are in danger of becoming concerned about something that’s normal for them and heading to the doctor, where they run a higher risk of overdiagnosis and overtreatment, he said.
With the release of Apple's EKG app. you might want to familiarize yourself with the following ICD10 code: Z71.1#worriedwell pic.twitter.com/enTSPVpzXs
— C. Michael Gibson MD (@CMichaelGibson) September 12, 2018
Apple submitted to the FDA a study that included 588 individuals, according to an agency spokesperson. The ECG feature positively identified 98.3% of individuals with atrial fibrillation, and correctly identified 99.6% of the individuals that didn’t have atrial fibrillation, the spokesperson said; about nine out of 10 of the ECG recordings could be interpreted by a cardiologist.
Results for the other watch feature found that of 226 participants for whom the watch indicated irregular rhythm, about 41.6% were determined, when tracked for an average of six days, to have atrial fibrillation as measured by an ambulatory cardiac monitor. When atrial-fibrillation notifications were seen on the watch during the monitoring period, the proportion of individuals who had the same reading on the cardiac monitor was 78.9%, according to the FDA.
Even very reliable screening tests result in many false positives, because they are used on many people, Mandrola noted. That’s also likely to be the case with the Apple Watch, he said.
