Are EDs bombarded with Apple Watch Afib alerts?

This is a MedPage Today story.

Paul Chernoff was in the middle of a Zoom call this past June when his Apple Watch sent him an alert.

His heart rate had jumped to 142 beats per minute, and he might be in atrial fibrillation, or Afib, the alert said.

He felt fine -- no dizziness, lightheadedness, or shortness of breath. But his brother has Afib that has proven difficult to treat, and a family friend who is a physician said it couldn't hurt to go to the emergency department (ED).

So Chernoff, who's in his early 60s, caught a ride to a nearby hospital in Virginia, where emergency doctors confirmed an episode of Afib. Paired with his low blood pressure, they decided to admit him.

It wasn't until the next day that he saw a cardiologist, who noticed in Chernoff's medical history that low blood pressure was normal for him.

"If he'd seen me [the day before], he would have said not to go to the hospital," Chernoff, the director of information technology at Washingtonian Media, told MedPage Today in a phone interview.

The cardiologist recommended an electrocardiogram (EKG), but there was no reason for Chernoff to stay in the hospital to wait for it. He had no major risk factors for the big worry with Afib -- having a stroke -- and the arrhythmia likely was temporary and would resolve on its own.

More than 100 million people around the world reportedly have an Apple Watch, which touts the ability to detect Afib, and untold more have other wearable devices, like Kardia Mobile, that can alert them to irregular heart rhythms.

So how is the rise of arrhythmia-detecting devices playing out in EDs across the country?

There aren't any hard data on that, but anecdotally, emergency physicians say the technology is becoming a much more common part of their interactions with patients.

"I've been seeing more and more people for whom their watch is an adjunct to their healthcare," said Sean McGann, MD, an emergency physician at Thomas Jefferson University Hospital in Philadelphia and a spokesperson for the American College of Emergency Physicians (ACEP). "I think the trend is that these are going to be more pertinent in peoples' lives and their healthcare."

McGann sees the arrhythmia-detecting technology as "something that can go either way."

"It could cause a lot of anxiety in people," he said. "But if the technology continues to improve, it could be something that's useful for us in the ED and for all of healthcare."

He said the literature is pretty convincing that these devices are good at detecting abnormal heart rhythms, particularly Afib. Surely, they're not as good as telemetry monitors used in the ED, McGann said, but they can help with decision-making in some instances.

"A lot of what we do in the emergency department is making risk-benefit decisions, and it's another piece of data we can use to help us with those decisions," he said.

One of the most frequent complaints he sees in the ED is palpitations, "which could mean anything," he said. If someone who had palpitations earlier now shows a normal EKG in the ED, McGann can go back and look at Apple Watch data.

"If their heart rate was 150 bpm for 10 minutes [when they felt palpitations], that's pretty good evidence that something was going on during that time," he said. "I might be more likely to refer that patient to cardiology, or give them a wearable monitor for a couple of days."

On the other hand, if there was no blip in the watch data, that "makes me less likely to suspect there's something dangerous going on."

But what about a completely asymptomatic person, like Chernoff, who gets an alert but probably doesn't need immediate care?

"The downside here is false positives," McGann said. "The downstream effects are cost and time for yourself, resource utilization, overtesting, and things like that."

Gregory Marcus, MD, an electrophysiologist at the University of California San Francisco, warned that an Afib episode itself "is not an indication for an emergency department visit."

"By itself, it's not an emergency, nor does it require emergent, and usually not even urgent, attention or treatment," he said, adding that "going to the ED is almost certainly a waste of valuable healthcare resources and an inappropriate response."

People alerted to an abnormal rhythm should only go to the ED if they would have gone anyway based on their symptoms, Marcus said.

"If someone is having crushing chest pain or they are having difficulty breathing, sure, then an ED visit is likely appropriate," he said.

McGann said symptoms are "more important than the rhythm that pops up on your watch." He said the best course of action if someone gets an Afib alert while asymptomatic would be to call their primary care doctor "and see what next steps would be indicated, such as going into their office to get an EKG."

"That would probably make the most sense, rather than going right to the cardiologist based on what your watch tells you," McGann said.

As for patients who've been previously diagnosed with an arrhythmia, Marcus said, the devices "can be extraordinarily valuable in both detecting and even characterizing clinically important arrhythmias" -- and might even lead to less healthcare utilization.

For instance, Marcus recently performed an ablation for premature ventricular contractions (PVCs) on a symptomatic patient. During a routine follow-up, the patient said she felt better but intermittently felt a bit off. When Marcus reviewed her Apple Watch data during those vague symptoms, there was no evidence that her PVCs had returned.

For instance, Marcus recently performed an ablation for premature ventricular contractions (PVCs) on a symptomatic patient. During a routine follow-up, the patient said she felt better but intermittently felt a bit off. When Marcus reviewed her Apple Watch data during those vague symptoms, there was no evidence that her PVCs had returned.

"She, her insurance, our clinic, and the healthcare system was therefore saved from another wearable [EKG] monitor, interpretation, subsequent communications, and subsequent visits," he said.

But Marcus is far more hesitant about using these devices to screen the general population for Afib. Without professional recommendations on Afib screening in asymptomatic people, private industry has jumped ahead of the science, he said.

Even though the devices have been shown to be accurate for detecting Afib -- notably in the Apple Heart Study, which was published in the New England Journal of Medicine in 2019 -- only about 3 million people in the U.S. are estimated to have the condition.

"Even with highly accurate devices, when the prevalence of any disease is very low in a given population, the number of false positives will be very high just due to simple, inescapable math," Marcus said. In addition to the unnecessary testing and stress for patients, this surveillance could even lead to inappropriate anticoagulant prescribing, he said -- and that could come with an increased risk of serious bleeding.

"Recognizing there is always a balance between the benefits of possible thromboembolic prevention versus the harms of false positive test results, investigators and clinicians are busy playing catch-up," said Marcus.

Chernoff went to the cardiologist's office for an EKG 2 days after his hospital stay, and his Afib had resolved by then. His Apple Watch alerted him to one more Afib episode that following weekend, but he hasn't had one since, he said.

Overall, he was happy with the way things worked out. He only paid about $150 out-of-pocket for the entire hospital encounter because he had good insurance. And now he has a cardiologist who he'll probably see regularly.

That cardiologist told him that as he gets older, he will most likely have more episodes of Afib; but without serious risk factors for stroke, he's not likely to have an adverse outcome.

"He recommended I turn off Afib detection," Chernoff said. "He says it's useful, but there are many people who are constantly looking at the numbers, and it's not doing them any good. It's probably just creating more stress for them."