Sept. 7, 2021 — Susan Carney had just gotten herself a shiny red Apple Watch Series 6 for Christmas when she glanced down at its face and spotted an alarming warning: She had an “irregular heart rhythm suggestive of atrial fibrillation.” At first, she rolled her eyes.
“I said, ‘Come on. It’s just a watch,’” recalls Carney, 62, a medical technician at a hospital in South Hampton, NJ.  She went to a doctor anyway, where a series of tests confirmed she was, indeed, experiencing AFib, a common but potentially deadly irregular heart rhythm that boosts risk of stroke fivefold.
Her doctor prescribed blood thinners immediately to cut the chance of stroke, urging her to steer clear of certain decongestants, which seemed to be kicking it off. Now, Carney is urging her friends to get a watch.
“It’s incredible that they can do this. I just wonder how long this was happening without me knowing,” she says.
Many women are finding their way to emergency rooms or cardiologist’s offices after smartwatches equipped with heart rhythm monitoring apps tip them off to a disorder many know little about. Many assumed that their fatigue, brain fog, and shortness of breath were just part of getting older. Others knew they had heart problems and, per the advice of their doctor, used their watch to keep a close eye on their pulse.
Some are young, healthy, and completely asymptomatic.
“I used to refer to atrial fibrillation as the most common heart problem that no one knows they have. But since these watches came out, awareness has exploded,” says John Day, MD, a cardiac electrophysiologist, in Salt Lake City, and author of the new book The AFib Cure. “They’ve been an absolute game changer and they’ve saved a lot of lives.”
Why Early Detection Matters
Put simply, atrial fibrillation is a chaotic electrical activity in the heart’s upper chambers.
“Instead of beating in a coordinated fashion, the atria quivers like a bag of worms,” explains Christine Albert, MD, chair of the Department of Cardiology at Cedars Sinai Medical Center in Los Angeles.
If AFib persists, blood can pool in the heart, blocking blood flow to organs and setting patients up for stroke, heart attacks, and cognitive decline. While it is generally more common in men, AFib generally impacts women’s quality of life more.
For some, it’s so intermittent that it’s hard to detect. For others, it’s a chronic part of daily life.
Left unchecked, it can lead to scarring in the heart, which is hard to reverse.
“But there is a window of opportunity where you have a good chance of putting atrial fibrillation into remission without drugs or procedures,” Day says.
Since 2018, when Apple rolled out the first app enabling people to take an electrocardiogram (ECG), measurement of the heart’s electrical signature, from their wrist, more people began arriving in his office within that window.
While the watches are helpful, they are not foolproof, cautions Sunjeet Sidhu, MD, an electrophysiologist at MedStar Union Memorial Hospital in Baltimore.
Some monitor pulse continuously and alert the wearer of an irregular rhythm that could be AFib. Others feature an app that allows wearers to press a button and get an ECG reading in 30 seconds.
In either case, further tests are necessary.
“It is not a definitive diagnosis by any means, and there can be false positives which make people more nervous than they need to be,” Sidhu says.
According to one industry-sponsored study of about 420,000 Apple Watch wearers, only about one-third of those who got an irregular pulse notification were diagnosed with atrial fibrillation upon subsequent testing with a device called an electrocardiography (ECG) patch 2 weeks later. Since AFib can be very intermittent, that’s not surprising, the authors noted.
In a separate experiment, the watch accurately predicted AFib 84% of the time.
On the flip side, some have cautioned that the watch may not be sensitive enough to catch some AFib. Only 13% of people who were later diagnosed with atrial fibrillation had gotten an irregular heart rhythm notice previously.
“In some cases, it might actually give people a false sense of security, leading them to blow off symptoms they shouldn’t be blowing off,” Sidhu says.
That said, he and others see the watches as an inevitable, mostly positive addition in the arsenal against AFib.
“I would gladly look at thousands of false positive ECGs from my patients if it means that we could prevent even a single stroke,” Day says.
So, what should you do if your watch gives you a warning? First: Don’t panic. Second: Call your doctor.
Once a doctor diagnoses atrial fibrillation, depending on their overall health, patients can often start with lifestyle measures alone to rein it in.
For those at high risk of stroke or those with more intractable symptoms, doctors may prescribe medications, a minimally invasive procedure called an ablation, or antiarrhythmic drugs to stabilize rhythm.
And once a patient goes home, many are suggesting they keep that watch clicking.
“It brings you peace of mind and keeps you in touch with your cardiologist without having to go into the office,” says Jacqueline Wilson, a 66-year-old loan officer from Baltimore. She recently had ablations to address her AFib.
She’s watching her diet, getting more sleep, and exercising. She checks her watch for AFib every couple of days. If she were to have an episode, she’d send her ECG report to her doctor via email for further analysis and a recommendation on what to do next.
She hasn’t had one since her surgery.
“I’m feeling better every day,” she says. “I’m really hopeful.”
By the Numbers
6 million people in the United States are affected by atrial fibrillation.
700,000 people have it but don’t know it.
1 in 3 U.S. adults will experience an episode of atrial fibrillation at some point in their lives.
2 million people under the age of 65 have atrial fibrillation.
10% to 12% of people over 85 have atrial fibrillation.
7 Ways to Tackle AFib Without Drugs or Surgery
Address sleep disorders: People with obstructive sleep apnea are four times more likely to have atrial fibrillation and more likely to have a recurrence after surgery. Even a few nights of lost sleep increases risk of AFib, research shows.
Quit smoking: It doubles your risk to begin with, and quitting can cut it by 36%.
Kick energy drinks: While studies generally don’t show a strong link between things like coffee and chocolate and AFib, stimulants found in energy drinks like Red Bull have been linked to it, especially in younger patients.
Exercise less (or more): Endurance athletes, like marathon runners tend to have higher rates of AFib, particularly as they age. For them, cutting back on mileage can help. On the flip side, a sedentary life can also be a risk factor.
De-stress: Research shows people are 85% less likely to go into AFib on “happy days” than on sad, angry or stressful days.
Lose weight: One study of 355 overweight AFib patients waiting for surgery found that of those who lost significant weight, half went into complete remission with no further need for drugs or surgery.
Give up the booze: While some studies suggest moderate alcohol can reduce heart disease risk, AFib may be a different story. People are more likely to end up in the ER with AFib after heavy drinking. Just one drink a day boosts the risk. Research shows people who abstained entirely for 6 months had fewer episodes.