Apple Watch wristband detected abnormal heart rhythms, doctors say

Research shows Apple Watch KardiaBand detects heart arrhythmia

Anatomical illustration of a human heart.

Back in November 2017, Mashable spoke with Vic Gundotra, the CEO of the medical device company AliveCor, which after two years of testing had just been given the thumbs up from the Food and Drug Administration (FDA) to sell a heart-monitoring wristband for the Apple Watch, known as the KardiaBand.

After the KardiaBand hit the market, heart doctors at the Cleveland Clinic wanted to see how well it actually detected the most common type of abnormal heart rhythm, or arrhythmia, called AFib (short for atrial fibrillation)

Turns out, the $200 watch band is quite useful, according to new research

After studying 100 patients with AFib, researchers found that the band and its associated algorithm — which runs on the Apple Watch — correctly distinguished between AFib and a normal functioning heart over 90 percent of the time, when the watch received sufficient data.

The research, to be presented in March at the  American College of Cardiology's 67th Annual Scientific Session, shows the KardiaBand can give people an immediate and mostly-accurate understanding of what's going on with their heart.

The research has not yet been peer reviewed.

"If a cardiologist looks at the tracing they can make the diagnosis, but if the watch and algorithm can make the diagnosis — that's terrific," said Gordon Tomaselli, professor of cellular and molecular medicine at Johns Hopkins School of Medicine and former president of the American Heart Association, in an interview.  

"I’m not surprised by the result," added Tomaselli, who was not involved in the study. "It’s a relatively straightforward diagnosis."

Experiencing AFib isn't necessarily worrisome for all patients — that depends on the patient's heart health and doctor's assessment. But for some patients, AFib — when the heart beats erratically — can have serious consequences.

The KardiaBand and Apple Watch displayed on a wrist.

"There are some devastating outcomes that can result from patients that have a relatively high burden of AFib that don’t realize they have AFib," Tomaselli said. He specifically referred to strokes, and mentioned that a doctor might consider putting a patient who regularly experiences AFib on blood thinners to avoid such a harmful or deadly event.

Almost 10 percent of people over 65 experience AFib, making it "the most common sustained arrhythmia in human beings," Tomaselli said.

AliveCor's KardiaBand, however, often didn't pick up enough heart data to for its algorithm to make a determination about whether or not AFib was occurring. Nearly 35 percent of the time, the data was "undetermined." But when Cleveland Clinic doctors stepped in and reviewed this undetermined heart rhythm data from the Apple Watch, they were able to identify and diagnose AFib 100 percent of the time

And, this, says Gordon is how devices like the KardiaBand should be used — in consultation with a cardiologist, especially if someone is seeing AFib popping on their smartwatch for the first time

"It should be vetted by a physician to ensure what's happening is not a false diagnosis," said Tomaselli. "A new diagnosis of AFib should also be looked at by a cardiologist."

As more health and fitness devices are designed to work with popular consumer tech, like Apple iPhones and smartwatches, it's helpful that doctors are scrutinizing some of these devices to ensure they work as advertised — even after they pass the FDA's rigorous protocols. 


"Our patients are exposed to a growing number of health care devices that are available for purchase without a prescription," said Joseph Bumgarner, an electrophysiology fellow at the Cleveland Clinic and the study's lead author, in a statement.

"What we don't know is if these devices provide meaningful clinical information that patients and their physicians can interpret and use effectively."