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Mar 25, 2019

Mobile App Helps Detect Abnormal Heart Rhythm in Apple Watch Users

Smartwatch helps flag users with possible AFib and prompts them to seek further testing, finds Stanford study.

Smartwatches could help flag heart rhythm problems, based on a recent study that evaluated a mobile app for detecting atrial fibrillation in a large group of Apple Watch wearers. Findings were presented at the American College of Cardiology’s 68th Annual Scientific Session and suggest that the app can both alert watch wearers about an irregular heartbeat and prompt them to seek medical attention.

Atrial fibrillation (AFib) is the most common type of irregular heart rhythm, affecting up to 6 million Americans. It’s especially common in older adults and drastically increases risk for stroke, heart failure and other heart-related complications.

Since AFib doesn’t always cause symptoms, many people don’t know they have it. The good news is that smartwatches could help screen users and prompt them to seek medical attention, based on the latest findings.

Conducted at the Stanford University School of Medicine, this study evaluated a mobile app used to detect an irregular heartbeat. The app uses the watch’s light sensor technology to measure blood flow activity and detect any irregular changes in heart rhythm.

“The app continuously gathers data in the background without the wearer of the device doing anything, so it’s very opportunistic in this way,” said Mintu Turakhia, MD, associate professor of cardiovascular medicine, Stanford School of Medicine, and the study’s co-principal investigator, adding that the entire user experience was directly through the study application.

A total of 419,297 Apple Watch wearers participated in the study, and nearly 2,100 received an irregular pulse notification.

Participants with an abnormal rhythm were prompted to contact the study doctor through the app for a video consultation regarding further testing. Based on the consultations, 658 participants were mailed an electrocardiogram (ECG) patch and asked to wear it for up to a week for further heart monitoring.

A total of 450 participants completed the ECG portion of the study, and one-third were found to have AFib. However, these results were not entirely unexpected, according to researchers.

“AFib can come and go, particularly early on in the course of the disease. It’s not surprising for it to go undetected in subsequent ECG patch monitoring,” said Turakhia. “So while only 34 percent of people who were still having [signs of] AFib on the ambulatory ECG, that doesn’t mean that 66 percent didn’t have AFib. It just means that AFib may not have been there at the time.”

In fact, authors note that the app was very successful at identifying real cases of AFib. Analysis showed that if an alert occurred, the ECG monitor confirmed AFib 84% of the time. Perhaps most importantly, researchers found that more than half of participants who got an alert sought medical attention outside of the study, regardless of whether they contacted study doctors.

“This study improves our understanding of how this wearable technology and app works in the real-world setting and how well the technology can detect long periods of AFib,” said Turakhia. Not only were alerts rare, they were generally accurate and prompted users to seek further medical attention, explain authors.

Of course, additional research is needed to further evaluate the use of smartwatches in detecting AFib and other heart issues. However, experts believe that smartwatches have great potential in monitoring patients with heart rhythm problems and could complement tests currently used for screening and diagnosis.

Questions for You to Consider

  • What is atrial fibrillation?

  • Atrial fibrillation is an irregular heart rhythm caused by abnormal, chaotic electrical impulses in the heart’s upper chambers, the atria. These electrical impulses, which interfere with the heart’s natural pacemaker, fire so rapidly the atria cannot beat with a regular rhythm or squeeze out blood effectively. Instead, they merely quiver while the ventricles, the heart’s lower chambers, beat rapidly.
  • How is atrial fibrillation treated?
  • In general, the goals of atrial fibrillation treatment are to promote a regular heart rhythm or rate and prevent blood clots, which can cause stroke. However, treatment strategies depend on the unique needs of each patient. Treatment options may include antiarrhythmic medication, blood thinners, and a variety of procedures that can help control atrial fibrillation.

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