The first results were revealed from an extensive study that tested a new algorithm designed to detect irregular heart rhythms using data from smartwatches and fitness trackers. With almost half a million test persons, undiagnosed atrial fibrillation was detected in 98 percent of the cases in the study.
Irregular intervals between heartbeats, known as atrial fibrillation, can be an early sign of cardiovascular disease. Severe episodes of atrial fibrillation can manifest as symptoms similar to those of a heart attack, but shorter episodes can be asymptomatic.
The advent of wearable health monitors offers new ways to detect early asymptomatic episodes of abnormal heart rhythms, but researchers are still improving the technology to increase accuracy and reliability. A large Stanford study in 2019 showed Apple Watches’ potential to detect atrial fibrillation, and now FitBit has followed suit with its own large study that slightly improved Apple’s results.
The study, conducted by researchers at Massachusetts General Hospital (MGH), recruited around 455,000 fitness tracker users in the United States. Once activated, the novel algorithm tracks a user’s heart rate during periods of inactivity. Possible atrial fibrillation is detected after an irregular heartbeat for at least 30 minutes.
In the study, when possible atrial fibrillation was detected, the subject completed a telemedical consultation with a doctor and was then given an electrocardiogram (EKG) patch to wear next to the fitness tracker for a week. In the following week, the new algorithm effectively captured 98 percent of the atrial fibrillation episodes detected by the ECG patch.
“These results show that wearables are able to detect undiagnosed atrial fibrillation with high reliability,” says Steven Lubitz, an MGH researcher working on the project. “With so many consumers using wearables, it is possible that algorithms like the one we studied could be widely used to identify undiagnosed atrial fibrillation so that patients can be cared for before devastating complications like a stroke can occur.”
Lubitz points out that the heart monitoring software would be most effective when used at night. So the goal would be to wear the fitness tracker while you sleep when it is best at tracking irregular heart rhythms.
“Most episodes of undiagnosed atrial fibrillation occurred during sleep, and we suspect these episodes were asymptomatic,” adds Lubitz. “Since the algorithm is most active when the wearer is physically inactive, it is best to wear the wearable while sleeping.”
Fitbit is currently working with the US Food and Drug Administration (FDA) on market approval so that the algorithm can be used widely.
Source: American Heart Association
