A huge study suggests the Apple Watch can detect a worrisome irregular heartbeat at least sometimes – but experts say more work is needed to tell if using wearable technology to screen for heart problems really helps.
More than 419,000 Apple Watch users signed up for the unusual study, making it the largest ever to explore screening seemingly healthy people for atrial fibrillation, a condition that if untreated eventually can trigger strokes.
“The findings are exciting and encouraging, but clearly there is a lot more to be done,” said Lloyd Minor, dean of Stanford’s medical school. The study could help pave the way for more research into how modern digital tools can help improve health.
People who have atrial fibrillation are at risk of blood clots and strokes. In the U.S., it causes 750,000 hospitalizations a year and contributes to 130,000 deaths, according to the Centers for Disease Control and Prevention. Because it doesn’t always produce outward symptoms, it can go undiagnosed.
According to results presented Saturday, about 0.5 percent of patients in the study — or almost 2,100 people — received notices from their watch indicating that they might have a heart-rhythm problem. That relatively low number showed that the technology wasn’t inundating people with worrisome alerts.
How does the Apple Watch check for fibrillation?
A mobile app uses the optical sensor on certain versions of the watch to analyze pulse rate data. If it detects enough variation from beat to beat over a 48-hour period, the user receives a warning of an irregular heart rhythm.
The latest version of the Apple Watch also allows wearers to push a button to take an EKG and share the reading with doctors. Saturday’s study didn’t include watches with that capability.
Further study
Of the minority of patients who got notifications and agreed to wear a portable electrocardiogram for up to a week, about 34 percent were found to have atrial fibrillation. That may be because atrial fibrillation can come and go, and doesn’t necessarily mean that the other 66 percent didn’t have the condition, Mintu Turakhia, a Stanford professor of cardiovascular medicine and one of the leaders of the study, said in a statement.
Apple looks forward “to learning more about the impact of Apple Watch alongside the medical community,” said Jeff Williams, the company’s chief operating officer.
The study isn’t likely to immediately shift medical practice.
“We have got more work to do to understand specifically how the data form this technology can be integrated into routine clinical assessment and patient management decisions,” said Kenneth Mahaffey, a cardiologist at the Stanford University School of Medicine, who chaired the study.
