It’s one of the goals of digital medicine: you wear a device on your wrist that constantly monitors aspects of your health, and if anything is off, it sends you an alert. That’s your cue to connect with your doctor or get a more thorough checkup to head off any potentially serious problems down the road.
That’s the idea behind the Heart app on the Apple Watch, which can monitor heart pulse patterns, and detect abnormalities, which could indicate a condition called atrial fibrillation, or AFib. The irregular heart beats characteristic of AFib could lead to stroke, blood clots and heart failure.
Researchers at Stanford University have been working with Apple to study how accurately the tech giant’s app could detect AFib in a general population. Early results of the research project, known as the Apple Heart Study, were presented at the annual meeting of the American College of Cardiology last spring. Now, in a paper published Nov. 13 in the New England Journal of Medicine, they report that the app’s alerts matched up with electrocardiography, or ECG readings (the gold standard for detecting atrial fibrillation) 84% of the time.
In the NEJM study, the scientists reported results from nearly 420,000 people who already owned Apple Watches and volunteered to participate. Over a period of nearly four days, the watch notified 0.5% of this group of potential abnormal heart rhythms. These people were then asked to contact the study team, which sent them ECG patches to wear on their chest for up to seven days while still using the app.