In an era where Internet-connected devices can measure your pulse, the ability of these smartphone devices to identify cardiac diseases is still unknown — and presents an untapped potential. More than half a million people in the United States are unaware they suffer from cardiac disorders, such as atrial fibrillation. This condition, in which the heart beats irregularly, increases the risk of suffering a stroke by five times, and could even lead to heart failure. But can an app in your smartwatch detect it?

Researchers set out to investigate if a notification algorithm in an Apple Watch application was capable of identifying atrial fibrillation. In the Apple Heart Study, participants used a smartwatch app to monitor for irregular pulses during an average of 117 days. In the study, participants that received an irregular pulse notification from the app — which may be possible atrial fibrillation — were asked to start a e-health consult through the app and received, via the mail, an electrocardiogram-patch to wear at home for up to a week to confirm the disorder. 

Atrial fibrillation was confirmed in 34% of the participants who received irregular pulse notifications by the app and completed the electrocardiograms. Overall, the chance of getting an irregular pulse notification while suffering from this cardiac disease at the same time was 84%. 

Even though detection technologies are rapidly advancing, additional studies are still necessary to further develop notification algorithms in smartwatches as reliable tools for disease diagnosis. People who experience atrial fibrillation symptoms, such as racing heartbeats, shortness of breath, or chest pain, should still pay a visit to the doctor.