Oh look, the Apple Watch might actually be good for something

Eighty-four percent of the time, it works every time. 
A study involving more than 400,000 participants and their Apple Watches indicated that the smart device may provide some form of early warning for those experiencing the heart rate irregularity known as atrial fibrillation. So reports Reuters, which notes that the research was funded by Apple. 
The study, done in collaboration with Stanford Medicine, required people to wear an Apple Watch and made use of the watch's irregular rhyt