This led Apple to work together with Stanford Medicine on a study involving irregular heart rates using the Apple Watch. That being said, it looks like about a year later, that study is coming to an end. This is according to notifications to users who participated in the study (via an app on the Apple Watch) in which they were thanks for their participation.
The study is expected to come to a conclusion in January 2019, but it looks like it has ended early for some. It is unclear as to what Apple and Stanford Medicine will be doing with the results from their study, and if it could be potentially used in future Apple Watch devices to make it better.
There have been rumors suggesting that the Apple Watch Series 4 will have more advanced heart rate tracking features that goes beyond just measuring one’s heart rate during exercise, but we’ll have to wait and see. Apple will be most likely announcing the device at their iPhone event which takes place on the 12th of September.