https://techcrunch.com/2018/09/12/apple-watch-series-4-can-detect-afib-and-perform-an-ecg/

Today at a special event at Apple’s headquarters, Apple’s COO Jeff Williams unveiled the next generation Apple Watch. It’s thinner, faster and has a larger screen than previous generations. But that’s to be expected. The Apple Watch Series 4 is packed with several features that use the built-in heart monitor for medical purposes.

The Apple Watch has always included a built-in heart rate monitor but it has been limited to basic, standard functions of tracking the wearer’s heart rate.