In accordance with the Apple Store documentation obtained using the Apple Store program, you can finally get support in the upcoming WatchOS version 5.1.2, which is the long-awaited Electrocardiogram (EKG) of the Apple Watch Series 4 (EKG). Macrumors,
This feature will allow you to wear an EKG device using electrodes embedded in the back of the watch and a digital crown, which improves the Apple Watch's ability to measure and control the hearts of users. Apple received FDA Type II approval for the Apple Watch in the United States, which, as Angela Chan explains, is not exactly the same as FDA Type III full approval.
According to the training document, the EKG features will only be available in regions where the Apple Watch has been cleared for use, which seems to be only the US when it is first launched. However, it’s hard to imagine that Apple is not yet working to get medical approval for other countries.
The updated watchOS 5.1.2 is in beta for developers, but there are no words about when the final version will be released.