ecg function not working on series 8 watch
ECG function stopped working on New series 8 GPS watch. How to fix?
Apple Watch Series 8
See the 'How to get the best results' section in:
Take an ECG with the ECG app on Apple Watch - Apple Support
However, it may be a hardware problem. Your best option, at this point, may be to make an appointment at the Genius Bar in an Apple Store near you and let them look at it. If that is not possible, use the online Apple Support option. Either way:
Genius Bar Reservation and Apple Support Options - Apple