Yes, Absolutely Yonian and also IdrisSeabright, I agree that the EKG(ECG) whichever you prefer to define it SW has to 1) be accurate, proven, uneventful, non-negatively observed by the human world public when released
2) Yes, the US FDA regulatory will and shall be involved and approval gained from that agency which oversees Life monitoring medical grade devices and systems as this Watch intends to be. Why not.
My AICD/Pacemaker medical implanted device had/has went through that same approval cycle format. It is a St. Jude Medical Co device I've had since May2011, and for my model and type has been on an FDA recall notice for early battery depletion. Not a good sign of protection inside my upper left chest quadrant.
Apple Watch Series 4 SW should be no different in gaining FDA and other approvals.
My concern is that Apple should be more transparent and pro-active in their consumer awareness and interest in the purpose of this heart(cardiac) monitoring function. My thoughts are not Apples thoughts necessarily.
Doug