You do not play with people's health, and in this sense, Apple is very clear about it and does things as it should be, even if it will lose sales of its devices. It does not launch a health function in a country, if previously the corresponding body of each nation does not approve.
Now (finally) the corresponding body of the Chinese government has approved the use of the ECG Apple Watch in that country, so shortly, Apple will incorporate it through an update to all Apple Watch Series 4, 5 and 6 that have been sold in China.
China has officially approved the electrocardiogram (ECG) feature of the Apple Watch that first saw the light of day in Series 4. Regulatory approval means that Apple could release the health feature in a software update for Chinese users shortly.
Apple announced its ECG feature alongside the Apple Watch Series 4 in the fall of 2018 initially implemented only in the US It has gradually been implemented in the rest of the countries, as their governments gave the green light. The last countries to have this function have been Australia and Vietnam thanks to Watch 7.4.
The ECG of the Apple Watch in Series 4 and later can detect the atrial fibrillation (Afib) and has proven to be accurate enough to have been credited as a 'lifesaver' in many cases in recent years.
Last week, the China National Medical Products Administration revealed that the Apple Watch ECG has been approved. That gives Apple the green light to incorporate such a feature in all Apple Watch Series 4, 5 and 6 sold in China, with a update from watchOS.
We'll see if the company does it soon with an exclusive update for China's Apple Watch, or is expected to include it in an upcoming general update of WATCH.