https://www.techradar.com/news/you-may-have-a-long-wait-for-the-apple-watch-4s-coolest-feature

One of the big new features on the Apple Watch 4 is an ECG (electrocardiogram) that can check your heart rhythm and potentially detect atrial fibrillation, but if you live outside the US it’s a feature you might not have access to for a long time – if ever.

That’s because so far Apple’s ECG tech has only been approved in the US, so the company will have to seek approval in other countries before the ECG feature can be enabled in them.