The electrocardiogram (ECG) feature is coming to Apple Watch customers in Taiwan on Tuesday, December 15 (Taiwan time), with the upcoming watchOS 7.2 and iOS 14.3 updates.
watchOS 7.2
Apple has updated the Apple Watch ECG algorithm in OS 14.3 and watchOS 7.2
Apple has created a new version 2 algorithm for the Apple Watch Series 4 and later to measure electrocardiogram (ECG) waves of one's heart via the optical heart sensor.