The ECG feature on the Apple Watch Series 4 that the company was so proud about at the announcement might be enabled in the next watchOS update, according to a recent report. Version 5.1.2 that is currently in beta will enable the Apple Watch Series 4 ECG functionality, as per an alleged internal Apple Store training document.
The watchOS update, once public, final, and pushed to devices, will contain a special ECG app. Said app will alert in case the watch detects signs of atrial fibrillation. The special ECG app will only be available on the Apple Watch Series 4, that actually has the hardware to support it.
Heart-rate, ECG, and other data will be collected and available to users through the Health app on the iPhone. Said document mentions that you have to have at least an iPhone 5s that’s running iOS 12.1.1, which is currently in beta, but will most likely be pushed to phones soon.
The document referenced in the leak also mentions that the ECG app is regulated and will only be available in regions and countries where it got clearance. Initially, it will be limited to the US, where the Apple Watch Series 4 ECG has been FDA approved. As far as other regions and countries are concerned, you’ll probably have to wait until Apple managed to get clearance.