watchOS 5.1.2 will feature an ECG application designed by Apple that can tell if your heart rate shows signs of atrial fibrillation, a severe form of irregular heartbeat, or normal sinus rhythm. Apple Watch Series 4 is capable of generating an ECG similar to a single probe electrocardiogram, according to the FDA.
The ECG and other cardiac data are collected in the Health app on a paired iPhone. The Apple document indicates the minimum system requirements for an iPhone 5 or later running iOS 12.1.1, being beta tested or later.
To take an ECG reading from the Apple Watch, users will have to place their finger on the Digital Crown while wearing the watch. Reading is completed in 30 seconds, allowing users to determine if their heart beats regularly or if there are signs of atrial fibrillation.
Apple's training document states that the ECG application is regulated and available only in areas authorized to be used. The application will initially be limited to the United States, where Apple has received clearance from the FDA, but the Apple Watch Series 4 models sold worldwide include the electrical heart sensor for future expansion.
Employees at the Apple Store are instructed to inform customers that the ECG application "should not be a diagnostic device or replace traditional diagnostic methods," Doctor, according to the Apple document.
Apple has promised that the ECG application would be available later this year, but it is unclear when watchOS 5.1.2 and iOS 12.1.1 will be released. watchOS 5.1.2 has been in beta testing since November 7, while iOS 12.1.1 has been in beta testing since October 31st. Both software updates should be published fairly quickly.
A separate Apple training document obtained by MacRumors suggests that irregular heartbeat notifications will also be enabled in watchOS 5.1.2 on Apple Watch Series 1 models at Apple Watch Series 4.
The ECG application will not be available on Apple Watch models of the previous generation, including the original via the 3 series.