The ECG apps and irregular rhythm notifications feature can alert users to signs of AFib. Left untreated, AFib is one of the leading causes of stroke, the second most common cause of death in the world.
"We've seen the ECG app and irregular rhythm notifications on the Apple Watch have a significant impact on our customers in the United States," said Jeff Williams, Apple's chief operating officer. "We are pleased to make these features available to customers in Europe and Hong Kong so that they can receive information about their heart health."
New electrodes in the backbone and Digital Crown of the Apple Watch Series 4 work together with the ECG app to give customers the ability to take an ECG similar to a one-conductor electrocardiogram. Taking an ECG recording is as easy as starting the ECG app on the Apple Watch Series 4 and touching the Digital Crown. This completes the circuit and allows electrical signals to be measured in the user's heart. After 30 seconds, the ECG app can classify the user's heartbeat as AFib or sinus rhythm.