The ECG app on Apple Watch Series 4, which was initially released in the U.S., is now available in Hong Kong and 19 European countries — including France, Germany, Italy, Spain and the United Kingdom. In other words, the ECG app and irregular rhythm notification are now CE marked and cleared in the European Economic Area.

Part of the free watchOS 5.2 software update, the ECG app can capture heart rhythm on demand in a moment when users experience symptoms such as a rapid or skipped heart beat and help provide clinically important data to physicians. The irregular rhythm notification feature on Apple Watch occasionally checks heart rhythm in the background and sends a notification if an irregular heart rhythm that appears to be atrial fibrillation (AFib) is identified. The app can also alert users to signs of AFib, which is one of the leading conditions that can result in stroke.

“We’ve seen the ECG app and irregular rhythm notifications on Apple Watch have meaningful impact on our customers across the United States,” Jeff Williams, Apple’s chief operating officer, said in a statement. “We are excited to bring these features to customers in Europe and Hong Kong, giving them access to empowering information about their heart health.”

The ECG app relies on electrodes built into the back crystal and Digital Crown on Apple Watch Series 4 to enable customers to take an ECG similar to a single-lead electrocardiogram. Taking an ECG recording is as simple as launching the ECG app on Apple Watch Series 4 and touching the Digital Crown, which completes the circuit and allows electrical signals across the user’s heart to be measured. After 30 seconds, the ECG app can classify the user’s heart rhythm as AFib or sinus rhythm.

All recordings, their associated classifications and any noted symptoms are stored securely in the Health app on iPhone, from which users can share a PDF of the results with physicians.

As for the irregular rhythm notification, it is available on all Apple Watch devices, occasionally checking the user’s heart rhythm in the background for signs of an irregular heart rhythm using the optical heart sensor. If an irregular rhythm is detected on five rhythm checks over a minimum of 65 minutes, Apple Watch alerts the user with a notification.

To enable these new heart features, customers will open the Health app on iPhone where they will be presented with details about who can use these features, what the features can and cannot do, what results users may get, how to interpret those results and clear instructions for what to do if users are feeling symptoms that require immediate medical attention.

watchOS 5.2 is now available but in order to take advantage of the new features, users must also update their iPhone to iOS 12.2.