Apple Watch heart monitor ECG app included in WatchOS 5.1.2 update

Starting on Thursday, the latest Apple Watch models will be able to take an electrocardiogram (ECG) reading, a kind of heart-rate reading that doctors can use to diagnose heart conditions.

To activate the feature, you need the Apple Watch Series 4 and the latest version of WatchOS, which will be available for download on Thursday.

Apple made it easy to access the feature: turn on the app, hold your finger on the device’s crown for 30 seconds, and it will provide a heart rhythm reading that you can use to figure out whether you need to contact your doctor to get your heart checked out. It saves the reading in a PDF file that you can send to your doctor.

Read more: The new Apple Watch Series 4 isn’t for everyone — but if you’re looking for an Apple Watch, it’s the one to get

Apple also announced another heart health feature for Apple Watch: Now, it can notify you if your heart rate may be irregular, a condition known as atrial fibrillation (AFib).

The AFib feature doesn’t require the latest Apple Watch, and it checks your heart rate every few hours. When there are a series of readings that are out of whack, it will give you a notification.

It’s important to note that neither of these new features can replace a doctor — they can simply encourage you to go visit or get in touch with your physician.

Both features are “cleared” by the Food and Drug Administration, but haven’t been approved by overseas bodies, so the features are only available for the United States at the moment.

From Apple’s announcement:

“Starting today, the ECG app on Apple Watch Series 4 marks the first direct-to-consumer product that enables customers to take an electrocardiogram right from their wrist, capturing heart rhythm in a moment when they experience symptoms like a rapid or skipped heart beat and helping to provide critical data to physicians. The irregular rhythm notification feature on Apple Watch can now also occasionally check heart rhythms in the background and send a notification if an irregular heart rhythm that appears to be atrial fibrillation (AFib) is identified. Apple worked with the Food and Drug Administration (FDA) for a number of years to receive De Novo classification for the ECG app and the irregular heart rhythm notification, making the features available over the counter.”

Apple first announced these features when it revealed the Apple Watch Series 4 at a launch event in September.