Apple has launched a new app today that will allow the company to gather irregular heart rhythm data from the Apple Watch’s heart rate sensor. Called the Apple Heart Study app, it will detect irregularities and send notifications to users who may be suffering from atrial fibrillation (AFib).

Apple first mentioned its Heart Study initiative back in September when it launched watchOS 4. The company is partnering with Stanford University on the project. The company plans on using heart rate data to better inform patients, doctors, and researchers of cases of heart irregularity.

“Working alongside the medical community, not only can we inform people of certain health conditions, we also hope to advance discoveries in heart science,” said Jeff Williams, Apple’s chief operating officer, in a statement. The app uses the Apple Watch’s existing technology to measure heart rate through green LED lights flashing hundreds of times per second and photodiodes that detect the amount of blood flowing through the wrists.

Users who participate in the survey will be notified on their iPhone and Watch if an irregular heartbeat is detected and provided a free consultation with a study doctor and an electrocardiogram (EKG) patch for further observation. The app is currently available in the US App Store, and users who want to participate in the study have to be 22 years or older with an Apple Watch Series 1 or later.

Earlier today, the FDA approved the first medical device accessory for the Apple Watch — AliveCor’s KardiaBand electrocardiogram (EKG) reader, a sensor that pairs with an app and can detect abnormal heart rhythm and AFib, too. There are already plenty of apps that flag things like abnormal spikes in heart rates, stress levels, and also analyze the data that’s pushed into Apple’s Health app. Earlier this year, a study showed that the Apple Watch can detect heart irregularity with 97 percent accuracy, which isn’t quite good enough for an official diagnosis, but is still useful as a screening tool.