Apple has teamed up with Stanford Medicine for a study that uses a new Apple Watch app to help determine whether a user is experiencing abnormal heart rhythms.

Available for iPhone and Apple Watch users in the U.S., the Apple Heart Study app uses the heart-rate sensor on the underside of the Apple Watch to gather data. The study represents a “first-of-its-kind” research project to establish the potential use of wearables such as Apple Watch to detect atrial fibrillation (AFib) — a condition associated with an increased risk of strokes and heart failure.

Needless to say, early diagnosis and treatment of irregular hearth rhythms can help prevent more serious complications. As part of the study, participants — that is, anyone who installs the app and is aged 22 years and over — who may have an irregular heart rhythm will receive a notification on their watch and their iPhone, and will be invited to attend a free medical consultation and be fitted with an electrogram (ECG) patch for continued monitoring.

Above: Apple Heart Study app

To be clear, this is less about diagnosing than it is about providing ongoing screening — the Apple Watch is not yet a regulated medical device. The in-built sensor uses LED lights and “light-sensitive photodiodes” to detect the amount of blood flowing through the wearer’s wrist, gathering signals from four separate points. The watch then uses algorithms to isolate heart rhythms from other “noise.”

“Through the Apple Heart Study, Stanford Medicine faculty will explore how technology like Apple Watch’s heart rate sensor can help usher in a new era of proactive health care central to our Precision Health approach,” noted Lloyd Minor, dean of Stanford University School of Medicine, in a press release.

Healthy living

Apple has long touted the Apple Watch as much more than a simple wearable for tracking your steps or receiving notifications from your phone. Back in 2014, the company launched the HealthKit platform and Health app with a view toward collecting health metrics such as blood pressure, heart rate, and stats on diet and exercise. A year later, Apple announced ResearchKit for medical researchers, which — in conjunction with the Apple Watch, particularly — opens up new avenues for carrying out health studies at scale.

“Every week, we receive incredible customer letters about how Apple Watch has affected their lives, including learning that they have AFib,” said Apple COO Jeff Williams. “These stories inspire us, and we’re determined to do more to help people understand their health. Working alongside the medical community, not only can we inform people of certain health conditions, we also hope to advance discoveries in heart science.”