Apple has long said it hopes to change the face of healthcare through technology, and recently a heartwarming example showed one way it’s already helping.

A first-generation Apple Watch helped to save a man’s life as it warned him to seek urgent medical attention ahead of a potentially fatal condition.

Having previously survived a pulmonary embolism, 28-year-old New Yorker James Green took to using the Heart Watch app for the Apple Watch to track his heart rate. Whenever it rose above a predefined threshold, the app would notify him with a warning alert.

One such alert showed a consistently higher-than-usual resting heart rate, which prompted Green to contact his doctor, and he was quickly able to get the treatment he needed to treat a second life-threatening pulmonary embolism. The doctor noted that it “would have been fatal” had he waited much longer to deal with the blood clots.

A third-party app was necessary for this level of tracking as Green is using an original Apple Watch. Newer models running watchOS 4 have much more detailed heart tracking capabilities as standard.

This isn’t the first time Apple Watch has made the news for saving a life – two years ago a 17-year-old football player received a call from Tim Cook and an internship from Apple after a similar event.

Related reading: how Apple can change healthcare for the better