Apple Watch is being credited with helping another user detect atrial fibrillation. Today, local news outlet WHAS11 tells the story of Rosemary Stiles, who asked for an Apple Watch for Christmas in 2018 and now says the device accurately detected the heart condition while she was asleep.

Rosemary says that she was feeling tired and run down on a daily basis, and would often fall asleep shortly after sitting down. At the time, she had no ideas those were key symptoms of AFib.

After falling asleep one day last year, Rosemary woke up to a notification from her Apple Watch that said it detected atrial fibrillation. It was that notification that prompted her to see medical attention at Norton Hospital in Louisville, Kentucky.

Speaking to WHAS11, APRN Tara Mudd said that Rosemary was one of the first patients to come to Norton where the Apple Watch was the first indicator of atrial fibrillation. Now, Rosemary has a renewed feeling of purpose:

When the Apple Watch detects an irregular heart rhythm, it sends a notification to the user saying, “Your heart has shown signs of an irregular rhythm suggestive of atrial fibrillation.” The user is then instructed to contact their physician if they have not previously been diagnosed with AFib.

Read more stories about the Apple Watch’s health features here.