https://wccftech.com/apple-watch-detects-widow-maker-heart-attack/

Once more, the Apple Watch was triumphant in preventing a tragedy befalling a family by alerting a woman of a heart attack that she did not realize had taken place. The wearer, who resides in Michigan, states that the smartwatch alerted her to a high heart rate, prompting her to seek medical attention and later finding out what it was.

Diane Feenstra, the owner of the Apple Watch, recalls how her heart rate rose even though she hardly partook in any vigorous exercises.