abnormal heart rhythm

Apple Watch could be used to detect an abnormal heart rhythm with 97% accuracy

The study began last year to discover whether the Apple Watch could detect an oncoming stroke, quarter of which are caused by an abnormal heart rhythm.
Apple Watch - heart sensor

Cardiogram study: Apple Watch can detect diabetes with an 85% accuracy

Researchers used data from 14,000 Apple Watch users and was able to detect that 462 of them had diabetes by using the Watch's heart rate sensor.