On a related note, see FDA clears first EKG reader for Apple Watch (The Verge)
"Health and fitness have been a key focus for Apple, especially since launching the Apple Watch two years ago. That has allowed the company to tap the $3 billion health care market and, analysts say, find new audiences for its products and services. Apple already employs a small staff of medical professionals to develop its health products, and it is reportedly working on a diabetes glucose-monitoring device that won’t pierce the skin. It's also worked with hospitals to include more of its tech in patients' rooms.
The new study takes all of that a step further: Now Apple itself will be running a study and submitting data to the Food and Drug Administration. The heart-rate researcher will look specifically at atrial fibrillation — or afib — which refers to an irregular heart rate and is a leading cause of stroke and other heart conditions. The condition kills around 130,000 people per year, according to estimates from the Centers for Disease Control and Prevention."Apple wants to know your heart rate. For science. - The Washington Post