Jeff Williams, Chief Operating Officer of Apple, speaks about the the new Apple Watch Series 4 at an Apple Inc product launch event at the Steve Jobs Theater in Cupertino, California, September 12, 2018. Stephen Lam | Reuters

The Heartline Study app Johnson & Johnson

"The Heartline Study is a nationwide, randomized, controlled, app-based, virtual research study sponsored by Janssen Pharmaceuticals, Inc., a member of the Janssen Pharmaceutical Companies of Johnson & Johnson," the companies said. "The team worked with Apple to jointly design the research study and the Heartline Study app." Open enrollment for the new study begins Tuesday. It's open to anyone 65 or older with traditional Medicare and an iPhone 6s or later model running iOS 12.2 or newer. "Eligible participants will be randomized to one of two possible groups. One group will participate by only using the Heartline Study app on their iPhone," Johnson & Johnson explained. "The other group will participate by using the study app on their iPhone in addition to obtaining an Apple Watch to use the ECG app and irregular rhythm notification feature. Participants who already own an Apple Watch may be eligible to join the study as well, with certain restrictions." Participants selected in the Apple Watch group can either purchase a watch at a discounted price or can borrow a watch on loan for no cost. Those who borrow will have to return the watch at the end of the study. The exact discounted price wasn't disclosed. The app is available for free in the iTunes App Store.

The Heartline study app Johnson & Johnson