Why Demi Lovato Performed 'Heart Attack' at Heart-Health Event

Demi Lovato is using their voice to make a difference. The singer took the stage at the American Heart Association's Go Red for Women Red Dress Collection Concert in New York City and surprised attendees when they decided to perform their song, 'Heart Attack.' ET has learned why Demi sang the 2013 track at the event after going through their own near-death experience with a heart attack years ago.