Demi Lovato teases new single 'Heart Attack' and talks 'X Factor' regrets

Demi Lovato's new single "Heart Attack" will start streaming March 4, but fans can get a gander of it now. The former Disney star teased the high-octane song with a video posted today (Feb. 12), featuring close-ups of her face and chatter about how the as-yet-untitled album boasts "songs about the celebration of life and how rewarding it can be.