This is my heartbeat song, and I'm gonna play it," Kelly Clarkson sings on her new single, out Tuesday. "Been so long I forgot how to turn it up-up-up-up all night long." It's been a long time for her fans, too, who have waited more than three years for a follow-up to 2011's Stronger. The high-energy Heartbeat Song serves as a sonic defibrillator, starting with a jolt of melody, its rhythms shifting a couple times before finally settling into its steady pulse.