HOUSTON (KTRK) -- Taking a human heart out and replacing it with an artificial heart is rare. Only 800 adults have had a total artificial heart, and it's even rarer for children.

But Texas Children's Hospital has performed its first total artificial heart surgery on a Houston teenager. Three weeks later, he is doing well and getting used to his mechanical heart.

When you talk to Jordan Merecka, the first thing you notice is the pumping sound.

"It never really bothered me. In fact it's almost comforting because you hear it and you know it's still pumping," he said.

It's his artificial heart beating. He needed a heart transplant, but one wasn't available. So Texas Children's surgeons removed his old heart and replaced it with pumps attached to a 400-pound console.