HOUSTON --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. "I don't have any chest pain. My energy level has skyrocketed," Jordan said. He lived to turn 18. One week later, he graduated from high school. His sister, Allison, walked across the stage for him. "He's amazing. He's one of my biggest heroes now," she said. "I don't know how he's been able to get through all this," said Jordan's brother, Brandon. "He's just changed all of our lives." The mechanical heart will give Jordan time to wait for a heart transplant, and he'll be able to wait at home. "So this is the backpack we were talking about and this will take the place of Big Blue over there," said Dr. David Morales, Jordan's heart surgeon. Dr. David Morales shows him the portable battery pack that will free Jordan from Big Blue. "There's the potential to go home. Just three or four years ago, if you had this device you had to stay in the hospital," Dr. Morales said. Jordan credits God for making the artificial heart available at Texas Children's just in time for him. "Through him, all things are possible," he said. And his parents are amazed at his courage the past three months. Jordan has already gotten stronger with the artificial heart, and that will make it safer for him when a heart does become available for transplant. And now that is what this Houston family is praying for.