Hold out your hand and make a fist. If you're a kid, your heart is about the same size as your fist, and if you're an adult, it's about the same size as two fists. Your heart beats about 100,000 ...

With traditional valve replacements, “kids grow but the valves don’t,” said Taufiek Rajab, MD, a pediatric heart surgeon at the Arkansas Children’s Hospital in Little Rock, Arkansas ...