DENVER (CBS4) – A new baby is recovering in Denver from a surgery usually associated with older adults.

Knoxley Lou Colton’s condition was discovered before she was born. A doctor noticed Knoxley’s heartbeat was abnormally slow. An ultrasound showed she had a rare heart defect.

“The ventricles on the bottom chambers of her heart had been switched,” said Kate, her mom.

Kate and Chance Colton were told their baby girl would probably need a pacemaker.

“The first time I heard about the pacemaker Kate called me hysterical,” Chance said.

But Kate had a healthy pregnancy. At 39 weeks Knoxley was born. At just 3 days old she had surgery at the Rocky Mountain Hospital for Children.

“We made an incision over the lower sternum and the upper abdomen,” said pediatric heart surgeon Dr. Steven Leonard.

“It was pretty terrifying,” Kate said.

Leonard implanted a pacemaker about the size of a 50 cent piece into Knoxley’s chest.

Dr. Steven Leonard (credit: CBS)

Dr. Steven Leonard (credit: CBS)

“As soon as we attached the leads it started working beautifully,” Leonard said.

Knoxley will live a minor limitation or two — no intense contact sports, for instance — but nothing should stop her from keeping pace with big brother Caysen.

“If she’s anything like her brother she won’t stop running,” Chance said.

Knoxley is still recovering in the hospital this week.

“She’s doing great right now. I want to take her home,” her dad said.

“She’s a sweet little angel,” her mom said.

Leonard says Knoxley will probably need a new pacemaker every 5 to 8 years.