HOLLISTER, Mo. (KY3) -- Zach Smith is a junior at Hollister High School.
"He's like the most healthy active kid we know. Never in a million years would we have though Zach's heart isn't working right," says Heather Smith, Zach's mother.
Last tuesday, Zach was doing pull-ups for the marine recruiter when something went wrong, really wrong.
"I did a couple pull ups and then once I got down I got really light headed and I passed out and I don't remember anything else from there," says Zach.
His heart stopped. He didn't have a pulse and was turning blue.
The school resource officer ran to get the AED.
Coaches, teachers, and the school nurse rushed to his aid.
They hooked him up to the defibrillator, which recommended him for a shock. They shocked him, and his heart started pumping again.
He left school in an ambulance.
At the hospital, doctors told Zach's parents they weren't sure what was causing his irregular heart beat and they flew him by helicopter to a children's hospital in St. Louis.
After a week there, doctors determined Zach had a genetic heart defect and put a defibrillator in his chest.
"His attack, this happening, has made us aware about the genetic thing so we still have time to get our grand kids and our other kids tested. So they saved his life and possibly he could be saving our other children's lives. They didn't know they had this," Heather says.
Today, Zach walked back into school on his own two feet, to say thanks.
Monday, he'll return to class.
The school has had the AED mounted on a wall for over 5 years, and they'd never had to use it before. Now, the district is ordering 3 more for other buildings and training more staff on how to use them.
"I mean if they hadn't had that defibrillator in that school then my son wouldn't be here," says Heather. "Maybe you'll never have to use it but if you only have to use it that one time, it can change a lot of lives. It changed ours."