A device slightly smaller than a hockey puck was the only thing that stood between Charles Cook and death.

It was 2007, and the then-36-year-old was living in Alabama.

An internal defibrillator had been installed in his chest several years previously due to a hereditary heart condition – but up to that point, it had only been an insurance policy of sorts.

All of a sudden, that changed.

“It was like somebody flipped a switch,” Cook tells CTV News.

“Everything went black. Technically I was dead for 24 seconds, and then the device zapped me and brought me back to life.”

Not long after that incident, Cook and his wife moved to Waterloo.

When his defibrillator’s battery started to fail earlier this year, Cook underwent a new procedure at St. Mary’s General Hospital – the installation of an implantable cardioverter defibrillator.

“Going in knowing that they're basically going to put a battery and jumper cables in your heart to get it started again if it stops is a little scary,” he says.

Dr. Claus Rinne, a cardiologist at St. Mary’s, says the implants are only offered to patients who have a significant risk of sudden death from heart racing.

“They are an engineering marvel,” he says.

“There is no question that these devices save lives.”

The units monitor every heartbeat and record information that can later be viewed by doctors.

Approximately 16,000 Canadians suffer fatal heart attacks each year.

CTV’s David Imrie is looking at cardiac care in Waterloo Region in a special series airing this week on CTV News.