OAK LAWN, Ill. (CBS) — Oak Lawn Community High School hosted a potentially life-saving event on Thursday.

Dale Nickos called it, “the screening that could have saved my son’s life.”

His 17-year old son, Tim, died in the summer of 2011, between his junior and senior years at Oak Lawn High. Autopsy results determined Tim had died of an enlarged heart, a problem that might have been detected if he had an EKG.

That’s why Dale worked to bring the group Young Hearts for Life to Oak Lawn on Thursday.

All 1,800 students were offered the chance to get free EKGs, and Supt. Mike Riordan said he believes at least 1,000 of them got the four-minute heart scan.

“Anything we can do as a school to ensure the safe, security and well-being of our kids is part of our mission,” Riordan said.

Johneen Davis, program director for Young Hearts for Life, said “the school physicals do not capture what we’re screening for.”

Davis said at least 17,000 high school and college students in the Chicago area will get similar EKG tests this year.

Dr. Frank Zimmerman, of Advocate Children’s Hospital, has volunteered to read the EKGs.

In January, Young Hearts for Life did its 100,000th EKG. The organization began in 2006.

Davis said potential heart trouble is detected in one to two percent of those screened.

Oak Lawn High School senior David Michaels said he wanted to get the EKG “to make sure I was healthy because I’m in sports.”

Nariman Shehaiber, a 16-year old junior at Oak Lawn High School, said she planned to get the free EKG after hearing that two of the school’s students had died of enlarged hearts in the past eight years.

“It’s kind of frightening that something could be happening without me knowing,” she said, since problems with enlarged hearts can happen without any previous symptoms.

Also volunteering at the event were John and Laura Regalado whose 15-year old athletic son, Robert — or “Bobbo” — died in 2009 of this silent killer. The Regalados volunteer for about a dozen events a year.

On May 11, a charity walk will be held in Bobbo’s memory. called “Bobbo’s Walk for Young Hearts” in Burbank. Proceeds from the walk help sponsor EKG screenings for high school students and the donations of portable AEDs for local schools and youth sports groups.