Nat sound: The day Sarah died, my life ended.

12-year-old Sarah Friend had everything to live for. The fearless middle school student loved her family, her friends. Doctors had recently given her a clean bill of health. No one could detect the hidden heart problem that would lead to her untimely death.

Laura Friend/Sarah's mom: You can't know it, you can't hear it on a stethoscope.

Sarah collapsed and died at a water park while playing with friends. She's one of the seven to 10-thousand children who die each year from "sudden cardiac arrest," or S-C-A. S-C-A occurs when the heart stops unexpectedly and no longer pumps blood.

Jennifer Blomquist/Reporting: The condition can be genetic, viral or caused by a blow to the chest. But not all cases of S-C-A have to end like Sarah's. The use of a portable defibrillator, or A-E-D, may have been able to save Sarah's life.

Laura Friend: With C-P-R alone, your chances of survival are up 7-percent, With an A-E-D, your chances increase over 70-percent.

Judy Beverly's school district has at least one A-E-D on every campus. Nurses, coaches, bus drives, teachers and even front office personnel are trained to use it.

Judy Beverly/Parent: The A-E-D is set up so a layperson can use it. You don't have to have medical training. It walks you through the use of it.

Friend and other members of the group, "Parent Heart Watch" are now on a mission to educate all schools on the lifesaving benefits of A-E-Ds and cardiac screenings.

Laura Friend: There's not a day that goes by that you don't think of the child that you lost, you just try to save others along the way. I just try and make her proud.

I'm Jennifer Blomquist for Indiana's Newscenter.