Frisco teachers used an automated external defibrillator to revive a 12-year-old student.
Seventh-grader Kylee Shea collapsed while walking to gym class.
"I sat down, then I fell over, and I don't remember anything after that," she said.
Doctors have have diagnosed Kylee with a heart arrhythmia, meaning her heart was quivering rapidly but wasn't pumping blood.
"Survival for somebody who collapses outside a hospital for a child is about 3 percent -- not very many," said Dr. William Scott, her physician.
Kylee's classmates at Frisco Middle School rushed to get help. Brent Reese and Kristen Goodgion, the two teachers who responded, calmly performed CPR and used the AED.
By the time paramedics arrived, Kylee was speaking and asking for her mother.
"They had a hand in a miracle, and it's just, 'Thank you,'" Sheryl Shea said.
She and her husband, Mike, now both advocate putting AEDs in all schools and public buildings nationwide.
"If it wasn't for this machine and what they did, our daughter still may be with us today, but she wouldn't be the Kylee we know," Mike Shea said.
Doctors still don't know what caused Kylee's heart problem. She now has a pacemaker, which will physically limit her from participating in contact sports.
Kaylee will resume school next week. She has a long list of people she wants to thank, starting with Reese and Goodgion.
The teachers said their efforts on Kylee's behalf emphasize the importance of AEDs and of teachers.
"The biggest thing is, we were here for a reason, and that was Kylee," Goodgion said.