On a beautiful Leap Day morning 9-year-old Caitlyn O’Reilly’s own heart took a leap of sorts, causing the girl to collapse on the playground of Hannum Elementary School.

If not for the quick thinking actions of a teacher and school nurse, and a nearby automated external defibrillator or AED—Caitlyn’s survival of a potentially fatal heart arrhythmia is pure serendipity.

“It was such a shock at first and then it was so amazing that she made it,” Caitlyn’s mother, Joanne O’Reilly said, who was on her way to lunch when she received a call from the school on her cell phone. “Ninety-eight percent don’t survive it.”

Born with a complex form of birth heart defect involving switching pumping chambers and great arteries with a hole in the heart, the Oak Lawn girl is no stranger to Advocate Hope Children’s Hospital. Caitlyn has already undergone a sophisticated repair by Hope Children's cardiovascular surgeons.

Until the morning of Feb. 29, however, Caitlyn had never shown the potential for a fatal arrhythmia. Playing with two young friends at recess, Caitlyn “stared blankly” and fell over, her mother said.

“[Her friends] thought she was kidding around,” Joanne continued. “Then they got scared and knew she needed help.”

After Caitlyn’s friends alerted the recess supervisor that she had collapsed, a gym teacher and nurse moved into swift action.

School nurse Therese Carberry administered CPR while gym teacher Gregory Guzzo grabbed the school’s AED, a device that diagnoses and treats potentially fatal arrhythmias and allows the heart to reestablish an effective rhythm.

Confirming the presence of a lethal arrhythmia, the AED was activated to shock Caitlyn and restore the activity of her heart muscle. The device ultimately saved her life in the interim of waiting for paramedics to arrive on the scene.

Any delay in diagnosing and treating Caitlyn’s arrhythmia could have resulted in her death, her mother said.

“I’m so thankful [the school] had it and knew how to use it,” Joanne O’Reilly said. “The gym teacher kept his calm and knew exactly what to.”

Caitlyn was rushed to Hope, where her pediatric cardiologist, Dr. Tarek Husayni, stabilized her condition

“Upon arrival to our hospital, Caitlyn was unresponsive, intubated and ventilated to support her breathing,” Dr. Husayni said. “Analysis of respiratory gases in her blood showed that the period of cardiac arrest was brief and it did not result in major dysfunction.”

At first there was concern that a lack of blood flow to her brain may have caused brain damage, but “we found that Caitlyn’s lack of circulation was short enough to most probably not cause any significant, serious damage to her organs.”

Thursday, Caitlyn underwent a procedure at Hope to have an ICD—a combination pace maker and defibrullator—placed in her heart. The device will help determine what caused the near fatal heart arrhythmia.

Except for a mild problem with short-term memory loss, Caitlyn has few complications from her Leap Day ordeal.

“If Caitlyn’s school did not have a defibrillator, she might not be here with us today. The AED truly served as a gift of life for Caitlyn and prevented a near sure death,” Dr. Husayni said.

Sudden cardiac arrest strikes approximately 7,000 children in the United States every year. Often these children, like Caitlyn, fall victim while at school or on a playing field.

Many states, including Illinois, New York and Pennsylvania, are mandating the placement of AEDs in schools. Other states have pending legislation.

Joanne gave Advocate Hope permission to release information about her daughter's experience to bring greater awareness of the importance of having the life-saving AEDs on hand at schools and other public places.

“In a way it happened in the best possible place rather than at home because the AED saved her life,” Joanne said. “The devices are relatively inexpensive and easy to use.”