D'Zhana Simmons, who was kept alive for almost four months by mechanical pumps, had her first heart transplant fail July 4. Her chest became an empty cavity until Oct. 29, when she was well enough for doctors at Holtz Children's Hospital at the University of Miami/Jackson Memorial Medical Center put a new heart in.

''It was scary not knowing from day to day if it might be fatal,'' D'Zhana's mother, Twolla Anderson, told the Miami Herald.

This was the first time such mechanical pumps -- normally used to help disease-weakened hearts pump blood -- were used for a child with no heart, hospital officials said.

Now that she is out of the hospital, D'Zhana -- who turns 15 Saturday -- will live on immunosuppressors to keep her body from rejecting the heart, doctors said.

"But she'll be able to do most things a girl her age does -- go to school, go out," Dr. Marco Ricci, director of pediatric cardiac surgery, told the newspaper.

There's a 50 percent chance that within 12 or 13 years, D'Zhana will need another heart transplant, said Dr. Paolo Rusconi, director of pediatric cardiac transplants.