"It was like I was a fake person, like I didn't really exist. I was just here," she said at Holtz Children's Hospital in Miami, "But I know that I really was here."

The modern science miracle began last spring when Simmons learned that her enlarged heart was too weak to pump enough blood, a condition called dilated cardiomyopathy.

Surgeons at the hospital performed a transplant on July 2, but two days later the heart malfunctioned and had to be removed.

"In the past, this situation could have been lethal," said Dr Marco Ricci, director of pediatric cardiac surgery at the University of Miami.

Instead, Dr Ricci modified the Thoratec Corp-made ventricular-assist device, which are commonly used for only hours at a time, into a long-term artificial heart.

"She essentially lived for 118 days without a heart, with her circulation supported only by two blood pumps," Dr Ricci said.

A second transplant on October 29 was successful.

Dr. Peter Wearden, a cardiothoracic surgeon at Children's Hospital of Pittsburgh who works with the kind of pumps used in this case, said what the Miami medical team managed to do "is a big deal." "For (more than) 100 days, there was no heart in this girl's body? That is pretty amazing," Wearden said. The pumps, ventricular assist devices, are typically used with a heart still in place to help the chambers circulate blood. With D'Zhana's heart removed, doctors at Holtz Children's Hospital crafted substitute heart chambers using a fabric and connected these to the two pumps.

D'Zhana said now she's grateful for small things: She'll see her five siblings soon, and she can spend time outdoors.

"I'm glad I can walk without the machine," she said, her turquoise princess top covering most of the scars on her chest. After thanking the surgeons for helping her, D'Zhana began weeping.

Doctors say she'll be able to do most things that teens do, like attending school and going out with friends. She will be on lifelong medication to keep her body from rejecting the donated heart, and there's a 50-50 chance she'll need another transplant before she turns 30.

For now, though, D'Zhana is looking forward to celebrating another milestone. On Saturday, she turns 15 and plans to spend the day riding in a boat off Miami's coast.