When Georgia Bowen was born by emergency Caesarean on May 18, she took a breath, threw her arms in the air, cried twice, and went into cardiac arrest.

Her heart was profoundly damaged; a large portion of the muscle was dead, or nearly so.

Doctors kept her alive with a cumbersome machine that did the work of her heart and lungs. The physicians at Boston Children’s Hospital decided to try an experimental procedure that had never before been attempted in a human following a heart attack. They would take 1 billion mitochondria — the energy factories found in every cell in the body — from Georgia’s abdominal muscle and infuse them into the injured muscle of her heart.

Mitochondria are tiny organelles that fuel the operation of the cell, and they are among the first parts of the cell to die when it is deprived of oxygen-rich blood. Once they are lost, the cell itself dies. But a series of experiments has found that fresh mitochondria can enable cells to recover.

For Georgia, though, the transplant was a long shot — a heart attack is different from a temporary loss of blood, and the prognosis is stark.

The idea for mitochondrial transplants was born of serendipity, desperation and the meeting of two researchers at two Harvard teaching hospitals both wrestling with how to fix hearts deprived of oxygen.

While preparing to give a talk to surgeons, James McCully of New England Deaconess Hospital created electron micrographs of damaged cells. The images showed that the mitochondria in the damaged heart cells were abnormally small and translucent, instead of a healthy black.

The mitochondria were damaged — and nothing McCully tried revived them. One day, he decided to pull mitochondria from healthy cells and inject them into the injured cells.

Working with pigs, he took a plug of abdominal muscle the size of a pencil eraser, whirled it in a blender to break the cells apart, added some enzymes to dissolve cell proteins, and spun the mix in a centrifuge to isolate the mitochondria.

He recovered 10 billion to 30 billion mitochondria, and injected 1 billion directly into the injured heart cells. To his surprise, the mitochondria moved like magnets to the proper places in the cells and began supplying energy. The pig hearts recovered.

Meanwhile, Dr. Sitaram Emani, a pediatric surgeon at Boston Children’s, was struggling with the same heart injuries in his work with babies.

He can hook the baby up to a machine like the one that kept Georgia Bowen alive, an extracorporeal membrane oxygenator, or ECMO. But that can work for only two weeks.

But one day Emani was told of McCully’s work, and the two surgeons met. McCully moved to Boston Children’s, and he and Emani prepared to see whether the new technique might help tiny babies who were the sickest of the sick — those surviving on ECMO.

Early one Saturday in March 2015, the hospital got a call from Maine. Doctors there wanted to transfer to Boston Children’s a newborn boy whose heart had been deprived of oxygen during surgery to fix a congenital defect.

“We turned the intensive care unit into an operating room,” Emani said.

He snipped a piece of muscle from the baby’s abdomen. McCully grabbed it and raced down the hall. Twenty minutes later, he was back with a test tube of mitochondria.

Emani injected 1 billion mitochondria, in about a quarter of a teaspoon of fluid.

Within two days, the baby had a normal heart. “It was amazing,” Emani said.

The scientists have now treated 11 babies, and all but one were able to come off ECMO, Emani said. Two died because their hearts were so damaged, and one died of an infection.

In comparison, the death rate among a similar group of babies that did not get mitochondrial transplants was 65 percent.

For Georgia Bowen, the procedure came too late: The portion of her heart muscle affected by the heart attack had died. Her doctors implanted a device that takes over the heart’s pumping. Her heart is showing signs of healing.

“Georgia is a miracle who continues to fight,” said her mother, Kate. “In our hearts, we know she will pull through.”