NEW YORK -- In a medical first, an infant whose genetically narrowed heart valve was corrected in his mother's womb surprised doctors recently when he was born with two functioning ventricles, one of the surgeons told AFP Monday.

"We have changed a child who would have been born with one ventricle into one born with two," said Cardiologist Stanton Perry.

By expanding the width of the fetus's aortic valve, a team of 10 doctors at Boston's Children's Hospital allowed his left ventricle to pump blood successfully through the diminished valve.

Blocked from carrying out this function, the ventricle could die, leading to a debilitating and often deadly condition known as hypoplastic left heart syndrome.

"Once the ventricle dies, then your options are much different," Perry said. "You need three major operations. We think we prevented hypoplastic left heart syndrome in this child."

"We made it easier for the muscle to pump through it and, therefore, survive," Perry added.

In avoiding the onset of the syndrome, Perry said, doctors have likely allowed the child -- named Jack -- to lead an active life with a normal life expectancy, suffering only from a relatively treatable condition known as aortic stenosis, a narrowing of the valve.

"If the ventricle is all right and the muscle survives, the rest is just plumbing," he added. "We gave Jack the chance to have aortic stenosis instead of hypoplastic left heart syndrome."

Among the possible factors contributing to the success of the procedure was that the fetus was relatively young -- just 23 weeks old, Perry said. This is a full month younger than the next-youngest fetus that was operated on.

"The theory, at least, is the sooner you intervene, the more likely the ventricle is to recover," Perry said.

**** The New York Times ****, citing an article in **** The American Journal of Cardiology ****, said that, from 1989 to 1997, just two of 12 babies survived the procedure, both of whom required surgery after birth.

According to Perry, only one of the two survived long term, and that fetus's valve-widening procedure was not even technically a success.

Opening a valve in a fetus is particularly risky, **** The Times **** report said, because the fetus's heart, a moving target, is about as small as a grape and no standard instruments exist for such a procedure.

"The limitations at the moment are the size of the equipment we have," Perry said. "The balloon (we used) is the same as for an adult, blown up to an eighth of an inch. (The hope is that) we'll get better tools designed specifically for this."

The result, Perry said, was "what everybody's hoping for."

"This is a major undertaking. It's a major feat to do this successfully. Before, people asked, 'What is the gain?' here, for the first time, we can see what the potential is for gain."

"I think this will definitely spur people on to try (the procedure again)," he added. "On the other hand, it's one case, so you can't make too much of that. We could go the next 10 and not have a success."

Perry said about 10 doctors participated in the surgery, including two anesthesiologists (one for the mother, another for the fetus); two obstetricians (one to puncture the mother's abdomen and enter the fetus's heart with a hollow needle, another to watch the ultrasound screen); a fetal surgeon (to hold the baby in place through the mother's abdomen); and four cardiologists, including Perry.