Whitney Ray Petersen, the unborn son of a Murray couple, is one step closer to receiving a new heart. The child has been placed on the heart-transplant list at Loma Linda, Calif., University Medical Center.

However, there are now four on the group's list of approved recipients. Physicians cannot foretell when a heart from a matching donor with O-positive blood will become available or when Whitney Ray's transplant is likely to occur."As soon as an appropriate donor is found, the baby will be delivered by Caesarean section and will have a transplant," hospital spokeswoman Anita Rockwell said.

The sooner a donor heart is found, the better. The child's mother, Cynthia Petersen, is expected to deliver Oct. 23, and the child's life is in danger immediately after birth.

Whitney Ray suffers from hypoplastic left ventricle. The lethal heart malformation, involving the cardiovascular system, prohibits the main ventricle, or pumping chamber of the heart, to develop properly.

Dr. Greggory De Vore, director of maternal-fetal medicine for Intermountain Health Care, who diagnosed the problem, said it occurs in 8,000 to 10,000 live births annually.

"The hypoplastic left ventricle doesn't create a problem for the unborn fetus, but once birth does occur the survival rate is zero. Most babies die within three to four weeks of life," De Vore said.

If all goes well, the unborn fetus will become the second baby in history to receive a heart transplant immediately after birth. The other case was Baby Paul from Canada, who like the Utah fetus, suffered from hypoplastic left ventricle.

Cynthia Petersen flew to Southern California earlier this month after De Vore diagnosed the malformation. In order to save the life of their child, she and her husband, Daymon, had no choice but to accept the expensive surgery, not covered by their insurance.

A few years ago Loma Linda University Medical Center received extensive publicity for transplanting the heart of a baboon into an infant named "Baby Fae." The newborn died 20 days later.

Following that historic cross-species transplantation, the team began doing human-to-human transplants. The first took place on Nov. 20, 1985. Since then, center physicians have performed 20 heart transplants in children under six months of age. Sixteen of these children have survived the operation.

"The problem with transplanting a newborn whose diagnosis is made after delivery is that with hypoplastic left ventricle, unfortunately only 50 percent of the children referred to the center actually receive the transplant," De Vore said. "The reason is because there is no way to determine when a donor will become available. The doctors have a short period of time to keep the baby alive."

However, the specialist added that because a newborn's immune system isn't developed, a transplant is more likely to take. But there is still the possibility of rejection.