Whitney Ray Petersen, the 2 1/2-week-old Murray child who's been battling a fatal heart disease diagnosed before birth, got a new lease on life Saturday at the Loma Linda University Medical Center.

A suitable donor heart finally became available."We are so grateful that someone saw through their pain and donated a heart from their baby and saved our baby," the child's father, Daymon Petersen, told the Deseret News in a telephone interview. "A lot of pressure has been taken off. This is the first day we feel there is a chance that he may live."

Petersen, a 31-year-old maintenance worker for the Utah National Guard, said his son was doing "fantastic" two hours after surgery.

"He went through it with flying colors," the tired, but relieved father said. "Unlike other babies, who often go downhill before a transplant, he was was in great shape. In fact, they had even cut down on his medication. Then we got the call last night."

Members of the Loma Linda University Infant Heart Transplant Group completed the 41/2 hour surgery Saturday at 1 p.m.

Hospital spokeswoman Anita Rockwell said Whitney Ray was listed in critical condition Saturday night at the medical center - his home-away-from-home since early September.

That's when the unborn fetus was diagnosed by a Utah physician as suffering from hypoplastic left ventricle, which occurs in 8,000 to 10,000 live births annually. The lethal malformation, involving the cardiovascular system, prohibits the main ventricle, or pumping chamber of the heart, from developing properly.

Dr. Greggory De Vore, director of the Intermountain Fetal Diagnostic and Treatment Center at LDS Hospital, said the hypoplastic left ventricle doesn't create a problem for the unborn fetus. But once birth occurs, the survival rate is zero.

"Most babies die within three to four weeks of life," said De Vore, who diagnosed the Petersen's 32-week-old fetus as suffering from the rare and lethal deformity.

Because of the type of malformation, Cynthia Petersen, a 29-year-old licensed practical nurse and mother of Courtney, 51/2, and Zachery, 21/2, flew to Loma Linda. Her unborn child was put on the medical center's heart transplant list Sept. 21.

Had a donor heart become available, physicians would have delivered the baby early by Caesarean section and performed the transplant.

But Whitney Ray, born Oct. 26, waited 71/2 weeks before a suitable donor heart was found. Nevertheless, hospital officials say his chances for survival are now good.

According to Rockwell, the Utahn is the 23rd infant under six months of age to undergo human heart transplant surgery at Loma Linda. Including Whitney Ray, 19 have survived.

Seven infants under six months of age remain on the heart-transplant list at Loma Linda - the U.S. institution to do the first and most infant heart transplants.

In October 1984, Loma Linda received national attention for being the first hospital to transplant a baboon heart 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.

Rockwell said Whitney Ray will likely be hospitalized for several weeks "depending on his progress."

Whitney Ray's surgery alone will cost an estimated $150,000 to $200,000. A trust fund for the child has been established at Tracy Collins Bank, 4900 S. Highland Dr., Salt Lake City, UT 84117. A second trust fund has been established at LDS Hospital's Deseret Foundation.