NEWBORN GIRLS SHARE A HEART AND LIVER : DOCTORS EVALUATE TWINS' CONDITION.

Byline: David Bloom Daily News Staff Writer

Twin girls born at UCLA Medical Center share a heart and a liver, and doctors now are unsure whether the newborns must be separated to survive or if they can even live as one.

``The female twins are conjoined at the chest and abdomen and are in critical condition,'' said Simi Singer, a medical center spokeswoman. ``It is a complex situation that is being evaluated. They are sharing several organs.''

The university released little information Friday about the birth. The twins' mother and doctor both declined to be interviewed.

But a source at the medical center said the girls share a malformed heart and a liver.

The twin with the heart - which has three ventricle chambers, instead of the normal two - has underdeveloped but complete lungs, while the one without the heart has a full pair of lungs, the source said.

Such a configuration bodes poorly for both children, said Dr. Rangasamy Ramanatahn, the director of County/USC Medical Center's neonatal intensive care unit and associate medical director of its neonatology department.

``The overall outcome for conjoined twins is not good,'' Ramanatahn said. ``When they try to separate (the twins), it probably won't go well.''

Conjoined twins with a similar profile born two years ago at County/USC died during separation surgery at UCLA, Ramanatahn said.

Part of the problem with separating such twins is that they occur so seldomly, and each case is so unique, that ``at this stage, it's pretty experimental,'' Ramanatahn said.

Because of the complexity of the shared organs, UCLA doctors are trying to figure ``what, if anything, can be done for'' the twins, Singer said.

A set of conjoined twins occurs once in every 50,000 to 60,000 live births, but most such twins are stillborn, said Dr. Marion ``Jack'' Walker, a neurosurgeon at Primary Children's Medical Center in Salt Lake City, Utah.

There are many kinds of conjoined twins, the result of a fertilized egg that splits into twins but doesn't fully separate.

Among survivors, those who share the ``heart, liver, lungs or brain are the tough ones'' to successfully separate, Walker said.

Dr. Kathryn Anderson, chief of surgery at Childrens Hospital of Los Angeles, said she had worked with five pairs of conjoined twins, none of whom survived the separation process.

Separation surgery is more likely to be successful these days, because doctors can use MRI and other imaging technology to study thoroughly what organs are shared and plot a strategy before beginning surgery.

Children's Hospital in San Diego separated two girls, Sarah and Sarahi Morales of Tijuana, in January 1996, but the weaker Sarahi died soon after the surgery.

The two girls were connected at the chest and belly. Each girl had her own heart.