Coming Home at Last : Medicine: Two-month-old Jonathan Mark is released from the hospital after undergoing heart transplant surgery.

Finally, after a two-month delay, Eva and Kevin Mark are settling into parenthood.

This week, the young couple took their infant son home from the hospital for the first time since his birth in mid-December. Only now are they learning to change diapers and wake up every few hours for nightly feedings.

Kevin Mark, 26, sounds like he’s enjoying it.

“I’ve been waiting 11 months to be able to hold him,” the first-time father said.

For the Marks, the two months since Jonathan Laszlo Mark’s birth have been plagued by uncertainty and fear.

Born with a defective heart, Jonathan underwent heart-transplant surgery Jan. 22 when he was just 5 weeks old. He has spent most of his life in neonatal intensive-care units, surrounded by tubes and machines.

But on Tuesday evening, Jonathan was discharged from Loma Linda University Medical Center in San Bernardino County and traveled to his parents’ new home in Grand Terrace. The couple moved there a few weeks ago from Redondo Beach so they could be closer to the Loma Linda hospital that will be monitoring Jonathan’s progress.

“Babies are very demanding and he’s no exception,” said Mark, who is commuting 75 miles each way to his job as a retail sales manager at a Beverly Hills men’s clothier. “It’s a great feeling, it’s a big relief, it’s a lot of fun, there’s a lot of work.”

The Marks must spend the next six months living near the hospital, but eventually plan to return to Redondo Beach.

In the meantime, Jonathan is required to take nine different types of medication, and the Marks must keep a daily diary of what drugs he takes and how much he eats.

On Thursday, they paid their first visit to the hospital outpatient clinic, where Jonathan will be examined twice a week for any signs of rejection or other problems.

Just days after his Dec. 16 birth, Jonathan was found to have a rare heart defect called hypoplastic left-heart syndrome, in which his heart’s left side was so underdeveloped that it could not pump blood properly. Doctors said he would die within a few months without a transplant.

He was transferred to the Loma Linda neonatal intensive-care unit until a new heart could be found. His color paled, and his breathing was forced.

Finally, on Jan. 22, the Marks received a pre-dawn telephone call that a donor heart had been located.

In surgery that lasted about five hours, Dr. Leonard L. Bailey placed a new heart, about the size of a walnut, in Jonathan’s chest.

Jonathan was the 124th infant under 6 months of age to receive a heart transplant at the San Bernardino County hospital since it began the technique in November, 1985. The Loma Linda program has an 82% success rate, and two more infants have received new hearts there since Jonathan’s surgery a month ago.

The Marks had worried that their son would not live long enough to get a new heart.

Now, they have befriended a Canadian couple whose infant son, Francois Hotton, born Sept. 27, has been waiting nearly five months for a similar transplant. That is believed to be the longest time any infant has survived with hypoplastic left-heart syndrome, said Loma Linda hospital spokeswoman Anita Rockwell.

In interviews this week, the Marks talked about Francois’ plight in hopes that a donor might come forward.

“There’s pretty much world history being set here, which is not a good thing,” Mark said of the long wait. “We understand what they’re going through, to an extent--but our wait was so brief, (and) theirs is so long.”

The Marks do not know the identity of the donor who provided the heart for their son. They are preparing a letter of condolence and thanks, which the hospital will pass along to the donor family.

Meanwhile, the Marks must feed their son every three hours throughout the night. He remains small--7 pounds, 10 1/2 ounces, less than a pound more than his birth weight--but he is gaining weight and starting to grow some blond hair.

“He doesn’t have all the tubes and wires running out of him,” his father said. “Now, he looks like a baby.”