Adult pacemakers used to buy time for tiny hearts

WASHINGTON -- Four-month-old Damaris Ochoa was near death, born with an enlarged heart that was quickly giving out. Obtaining a transplant in time was a long shot. Then Dr. Edward Rhee attached a souped-up adult pacemaker to her tiny heart, and six months later Damaris is thriving.

The Kansas City, Mo., tot is among the youngest of just a few dozen children to try an experiment in which doctors are adapting a new technology for adults' failing hearts to the special needs of their smallest patients.

It's too early to know how well the therapy, called cardiac resynchronization, will work. But so far, a handful of youngsters are doing so well they've been taken off the heart transplant waiting list, and the hope is that others improve enough to postpone that operation.

"At least in the short term, we can improve their symptoms and quality of life," predicted Rhee, the electrophysiology chief at St. Louis Children's Hospital.

Cardiac resynchronizers, which hit the market three years ago, can dramatically help many adults with heart failure. Their hearts are weakened by age, a survived heart attack or some other disease, and get flabbier as they struggle to pump blood through the body.

Pacemakers are best known for speeding up a sluggish heartbeat. The resynchronizers are souped-up pacemakers that work differently -- because in heart failure, the struggling heart beats too fast. Instead, three wires that deliver electricity are threaded deep into various parts of the heart to make the pumping chambers, called ventricles, move together in rhythm, thus increasing their power.

Children's heart failure has different causes. Some are born with an enlarged heart or suffer a heart-damaging viral infection. Others are born with structurally abnormal hearts, and surgeries to correct those birth defects can hurt the heart's electrical system in ways that, years later, show up as weakened pumping action.

'Have to bend the rules'Implanting the pacemaker can be different, too. Very young children's blood vessels are too small to thread the wires through, requiring open surgery to put the pacemaker "leads" on the outside of the heart instead of the inside. Some hearts are so small they can handle only one wire.

"We have to bend the rules a little bit and come up with new ways to use this very powerful technique," said Dr. Anne M. Dubin, a pediatric electrophysiologist at Stanford University Medical Center.

Patients like Damaris Ochoa are fueling supporters' drive to improve study of the experimental option.

Her heart never properly hardened into smooth muscle, and by age 4 months Damaris had only 10 percent heart function. Rhee said the baby likely had weeks to live.

But Damaris was home in Kansas City a week after the procedure, and now at age 10 months has doubled her weight to 18 pounds and crawls around the house chasing her four siblings. "It's like nothing was ever wrong," said her father, Oscar Ochoa.

"To reverse somebody who is that far gone is pretty much unheard of," said Rhee. "It's pretty gratifying."