"This technique has the advantage of destroying only the tissue that is causing the abnormal rhythm without damaging normal tissue. We correct the problem and generally avoid the need for a pacemaker."

--Ian Law, M.D.

University of Iowa Children's Hospital cardiologists help pioneer the use of cryoablation to freeze heart rhythm problem in its tracks

Born three years ago with a life-threatening heart defect, little Valeria Chupp's future rests squarely on the shoulders of pediatric cardiologists and pediatric cardiac surgeons.

While her initial care was received at Blank Children's Hospital in Des Moines, she was referred to University of Iowa Children's Hospital, located at University of Iowa Hospitals and Clinics, for further evaluation and repair of the defect. UI cardiologists determined that Chupp's long-term survival required at least three surgical procedures, in addition to medications, growth management, and extensive monitoring.

Last fall, following the first two surgeries, University of Iowa Children's Hospital pediatric cardiologist Larry Mahoney, M.D., recommended that before undergoing a third procedure, something be done to fix a heart rhythm problem.

"At one point her heart raced at an alarming rate of 200 beats per minute," said Valeria's mother, Mabel Chupp of Woodward, Iowa. "Everyone was very concerned. Fortunately, Dr. Mooradian (Stephen Mooradian, M.D., affiliated with Pediatric Cardiology P.C. in Des Moines) prescribed drug therapy to control the problem."

The recommended long-term solution involved cryoablation, a new, FDA-approved freezing technique to destroy cells that cause abnormal heartbeats. Experts at Children's Hospital of Iowa are the first in the state to offer the technique.

During the procedure, which was performed in late October 2003 by Ian Law, M.D., a pediatric electrophysiologist, a thin catheter was inserted into Valeria's heart, freezing a tiny area of heart muscle at minus 70 degrees Celsius.

Law said the technique provides more precise and effective treatment for heart rhythm disorders.

"Cryoablation allows us to test the treatment site before we proceed with the ablation, which means we can destroy fewer cells and perhaps avoid unnecessary damage to the heart," Law said.

Heart specialists have previously used radioablation, in which radio waves destroy the cells that cause an arrhythmia. While that approach is often successful, it doesn't allow physicians to evaluate the effects of the treatment before delivering the ablation. On rare occasions, patients may require pacemakers following the radioablation procedure.

Cryoablation offers an effective alternative. During the procedure, a physician inserts a catheter into the patient's leg and guides it into the heart. When the tip of the catheter reaches the treatment site, its temperature is dropped to minus 25 degrees Celsius. If the catheter is not positioned correctly, the cells in that location can recover. If the catheter is on target, its temperature is dropped to minus 70 degrees Celsius to actually destroy the tissue.

Cryoablation is effective for both children and adults with heart rhythm disturbances.

The technique worked perfectly for Valeria Chupp.

"We've had no heart rhythm problems since then and she's doing great," Law said.

Mabel Chupp said her daughter has been growing well of late, though she had been a slow grower in earlier months because of her heart problem. "We've been given some valuable growth management tools by Dr. Linda Cooper-Brown and the feeding team at University of Iowa Children's Hospital," she said. "Otherwise, she's doing fine. She's a real go-getter."

For more information about cryoablation, patients may call UI Health Access at 800-777-8442 and physicians may call UI Consult. Callers should mention having seen this article in PACEMAKER magazine, and ask for Dr. Ian Law in pediatric cardiology. Law can also be reached directly at 319-356-3538.

Staying on track
Valeria Chupp plays with a train set in the pediatric specialty clinic. Her friend is Ian Law, M.D., who used a new freezing technique to end her problems with an irregulr heartbeat and set the stage for surgical repairs that will give her a normal life expectancy.