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Technology Cures Bad Heartbeats

Erratic heart cells found and zapped, cardiologists report

MONDAY, Jan. 28, 2002 (HealthDayNews) -- A sophisticated technology can wipe out the rogue cells that cause life-threatening irregular heartbeats, a new study shows.

In a condition called atrial fibrillation, extra heartbeats disrupt the normal rhythm of the two upper chambers of the heart. These erratic heartbeats can cause blood to pool inside the chambers. Clots can form and block arteries, causing strokes or heart attacks.

About 2 million Americans have atrial fibrillation, according to the American Heart Association (AHA). In most cases, the condition can be controlled by drugs such as digoxin or by an implanted defibrillator that delivers shocks to restore normal beating. However, the condition can worsen over time.

Now, cardiologists at the University of Michigan report the successful use of a technology called radiofrequency ablation to find the cells responsible for the abnormal beats and destroy them with pulses of electricity.

In a study of 70 patients, the technique restored normal heart rhythm in 70 percent of those with intermittent atrial fibrillation and 30 percent of those with a persistent condition, says a report in tomorrow's issue of the AHA's journal, Circulation.

"This is a curative treatment for many cases of atrial fibrillation," says Dr. Hakan Oral, study leader and an assistant professor of medicine at Michigan. The treatment can be done with just an overnight hospital stay, he adds.

French cardiologists first developed the technique used in the study, Oral says. It's based on a finding that the cells causing the irregular beats are located in the pulmonary veins, which carry blood from the lungs to the left atrium. The cardiologists target those cells by threading a catheter into the pulmonary veins. The tip of the catheter has a detector that picks up the errant signals. Once found, they are destroyed by a 30-watt to 35-watt burst of electrofrequency radiation.

The technique works best in patients with intermittent fibrillation, Oral says, so one lesson is that "it pays to interfere early." However, while the cure rate for patients with the persistent problem was low, most of them showed improvement.

Another lesson is that "new ablation techniques will be necessary" to make the technique more effective, Oral says. His group is working on such improvements, he adds.

Radiofrequency ablation is "a very sophisticated technique that is not yet widely established in practice because of technical difficulties and risks. It is available at certain medical centers, perhaps 25 in the country, including ours, centers where there are sophisticated experts in the field of radiofrequency ablation," says AHA spokesman Dr. Kenneth A. Ellenbogen, a professor of medicine at the Medical College of Virginia/Virginia Commonwealth University.

When should the technique be used? Both patient and physician must decide together, Oral says.

"The first issue is patient preference," he says. "Drug therapy is not without side effects. This can effect a cure in less than four hours. If a patient is bothered by symptoms of atrial fibrillation, it is useful to proceed with this procedure because it is effective and safe. The incidence of complications is less than 1 percent."

What To Do

"If a patient has been tried on medications and the symptoms do not respond to medication, there should be a referral to a center where there is expertise in performing this procedure," says Ellenbogen.

Basic information about atrial fibrillation is available from the AHA.

Go to the University of Michigan for more details on radiofrequency ablation.

SOURCES: Interviews with Hakan Oral, M.D., assistant professor of medicine, University of Michigan, Ann Arbor; Kenneth A. Ellenbogen, professor of medicine, Medical College of Virginia/Virginia Commonwealth University, Richmond, Va.; Jan. 29, 2002, Circulation
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