WEDNESDAY, March 1, 2006 (HealthDay News) -- Generating intense radio waves to kill tiny areas of flawed heart tissue can bring permanent relief to people who have suffered for years from atrial fibrillation, the most common form of abnormal heart rhythm, a new American-Italian study finds.
Some 2.3 million Americans live with atrial fibrillation, in which the normal pattern of electrical impulses that cause the heart to beat regularly are disturbed in the atria, the upper chambers of the heart. Many can be helped by medications or an electric shock treatment called cardioversion, but others cannot. Atrial fibrillation increases heart attack risk in several ways, most notably by encouraging the formation of blood clots.
The new research included 146 people with chronic atrial fibrillation who were treated at the University of Michigan in Ann Arbor and the San Raffaele Hospital in Milan. Half got standard treatment, while 77 got standard treatment and catheter ablation, in which a circle of cells around the source of the abnormal heartbeats is killed by radio waves emitted by a catheter threaded into the heart.
A year after the treatment, 55 of the patients who had catheter ablation were free of their irregular heartbeats, reported a steep drop in symptoms, and stopped taking medications (although 26 of them required a second ablation). In contrast, 53 of the people in the other group had catheter ablation in the following year, and only three of those who did not get the therapy regained normal heart rhythm.
"Catheter ablation has been available for 20 years or so for other arrhythmias [abnormal heartbeats]," said study author Dr. Hakan Oral, an associate professor of medicine at the University of Michigan Medical School. "Atrial fibrillation is much more complex than other arrhythmias. Much progress has been made in recent years in using this for atrial fibrillation, and this study is reflection of those prior advances."
The finding is reported in the March 2 issue of the New England Journal of Medicine.
An accompanying editorial, however, warns against speedy adoption of catheter ablation for atrial fibrillation.
The impressive results were reported by physicians who are highly skilled in the technique, and "it might not be ready for the doctor on the corner," said Dr. Kenneth A. Ellenbogen, a professor of medicine at the Virginia Commonwealth University School of medicine, and co-author of the editorial.
"The physicians in the study were very experienced with the technique," Ellenbogen added. "It's possible that this technique will prove to be very successful, and that is what the study begins to show. But like any new technology, it needs to be studied in the hands of people who are not yet masters of it."
The new study also included a relatively small number of patients, Ellenbogen noted. "It needs to be studied in larger groups of patients and tested against other competing techniques," he said.
However, the technique is not all that difficult to learn, Oral said. "It is doable by most people and the learning curve is steep," he said. "It can be learned in a short time."
Meanwhile, he and his colleagues are planning studies to improve the effectiveness of the procedure. "We are exploring different mechanisms and devices," Oral said.
The primary targets of catheter ablation will be people whose atrial fibrillation has not been controlled by medication, cardioversion or other treatments, he said. Another group that might want to undergo the procedure are patients who are young and are not willing to take medications for the rest of their lives, Oral said.
Catheter ablation is explained by the U.S. Food and Drug Administration.