Procedure for Irregular Heartbeat Gives Lasting Relief

People who have endured the symptoms and risks of an irregular heartbeat for years can get long-lasting relief from a procedure that takes less than two hours, a definitive new study shows.

In the March 2 issue of the New England Journal of Medicine, researchers from the University of Michigan Cardiovascular Center and the San Raffaele Hospital in Milan, Italy report the results of a rigorous study of radiofrequency catheter ablation for the chronic form of the most common heart-rhythm disorder: atrial fibrillation.

Although the treatment has shown promise for several years in studies by U-M researchers and others, the new paper gives conclusive evidence of catheter ablation's positive effects on heart rhythm, symptoms, quality of life and heart function - even in the most difficult-to-treat chronic atrial fibrillation patients.

In all, 74 percent of study participants who had the procedure were free of their irregular heartbeat a year afterward, and did not need rhythm-regulating drugs. They reported a steep drop in the severity of symptoms, and their hearts' left upper chambers returned to normal size. No side effects were reported, though some of the patients needed a second procedure to fully treat their heart rhythm disturbance.

"We have shown objectively, and with rigorous follow-up, that this procedure is a very good option for patients with symptomatic, chronic atrial fibrillation who otherwise may have to live with atrial fibrillation for the rest of their lives," says lead author Hakan Oral, M.D., an associate professor of medicine at the U-M Medical School and member of a U-M Cardiovascular Center team that has treated more than 2,000 atrial fibrillation patients using catheter ablation.

The study was a randomized, controlled trial, and used long-term automatic daily monitoring of heart rhythm, to assess the efficacy of ablation. It involved 146 patients, 77 of whom were randomized to receive a left atrial catheter ablation procedure known as circumferential pulmonary-vein ablation. The remaining 69 patients were randomized to a control group.

The study was supported by U-M's Ellen and Robert Thompson Atrial Fibrillation Research Fund, founded in 2001 by a Detroit philanthropist who has the condition.

More than 2.3 million Americans live with atrial fibrillation, which is caused by electrical "misfires" in the heart muscle that make the upper chambers of the heart quiver and pump erratically. This causes weakness and other debilitating symptoms, and encourages the formation of clots, putting patients at much higher risk of stroke.

Some patients have rhythm problems only occasionally, but most, like those in the study, have them all the time. Usual treatments for atrial fibrillation include electric-shock procedures called transthoracic cardioversions, which requires sedation, and drugs to regulate rhythm and thin the blood, which can cause side effects and often lose effectiveness. Moreover, these measures often are only temporarily effective, and the majority of the patients develop recurrences of atrial fibrillation sooner or later.