Procedure may reduce stroke risk with irregular heartbeat

A heart procedure may be an effective alternative for treating the leading cause of strokes in the U.S., an abnormal heart rhythm called atrial fibrillation, suggests a large new study.

In a group of nearly 38,000 people, researchers compared individuals with similar stroke risk profiles to one another, and found that those with atrial fibrillation who underwent the catheter ablation procedure fared better than those on medications alone over three years.

During that time, ablation patients had about as many strokes as the general population without atrial fibrillation, while people on just medication had about twice as many.

"The risk going in doesn't seem to matter on the outcome," said Dr. Douglas Packer at the Mayo Clinic in Rochester, Minnesota. "Those at the highest risk (of stroke) still appear to have received substantial benefit from the ablation."

The study is "a very important piece of work and has all kinds of implications for patients with (atrial fibrillation)," said Packer, who studies the causes of atrial fibrillation but was not involved in the new research.

According to American Heart Association figures, as many as five million Americans experience the chaotic heart-muscle contractions of atrial fibrillation, a condition that becomes more common with age, and also with other diseases, including diabetes and high blood pressure.

The disordered beating can cause blood clots to form inside the heart chambers, and those clots may escape and travel to the brain. Atrial fibrillation is thought to cause about 15 percent of all strokes in the U.S., according to the National Stroke Association.

Drugs to restore normal heart rhythms work poorly and come with unpleasant side effects, so blood-thinning medications to reduce stroke risk are the mainstay of treatment for atrial fibrillation, though they do not treat the fibrillation itself.

Catheter ablation involves threading a thin tool through blood vessels to the interior of the heart, where it applies electrical current to burn tissue that generates the abnormal rhythms.

To see how well ablation reduces stroke risk in atrial fibrillation patients and how it compares to standard care, Dr. Thomas Bunch, a heart rhythm specialist at Intermountain Medical Center in Murray, Utah, and his colleagues looked at data on 37,908 participants in a large healthcare network. They ranged in age from 60 through the late 80s.

The group included 4,200 people with atrial fibrillation who underwent ablation, 17,000 with atrial fibrillation who did not have the procedure and another 17,000 people matched with the first two groups for age and gender who did not have atrial fibrillation or ablation.

The researchers also matched people in the three groups based on their risk profiles for stroke because of previous strokes, high blood pressure, diabetes and congestive heart failure.