BY AMERICAN HEART ASSOCIATION NEWS

1221-Feature-Top Ten_Blog

Editor’s note: This is one in a 10-part series of the top medical research advances as determined by American Heart Association volunteer and staff leaders.

It’s not necessary to burn extra tissue in the heart when treating persistent atrial fibrillation, or AFib, according to new research.

AFib, which is a quivering or irregular heartbeat, affects an estimated 2.7 million to 6.1 million Americans. Some have paroxysmal AFib, which means their hearts go in and out of the quivering state. Others have persistent AFib and require medication to keep their heart in rhythm, but those medications do not always work.

When medications alone aren’t enough, catheter ablation is commonly used to nonsurgically ablate, or burn, the tissue causing the irregular beat so that a normal heart rhythm returns.

Standard practice has been to burn around the pulmonary veins, the blood vessels that connect the heart to the lungs, said the study’s lead investigator Atul Verma, M.D., director of the heart rhythm program at Southlake Regional Health Centre at the University of Toronto.

“That has been the cornerstone for procedures for patients with atrial fibrillation for a long time,” he said.

The problem was, ablating only the pulmonary vein tissue wasn’t thought to be as good for patients with persistent AFib as for those with paroxysmal AFib.

“We assumed maybe it was because we weren’t burning enough [tissue], and there may be other targets that we have to go after in addition to burning around the pulmonary veins,” Verma said.

To find out, researchers compared the strategy of burning only around the pulmonary veins with two more complex strategies involving more extensive ablation.

The researchers studied 589 patients with persistent AFib and reported on how those patients did 18 months after having the procedures.

“We were surprised to find, at the end of the day, there was no significant difference between any of the three groups. The patients that we only burned around the veins did equally well compared to the other two groups,” Verma said.

The study, published this spring in the New England Journal of Medicine, was selected as one of the top 10 research advances in 2015.

Nearly 60 percent of patients who had the simpler procedure, called pulmonary vein isolation, were free of AFib 18 months later. That’s a success rate similar to what ablation studies have found with paroxysmal AFib, according to Verma. The more extensive ablation procedures worked in nearly half of patients, researchers found.

The findings not only suggest that less is equal when it comes to catheter ablation approaches for persistent AFib, but performing the less complicated procedure might also be safer.

“The more burning, the more likelihood that there may be a complication and the longer the procedure. And if we’re not getting any additional benefit for the patient, then we shouldn’t be doing it,” Verma said.

Catheter ablation for AFib is becoming more routine, said William Lewis, M.D., chief of cardiology at MetroHealth Medical Center in Cleveland and chair of the American Heart Association’s Get With The Guidelines-AFib work group.

“This study shows that we are really beginning to refine the techniques to treat atrial fibrillation effectively with catheter ablation,” he said.