Searing the heart for the better

Catheter destroys heart tissue to stifle atrial fibrillation

Talk about heartburn. Using a catheter with a charged tip, doctors can sizzle wayward heart cells and correct an irregular heartbeat better than standard drugs can, a head-to-head comparison shows. The report appears in the Jan. 27 Journal of the American Medical Association.

The procedure isn’t new, having been used for more than 20 years. But despite a long track record and an upsurge in use during the last five years, the technique hasn’t been fully accepted by the U.S. medical community. It can correct atrial fibrillation, a weak, rapid heartbeat that carries health risks.

“There are doctors who take a more conservative view and continue to try drugs” to treat atrial fibrillation, says cardiologist David Wilber of Loyola University Health Center in Maywood, Ill., who coauthored the new study. As a result, the procedure, called catheter ablation, has remained a second-line treatment and continues to undergo testing, he says, even though about half of patients fail to control their atrial fibrillation with medication.

In the new study, Wilber and an international team identified patients with atrial fibrillation, the most common form of heart arrhythmia. All had failed to improve on at least one drug. The researchers randomly assigned 100 patients to get the catheter procedure and 51 to receive a standard drug they hadn’t previously taken.

After nine months, 66 percent of those getting the procedure remained free of atrial fibrillation episodes compared with only 16 percent of those receiving medication. Patients getting the procedure also reported substantial improvements in quality of life.

Earlier trials had found that up to 6 percent of patients getting catheter ablation experienced serious complications such as a heart puncture, blood clotting or damage to nearby nerves or to the esophagus. None of these side effects occurred in the new study. The authors note that many of the doctors performing these procedures had “considerable experience in atrial fibrillation ablation,” which may explain in part the low complication rate.

The doctors used a cooled catheter approved by the U.S. Food and Drug Administration last year. In Europe, where the new device has been used since 2004, researchers have found that it works well, says Giuseppe Stabile, a cardiologist at the Mediterranean Clinic in Naples, Italy. The new device also probably lessened the number of serious complications in this trial, says Stabile, who didn’t participate in the study.

Atrial fibrillation is marked by a rapid, chaotic heartbeat that can cause blood clots and increase the risk of stroke. The condition also causes fatigue, shortness of breath, chest pain and fainting, and can eventually cause heart failure.

While the root cause of atrial fibrillation remains unclear, scientists have traced the problem to when pacemaker cells in the heart fail in their job of generating regular electrical impulses. Doctors target these aberrant cells with an electrode-tipped catheter that destroys the cells in much the same way wounds are cauterized.

Roughly 2 million people in the United States have atrial fibrillation. Wilber estimates that 50,000 to 100,000 catheter ablations are now performed each year.

It remains unclear how long the effects of catheter ablation last, which patients are most likely to benefit and whether the procedure extends life span. Those issues are still under investigation, Wilber says.

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