Features August 2012 Issue

New Research Shows Radiofrequency Ablation as Safe as Medication Therapy

A recent study finds that ablation with pulmonary vein isolation also outperformed standard medical therapy in reducing the odds of recurring episodes of atrial fibrillation.

A diagnosis of atrial fibrillation is usually followed by a course of treatment involving antiarrhythmic drugs designed to keep the heart’s electrical system under control. Atrial fibrillation (AF) is a condition in which the heart beats abnormally due to erratic electrical impulses originating in the heart’s upper chambers, the atria.

Reprinted with permission, Cleveland Clinic Center for Medical Art & Photography ? 2012. All Rights Reserved.

In radiofrequency ablation with pulmonary vein isolation, an energy catheter is guided into the heart to where the pulmonary vein connects to the left atrium. There it heats and deadens the tissue causing the atrial fibrillation.

AF can also be treated with procedures such as radiofrequency ablation, which attempts to destroys the tiny amount of heart tissue that appears to be causing the arrhythmia. Generally, ablation is attempted only after medications prove to be ineffective at controlling AF symptoms.

But a recent study, presented at the Heart Rhythm Society 2012 Scientific Sessions in Boston earlier this year, found that radiofrequency ablation with pulmonary vein isolation may be just as safe as medication for a first-line treatment, and maybe even more effective at reducing the risk of recurring episodes of AF.

“For most people, medical treatment remains first line therapy,” says Cleveland Clinic cardiac surgeon Marc Gillinov. “But for some, younger and highly symptomatic people, it may be reasonable to consider catheter ablation first.”

The average age of AF patients in the study was 55, and the oldest was 75. Researchers acknowledged that radiofrequency ablation is not a permanent solution for many AF patients, but that the study supports its consideration as first-line therapy for individuals with paroxysmal AF, a condition in which episodes of abnormal heart rhythms appear suddenly. Some AF patients experience chronic AF, a state in which the heart is always or almost always in abnormal rhythm.

How It Works
Radiofrequency ablation is performed by guiding a catheter up through a blood vessel in the leg to the heart. The tip of the catheter can emit a tiny electrical charge that can destroy the heart tissue suspected of causing the arrhythmia. In this study, the areas targeted for ablation are the connections between the pulmonary vein and the left atrium. The pulmonary vein carries oxygenated blood from the lungs to the heart for it to be pumped throughout the body.

“The idea is to use radiofrequency energy to burn the inside of the heart in strategic areas, blocking impulses from exiting the pulmonary veins,” Dr. Gillinov says. “Abnormal impulses from the pulmonary veins often initiate AF.” Impulses can originate from other parts of the atria, too.
The scars that form in the areas that have been ablated block the erratic electrical impulses, essentially “isolating” them from the rest of the heart. The result should be the elimination of AF episodes, at least for a long period of time.

Radiofrequency Ablation Risks
While radiofrequency ablation is generally well-tolerated, it is not without risks. “It is an invasive procedure with risks of injury to the blood vessels in the legs and to the inside of the heart,” Dr. Gillinov says. “There is also a small risk of stroke. But the risks are low.”

The risk of stroke is half of 1 percent, and the risks of other injuries, such as damage to a blood vessel, are around 1 percent, according to data collected by Cleveland Clinic. As with any procedure, you should discuss all of the potential risks and benefits of radiofrequency ablation with your doctor ahead of time, and make sure you cunderstand why the procedure is being recommended.

Medication Limitations
As mentioned earlier, most AF patients are started on antiarrhythmic drugs, which are meant to return the heart to normal rhythm, maintain a healthy rhythm in the heart and/or slow the heart rate during an AF episode.  Among the more common antiarrhythmics are amiodarone (Cordarone, Pacerone), disopyramide (Norpace), dronedarone (Multaq), flecainide (Tambocor) and sotalol (Betapace AF).

“They are ultimately effective in about half of AF patients,” Dr. Gillinov says. “Possible side effects include generation of abnormal heart rhythms.” Yes, unfortunately, the medications you take to control your heart rhythm may, in turn, cause more serious arrhythmias. For many patients, however, the drugs are effective. But for anyone taking these medications, part of your treatment involves the careful monitoring by your doctor and the awareness of symptoms indicating problems with the medications.

Signs antiarrhythmic drugs are causing serious problems and should prompt a 911 call include shortness of breath, palpitations and feeling faint. For a complete list of potential side effects associated with a particular drug, talk with your pharmacist and doctor.