Summer 2005

Catheter Ablation, An Alternative to Drugs for Atrial Fibrillation

Radiofrequency (RF) ablation is providing an increasingly attractive alternative for patients with refractory atrial fibrillation (AF).

"The treatment of patients via catheter ablation is evolving on a monthly basis," says cardiac electrophysiologist Jeffrey Olgin, M.D. "Depending on the patient and the type of atrial fibrillation, we can cure upwards of 85 percent of those with A-Fib."

Uncontrolled atrial fibrillation, though not as dangerous as ventricular fibrillation, can have an adverse impact upon patients’ quality of life. Such negative effects are often not taken into sufficient account when physicians consider which therapy to use, or whether to treat AF at all, Olgin says.

A recent research study, called the AFFIRM trial, which to some people seemed to support the idea of not treating AF aggressively, has been overinterpreted, Olgin says. The AFFIRM study compared a strategy of trying to keep the heart in sinus rhythm versus allowing the atrial fibrillation to continue while working to control the ventricular rate. "The study showed that there was no difference in survival between these two options, but it didn't account for whether these patients were symptomatic or not, didn't account for whether the drugs were effective or not, didn't ask whether keeping someone in sinus rhythm is better than letting them stay in AF. It only compared the strategies, not whether the strategies were effective," Olgin says.

The study was important because it showed that for those without symptoms attributable to AF, it was reasonable to simply control their heart rate because it does not seem to have an impact on mortality.

"The result has been that some people say to patients, 'We can let you stay in A-Fib and you'll be fine,'" Olgin says. "Meanwhile, the patient is terribly symptomatic and limited."

Over the past eight years, UCSF and other medical centers have developed catheter-based RF ablation as an alternative to drugs in the treatment of AF. Tissue ablation -- cauterization via a transvenous catheter -- interrupts conduction in the heart from areas that cause atrial fibrillation.

Researchers have found that atrial fibrillation often originates in and around the pulmonary veins. It proved difficult to find the exact spot where these signals came from, and many patients have multiple sources of fibrillation. Most physicians have now adopted a strategy of ablating a ring or collar of tissue around the vein. That ring of ablation keeps any signals originating in the vein from entering the atrium. Researchers in Olgin's group at UCSF are now looking for other areas that commonly initiate and maintain AF.

Olgin's work also focuses on looking at ways to prevent AF from developing in the first place. Laboratory work has demonstrated that most AF occurs because of the development of scar tissue in the heart. Even small amounts of fibrosis can act as a focus for initiating AF, Olgin says. The hope is that there might be a medication that would help those who are at risk for AF from developing the disorder, and could help those with paroxysmal AF from developing chronic AF.

To contact Dr. Jeffrey Olgin, call (415) 476-5706.

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