NOV. 15, 2011

Patients with atrial fibrillation sought for study of novel alternative to open-chest surgery

BY TANYA LEWIS

Renee Reijo Pera

Paul Wang

Researchers at the Stanford University School of Medicine are seeking participants for a study examining the effectiveness of an experimental treatment for a heart condition known as atrial fibrillation.

The treatment targets abnormally beating heart cells from both inside and outside of the heart. It pairs minimally invasive radiofrequency energy to destroy cells from the outside of the heart with catheter ablation using the same energy from inside the heart. Stanford is one of six sites nationwide conducting the trial, and the only one on the West Coast.

Atrial fibrillation is a type of heart arrhythmia that affects 2.2 million Americans. It occurs when the upper chambers of the heart, called the atria, beat irregularly, leading to poor blood flow to the rest of the body. If the disorder lasts more than seven days or requires medical intervention, it’s considered persistent.

The first line of treatment is cardioversion: resetting the heart’s rhythm using medication and electrical stimulation. If these treatments fail, patients may require other treatments, such as surgical or catheter ablation.

Surgical ablation may be performed through small ports in the chest to access the outside of the heart. Catheter ablation uses small plastic tubes that deliver energy from within the heart.

“We didn’t think that either surgical or catheter ablation alone was achieving the success rates that we would like to have with the most advanced patients,” said Paul Wang, MD, the cardiologist and professor of cardiovascular medicine leading the Stanford portion of the study. “What we want to examine is whether combining the surgical and catheter components gives better results.”

What’s involved? First, surgeons advance tiny cameras called endoscopes through small incisions in the chest wall. Then, they use an instrument that delivers radiofrequency energy to areas on the outside of the heart to destroy a portion of the problem cells. Next, cardiac electrophysiologists thread a catheter from a thigh vein up into the heart’s interior, to aim radio energy at cells on the inner side. “The goal is to treat the full thickness of the tissue,” said Wang.

Compared to traditional treatments requiring open-chest surgery, this minimally invasive surgery involves small chest incisions and does not require the use of a heart-lung bypass machine during the procedure.

To qualify for the study, participants must have persistent atrial fibrillation that arrhythmic therapy and/or catheter ablation have failed to treat, and be age 18 or older with a life expectancy exceeding two years. After surgery, participants will receive extensive monitoring and opportunities to report symptoms. Patients who are pregnant or who have had prior cardiothoracic surgery or heart or kidney failure are ineligible. AtriCure Inc., the company that manufactures the radiofrequency instrument, is sponsoring the study. Wang has an unpaid advising role in developing AtriCure’s protocols.

For more information about the study, contact the Stanford Atrial Fibrillation Center at (650) 723-7111 and select option 1.


Tanya Lewis is a science-writing intern in the Office of Communication & Public Affairs.

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