UMASS MEMORIAL CARDIAC SURGEONS PERFORMING MAZE PROCEDURE

Few medical centers offer procedure; new technology may prove faster, easier

November 16, 2001

Worcester, Mass. - For several years, surgeons at UMass Memorial Medical Center have been performing a delicate procedure to treat atrial fibrillation but are finding that patients-and referring cardiologists-aren't taking advantage of the surgical cure to a potentially deadly cardiac disease.

"Unfortunately, atrial fibrillation is viewed as a harmless rhythm irregularity by some doctors, but the accompanying risk of stroke is in fact quite high," said Thomas J. Vander Salm, MD, chief of the division of cardiothoracic surgery at UMass Memorial and professor of surgery at the University of Massachusetts Medical School "Atrial fibrillation, or AF, is far more than a nuisance; it can be a killer."

Atrial fibrillation, which affects an estimated 2.2 million people nationwide, is an irregular and rapid heart rhythm in which chaotic electrical impulses spread erratically through the right and left atria, two of the heart's four chambers, interfering with the heart's ability to pump blood effectively. The scrambled impulses disrupt the normal rhythmic contractions of the heart and as a result, blood does not pump properly and may instead pool in the atria. It is this pooling of blood that can lead to the formation of blood clots which may break loose and travel to the brain or elsewhere, causing stroke or irreversible damage to internal organs.

"Patients say they feel like walking time bombs, wondering if and when they'll have a stroke related to their AF," said James S. Gammie, MD, UMass Memorial chief of cardiac transplantation and assistant professor of surgery at UMass Medical School. Symptoms of AF, which can be caused by conditions such as abnormal heart valves, hypertension, coronary artery disease and congenital heart disease, include heart palpitations, dizziness, lethargy, chest pain or discomfort, and shortness of breath. Atrial fibrillation is responsible for 15% of all strokes in the US and costs more than $6.6 billion per year, exclusive of the cost of medication and physician fees, according to the Health Care Financing Administration. Patients with AF are five times more likely to suffer a stroke than are people without AF.

There are a number of treatment options for people with AF, including medications to restore normal heart rhythm and prevent blood clots and stroke; some patients may also require permanent pacemakers. Many medications, such as the blood thinner coumadin, however, increase the patient's risk of internal hemorrhage.

"The Maze procedure, which is relatively new, cures atrial fibrillation," said Vander Salm. "It can be thought of as the appendectomy of heart surgery in that, once performed, the disease should be permanently eliminated." Although it can be technically demanding of the surgeon, its risk is lower than for most other heart operations, as Vander Salm and Gammie have found in the 25 Maze procedures they have performed.

The Maze procedure is so named for the maze-like network of incisions cut into the heart muscle and then sewn closed. These incisions create a permanent line of thin scar tissue that reroutes the electrical impulses in the correct direction, eliminating the chaotic spasms common to AF and restoring the heart's normal pumping function, preventing the dangerous pooling of blood.

These therapeutic scars can also be produced by freezing or heating the heart muscle. Using a newly approved device that utilizes microwave energy, Gammie was able to achieve the same effect as incisions made by scalpel in the traditional Maze procedure. Microwave energy emitted from a long, thin wand placed on the surface of the heart warms the heart tissue and creates the scars that confine and redirect the erratic electrical impulses. The device, developed by AFx Inc. of Fremont, California, was approved by the US Food and Drug Administration in May and has been used only a handful of times in the US, according to Gammie, who in October performed New England's first microwave cardiac surgery to cure AF.

"We are optimistic that this new technology will soon allow the Maze procedure to be performed more quickly, and perhaps without the use of the heart-lung machine," Vander Salm said. "This may be a safer, less invasive way of curing what can be a debilitating problem for many people."