Emory scientists link atrial fibrillation with decrease in nit...( ORLANDO - Emory research presented at...),Health

ORLANDO - Emory research presented at the Abstract Oral Sessions of the American Heart Association's Scientific Sessions today entitled "Atrial Fibrillation Causes Increased Oxidative Stress and Decreased Nitric Oxide Bioavailability in the Left Atrial Appendage" offers a possible explanation for one of the most serious, and sometimes deadly, complications associated with the heart rhythm disorder known as atrial fibrillation (AF) -- stroke.

AF, which is characterized by a rapid and irregular beat originating from the upper chambers of the heart, is the most common sustained heart rhythm disorder. According to the Centers for Disease Control (CDC), an estimated 2.2 million adults in the United States have been diagnosed with this arrhythmia. A-fib increases the risk for heart disease and stroke, both leading causes of death in the United States. AF associated stroke is known to be due almost exclusively to blood clot ( hrombus) formation in the left atrial appendage (LAA), a small, thumb-shaped pouch in the heart's left upper chamber.

"Previous studies have indicated that more than 90 percent of non-rheumatic AF-related strokes are the result of blood clots that form in the LAA and then travel to blood vessels leading to the brain, causing stroke, " says Emory Heart Center and Atlanta Veterans Administration Medical Center cardiologist Samuel C. Dudley, MD, who headed the Emory research team. "The mechanisms underlying AF perpetuation and localized formation of LAA thrombus continue to be poorly understood. However, we recently found that AF is associated with decreased endocardial nitric oxide (NO) in the LAA . We believe that may play a role in blood clot formation."

The Emory researchers, working with pig hearts, examined atrial tissue (from the upper chambers of the heart) from animals that had experienced induced AF and compared them with the hearts of control animals. They found that superoxide (O2) levels were twice as high in
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Contact: Sherry Baker
emoryheartnews@aol.com
404-377-1398
Emory University Health Sciences Center
11-Nov-2003

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