A drug that is used to treat atrial fibrillation, the most common heart rhythm disturbance in the United States, may have wider applications than previously thought, according to researchers at the University of California San Francisco.

In two recent studies, UCSF cardiologists have shown that Ibutilide, a class III drug approved by the FDA two years ago to treat atrial fibrillation, may be an important tool for treating adults and children who have a congenital heart defect, Wolff-Parkinson-White Syndrome (WPW), as well. Their most recent findings will be presented at the North American Society of Pacing and Electrophysiology (NASPE) meeting on May 14 in Toronto.

"We've shown that Ibutilide is an effective and safe drug to use in patients with WPW, atrial fibrillation, and otherwise normal hearts," says Kathy Glatter, MD, a UCSF cardiology fellow and principle investigator of the study. "This finding is important because it could give WPW patients a better chance to either slow their heart rate during atrial fibrillation or restore the normal rhythm."

Wolff-Parkinson-White Syndrome is a congenital birth defect in which extra electrical connections, or accessory pathways, are present in the heart. Although people with WPW are otherwise healthy, the extra connection can cause an electrical "short circuit" and a very fast heartbeat. Additionally, 30 to 40 percent of WPW patients will develop atrial fibrillation at some point during their lives.

The combination of having WPW plus atrial fibrillation can be deadly. Some of the drugs that are routinely used in emergency rooms to treat atrial fibrillation can also impair the heart's normal electrical pathways. For someone with WPW, this can allow electrical impulses to travel down the shorter accessory pathway and cause the heart to beat even faster, rather than slowing it down, said Glatter.

"Ibutilide seems to be as safe and more effective than Procainamide and other drugs currently used f
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Contact: Rebecca Sladek Nowlis
rsnowlis@pubaff.ucsf.edu
415-476-2557
University of California - San Francisco
13-May-1999