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Strokes not diminished with rhythm control, according to national atrial fibrillation AFFIRM study

San Antonio (April 9, 2003) — Anti-arrhythmic drugs are widely prescribed today, but how successful are they at preventing stroke, one of the most severe and common complications of irregular heartbeat? New findings suggest they're not as effective as hoped.

David G. Sherman, M.D., a researcher from The University of Texas Health Science Center at San Antonio who tracked stroke events during the six-year AFFIRM study of 4,060 atrial fibrillation patients, was one of the presenters April 2 in Honolulu at the annual meeting of the American Academy of Neurology. "While the trial confirmed that use of warfarin, an anticoagulant, reduces the risk of stroke by almost 70 percent, aggressive efforts to control atrial fibrillation did not seem to have nearly as beneficial an effect," he said.

In fact, 8.9 percent of AFFIRM patients receiving anti-arrhythmic therapy for atrial fibrillation suffered strokes, compared to 7.4 percent of patients receiving a simpler, alternative therapy known as rate regulation. Both groups of patients took warfarin.

The Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM) study is sponsored by the National Heart, Lung, and Blood Institute and is headquartered in Seattle. Dr. Sherman and Robert G. Hart, M.D., professors of medicine at the UT Health Science Center and staff physicians with the South Texas Veterans Health Care System, served on the AFFIRM Stroke Events Subcommittee. "When a patient was known or suspected to have a stroke while on the study, we received the information to corroborate it and determine the stroke mechanisms, such as clots causing ischemia or bleeding into the brain." A total of 160 strokes were reported in the AFFIRM patients, whose mean age was 69.7 years.

Current therapies to keep atrial fibrillation patients in normal sinus rhythm are "not all that successful" at improving survival or stroke risk, Dr. Sherman said. The Stroke Events Subcommittee concluded that "in the AFFIRM Study, the presence of atrial fibrillation increased ischemic stroke risk and the use of warfarin reduced stroke risk, regardless of assigned treatment strategy."

Contact: Will Sansom