BACKGROUND: Researchers have developed a new procedure to prevent strokes in people with atrial fibrillation. The pilot trial for the procedure has been completed, and a larger open trial has begun at about 60 sites around the U.S. The main purpose of the procedure is to reduce or eliminate the need for patients to take Coumadin, a blood-thinning medication that is basically rat poison. People taking the medication must be monitored constantly, since too high a dosage leads to excessive bleeding, while too low a dosage leads to increased risk of stroke. Because of this, only 30-40 percent of those who have atrial fibrillation opt to take Coumadin, even though it increases their risk of stroke.

HOW IT WORKS: A permanent implant -- essentially a heart blood filter -- is inserted through the groin and places just behind, or at the opening, of the left atrium of the heart to block it off. That's because more than 90 percent of clots found in patients with atrial fibrillation occur there. This is similar to traditional angioplasty, in which blood flow can be increased through a clogged artery without surgery. An instrument called a catheter is equipped with a tiny balloon to widen the opening in a partially blocked artery.

