Can a Device Block Strokes?

The Associated Press has a feature on the Watchman, an experimental device that could prevent those with atrial fibrillation from getting strokes. The condition causes an irregular heartbeat, which can cause blood clots to be shot to the brain, causing stroke. The current treatment is the blood-thinning drug Coumadin, which is hard for many patients to tolerate. It so happens that the majority of the potentially fatal clots collect in a flap of tissue that hangs over the left atrium.