Atrial Fibrillation (AF) as defined by the American Heart Association is an irregular heart beat (rhythm) where the small upper chambers of the heart (atria) beat ineffectively. The atria cannot pump all of the blood out of the chambers, resulting in pooling of the blood or clot formation. Unfortunately, if a part of the clot leaves the atria, it can become lodged in an artery in the brain resulting in an ischemic stroke.
