Stroke risk when you have atrial fibrillation

Now we have a better tool to calculate your chance of a brain attack if you've been diagnosed with afib.

Atrial fibrillation (afib) is among the most common heart rhythm irregularities. During a bout of afib, the usually rhythmic contractions of the heart muscle's upper chambers (the atria) are replaced by an ineffectual quiver that does not completely move blood out of the heart chamber. As a result, blood can stagnate and form clots. These clots can then travel to the brain and cause an ischemic stroke.