How can atrial fibrillation (AFib) cause a stroke?

Dr. Jeanne Morrison, PhD
Family Practitioner

Having a stroke is the biggest risk when you have atrial fibrillation. Your heart doesn't pump out all the blood in its chambers with each beat, so a small amount of blood may pool and form clots. If a blood clot gets pumped into a brain artery, it can block it and cause a stroke. To help prevent a stroke, your doctor may prescribe a medication that "thins" the blood, preventing blood clots in the first place.

People who have atrial fibrillation, a condition in which the heart does not pump properly, are at an increased of suffering an ischemic stroke. Because their heart pumps irregularly, pools of blood are created—posing a risk for clots. This condition can be treated with medication.

Your heart’s beating is governed by a series of natural electrical impulses that cause the chambers of the heart to contract in a carefully timed sequence.

Atrial fibrillation (AF) is a condition in which the electrical system in the heart does not function properly. The two small upper chambers of the heart (the atria) quiver instead of beating normally. In AF, this lack of normal atrial contractility can cause blood to pool in the heart, increasing the risk of a clot forming. Clots in the heart often break loose and can travel anywhere in the body. If the clot goes to the brain, it will cause a stroke.

This risk of a stroke can be significantly reduced by taking blood thinners, such as Coumadin or Pradaxa. Anyone with a history of atrial fibrillation should discuss taking blood thinners with their doctor. According to the National Institute of Neurological Disorders and Stroke, a person with AF has a stroke risk that is 4 to 6 times greater than those without AF. Stroke risk in people with AF increases with age.

Continue Learning about Stroke Risk Factors

Does gender or race affect stroke risk?
Discovery HealthDiscovery Health
Men are at a higher risk for stroke than women, until their later years when the odds become more ev...
More Answers
How common are strokes in women?
Dr. Mehmet Oz, MDDr. Mehmet Oz, MD
A stroke happens when a blood clot travels to or forms in a part of the brain. Deprived of oxyge...
More Answers
Can sugary drinks increase my risk of stroke?
Dr. Robin Miller, MDDr. Robin Miller, MD
Sugary beverages can damage more than your waistline. In this video, Dr. Robin Miller how women who ...
More Answers
Could the increased risk of stroke in the southern U.S. be due to diet?
Dr. Robin Miller, MDDr. Robin Miller, MD
The way food is prepared can make healthy food bad. In this video Robin Miller, MD talks about the i...
More Answers

Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.