How Does AFib Cause Stroke?
Learn how a blood clot can form in your heart and travel to your head to cause a stroke.
Your brain needs oxygen and other nutrients — carried to it by your blood — to function properly. A stroke occurs when the flow of blood to part of your brain is significantly reduced or blocked—resulting in the death of brain cells, which can lead to permanent damage or even death. The most common cause of stroke is a blood clot — a solid mass of blood that clumps together and blocks the flow of blood through an artery in or leading to your brain.
Sometimes, blood clots form in the arteries themselves. Other times they form in other areas of your body and move through your blood until they lodge themselves in an artery in or leading to your brain where they cause a stroke. Atrial fibrillation is the most common cause of these types of clots.
This illustration shows how AFib can cause a blood clot to form in your heart and travel to your brain, leading to a stroke.
- When your heart is working normally, it contracts and pumps blood in a regular pattern.
- When you have AFib, your atria (the upper chambers of your heart) beat too fast and irregularly — preventing blood from being pumped out to your ventricles (the lower chambers of your heart).
- Some of this blood can pool in your heart.
- The pooled blood can clump together and become a solid mass (called a blood clot).
- The blood clot can travel out of your heart and most often goes to your brain. When this happens, it blocks the flow of blood to a part of your brain, causing a stroke.
- Within minutes, brain cells begin to die — which can lead to permanent damage and even death.
Not only does AFib raise your risk of stroke, but strokes that occur in people who have AFib are usually more severe and are about twice as likely to be fatal or severely disabling.
Learn more about the effects of stroke >
