The Link Between Atrial Fibrillation and Stroke

There is a link, and stroke risk can be lowered with treatment

Atrial fibrillation is a common abnormal type of heart rhythm that is considered one of the leading potential risk factors for stroke. If you have atrial fibrillation, preventative treatment can substantially reduce your chances of having a stroke, so it is important to know whether you have this condition.

Atrial fibrillation is a recurrent, rapid, irregular heart contraction of the heart's atria, which are the upper chambers of the heart. Most people who have atrial fibrillation develop it during adulthood. It usually doesn't cause any symptoms, and it can be diagnosed with noninvasive studies, such as electrocardiography (EKG).

This article will discuss how atrial fibrillation increases stroke risk, how to prevent a stroke, and how to recognize a stroke.

Atrial fibrillation is diagnosed with electrocardiogram

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How Atrial Fibrillation Can Cause a Stroke 

A stroke is when brain damage occurs due to an interruption of blood flow in a blood vessel in the brain. It is usually caused by a blood clot. Blood clots can form within a blood vessel in the brain, or they can travel to the brain from the heart or the carotid arteries (located in the neck). 

Atrial fibrillation can increase the chance of a blood clot forming, especially in the left atrium of the heart. It is widely understood that the irregular heart rhythm of atrial fibrillation causes blood to pool in the left atrium, where it has the chance to form a clot.

Researchers suggest that abnormal function or structure of the heart muscle associated with atrial fibrillation may also contribute to blood clot formation.

A blood clot in the left atrium can eventually travel to the brain in the following path:

  • Oxygenated blood flows from the blood vessels of the lungs to the left atrium.
  • Blood flows from the left atrium to the left ventricle and then out through the aorta (the largest artery in the body).
  • The aorta branches into smaller arteries, including branches that provide blood to the brain.

A clot that forms in the left atrium due to atrial fibrillation can travel through this route to a blood vessel in the brain, blocking it and causing a stroke. 


Atrial fibrillation leads to a five-fold increased risk of stroke. And for people over 80 years old, atrial fibrillation is the direct cause of 1 in 4 strokes. Anticoagulation drugs reduce the risk of atrial fibrillation-associated stroke by approximately two-thirds.

Lowering the Risk of AFib-Associated Stroke 

If you are diagnosed with atrial fibrillation, your doctor may prescribe medication to help reduce your risk of stroke. There are several treatment approaches that can help prevent a stroke if you have atrial fibrillation. 

Strategies include:

  • Prevention of blood clots: Medications to prevent blood clot formation include Coumadin (warfarin), Pradaxa (dabigatran), Xarelto (rivaroxaban), Eliquis (apixaban), Savaysa (edoxaban), aspirin, and Plavix (clopidogrel). Taking medication to prevent blood clots reduces the risk of stroke by approximately two-thirds in people who have atrial fibrillation.
  • Regulating heart rhythm: Medication to regulate the heart rhythm can prevent blood from pooling in the heart and can help prevent a stroke.
  • Procedures: For some people, a pacemaker (implanted device) or a surgical procedure may be needed to regulate the heart rhythm. 

Your treatment plan may be determined by how frequently you have atrial fibrillation, as well as your other stroke risk factors.

Taking a blood thinner increases your risk of bleeding, so you need to be careful to avoid injuries while taking any of these medications.


Atrial fibrillation is an irregular heart rhythm that can increase the risk of blood clots in the heart, potentially leading to a stroke. Medication to prevent blood clots and treatment to regulate heart rhythm are often prescribed to lower the risk of atrial fibrillation-associated stroke.

Stroke Risk Factors

Besides atrial fibrillation, several other risk factors increase the likelihood of having a stroke.

A stroke can occur suddenly and without warning. Sometimes, temporary blood flow obstruction in the brain can cause stroke-like symptoms that resolve before brain damage occurs.

This is a transient ischemic attack (TIA). It usually means that a person has a high chance of having a stroke at some time in the future. TIAs usually have the same risk factors as stroke. 

Common stroke risk factors: 

  • Age: A stroke is more common with advancing age.
  • Sex: Overall, strokes are more common among females than males. Females are more likely to have a stroke after menopause. 
  • High blood pressure: Chronic high blood pressure causes damage to the heart, the carotid arteries, and the blood vessels in the brain, making them prone to blood clots. 
  • Diabetes: Diabetes damages blood vessels, increasing the risk of blood clots. 
  • History of heart conditions: Besides atrial fibrillation, other heart conditions can increase the risk of having a stroke. These include anatomical heart defects, heart valve disease, congestive heart failure, other types of arrhythmia (irregular heart rhythms), and coronary artery disease (disease of the blood vessels that supply the heart).
  • History of stroke: If you have already had a stroke, this is associated with an increased risk of having another stroke because you likely have underlying risk factors. 

If you have more than one stroke risk factor, this further increases your risk of stroke. Most of these risk factors can be managed with medication, which lowers your likelihood of stroke. 

Stroke Prevention

Stroke prevention is important for everyone, especially those with a known stroke risk factor, such as atrial fibrillation. Reducing the risk of stroke involves lifestyle strategies and medication. 

Lifestyle approaches for lowering stroke risk:

  • Maintain a healthy weight. 
  • Exercise regularly.
  • Avoid trans fats and saturated fats in your diet.
  • Get a diet that has a variety of fresh fruits and vegetables, which contain natural antioxidants.
  • Don’t smoke.
  • Don’t use illegal drugs. 
  • If you drink alcohol, use moderation.

Medical prevention of stroke: 

  • Maintain a healthy blood sugar if you have diabetes. 
  • Take medication to keep your blood pressure at a target level if you have high blood pressure.
  • Take medication to lower your cholesterol if it can’t be managed with diet. 
  • Get treatment for any heart conditions that you have. 

And there are also surgical procedures that are sometimes necessary to prevent a stroke. 

How to Recognize a Stroke

A stroke can cause a variety of symptoms. A stroke is a health emergency that requires prompt medical attention. 

Signs of a stroke include sudden:

  • Vision changes 
  • Weakness of the face, arm, and/or leg on one side 
  • Loss of sensation or unusual sensations on one side of the body or face 
  • Difficulty speaking 
  • Difficulty understanding what others are saying 
  • Changes in consciousness 

Often, a person who is having a stroke does not notice the symptoms, so it is vital to call for medical help if you see someone having these symptoms. 


Atrial fibrillation is among the leading risk factors for having a stroke. The condition can cause blood to pool in the heart, causing the formation of blood clots that can travel to a blood vessel in the brain and block it. Atrial fibrillation is diagnosed with EKG.

To prevent blood clots, people with atrial fibrillation can be treated with blood thinners, and medication or procedures can regulate the heart rhythm. Treatment reduces the risk of having a stroke.

A Word From Verywell 

If you have been diagnosed with atrial fibrillation, it’s important that you take steps to get treatment—but you need not be stressed or anxious about your condition. It is a stroke risk factor, but the risk of stroke can be significantly reduced if you get preventative treatment.

You may have some restrictions in your activity—such as avoiding injuries if you need to take a blood thinner. Overall, you should be able to do all the things you want to do. 

Frequently Asked Questions

  • What are the odds of having a stroke with AFib?

    Atrial fibrillation is associated with a five-fold increased risk of stroke. The risk is substantially reduced with preventative treatment.

  • What type of stroke does AFib cause?

    Atrial fibrillation increases the risk of an embolic ischemic stroke. This type of stroke is caused by a blockage of blood flow in a blood vessel in the brain by a blood clot that traveled from somewhere else in the body.

  • What is the life expectancy of a person with AFib?

    Atrial fibrillation is associated with a two-fold to four-fold increased risk of death each year. The risk is higher with advancing age, for people who are not treated, and for people who also have other health problems.

8 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Heidi Moawad, MD
Heidi Moawad is a neurologist and expert in the field of brain health and neurological disorders. Dr. Moawad regularly writes and edits health and career content for medical books and publications.