Atrial fibrillation (AFib), a type of irregular heartbeat, can cause blood to pool and move more slowly than usual. This can result in a blood clot, which may cause a stroke.

This article discusses AFib and stroke and the links between the two. It also explores the treatment and prevention of AFib and stroke.

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AFib refers to a type of irregular heartbeat, or arrhythmia, that can lead to various heart-related problems, including stroke. Around 2.7 million people in the United States have AFib.

In AFib, the upper heart chambers, called the atria, beat irregularly. This can result in ineffective movement of blood into the ventricles, or lower heart chambers. The sluggish movement of blood can lead to the formation of blood clots. A stroke may occur if a clot breaks away, enters the bloodstream, and blocks an artery that leads to the brain.

According to the American Heart Association, If a person does not receive treatment for AFib, their risk of stroke increases by 5 times. As many as 20% of people who have strokes also have AFib. Strokes caused by AFib are also typically more severe than those with other causes.

The most common symptom of AFib is a quivering heartbeat. Other symptoms include:

Learn whether AFIb can cause heart failure here.

The brain requires oxygen to function, which the heart delivers through oxygen-rich blood. A stroke occurs when something blocks the blood supply, and therefore, oxygen, from reaching part of the brain or when a blood vessel in the brain bursts.

Brain cells begin to die within minutes of oxygen starvation. This causes damage to areas of the brain. Stroke can result in long-term brain damage, disability, and death.

Most strokes are ischemic strokes, which occur due to a blockage of blood vessels in the brain. Other strokes are hemorrhagic, which occur when an artery in the brain breaks open or leaks blood.

Symptoms of stroke include:

  • sudden weakness or numbness, especially in one side of the body or face
  • sudden severe headache with no obvious cause
  • sudden difficulty understanding speech or speaking
  • sudden confusion
  • sudden loss of balance and coordination, and difficulty walking
  • dizziness
  • sudden difficulty seeing in one or both eyes

Learn more about the FAST symptoms of stroke here.

AFib is a leading cause of stroke and is responsible for 10-12% of all ischemic strokes in the United States each year, according to research.

Studies have found that AFib is associated with a five-times higher likelihood of ischemic stroke after accounting for other standard risk factors of stroke. Researchers also note that strokes caused by AFib-related complications are generally more severe than strokes with other causes.

Despite the strong link between the two conditions, research indicates that doctors only have a moderate ability to predict the risk of stroke in individuals with AFib. This may cause difficulty in reducing the risk of stroke in people with AFib, as treatments that could potentially prevent stroke, such as anticoagulant therapy with drugs such as warfarin, carry risks of bleeding.

Doctors will weigh the risks of stroke against those of bleeding in each individual with AFib to determine the safest and most effective treatment for them.

A healthcare professional may use the CHA2DS2-VASc score to determine a person with AFib’s risk of stroke based on their:

Learn more about cardiovascular disease in our dedicated hub here.

Possible limitations

A 2016 study suggests that some researchers may have overestimated the association between AFib and stroke.

The researchers dispute that AFib may increase the risk of stroke five-fold and state that other risk factors for stroke may have largely contributed to their assessment. They suggest that when other multiple risk factors are present, AFib represents a marginally increased risk of stroke, and other factors, such as an increase in age, represent a higher risk.

However, organizations such as the Centers for Disease Control and Prevention (CDC) and the American Heart Association maintain that AFib may significantly increase the risk of stroke.

Treatments for AFib and stroke differ, but both may involve medications and surgery.

AFib treatment

Treatment may include:

Learn about AFib surgery here.

Stroke treatment

Stroke treatment may vary depending on the type of stroke a person has and the stage of treatment. It typically includes medication, surgery, and rehabilitation.

Medication for ischemic stroke includes:

Sometimes, surgery may include a procedure to open a blocked carotid artery.

Medication for hemorrhagic stroke includes blood pressure medications.

Surgery options include repairing an arteriovenous malformation (AVM), a tangle of arteries and veins that may have ruptured in the brain. Another option is coil embolization or aneurysm clipping to prevent blood from leaking from an aneurysm.

Rehabilitation for either type of stroke aims to help a person recover skills they lost due to the stroke and help them to gain independence and increase their quality of life.

Learn more about the first-line medications to treat and prevent a stroke here.

Through medication and lifestyle changes, a person can help to prevent AFib by:

  • rate control, which involves bringing down a high heart rate
  • rhythm control, which involves restoring the heart’s rhythm
  • preventing blood clots
  • reducing risk factors of other heart problems
  • managing risk factors for stroke

A person may reduce some risk factors of stroke by:

Learn how to stop an AFib episode here.

AFib can lead to stroke. It is a type of irregular heartbeat that probably happens when the heart does not pump blood effectively. When this happens, the blood moves sluggishly and can pool and clot. A blood clot can block an artery to the brain, starving the brain of oxygen and causing a stroke.

When a person has AFib, a doctor may prescribe blood thinning medications to prevent stroke. Other treatment for AFib includes beta-blockers, calcium channel blockers, and surgery.

A person may reduce the risk factors for stroke by making lifestyle changes, such as maintaining a heart-healthy diet, exercising regularly, and stopping smoking.

People should speak with a doctor if they think they have AFib. A stroke is a medical emergency, and a person should call 911 if they are experiencing symptoms.