Atrial Fibrillation and Blood Clots

Medically Reviewed by Melinda Ratini, DO, MS on July 31, 2020

If you have atrial fibrillation -- an irregular and sometimes fast heart rate -- you could also get blood clots in the top part of your heart. Clots can stop the blood flow to your brain and possibly cause a stroke.

Blood clots usually form in the left atrium, or upper left part, of your heart. If they break away from there, they'll travel down to the left ventricle. From there, the clot will move throughout the arteries, which carry blood from your heart to other parts of your body. If you have AFib, the most common place your blood clot may travel is your brain.

Strokes related to AFib are about twice as likely to cause death and disability as strokes from other causes. So it’s important to know the warning signs of blood clots and strokes if you have AFib.

Symptoms of Blood Clots and Stroke With Atrial Fibrillation

You can have a blood clot that could lead to a stroke without any symptoms. If you do have symptoms, they can include:

If you have AFib, you may have symptoms of a stroke without knowing that you have a blood clot.

Symptoms of a stroke can include:

  • Numbness or weakness of the face, arm, or leg
  • Confusion or problems talking or understanding people
  • Trouble walking
  • Dizziness
  • Lack of balance
  • Vision problems
  • A strong headache with no known reason

It’s important to act quickly if you have any of these warning signs. The longer you wait, the worse the effects of your stroke could be. If you know that you have atrial fibrillation, you should tell your family and friends about stroke symptoms. That way, they can help, if you start to show symptoms.

How to Prevent Blood Clots That Can Cause Stroke

To lower the chances of blood clots that could lead to a stroke, your doctor may give you blood thinners to help prevent clots from happening. You might also get drugs to help your heart beat normally. A steady heartbeat will make a blood clot less likely.

If medication doesn’t work, your doctor may recommend a procedure, such as:

Electrical cardioversion. This sends a high-energy shock to your heart in order to regulate your heartbeat.

Catheter ablation. This process uses energy to make little scars in your heart tissue so that irregular signals do not affect your heart.

An important way to prevent blood clots and stroke if you have AFib is to treat any other conditions you might have that play a part in your AFib, including:

Make sure your doctor is up to date on any medical conditions you have.

A healthy lifestyle can play a huge role in keeping you away from blood clots and strokes. Make sure to:

Stop smoking. If you smoke, your blood can thicken, which increases the chances of a blood clot.

Limit or avoid alcohol. Ask your doctor if there's a safe amount of alcohol you can drink.

Lose weight.Obesity, and the issues connected to it, make strokes more likely.

Exercise.Working out will help you lose weight and lower your blood pressure. Both help make strokes less likely.

Eat healthy. Load up on fruits, vegetables, protein, and foods high in fiber. Stay away from foods heavy in fat, sugar, and salt. Read labels so that you know what you're getting.

What to Do if Someone Has a Stroke

If you or someone you know thinks that they’re having a stroke, call 911 immediately. Note the time that stroke symptoms started. This is important because some treatments only work if the stroke was within a certain time period.

Don’t go to sleep before you get treatment if you think you had a stroke. People will often feel tired right after one. But ignoring symptoms could cause more damage to your body.

Be sure not to eat, drink, or take any drugs right after a stroke because you may not be able to swallow correctly. Certain drugs could also make your symptoms worse.

Wait for emergency responders to drive you to the hospital. It’s dangerous to drive after a stroke because your symptoms could get worse while you’re on the road.

Other Types of Blood Clots

Most blood clots from AFib go to your brain, but not all.

If a blood clot is in your arm or leg, you’ll most likely notice:

  • Tenderness
  • Swelling
  • Pain
  • Warm feeling around the area of the clot.

If there is clotting in your abdomen, you may:

If you think you might have a blood clot anywhere in your body, it's serious. So it's crucial to talk with your doctor right away.

Show Sources


Mayo Clinic: “Atrial Fibrillation.”

National Blood Clot Alliance: “Atrial Fibrillation (AFib) And Clot-Provoked Stroke.”

National Cancer Institute: “Structure of the Heart,” NCI Dictionaries.

American Blood Clot Association: “Atrial Fibrillation & Blood Clots.” “Stroke Warning Signs.”

Penn Medicine: “If Someone is Having a Stroke: 3 Things To Do and 3 Things Not To Do.”

Johns Hopkins Medicine: “Electrical Cardioversion.”

National Heart, Lung, and Blood Institute: “Catheter Ablation.”

Heart and Stroke Foundation of Canada: “Atrial fibrillation.”

Harvard Medical School: “7 things you can do to prevent a stroke.”

Stroke Association: “Eat a healthy diet.”

American Society of Hematology: “Blood Clots.”

Indiana Hemophilia and Thrombosis Center: “Signs and Symptoms of Blood Clotting.”

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