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Atrial Fibrillation

Atrial Fibrillation: Complications

AFib has two major complications—stroke and heart failure.

Anatomy of the heart and brain with Atrial Fibrillation and Stroke

Atrial Fibrillation and Stroke

Click to enlarge image
This illustration shows how a stroke can occur with atrial fibrillation. A blood clot (thrombus) can form in the left atrium of the heart. If a piece of the clot breaks off and travels to an artery in the brain, it can block blood flow through the artery. The lack of blood flow to the portion of the brain fed by the artery causes a stroke.


During AFib, the heart's upper chambers, the atria, don't pump all of their blood to the ventricles. Some blood pools in the atria. When this happens, a blood clot (also called a thrombus) can form.

If the clot breaks off and travels to the brain, it can cause a stroke. (A clot that forms in one part of the body and travels in the bloodstream to another part of the body is called an embolus.)

Blood-thinning medicines that reduce the risk of stroke are an important part of treatment for people who have AFib.

Heart Failure

Heart failure occurs if the heart can't pump enough blood to meet the body's needs. AFib can lead to heart failure because the ventricles are beating fast and can't completely fill with blood and empty during each beat. Thus, the heart's ventricles may not be able to pump enough blood to the lungs and body.

Fatigue and shortness of breath are common symptoms of heart failure. A buildup of fluid in the lungs causes these symptoms. Fluid also can build up in the feet, ankles, and legs, causing weight gain.

Lifestyle changes, medicines, and procedures or surgery (rarely, a mechanical heart pump or heart transplant) are the main treatments for heart failure.

Clinical Trials

The National Heart, Lung, and Blood Institute (NHLBI) is strongly committed to supporting research aimed at preventing and treating heart, lung, and blood diseases and conditions and sleep disorders.

NHLBI-supported research has led to many advances in medical knowledge and care. However, many questions remain about various diseases and conditions, including atrial fibrillation.

The NHLBI continues to support research aimed at learning more about AFib. For example, NHLBI-supported research on AFib includes studies that explore:

  • ways to improve catheter ablation procedures in people who have AFib
  • whether fish oil supplements can lower the risk of repeat episodes of AFib
  • whether genetic factors can help determine the best dosing strategies for warfarin, a blood-thinning medicine
  • ways to predict the risk of complications, such as stroke, for people with AFib
  • whether an implantable cardiac monitor provides the ability to remotely and continuously evaluate a person for repeat episodes of AFib
  • the effectiveness of a new drug therapy for people with AFib who must stop taking their blood thinning drug prior to surgery

This research very much depends on the willingness of volunteers to take part in clinical trials to determine the effectiveness of new ways to prevent, diagnose, or treat AFib and other diseases and conditions.

For more information about clinical trials related to AFib, talk with your doctor. You also can visit the following Web sites to learn more about clinical research and to search for clinical trials:

Read More "Atrial Fibrillation" Articles

Atrial Fibrillation / Who Is at Risk for Atrial Fibrillation? / Atrial Fibrillation Complications / Diagnosis / Treatment

Winter 2015 Issue: Volume 9 Number 4 Page 23