Atrial Fibrillation

Overview

What is atrial fibrillation?

Atrial fibrillation (say “A-tree-uhl fih-bruh-LAY-shun”) is an irregular heart rhythm (arrhythmia) that starts in the upper parts (atria) of the heart.

Normally, the heart beats in a strong, steady rhythm. In atrial fibrillation, a problem with the heart’s electrical system causes the atria to quiver, or fibrillate. The quivering upsets the normal rhythm between the atria and the lower parts (ventricles) of the heart. The lower parts may beat fast and without a regular rhythm.

Atrial fibrillation is dangerous because it greatly increases the risk of stroke. If the heart doesn't beat strongly, blood can collect, or pool, in the atria. Pooled blood is more likely to form clots. If the heart pumps a clot into the bloodstream, the clot can travel to the brain and block blood flow, causing a stroke. Atrial fibrillation can also lead to heart failure or heart attack.

What causes atrial fibrillation?

Conditions that damage or strain the heart commonly cause atrial fibrillation. These include:

• High blood pressure.
• Coronary artery disease (CAD).
• Heart attack.
• Heart valve disease, especially diseases of the mitral valve.

Atrial fibrillation may also be caused by:

• Other medical problems, such as lung disease, pneumonia, or a high thyroid level (hyperthyroidism).
• Heart surgery.
• Heavy alcohol use. Having more than 3 drinks a day over many years can cause long-lasting atrial fibrillation. Drinking a large amount of alcohol at one time (binge drinking) may also cause a spell (episode) of atrial fibrillation.
• Use of stimulants. These include caffeine, nicotine, medicines such as decongestants, and illegal drugs such as cocaine.

Sometimes doctors can't find the cause. Doctors call this lone atrial fibrillation.

What are the symptoms?

Symptoms may include:

• Feeling dizzy or lightheaded.
• Feeling out of breath.
• Feeling weak and tired.
• A feeling that the heart is fluttering, racing, or pounding (palpitations).
• A feeling that the heart is beating unevenly.
• Chest pain (angina).
• Fainting.

Atrial fibrillation is common, especially in older adults, and it may not cause obvious symptoms. If you have any of the symptoms listed, see your doctor. Finding and treating atrial fibrillation right away can help you avoid serious problems.

How is atrial fibrillation diagnosed?

The doctor will ask questions about your past health, do a physical exam, and order tests. The best way to find out if you have atrial fibrillation is to have an electrocardiogram (EKG or ECG). An EKG is a test that checks for problems with the heart’s electrical activity.

You might also have lab tests, a chest X-ray, and an echocardiogram. An echocardiogram can show how well your heart is pumping and whether your heart valves are damaged.

How is it treated?

A number of treatments may be used for atrial fibrillation. Which treatments are best for you depend on the cause, your symptoms, and your risk of stroke.

Doctors sometimes use a procedure called cardioversion to try to get the heartbeat back to a normal rhythm. This can be done using either medicine or a low-voltage electrical shock (electrical cardioversion). Atrial fibrillation often comes back after cardioversion.

If you have mild symptoms, or if atrial fibrillation returns after cardioversion, your doctor may prescribe medicines to control your heart rate and help prevent stroke. These may include:

• Rhythm control medicines (antiarrhythmics) to help return the heart to its normal rhythm and keep it there.
• Rate control medicines to keep the heart from beating too fast during atrial fibrillation.

Many people with atrial fibrillation need to take blood-thinning (anticoagulant) medicine to help prevent strokes. People at low risk for stroke may take daily aspirin instead. If you are age 55 or older and have atrial fibrillation, you can find your risk of stroke using this Interactive Tool: What Is Your Risk for a Stroke if You Have Atrial Fibrillation?

Cardioversion and medicines don't work for some people who continue to have bothersome symptoms. In these cases, doctors sometimes recommend a procedure called ablation. Ablation destroys small areas of the heart. This creates scar tissue, which blocks or destroys areas that cause or maintain the irregular heart rhythm. Afterward, you may need a pacemaker to keep your heart beating regularly.

What can you do at home for atrial fibrillation?

Atrial fibrillation is often the result of heart disease or damage. So making changes that improve the condition of your heart may also improve your overall health.

• Don't smoke. Avoid secondhand smoke, too. Quitting smoking can quickly reduce your risk of stroke and heart attack.
• Eat a heart-healthy diet with plenty of fish, fruits, vegetables, beans, high-fiber grains and breads, and olive oil.
• Get regular exercise on most, preferably all, days of the week. Your doctor can suggest a safe level of exercise for you.
• Control your cholesterol and blood pressure. If you have diabetes, keep your blood sugar in your target range.
• Lower your stress level. Stress can damage your heart.
• Avoid caffeine, alcohol, and stimulants.
• Avoid getting sick from the flu. Get a flu shot every year.

More information How does the heart work? What is cardiac output? How does the heart control the timing of its beat? How does the heart keep its muscle healthy? Who gets atrial fibrillation?

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Author:	Robin Parks, MS	Last Updated January 18, 2007
Medical Review:	Caroline S. Rhoads, MD - Internal Medicine Laurence Epstein, MD - Cardiac Electrophysiologist
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