Atrial Fibrillation on the Rise

Each year, about two million Americans experience atrial fibrillation (AF). This condition causes about 15 percent of the strokes in the U.S. Atrial fibrillation can also cause chest pain and heart attacks.

According to one major study, up to 5.1 million Americans have atrial fibrillation. Many don't even know they have it.

What is atrial fibrillation?

A steady heart rate is about 60 beats per minute. In atrial fibrillation, the atria (the top two chambers of the heart) beat quickly, hundreds of times per minute, and irregularly. The lower heart chambers (the ventricles) also beat irregularly, but more slowly. You can have an episode of atrial fibrillation and not even know it. Some people are always in atrial fibrillation (persistent atrial fibrillation). Others go in and out (paroxysmal atrial fibrillation).

Another type of irregular rhythm is called atrial flutter. It is less common than atrial fibrillation.

Symptoms
Symptoms of atrial fibrillation include:

• Abnormally fast and irregular heartbeat
• Fainting or feeling light-headed
• Chest pain
• Weakness

People with atrial fibrillation may have some, all or none of these symptoms.

Dangers of atrial fibrillation

• Stroke. A clot may form within the atria, break off and travel to the brain.
• Chest pain or heart attack. The heart muscle may not get enough blood.

What causes it?

Older people are more likely than others to have atrial fibrillation, but age isn't the only factor. It often occurs in people who already have heart disease. High blood pressure can cause heart enlargement, which can lead to atrial fibrillation. It may be related to smoking, stress and caffeine use. Other conditions that are associated with atrial fibrillation include:

• Coronary heart disease
• Diabetes
• Overactive thyroid or too much thyroid medication
• Obesity

Testing for atrial fibrillation

Diagnosing atrial fibrillation can be a challenge because symptoms can come and go. An electrocardiogram or EKG, which is a snapshot of the heart's electrical activity, may look normal. To detect atrial fibrillation, your doctor may have you wear a small, portable EKG recorder known as a Holter monitor. It monitors the heart continuously over a day or more to help detect an irregular heart rhythm.

Treatment

Medication can be given to slow the heart rate. Electrical cardioversion is also often used for atrial fibrillation. This delivers a split-second electrical charge to the chest.

Another technique (catheter radiofrequency ablation) involves passing a long, narrow wire through a major artery in the groin or neck. Overactive electrical tissue is then destroyed. Blood thinners may be given to reduce stroke risk.

Your next steps

• Be up to date with your medical checkups.
• Keep atrial fibrillation risks (such as high blood pressure or diabetes) under control.
• Reach or maintain a healthy weight.
• Reduce or eliminate caffeine if symptoms are aggravated by its use.
• Quit smoking.
• If you have atrial fibrillation, talk to your doctor about blood-thinning drugs to prevent stroke.

Related Articles Lowering Your Risk for Stroke Risk Factors for Coronary Heart Disease Cardioversion

External Sources American Heart Association Miyasaka Y, Barnes ME, Gersh BJ, et al. Secular trends in incidence of atrial fibrillation in Olmstead County, Minnesota, 1980 to 2000, and implications on the projections for future prevalence. Circulation. 2006; 114(2):119-125. Wang TJ, Parise H, Levy D, et al. Obesity and the risk of new-onset atrial fibrillation. Journal of the American Medical Association. 2004;292(20):2471-2477.

This article was reviewed and updated June 2007.

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