Atrial fibrillation is an abnormal heart rhythm. The heart's electrical system normally sends regularly spaced signals. These signals tell the heart muscle to contract or beat.
The heart has two upper chambers called atria. It also has two lower chambers called ventricles. Each signal starts in the atria and travels to the rest of the heart. In atrial fibrillation, the electrical signals from the atria are fast and irregular. The atria shake instead of contract. Some signals do not reach the ventricles and the ventricles continue pumping. This pumping is usually irregular and sometimes rapid. This rhythm can reduce the heart’s ability to pump blood out to the body. Blood left in the heart chambers can form clots. These clots may sometimes break away and travel to the brain. This can cause stroke.
In most cases, atrial fibrillation is due to an existing heart condition. Atrial fibrillation can also occur in people who do not have structural heart problems. A thyroid disorder or other condition may cause the abnormal rhythm. The cause of atrial fibrillation is sometimes unknown.
Factors that may increase the risk of atrial fibrillation include:
Symptoms can be mild to severe. This depends on your heart function and overall health. Some people may not notice any symptoms.
The doctor will:
You doctor will order blood tests to help diagnose the problem.
The goals of treatment are to:
Your doctor may find another condition that is causing atrial fibrillation. This condition may be treated. In some cases, heart rhythm problems return to normal without treatment.
Treatment options include:
Your doctor may recommend that you make lifestyle changes, such as:
Follow your doctor's instructions if you are diagnosed with atrial fibrillation.
Avoid known triggers if you have risk factors for atrial fibrillation. Also, follow your doctor's advice for controlling chronic conditions, like heart disease and high blood pressure.
American Heart Association
Heart Rhythm Society
Canadian Cardiovascular Society
Canadian Family Physician
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Cardioversion procedure. Cleveland Clinic website. Available at: http://my.clevelan.... Updated December 28, 2011. Accessed November 9, 2012.
What is atrial fibrillation? National Heart Lung and Blood Institute website. Available at: http://www.nhlbi.nih.gov/health/health-topics/topics/af/. Updated July 1, 2011. Accessed November 9, 2012.
12/13/2010 DynaMed's Systematic Literature Surveillance https://dynamed.ebscohost.com/about/about-us: Lubitz SA, Yin X, Fontes JD, et al. Association between familial atrial fibrillation and risk of new-onset atrial fibrillation. JAMA. 2010;304(20):2263-2269.
5/11/2012 DynaMed's Systematic Literature Surveillance https://dynamed.ebscohost.com/about/about-us: Osbak PS, Mourier M, Kjaer A, Henriksen JH, Kofoed KF, Jensen GB. A randomized study of the effects of exercise training on patients with atrial fibrillation. Am Heart J. 2011;162(6):1080-1087.
Last reviewed November 2012 by Michael J. Fucci, DO
Last Updated: 11/9/2012