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
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.
—This procedure uses an electrical current or drugs to help normalize the heart rhythm.
—An area of the heart that is responsible for atrial fibrillation may be surgically removed or altered.
creates a pattern of scar tissue in the upper chambers of the heart. This makes a pathway for electrical impulses to travel through the heart. It also blocks the pathway for fast or irregular impulses. The Maze procedure may also be performed as minimally invasive surgery (called
Atrial fibrillation. EBSCO DynaMed website. Available at: ...(Click grey area to select URL) Updated September 17, 2012. Accessed November 9, 2012.
Atrial fibrillation. CardioSmart website. Available at: ...(Click grey area to select URL) Accessed November 9, 2012.
Cardioversion. Cleveland Clinic website. Available at: ...(Click grey area to select URL) Updated December 28, 2011. Accessed November 9, 2012.
Explore atrial fibrillation. National Heart Lung and Blood Institute website. Available at: ...(Click grey area to select URL) Updated July 1, 2011. Accessed November 9, 2012.
12/13/2010 DynaMed's Systematic Literature Surveillance ...(Click grey area to select URL) Lubitz SA, Yin X, 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 ...(Click grey area to select URL) Osbak PS, Mourier M, et al. A randomized study of the effects of exercise training on patients with atrial fibrillation. Am Heart J. 2011;162(6):1080-1087.
1/2/2014 DynaMed's Systematic Literature Surveillance ...(Click grey area to select URL) Abed HS, Wittert GA, et al. Effect of weight reduction and cardiometabolic risk factor management on symptom burden and severity in patients with atrial fibrillation: A randomized clinical trial. JAMA. 2013;310(19):2050-2060.