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Arrhythmias are uncoordinated or uneven beats of the heart muscle. They're caused by a problem in the electrical system of the heart. Some are harmless and won't cause problems. Others will cause more problems and will need to be treated.
The heart has 4 chambers:
The chambers need to beat in a certain way. This helps the heart to move blood all over the body. A nerve signal keeps the heart beating at 60 to 100 beats a minute.
The nerve excites the heart in a certain pattern. The relaxed atria fill with blood. Then, the signal forces them to contract. This pushes blood into the relaxed ventricles. As the signal moves down, the ventricles contract, pushing blood out to the lungs or body. At the same time, the atria relax and fill with blood. The cycle repeats with each heartbeat.
The electrical signal starts in the sinoatrial (SA) node in the right atrium.
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Arrhythmias cause problems with the timing of beats between the chambers. They can also interfere with how fast or strong the beats are. This may cause:
About arrhythmia. American Heart Association website. Available at: https://www.heart.org/en/health-topics/arrhythmia/about-arrhythmia. Accessed January 3, 2019.
Arrhythmia. National Heart, Lung, and Blood Institute website. Available at: https://www.nhlbi.nih.gov/health-topics/arrhythmia. Accessed January 3, 2019.
Heart diseases & disorders. Heart Rhythm Society website. Available at: https://www.hrsonline.org/Patient-Resources/Heart-Diseases-Disorders. Accessed January 3, 2019.
Last reviewed December 2018 by EBSCO Medical Review Board Michael J. Fucci, DO, FACC Last Updated: 1/3/2019