Arrhythmias are uncoordinated or irregular contractions of the heart muscle caused by a problem in the electrical system of the heart. Some arrhythmias are benign and will not affect your overall health or cause symptoms. Others may be more serious and require treatment.
It may help to first understand how the heart should work. The heart is made up of four chambers:
The contraction of these four chambers needs to be coordinated to be able to efficiently move blood throughout the body. The atria contract first to push blood into and help fill the ventricles. Then the ventricles contract to push blood to the body or lungs. The nerves of the heart stimulate and coordinate the heart muscles in an organized manner:
The electrical signal starts in the sinoatrial (SA) node in the right atrium.
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Arrhythmias may affect the timing of the contractions between the atria and ventricles or the speed and strength of contractions of four different chambers. Arrhythmias can be:
About arrhythmia. American Heart Association website. Available at: http://www.heart.org/HEARTORG/Conditions/Arrhythmia/AboutArrhythmia/About-Arrhythmia_UCM_002010_Article.jsp. Updated October 17, 2012. Accessed March 18, 2014.
Heart diseases & disorders. Heart Rhythm Society website. Available at: http://www.hrsonline.org/Patient-Resources/Heart-Diseases-Disorders#electrical. Accessed March 18, 2014.
What is an arrhythmia? National Heart, Lung, and Blood Institute website. Available at: http://www.nhlbi.nih.gov/health/health-topics/topics/arr. Updated July 1, 2011. Accessed March 18, 2014.
Last reviewed December 2014 by Michael J. Fucci, DOLast Updated: 12/20/2014