Smaller Larger

Conditions InDepth: Arrhythmias (Heart Rhythm Disturbances) by Ricker Polsdorfer, MD

Arrhythmias are abnormal beats of the heart, such as:

Heartbeats that are too slow ( bradycardia )
Heartbeats that are too fast (tachycardia)
Extra beats
Skipped beats
Beats coming from abnormal areas of the heart

Heartbeat: Anatomy of the Heart

Arrythmias can also be classified by the point of origination within the heart muscle:

Arrhythmias originating within the atria
Arrhythmias originating within the ventricles

The heart is a muscular pump with its own power supply and internal controls. It generates its own electrical signals to prompt each heartbeat and can therefore beat independently of the rest of the body. The electrical signal begins in a "pacemaker" called the sinoatrial, or sinus, node, which is in the back of the right atrium (upper right heart chamber). Arrhythmias can arise from any part of the heart's circuitry. Those that come from the atria are called atrial and are usually benign. Most of the dangerous arrhythmias start in the ventricles (lower chambers) or are due to failure of conduction through the atrioventricular (AV) node or due to abnormal electrical activity within the ventricles. The AV node is the electrical connection point between the atria and ventricles.

For descriptions of the many types of arrhythmias, click here.

References:

American Heart Association website. Available at: http://www.americanheart.org/ .
Harrison's Principles of Internal Medicine . 14th ed. McGraw-Hill; 1998.
Heart Rhythm Society website. Available at: http://www.hrsonline.org .
Mayo Clinic and Foundation for Medical Education and Research website. Available at: http://www.mayo.edu/ .
National Heart, Lung, and Blood Institute website. Available at: http://www.nhlbi.nih.gov/ .
Rosano GM, Rillo M, Leonardo F, et al. Palpitations: What is the mechanism, and when should we treat them? Int J Fertil Womens Med. 1997;42:94.

Last reviewed September 2012 by Michael J. Fucci, DO

All EBSCO Publishing proprietary, consumer health and medical information found on this site is accredited by URAC. URAC's Health Web Site Accreditation Program requires compliance with 53 rigorous standards of quality and accountability, verified by independent audits. To send comments or feedback to our Editorial Team regarding the content please email us at HLEditorialTeam@ebscohost.com.

This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.

Conditions InDepth: Arrhythmias (Heart Rhythm Disturbances) by Ricker Polsdorfer, MD

Heartbeat: Anatomy of the Heart

References:

Search Your Health