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Stephen R. Shorofsky, M.D., Ph.D.

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Arrhythmias

Definition:

An arrhythmia is any disorder of your heart rate or heart rhythm, such as beating too fast (tachycardia), too slow (bradycardia), or irregularly.

Alternative Names:

Dysrhythmias; Abnormal heart rhythms; Bradycardia; Tachycardia 

Causes, incidence, and risk factors:

Normally, the 4 chambers of the heart (2 atria and 2 ventricles) contract in a very specific, coordinated manner.

The electrical impulse that signals your heart to contract in a synchronized manner begins in the sinoatrial node (SA node), which is your heart's natural pacemaker.

The signal leaves the SA node and travels through the 2 upper chambers (atria). Then the signal passes through another node (the AV node), and finally, through the lower chambers (ventricles). This path enables the chambers to contract in a coordinated fashion.

Problems can occur anywhere along this conduction system, causing various arrhythmias. Examples include:

The risks of getting a tachycardia or bradycardia varies greatly, depending on the condition of your heart, prior heart attack, blood chemistry imbalances, or endocrine abnormalities.

Arrhythmias may also be caused by some substances or drugs, including beta blockers, psychotropics, sympathomimetics, caffeine, amphetamines, and cocaine. Sometimes antiarrhythmic medications -- prescribed to treat one type of arrhythmia -- can actually cause another type of arrhythmia.

Some types of arrhythmias may be life-threatening if not promptly and properly treated.

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