December 2, 2008

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Atrial Flutter

Atrial Flutter Overview

Atrial flutter is an abnormality of the heart rhythm, resulting in a rapid and sometimes irregular heartbeat. Such abnormalities, whether in the rate or regularity of the heartbeat, are known as arrhythmias.

The beating of the heart is controlled by electrical impulses.

  • Under normal circumstances, these impulses are generated by the heart's natural pacemaker, the sinoatrial (SA) or sinus node, which is located in the right atrium.

  • The impulse travels across the atria, generating a contraction of the atria.

  • The impulse pauses very briefly at the atrioventricular (AV) node, which is located in the upper part of the muscular wall between the two ventricles. This delay gives the blood time to move from the atria to the ventricles.

  • The impulse then moves down and through the ventricles, generating the ventricular contraction, which pumps the blood out of the ventricles.

Atrial flutter occurs when these electrical impulses take an abnormal path through the atria, typically circulating around the tricuspid valve in the right atrium.

  • The abnormal path of the impulses makes the atria contract very rapidly, typically about 250-350 beats per minute. The normal heart rate is 50-100 beats per minute.

  • These rapid contractions are slowed when they reach the AV node often with every second or third contraction reaching the ventricle.

  • The heart beats in a regular rhythm, but it beats rapidly.

  • This type of rhythm is called tachycardia (rapid heartbeat). Because atrial flutter comes from the atria, it is sometimes called a supraventricular (above the ventricles) tachycardia.
The main danger of atrial flutter is that the heart does not pump blood well when it is beating too fast. When blood is not pumped well, vital organs, such as the heart and brain, may not get enough oxygen from the blood.

Atrial flutter can come and go; it is then known as paroxysmal atrial flutter. More often, atrial flutter lasts for days to weeks and is known as persistent atrial flutter.

With proper treatment, atrial flutter is rarely life- threatening. Complications of atrial flutter, in particular stroke, can be devastating, but they can be prevented with medications ("blood thinners") such as warfarin (Coumadin).



Next: Atrial Flutter Causes »

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