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).
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