This irregular heartbeat is created by a
disruption in a web of nerves covering the surface of the heart. These nerves
send electrical signals that cause your heart to contract and pump blood out of
It is possible that the main title of the report Mitral Valve Prolapse Syndrome is not the name you expected. Please check the synonyms listing to find the alternate name(s) and disorder subdivision(s) covered by this report.
This web of nerves is controlled by a collection of
cells on the right atrium called the sinoatrial node. As it fires, so do the
rest of the nerves, causing all of the muscle cells in your heart to contract,
producing one forceful pump.
As mitral valve stenosis or MR
stretches out your heart, it too can disrupt this web of nerves. Communication
pathways may weaken because the sinoatrial node is no longer working correctly.
Without clear signals from this node, the nerves begin to fire randomly,
creating a chaotic network of electrical signals. When this happens, the heart
is no longer able to pump with one motion, and instead it starts beating
Atrial fibrillation is the most common arrhythmia that stems from mitral valve
stenosis and MR. Since the atria are the top two chambers of the heart, atrial
fibrillation refers to an irregular contraction and relaxation of these
chambers. Atrial fibrillation can happen constantly and unpredictably. Although
it can be a minor annoyance, it is often a serious condition and should be
Because the heart does not pump uniformly and smoothly in
atrial fibrillation, blood pools, allowing clots to form in the atrial chambers
of the heart. If one of these clots detaches and travels to the brain, it may
block the flow of blood, causing a stroke. Deprived of oxygen, these nerve
cells cannot function and likely will die within minutes. The body parts and
functions controlled by the affected nerves will be severely impaired as a
result. Because it is not possible to replace dead brain cells, the effects of
stroke are often permanent.
Most individuals with atrial
fibrillation will need medicine on a regular basis either to control the
continuing arrhythmia or to prevent recurrence. Three types of medicines can be
used (and are often combined) to prevent and treat the arrhythmia:
Medicines to slow the heart rate, such as
digoxin, beta-blockers, or calcium channel blockers. These medicines suppress
the flow of electrical impulses through the AV node and slow down the rate of
Medicines to help return the heart to
its normal rhythm, such as quinidine, propafenone, sotalol, and amiodarone.
These medicines also can be used to maintain the heart's normal rhythm after it
has been achieved and/or to reduce the heart rate while you are in atrial
Medicines to thin the blood (anticoagulants), such
as warfarin and aspirin. These medicines are designed to reduce any blood clot
formation and chances of stroke.
For more information, see the topic Atrial
Primary Medical Reviewer
E. Gregory Thompson, MD - Internal Medicine
Specialist Medical Reviewer
George Philippides, MD - Cardiology
February 12, 2010
WebMD Medical Reference from Healthwise
February 12, 2010
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