What Is Cardioversion?
Cardioversion (KAR-de-o-VER-shun) is a procedure
used to restore a fast or irregular heartbeat to a normal rhythm. A fast or
irregular heartbeat is called an
arrhythmia
(ah-RITH-me-ah).
Arrhythmias can prevent your heart from pumping
enough blood to your body. They also can raise your risk for
stroke,
heart
attack, or
sudden
cardiac arrest.
Overview
To understand arrhythmias, it helps to understand
how the heart works. Your heart has an internal electrical system that controls
the rate and rhythm of your heartbeat. With each heartbeat, an electrical
signal spreads from the top of your heart to the bottom.
As it travels, the signal causes your heart to
contract and pump blood. The process repeats with each new heartbeat. (For more
information on the heart's electrical system and a detailed animation, go
to the Diseases and Conditions Index article on
How
the Heart Works.)
A problem with any part of this process can cause an
arrhythmia. During an arrhythmia, the heart can beat too fast, too slow, or
with an irregular rhythm. Cardioversion is used to correct fast or irregular
heartbeats.
Cardioversion is done two ways: using an electrical
procedure or using medicines.
For the electrical procedure, low-energy shocks are
given to your heart to trigger a normal rhythm. You're temporarily put to
sleep before the shocks are given. This type of cardioversion is done in a
hospital as an outpatient procedure. This means you can go home after the
procedure is done.
Cardioversion also can be done by taking medicines
that correct arrhythmias. This type of cardioversion usually is done in the
hospital. It also can be done at home or in a doctor's office.
This article only discusses the electrical
procedure.
Many doctors prefer to do electrical cardioversions
because they work better and are more predictable. It's also easier to
find out right away if the procedure worked.
Cardioversion isn't the same as defibrillation
(de-fib-ri-LA-shun), although they both involve shocking the heart.
Defibrillation gives high-energy shocks to the heart to treat very irregular
and severe arrhythmias. Defibrillation is used to restore normal heartbeats
during life-threatening situations, such as cardiac arrest.
For more information on defibrillation, see the
Diseases and Conditions Index articles on
Sudden
Cardiac Arrest and
Implantable
Cardioverter Defibrillator.
Outlook
Cardioversion successfully restores normal heart
rhythms in more than 75 percent of people who have the procedure. However, fast
or irregular heartbeats can occur again. For this reason, you may need to have
more than one cardioversion over time.
The procedure has some risks. For example, it may
worsen arrhythmias. However, serious complications are rare.
July 2008
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