Cardioversion is a procedure that converts certain types of
abnormal heart rhythms (arrhythmias) to a normal one. There are
two types of electrical cardioversion, internal and external.
External Cardioversion may be performed in an emergency
situation (e.g., with a defibrillator) or in a
nonemergency situation. The most common type of non-emergency
external Cardioversion uses mild electrical shocks that are
carefully timed to stop an arrhythmia and restore a normal
heartbeat. In addition, Cardioversion may also be accomplished
External, non-emergency Cardioversion is usually performed on a
scheduled, outpatient basis. During the procedure, the patient
will receive either general anesthesia or a strong sedative, and
therefore not feel any pain. The procedure has shown great
success in correcting certain arrhythmias (e.g.,
that have not improved with medication alone. Patients may need
after a Cardioversion.
Cardioversion has limited success in treating people with
long–standing atrial fibrillation (a year or longer) or with
some other types of heart problems (e.g., hypertrophic
Cardioversion is a general term, although it is
usually used to refer to the procedure as it is performed in
prescheduled, non-emergency situations. The patient is
anesthetized, and the shock is delivered at a low level and at a
specific moment in the cycle of a heartbeat. Defibrillation is a
specific type of Cardioversion that is usually performed in
emergency situations to correct life-threatening arrhythmias
(e.g., ventricular fibrillation) and to re-establish a
heartbeat. Defibrillation shocks are delivered as needed and are
not timed to the heartbeat.
One alternative to electrical shocks associated with electrical
Cardioversion is to use medications that produce the same
desired results. This procedure is called chemical
antiarrhythmic medications (e.g., flecainide,
amiodarone) are used for this purpose. Chemical cardioversion
appears most effective when administered within 48 hours of a
person’s first episode of atrial fibrillation.
Researchers are experimenting with increasing the electrical
charge of the shock used during electrical Cardioversion. This
technique was found to be particularly useful for people with
atrial fibrillation lasting longer than 30 days.