Electrical Cardioversion (Defibrillation) for a Fast Heart Rate
cardioversion is a procedure in which a brief electric shock is given to the
heart to reset the heart rhythm back to its normal, regular pattern (normal sinus rhythm). The shock is given through paddles or patches
applied to the outside of the chest wall.
Usually, the person is sedated. If
the person is conscious, medicine is given to control pain and to cause the
person to relax to the point of being nearly unconscious during the
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After cardioversion, the person's heart
rate and blood pressure are monitored.
Additional drugs to help
prevent heart rhythm problems from recurring (antiarrhythmic drugs) may also be
given before and after the procedure. If antiarrhythmic drugs are not used
after cardioversion, the heart may be at greater risk of going back into a fast
After cardioversion, you may take a blood thinner, such as warfarin, for a few weeks to prevent dangerous blood clots.
Also, it is used in nonurgent
situations to convert atrial fibrillation or atrial flutter to normal heart rhythm.
How Well It Works
Electrical cardioversion of the heart
is very effective. Most people who receive cardioversion return to normal sinus
rhythm immediately after the procedure.1
Risks of the procedure include the
A blood clot may become dislodged from the
heart and cause a stroke. Your doctor will try to decrease this risk by using
anticoagulants or other measures.
The procedure may not work.
Additional cardioversion or other treatment may be
Antiarrhythmic medicines used before and after
cardioversion or even the cardioversion itself may cause a life-threatening
You can have a reaction to the sedative given before the
procedure. Harmful reactions are rare.
You can get a small area of
burn on your skin where the paddles are placed.
What To Think About
Cardioversion is only a temporary
fix for a fast heart rate. Medicines (such as beta-blockers and calcium channel
blockers or other antiarrhythmic medicines) may be used to keep the heart rate
slow when a person has an episode of supraventricular tachycardia (SVT). For
long-term treatment and to reduce the chance of having another episode of
either SVT or ventricular tachycardia (VT), catheter ablation or medicine can
Blomström-Lunqvist C, et al. (2003). ACC/AHA/ESC guidelines for the management of patients with supraventricular arrhythmias—Executive summary: A report of the ACC/AHA/ESC Committee for Practice Guidelines. Circulation, 108(15): 1871–1909.
Primary Medical Reviewer
Rakesh K. Pai, MD, FACC - Cardiology, Electrophysiology
Specialist Medical Reviewer
John M. Miller, MD, FACC - Cardiology, Electrophysiology
August 9, 2012
WebMD Medical Reference from Healthwise
August 09, 2012
This information is not intended to replace the advice of a doctor.
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