Cardioversion is a method to restore an abnormal heart rhythm back to normal.


Cardioversion can be done using an electric shock or medications.


Electric cardioversion may use a device that can be placed inside (internal) or outside (external) the body.

External electric cardioversion uses a device called a defibrillator.

Emergency external electric cardioversion is used to treat any abnormal heart rhythm (arrhythmia) that is life threatening, such as ventricular tachycardia or ventricular fibrillation. Such a shock can be life saving.

External electric cardioversion may also be used when there is not an emergency.

An implantable cardioverter-defibrillator (ICD) is a device that is usually placed underneath the skin of your upper chest or abdomen. Wires are attached that go into the heart.


Cardioversion can be done using drugs that are taken by mouth or given through an intravenous line (IV). It can take several minutes to days for a this treatment to work. If you are given drugs for cardioversion in a hospital, your heart rate will be regularly checked.

Cardioversion using drugs can be done outside the hospital, most often for people with atrial fibrillation that comes and goes. However, you will need to be closely followed-up by a cardiologist.

As with electrical cardioversion, you may be given blood thinning medicines to prevent blood clots from forming and leaving the heart (which can cause a stroke).


Complications of cardioversion are uncommon, but may include:

People who perform external cardioversion may be shocked if the procedure is not done correctly. This can cause heart rhythm problems, pain, and even death.


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Review Date: 6/22/2012
Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; and Michael A. Chen, MD, PhD, Assistant Professor of Medicine, Division of Cardiology, Harborview Medical Center, University of Washington Medical School, Seattle, Washington. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M. Health Solutions, Ebix, Inc.
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