Treatment Overview

Electrical cardioversion is a procedure in which an electric current is used to reset the heart's rhythm back to its regular pattern (normal sinus rhythm). The low-voltage electric current enters the body through metal paddles or patches applied to the chest wall. Cardioversion is used:

• To stop atrial fibrillation that has not stopped on its own or after a trial of antiarrhythmic medicines has failed.
• As an emergency procedure to correct a fast heart rhythm that is causing low blood pressure, chest pain, or heart failure.

Before cardioversion for atrial fibrillation, you will be given medicine to control pain and cause relaxation.

See pictures of:

• The electrical system of the heart.
• Atrial fibrillation.
• Low-voltage electrical cardioversion.

What To Expect After Treatment

You may take an anticoagulant medicine, such as warfarin, for a few weeks before and a few weeks after cardioversion. How long you take anticoagulants will depend on how long you had atrial fibrillation before the cardioversion procedure.

You might not need to take anticoagulants before the procedure if you have a low risk of stroke. For example, if a test, transesophageal echocardiogram, has ruled out the presence of blood clots in the upper heart chambers (atria), you will not need anticoagulants before the procedure. But you will still need to take anticoagulants for at least a few weeks after cardioversion, even if no clots were seen.

Additional medicines to help prevent the return of heart rhythm problems (antiarrhythmics) also may be given before and after the procedure. Your risk of having atrial fibrillation again is greater if antiarrhythmics are not used after cardioversion.

After cardioversion, you will be monitored to ensure that you have a stable heart rhythm.

Why It Is Done

Cardioversion is used as an emergency procedure when symptoms of very low blood pressure, chest pain, or heart failure caused by rapid, irregular atrial fibrillation are present.

Cardioversion also is used in nonemergency situations to stop atrial fibrillation and return the heart rhythm to normal.

For help deciding if you should have electrical cardioversion, see:

Atrial Fibrillation: Should I Try Electrical Cardioversion?

How Well It Works

The success of electrical cardioversion depends on how long you have had atrial fibrillation and what is causing it. Cardioversion is less successful if you have had atrial fibrillation for longer than 1 year.

After this treatment, about 9 out of 10 people get back a normal heart rhythm right away. But for many people, atrial fibrillation returns. About 3 to 5 out of 10 people still have a normal heart rhythm 1 year after cardioversion.¹ Normal rhythm may last less than a day or for weeks or months. It depends on your other health problems.

Staying in a normal rhythm is more likely when the cause of your rhythm problem is not heart disease. But for most people, atrial fibrillation is caused by heart disease and is very likely to return.

If your atrial fibrillation returns, you may be able to have cardioversion again. But if the problem comes back quickly (within a week or so), having the treatment yet again is less likely to help you.

If you take antiarrhythmic medicines too, they can help you stay in a normal rhythm longer.

Risks

Risks of the procedure include the following:

• 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 needed.
• Antiarrhythmic medicines used before and after cardioversion or even the cardioversion itself may cause a life-threatening irregular heartbeat.
• 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 may be less successful or may not be recommended if you:

• Have had atrial fibrillation for more than a year.
• Have significant valve problems.
• Have an enlarged heart as a result of heart failure or cardiomyopathy.
• Have multiple recurrences of atrial fibrillation.

Cardioversion is more likely to be successful if:

• Atrial fibrillation has been present for less than a year.
• This is your first episode of atrial fibrillation.
• You are young.
• Antiarrhythmic medicines are used along with cardioversion.

Complete the special treatment information form (PDF)(What is a PDF document?) to help you understand this treatment.

References

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