Electrical cardioversion for atrial fibrillation

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 medications 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 medication to control pain and cause relaxation.

See illustrations of:

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

What To Expect After Treatment

If you have had atrial fibrillation for longer than 48 hours, your doctor will probably recommend that you take the anticoagulant warfarin(such as Coumadin) for at least 3 weeks before and for 1 to 3 months after the procedure.

If you have had atrial fibrillation for less than 48 hours, anticoagulants may not be needed before this procedure. However, you may still need to take anticoagulants for at least 4 weeks after this procedure.

Alternately, if you have had atrial fibrillation for more than 48 hours but a test called transesophageal echocardiogram has ruled out the presence of blood clots in the upper heart chambers (atria), you will not need anticoagulants before the procedure. However, you will still need to take anticoagulants for at least 1 month after cardioversion, even if no clots are seen.

Additional medications to help prevent the return of heart rhythm problems (antiarrhythmics) also may be given before and after the procedure. Your risk of developing atrial fibrillation again is greater if antiarrhythmics are not used following 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 correct atrial fibrillation when medications have not been effective. Some doctors consider it the first choice in younger people or people who have developed atrial fibrillation within the last 48 hours.

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.

Electrical cardioversion is an effective treatment for recent-onset atrial fibrillation. About 86% of people who receive cardioversion return to normal sinus rhythm immediately after the procedure. This success rate increases to 94% when antiarrhythmic medications are given before cardioversion. However, only about 23% of those will remain in normal sinus rhythm after 1 year, and additional treatment may be needed.¹ Although cardioversion can return the heart rhythm to normal, it does not act in the long term to maintain a normal rhythm.

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 medications 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 medications are used along with cardioversion.

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

References

Citations

1. Fuster V, et al. (2006). ACC/AHA/ESC 2006 guidelines for the management of patients with atrial fibrillation-Executive Summary. A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and the European Society of Cardiology Committee for Practice Guidelines (Writing committee to revise the 2001 guidelines for the management of patients with atrial fibrillation). Circulation, 114(7): 700-752.

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