Treatment Overview

Electrical cardioversion is a treatment for a heartbeat that isn't normal, such as atrial fibrillation. It uses a brief electric shock to reset your heart's rhythm.

Before the treatment, you will get medicine to make you sleepy. You should not feel any pain.

Your doctor will put patches on your chest. Or you might get them on both your chest and back. They send a brief electric current to your heart. In most cases, this restores the heart's normal rhythm right away.

Cardioversion itself takes about 5 minutes. But the whole procedure will likely take about 30 to 45 minutes. That includes time to recover.

Abnormal heart rhythms sometimes come back after the treatment. You may need to take medicines. These may help your heart keep its normal rhythm.

What To Expect

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

You might take a medicine (called a blood thinner) that prevents blood clots before and after the procedure. This medicine lowers your risk of a stroke.

Other medicines to help prevent the return of heart rhythm problems (antiarrhythmics) also may be given before and after the procedure.

Why It Is Done

Cardioversion is used:

• As a non-emergency procedure to stop atrial fibrillation that has not stopped on its own. For people who have just started having episodes of atrial fibrillation, treatment typically includes cardioversion.
• As an emergency procedure to stop a fast heart rate that is causing low blood pressure or severe symptoms. These heart rate problems include atrial fibrillation, supraventricular tachycardia, and ventricular tachycardia.

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How Well It Works

The success of electrical cardioversion depends on how long you have had atrial fibrillation and what is causing it.

After this treatment, about 9 out of 10 people get back a normal heart rhythm right away.^{footnote 1} But for many people, atrial fibrillation returns. 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 another heart problem. But for most people, atrial fibrillation is caused by another heart problem and is very likely to return.

If your atrial fibrillation returns, you may be able to have cardioversion again. But you might not stay in a normal rhythm for very long. If atrial fibrillation comes back quickly (within a week or so), having cardioversion a third time, or more, is less likely to help you. Your doctor might recommend a different treatment, such as a rhythm-control medicine, to get your heart rhythm back to normal.

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

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.

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. You may need another cardioversion or other treatment.
• Antiarrhythmic medicines used before and after the procedure or even the procedure itself may cause a life-threatening irregular heartbeat.
• You could have a reaction to the medicine given to you before the procedure. But harmful reactions are rare.
• You can get a small area of burn on your skin where the patches are placed.