Cardioversion for AFib

Medically Reviewed by James Beckerman, MD, FACC on September 03, 2023
3 min read

If you have an irregular heartbeat (you might hear it called arrhythmia, atrial fibrillation, or AFib), your doctor will probably suggest a treatment called cardioversion to help you get a normal rhythm back.

If your heart beats too fast or unevenly, it can be dangerous. It may not be pumping enough blood to meet your body's needs. An irregular heartbeat also can lead to a stroke or a heart attack.

It’s an option when medications can’t control the problem.

Your doctor uses a special machine to send electrical energy to the heart muscle. The procedure restores a normal heart rate and rhythm, allowing your heart to pump better.

There are two kinds. Your doctor will talk to you about which one is right for you. Each is usually done in a hospital or outpatient center.

Chemical cardioversion: If your arrhythmia isn’t an emergency, a doctor will usually use medication to get your heart back to normal. This is called chemical or pharmacologic cardioversion. You typically get the medicine through an IV while doctors check your heart. But sometimes, people can take it as a pill.

The type of medicine used will vary based on your type of abnormal rhythm and your other medical problems. The following are some examples of medicines that your health care provider might use:

  • Amiodarone (Cordarone)
  • Dofetilide (Tikosyn)
  • Flecainide (Tambocor)
  • Ibutilide (Corvert)
  • Propafenone (Rhythmol)

Electrical cardioversion: Drugs alone may not correct your heartbeat. Electrical cardioversion gives shocks through paddles to regulate your heartbeat.

First, you'll get medicine to make you fall asleep. Then, your doctor will put the paddles on your chest, and sometimes your back. These will give you a mild electrical shock to get your heart's rhythm back to normal.

Most people only need one. Because you’re sedated, you probably won’t remember being shocked. You can usually go home the same day.

Your skin may be irritated where the paddles touched it. Your doctor can point you toward a lotion to ease pain or itching.

Defibrillation also uses electric shocks, but it isn’t the same as electric cardioversion.

In defibrillation, doctors use high-voltage shocks to treat life-threatening arrhythmias or a heart that has stopped.


Blood clots: Either kind of cardioversion could knock loose blood clots created from your abnormal heartbeat. Before the procedure, your doctor may do a type of ultrasound to look for blood clots in your heart. You’ll probably get medicine to take for 3-4 weeks before and after the procedure to help prevent blood clots.

Stroke: If a clot travels to your brain, it can cause a stroke.

It might not work: Cardioversion doesn't always fix a fast or irregular heartbeat. You may need medicine or a pacemaker to control things.

It might make things worse: It's unlikely, but there’s a small chance that cardioversion could damage your heart or lead to more arrhythmias.

Irritated skin: This often happens where the paddles are applied. The doctor can give you a cream to treat it.

Once your heart is back in a normal rhythm, your doctor will give you medicine to make sure it stays that way.

You'll go back to your doctor in a few weeks for an electrocardiogram (you may hear it called an EKG) to make sure your beat is still regular. Keep up with your doctor visits and follow your treatment plan, which may also include antiarrhythmic drugs to help your heart maintain its normal rhythm.

Let them know if you have any questions or notice any changes in your condition.

Electrical cardioversion is more than 90% effective, though many have AFib again shortly after having it. Taking an antiarrhythmic drug before the procedure can prevent this. How well it works depends on the size of your left atrium as well as how long you’ve been in AFib. If you have a large left atrium or you’ve been in constant AFib for a year or two, it may not work as well. Taking antiarrhythmic drugs can also prevent AFib after a successful electrical cardioversion.

Chemical cardioversion: You should know quickly if it works. It usually takes effect within hours, but sometimes it takes days. If it doesn’t work for you, the doctor might suggest electrical cardioversion.