What Is Electrical Cardioversion?

When your heart has an irregular heartbeat, the condition is called arrhythmia (uh-RITH-me-uh). It may mean that your heart is beating too fast, too slowly, or a combination of the 2. Arrhythmia occurs when the electrical signals that tell the heart to beat do not work properly.1

Arrhythmia may feel like your heart is racing, fluttering, or pounding when you have not been exercising. It may feel like chest pain. Or you may not feel it at all. Having an arrhythmia may be harmless but may also cause fainting, a stroke, heart attack, or death. That is why doctors will try to correct an arrhythmia quickly.1,2

Options for resetting the heart’s rhythm

There are a few options for resetting someone’s heartbeat to the correct rhythm, including:1-3

  • Medicine (chemical cardioversion)
  • Electrical shock (electrical cardioversion)
  • Installing a device, like a pacemaker
  • Surgery

The option used depends on several factors, including the type of arrhythmia you have and your overall health.2,3

Electrical cardioversion uses a high-energy electric shock to reset the heart’s rhythm. It may be performed as a scheduled procedure in a hospital or special clinic or in an emergency room.2

What causes arrhythmia?

Your heart has 4 chambers, 2 at the top called atriums and 2 at the bottom called ventricles. A special group of cells live in the upper right chamber, the right atrium, and send electrical signals down to the ventricles. As the electrical signals travel, they tell the different parts of the heart to beat (contract). When the electrical signals are organized, it makes the heart pump the way it should.2

If the electrical signals become disorganized, they may cause the heart to beat too fast (tachycardia), beat too slow (brachycardia), or have extra beats. Strangely, these extra beats may make it feel like your heart is skipping beats.1,2

When is electrical cardioversion used?

Cardioversion is most often used for certain types of arrhythmia, such as:1,4

Atrial fibrillation and atrial flutter are types of arrhythmias in which the heart beats too fast. Both can lead to a stroke if left untreated. Your doctor may also call these conditions tachycardia.1

Electrical cardioversion is useful in pregnant people because the pregnant person’s heartbeat can be reset without affecting the baby’s heartbeat.4

How does cardioversion work?

During cardioversion, you are sedated (asleep) and given anesthesia so you will not feel pain. A doctor then delivers a powerful electrical shock through the chest wall to the heart. The electricity activates the entire heart all at once, stops the arrhythmia, and resets the electrical signals. This restores the heart to its normal rhythm.4

During the procedure, your doctor will monitor your heart rate, blood pressure, breathing, and oxygen levels. Cardioversion itself only takes a few seconds. Most people awake 5 to 10 minutes later, after the anesthesia wears off.4

Cardioversion may be performed differently for people who have a pacemaker or implantable cardioverter-defibrillator.4

Risks and benefits of electrical cardioversion

Electrical cardioversion works for most people. But there can be complications. The type of risk or complication depends on your other health conditions, the type of arrhythmia you have, and your age. Possible complications include:2,4

  • A more dangerous heart rhythm that requires another shock or medicine to correct
  • Temporary low blood pressure
  • Stroke from a blood clot breaking free
  • Reactions to the anesthesia used
  • Some temporary damage to heart tissue

Other things to know

Most people are monitored for a few hours and then can go home. But they should not drive for 24 hours after the procedure because they have received anesthesia.4

If the skin is irritated or sore where the shock was delivered, ibuprofen (Tylenol) or a skin cream such as Aquaphor or Eucerin may help.4

Talk to your doctor about what to expect during a cardioversion and how to prepare. You may need to stop eating or drinking the night before your procedure. You may also need to take an extra medicine before or after cardioversion.2

Do not stop taking any of your regular medicines without talking with your doctor first.2

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Treatment results and side effects can vary from person to person. This treatment information is not meant to replace professional medical advice. Talk to your doctor about what to expect before starting and while taking any treatment.

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