Cardioversion is a medical procedure that uses quick, low-energy shocks to restore a regular heart rhythm. It's a treatment for certain types of irregular heartbeats (arrhythmias), including atrial fibrillation (A-fib). Sometimes cardioversion is done using medications.
Cardioversion is usually scheduled in advance but is sometimes done in emergencies. Usually, cardioversion quickly restores a typical heart rhythm.
Cardioversion is different from defibrillation, an emergency procedure that's done when the heart stops or quivers uselessly. Defibrillation delivers more powerful shocks to the heart to correct its rhythm.
Why it's done
Cardioversion is done to correct a heartbeat that's too fast (tachycardia) or irregular (fibrillation).
Your health care provider may recommend cardioversion if you have certain heart rhythm disorders, such as atrial fibrillation or atrial flutter. These conditions occur when the electrical signals that usually make the heart beat at a regular rate don't travel properly through the upper chambers of the heart.
There are two main types of cardioversion.
- Electric cardioversion uses a machine and sensors (electrodes) to deliver quick, low-energy shocks to the chest. Electric cardioversion allows a health care provider to instantly see if the procedure has restored a typical heartbeat.
- Chemical (pharmacological) cardioversion uses medicine to restore the heart's rhythm. It takes longer to work than electric cardioversion. If your provider recommends cardioversion with medications to restore the heart's rhythm, you won't receive electric shocks to your heart.
Complications of cardioversion are uncommon. Your health care provider can take steps to reduce your risk. Potential risks of electric cardioversion include:
Dislodged blood clots. Some people who have irregular heartbeats, such as A-fib, have blood clots form in the heart. Shocking the heart can cause these blood clots to move to other parts of the body. This can cause life-threatening complications, such as a stroke or a blood clot traveling to your lungs.
A health care provider may order tests to check for blood clots before doing cardioversion. Some people may be given blood thinners before the procedure.
- Irregular heart rhythms (arrhythmia). Rarely, some people develop other irregular heartbeats during or after cardioversion. If it happens, it usually occurs minutes after the procedure. Medications or additional shocks can be given to correct the heart's rhythm.
- Skin burns. Rarely, some people get minor burns on their skin from the sensors (electrodes).
Cardioversion can be done during pregnancy, but it's recommended that the baby's heartbeat be monitored during the procedure.
How you prepare
Cardioversion is usually scheduled in advance. If irregular heart rhythm symptoms are severe, cardioversion may be done in an emergency setting.
Before cardioversion, you may have an imaging test called a transesophageal echocardiogram to check for blood clots in the heart. Cardioversion can make blood clots move, causing life-threatening complications. Your provider will decide whether you need this test before cardioversion.
If you have one or more blood clots in the heart, cardioversion is typically delayed for 3 to 4 weeks. During that time, you'll usually take blood thinners to reduce the risk of complications.
What you can expect
Before the procedure
You typically can't eat or drink anything for about eight hours before cardioversion. Your provider will tell you whether to take any of your regular medications before your procedure.
During the procedure
Cardioversion is usually done in the hospital. A care provider will insert an IV into your forearm or hand and give you medications called a sedative to help you sleep during the procedure.
If you're having chemical cardioversion, you'll receive medications through the IV to help restore your heart rhythm.
If you're having electrical cardioversion, a care provider places several large patches (called sensors, or electrodes) on your chest and sometimes your back. Wires connect the sensors to a cardioversion machine. The machine records your heart rhythm. It delivers quick, low-energy shocks to the heart to restore a regular heart rhythm.
Electric cardioversion usually takes only a few minutes to complete.
After the procedure
You'll spend an hour or so in a recovery room being closely monitored for potential complications.
If electric cardioversion was a scheduled procedure, you can usually go home the same day. You'll need someone to drive you home. After cardioversion, your ability to make decisions may be affected for several hours.
Blood-thinning medications are usually taken for several weeks after cardioversion to prevent clots from forming. You'll need blood thinners even if no clots were found in your heart before the procedure.
For most people, cardioversion can quickly restore a regular heartbeat. Some people need additional procedures to keep a regular heart rhythm.
Your health care provider may suggest lifestyle changes to improve your heart health and prevent or treat conditions — such as high blood pressure — that can cause irregular heartbeats (arrhythmias).
Try these heart-healthy lifestyle changes:
- Limit or avoid alcohol
- Use less salt, which can help lower blood pressure
- Choose whole grains, lean meat, low-fat dairy, and fruits and vegetables
- Limit sugar and saturated fat and trans fats
- Increase physical activity
- Maintain a healthy weight
- Quit smoking
- Try to limit or manage stress and anger
© 1998-2022 Mayo Foundation for Medical Education and Research (MFMER). All rights reserved.