What Is Electrical Cardioversion?

Cardiologists at University of Utah Health use this therapy for people with heart rhythm disorders (arrhythmias), including atrial flutter and atrial fibrillation (AFib)

How It Works

Your heart’s electrical system is the power source that makes your heartbeat. When this system is working normally, the two upper chambers of the heart (atria) contract and pump blood into the two lower chambers (ventricles) in a well-coordinated way.

The system depends on specialized “pacemaker” cells in the upper atria to start each heartbeat. A heart arrhythmia develops when the electrical system of your heart is not working correctly or is replaced by short circuits. As a result, the heart’s upper chambers beat too quickly. This can make your heart rate fast and irregular. Arrhythmia episodes can last for a few minutes, hours, or even a few days.

A normal resting heartbeat is between 60 and 100 beats per minute. When a person with AFib or atrial flutter experiences an episode, the heart may beat as many as 300 times per minute or more in the upper heart chambers and 100-200 times per minute in the lower heart chambers. For AFib patients, the heartbeat is often chaotic and fast.

Electrical cardioversion is a little bit like “rebooting” your laptop. But instead of turning off your heart’s power source, it delivers a low current of electrical energy to the heart. This causes the heart cells to release all of their chaotic, disorganized energy at once. As a result, your heart’s pacemaker cells take over to restore the normal rhythm of your heart.

Man holding chest in pain

Best Candidates for Electrical Cardioversion

Most people who undergo electrical cardioversion have AFib episodes for four to six hours at a time. Electrical cardioversion is used less often for people with atrial flutter. In addition to a rapid heart rate, symptoms of these conditions can include:

  • anxiety,
  • dizziness,
  • shortness of breath,
  • palpitations (fluttering in the chest),
  • fatigue, and
  • chest pain or tightness.

Some people have “asymptomatic” or “silent” Afib or atrial flutter. This means they don’t feel symptoms, but the arrhythmia could still be damaging their heart.

Electrical Cardioversion Procedure

Electrical cardioversion is a scheduled, outpatient procedure. You will be asked not to eat or drink anything after midnight on the day of your electrical cardioversion. After you arrive at the hospital, our care team will take you to a procedure room and ask you to lie down on a treatment table. A nurse or other provider will stick large pads on your chest and back. These pads are attached to the external cardioverter-defibrillator by wires.

Just before the procedure begins, an anesthesiologist will give you sedation through an intravenous (IV) line. You will be asleep during the cardioversion, which will only take a few minutes.

The cardiologist will use the cardioversion device to analyze your heart rhythm, determine the energy level needed, and deliver the current. The cardiologist will know right away whether the cardioversion reset your heart rhythm.

After Your Cardioversion

After your procedure, the care team will watch you for an hour and then you will go home. You will need someone to drive you since you were under sedation for the procedure.

Most people who undergo electrical cardioversion don’t experience side effects and can resume their normal activities quickly. However, some people report minor side effects, such as:

  • fatigue (on the day of their cardioversion),
  • skin irritation where the pads were placed, and
  • soreness in their leg muscles.

Find a Cardioversion Specialist

Cardioversion vs. Defibrillation

You are probably familiar with automatic external defibrillation (AED) devices. First responders and bystanders use them in emergencies when a person has experienced a sudden cardiac arrest. Electrical cardioversion and AED devices both use pads on the chest and back to deliver an electrical current to help the heart re-establish an effective rhythm.

However, these procedures are different in some important ways. Electrical cardioversion delivers a current to the upper chambers of the heart. It almost always happens as part of a scheduled appointment to treat AFib or atrial flutter. AED devices deliver a shock to the lower chambers and are used only in emergency instances like when a person’s heart has stopped.

Electrical Cardioversion Risks

Stroke Risk

People who have AFib and/or atrial flutter are at an increased risk for developing blood clots, which can lead to stroke. Having an electrical cardioversion procedure can increase a person’s risk of stroke, too. To reduce the risk, your doctor may place you on blood-thinning medications before the procedure. You will probably continue taking these medications after the procedure.

This is more likely if you over 65 years of age and have:

If your irregular heartbeat has lasted more than 48 hours and you are not already on blood-thinning medication, the doctor may run tests to make sure a clot hasn’t formed in your blood.

Sedation Risk

Sedation can pose risks for people with pre-existing conditions such as advanced lung disease or advanced heart valve disease. The cardiologist and anesthesiologist will work together to make sure sedation is safe and effective for you. Another risk related to sedation is infection, which can occur at the site where the intravenous (IV) line was placed.

Electrical Cardioversion Success Rates

Cardioversions sometimes don’t work because the cells that are creating the arrhythmia overtake the normal pacemaker cells and do not allow the heart to reset. If cardioversion doesn’t restore your normal heart rhythm, your physician may want to repeat the procedure. Before doing so, he or she may start you on a medication to improve the chances of success. 

After a cardioversion, your heart may reset but may eventually develop an arrhythmia again. If that occurs, the doctor will do another cardioversion safely. Before doing so, he or she will likely talk to you about ways to improve the chances of success.

Cardioversion is just one treatment method your cardiologist may use to treat your AFib or atrial flutter. Other options include:

Your cardiologist may also recommend repeating the electrical cardioversion to improve your symptoms.

Senior couple smiles at each other

Make an Appointment with Our Cardiologists

Referrals are welcome but not necessary when making an appointment with a cardiologist at U of U Health. To make an appointment, call 801-585-7676. Our team will verify your insurance coverage before your visit. If you have had medical tests related to your condition, we will request the results from your provider. Our goal is to make your visit as efficient and helpful as possible.