A cardioversion is performed to treat a heart rhythm disorder, which may affect the heart’s ability to pump blood effectively.

The goal of cardioversion is to disrupt the abnormal electrical circuit(s) in the heart and to restore a normal heart beat. The synchronized electrical impulse causes all the heart cells to contract simultaneously, thereby interrupting and terminating the abnormal electrical rhythm without damaging the heart.

During cardioversion pads are placed on the chest and connected to an external defibrillator by a cable. The defibrillator allows the medical team to continuously monitor the heart rhythm and to deliver the electrical impulse. It is often successful at restoring a normal heart rhythm, although heart rhythm disorders can reoccur.

This is usually a scheduled procedure that is performed on an outpatient basis. It is often used to treat people who have atrial fibrillation.

Cardioversion is different from an automatic external defibrillator (AED) that is used in emergencies outside of the hospital where a person suddenly collapses.

Occasionally, a cardioversion is accomplished by using only medications (anti-arrhythmic drugs) to restore the heart's rhythm.