Why it's done

Cardioversion can correct a heartbeat that's too fast (tachycardia) or irregular (fibrillation). Cardioversion is usually done to treat people who have atrial fibrillation or atrial flutter. These conditions occur when the electrical signals that normally make your heart beat at a regular rate don't travel properly through the upper chambers of your heart.

Cardioversion is usually scheduled in advance but is sometimes done in emergency situations.

Cardioversion is usually done with electric shocks, which are given through electrodes attached to your chest while you're sedated. Electric cardioversion allows your doctor to instantly see if the procedure has restored a normal heartbeat.

Electric cardioversion takes less time than cardioversion done solely with medications. If your doctor recommends cardioversion with medications to restore your heart's rhythm, you won't receive electric shocks to your heart.

Cardioversion is different from defibrillation, an emergency procedure that's performed when your heart stops or quivers uselessly. Defibrillation delivers more powerful shocks to the heart to correct its rhythm.