Electrical cardioversion is a procedure that uses an electric current to stop the heart momentarily. This helps the heart have a normal rhythm when it resumes beating.

Usually a person is given a sedative before the procedure. Then a device called an external defibrillator—which consists of metal paddles or pads—is placed on the person's chest. The external defibrillator sends the electrical current to the heart. Doctors are prepared to help maintain a person's circulation during the procedure with medicines and other methods.

Cardioversion may be used to help the heart return to a normal rhythm after medicines have failed to do so. The procedure also may be done in emergency situations. For example, it may be done to correct a fast heart rhythm that is causing low blood pressure, chest pain, or heart failure.