Electrical cardioversion is a procedure that uses an electric current to stop the heart momentarily. This helps the heart attain 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, such as to correct a fast heart rhythm that is causing low blood pressure, chest pain, or heart failure.
WebMD Medical Reference from Healthwise