Cardioversion is the term used to describe the return of the heart to a normal rhythm.
Cardioversion is most commonly performed in symptomatic individuals with fast, or irregular (e.g. atrial fibrillation), heart beats. Cardioversion generally can be accomplished either through the use of medication or electrical current. A standard approach, following patient sedation, involves delivering an electrical current to the heart through large stickers/pads attached to the chest wall.
For more detailed information about the procedure, ask your physician.