Cardioversion switches one cardiac rhythm or electrical pattern to another, almost always from an abnormal to a normal one. This conversion can be accomplished by using medications or by electrical cardioversion using a defibrillator, which delivers a low-energy shock at the same time as the heartbeat, to restore a normal heart rhythm.

• Direct-current cardioversion (DCCV), or electric cardioversion, uses electric shock to momentarily stop — and then restart — the heart’s activity. This shock is delivered via paddles or patches on the chest while patients are sedated.
• Drug-induced cardioversion uses medications known as antiarrhythmics to help correct a heartbeat. These medications may be delivered orally (by mouth) or intravenously (by vein).