How is cardioversion or defibrillation done?
Internal cardioversion is delivered by an implanted device. If you have an implantable cardioverter defibrillator (ICD), it can sense a fast arrhythmia. The ICD then delivers a low-energy shock. The shock can stop the arrhythmias and restore a normal heartbeat. External cardioversion is delivered by an external device. This is a scheduled treatment often used to treat fast arrhythmias in the heart’s upper chambers (atria).