An implantable cardioverter defibrillator (ICD) is a small device implanted in the chest and delivers a low-energy electrical pulse to the heart to correct dangerous arrhythmias it detects. If this fails to restore a normal heartbeat, the ICD then switches to a high-energy pulse to defibrillate the heart. An ICD is similar to a pacemaker, but it’s able to act as both a pacemaker (low-energy pulses) and a defibrillator (high-energy pulses), while a pacemaker can only deliver low-energy pulses.
