Implantable Cardioverter Defibrillator

Wednesday, April 20, 2011

An implantable cardioverter defibrillator (ICD) is a small battery-powered device which is implanted in the patient's chest, when he is at risk of sudden cardiac arrest due to ventricular fibrillation. When an implantable cardioverter defibrillator detects ventricular fibrillation or tachycardia, it gives the heart a shock of electricity to restore the normal rhythm. The ability of the device to revert ventricular fibrillation has been extended to include both atrial and ventricular arrhythmias. An implantable cardioverter defibrillator has wires with electrodes on the ends that connect to your heart chambers. The ICD will continually monitor your heart rhythm. If the device detects an irregular rhythm in your ventricles, it will use low-energy electrical pulses to restore a normal rhythm.

An implantable cardioverter defibrillator constantly monitors the rate and rhythm of the heart and can deliver therapies, by way of an electrical shock, when the electrical manifestations of the heart activity exceeds the preset number. More modern devices can distinguish between ventricular fibrillation and ventricular tachycardia, and may try to pace the heart faster than its intrinsic rate in the case of ventricular tachycardia, to try to break the tachycardia before it progresses to ventricular fibrillation. This is known as fast-pacing, overdrive pacing, or anti-tachycardia pacing (ATP). ATP is only effective if the underlying rhythm is ventricular tachycardia, and is never effective if the rhythm is ventricular fibrillation.

Implantable Cardioverter Defibrillator