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Automatic Implantable Cardioverter - Defibrillator



   The AICD is an implantable electronic device designed to monitor the heart rhythm and to detect and treat ventricular tachycardia and ventricular fibrillation. When the AICD senses ventricular tachycardia or ventricular fibrillation, it delivers an internal shock to the heart to convert ventricualr the abnormal rhythm. If you are awake, you may find this shock uncomfortable for a short time-similar to a hard thump on the chest. You may not feel the shock at all if you have nearly passed out. However, you may have an uncomfortable feeling in your chest as you wake up. If the first shock does not stop the abnormal rhythm, the AICD can give three to four additional shocks. After the abnormal rhythm stops, the AICD will reset itself automatically and prepare to shock again if the abnormal rhythm reappears. As long as your heart rhythm remains normal the AICD wire monitor your heart rhythm and wait until a shock is needed.

DC - Cardioversion

DC - Cardioversion
Ventricular fibrillation results in very rapid fibrillatory waves which are irregular with varying contours and amplitudes. This EKG shows cardiac arrest due to ventricular fibrillation and the resuscitation with emergency DC - cardioversion (arrow), resulting in restoration of normal sinus rhythm.

   The AICD includes a pulse generator and leads. The Pulse generator is about the size and shape of a deck of cards and weighs about 1/2 pound. The pulse generate implanted in your abdomen just underneath the skin. It made of a special kind of metal that normally does not react to body tissue. The pulse generator is connected one or more leads that are placed in and near your heart The lead system sends electrical signals from your heart the pulse generator, which continuously monitors your heart rhythm. When the pulse generator receives signals from the lead system that your heart rhythm is ventricle tachycardia or ventricular fibrillation, it will send a shock through the lead system to your heart to stop the abnormal rhythm.

   Automatic Implantable Cardioverter-Defibrillator (AICD) is a device intended to convert life threatening rhythms of the heart which may cause sudden cardiac death also known as cardiac arrest, to a sinus (normal) rhythm. Sudden cardiac death is the cause of 50% of all cardiac related deaths. When a life threatening rapid or slow rhythm is sensed by the device, an electric discharge of about 25 to 30 joules is sent through a pair of electrodes; one is sent to the pacemaker and the other to the apex of the right ventricle. Many of these devices hold a memory so the rhythm which induced the AICD may be recorded for later analysis.