Illustration of<unk>  <unk>  An<unk>  <unk>  or automated<unk>  (AICD) is a device<unk>  inside the body, able to perform defibrillation, and depending on the type, cardioversion and pacing of the heart. The<unk>  is the first-line treatment and prophylactic therapy for patients at risk for sudden cardiac death due to ventricular fibrillation and ventricular tachycardia. "AICD" was trademarked by the Boston Scientific corporation, so the more generic "ICD" is preferred terminology. A single chamber<unk>  with its right ventricular lead connected into the header; note, starting from the end of the lead, the tip and adjacent first ring, used to sense the cardiac electrical activity and stimulate the right ventricle, the coil and the two rings for atrial sensing. Current device batteries last about six to ten years; with advances in technology (batteries with more capacity or potentially rechargeable batteries) it may be possible to increase this well past ten years. The lead (the electrical cable connecting the device to the heart) has a much longer average longevity but can incur various types of malfunction, specifically insulation failure or fracture of the conductor, and require replacement. A normal chest X-ray after placement of an<unk> , showing the<unk>  generator in the upper left chest and the<unk>  lead in the right ventricle of the heart. Note the 2 opaque coils along the<unk>  lead. The process of implantation of an<unk>  system is similar to implantation of a pacemaker. In fact,<unk> s are composed of an<unk>  generator and of wires. The first component or generator contains a computer chip or circuitry with RAM (memory), programmable software, a capacitor and a battery; this is implanted typically under the skin in the left upper chest. The second part of the system is an electrode wire or wires that, similar to pacemakers, are connected to the generator and passed through a vein to the right chambers of the heart. The lead usually lodges in the apex or septum of the right ventricle. Just like pacemakers,<unk> s can have a single wire or lead in the heart (in the right ventricle, single chamber<unk> , two leads (in the right atrium and right ventricle, dual chamber<unk>  or three leads (biventricular<unk> , one in the right atrium, one in the right ventricle and one on the outer wall of the left ventricle). The difference between pacemakers and<unk> s is that pacemakers are also available as temporary units and are generally designed to correct slow heart rates, i.e. bradycardia, while<unk> s are often permanent safeguards against sudden life-threatening arrhythmias. S-ICD lead and generator position Recent developments include the subcutaneous<unk>  (S-ICD) which is placed entirely under the skin, leaving the vessels and heart untouched. '
Implantable cardioverter-defibrillator
Transvenous pacing
Transcutaneous pacing
Pericardial window
Cardioversion
Cardiac pacemaker
Defibrillation
Automated external defibrillator