Implantable Defibrillator An automated implantable cardioverter defibrillator (AICD) or implantable cardioverter-defibrillator is a device which is implantable inside the body and it is able to perform defibrillation, cardioversion, and pacing of the heart (in modern versions). Therefore, the device is capable of correcting the most life-threatening cardiac arrhythmias. The ICD is a prophylactic therapy and the first-line treatment for patients at risk with sudden cardiac death due to the ventricular tachycardia and ventricular fibrillation. Currently, the devices can be programmed in such a way to detect abnormal heart rhythms and it will deliver therapy via programmable anti-tachycardia pacing in addition to the high-energy and low-energy shocks. “AICD” was given a trademark by the Boston Scientific Corporation, so more of the generic “ICD” is preferred terminology. A single chamber of ICD with its right ventricular lead that is connected to header: note, it starts from the end of the lead, the tip and also adjacent first ring is used to sense the cardiac electrical activity and will stimulate the right ventricle and the coil and the two rings are for atrial sensing. Currently, the device batteries last up to 6-10 years with the advanced technology.