title: Clinical experience with the automatic implantable defibrillator.
abstract: Since February 1980, worldwide, over 400 survivors of sudden arrhythmic death have been treated with the automatic implantable defibrillator. Recently, the device has been further improved; it is now a cardioverter-defibrillator (AICD), able to treat ventricular tachycardias as well as ventricular fibrillation. There are two defibrillating electrodes which are used also for waveform analysis; one is located in the superior vena cava, the other is placed over the cardia apex. A third bipolar right ventricular electrode serves for rate counting and R-wave synchronization. When ventricular fibrillation occurs, a 25-joule pulse is delivered; when ventricular tachycardia faster than a preset rate is detected, the discharge is R-wave synchronized. Special batteries can deliver over 100 shocks or provide a three-year monitoring life. Implantation of the device can be achieved through a thoracotomy or by a subxiphoid or a subcostal approach. Thus far, the longest follow-up period has been 58 months. Actuarial analysis shows the one-year mortality attributed to arrhythmias reduced to less than 2%. Thus, the automatic cardioverter-defibrillator can reliably identify and correct potentially lethal ventricular tachyarrhythmias, leading to a substantial increase in survival in properly selected high-risk patients.
mesh_terms: D003645:Death, Sudden / Q000517:prevention & control; D004554:Electric Countershock / Q000295:instrumentation*; D005069:Evaluation Studies as Topic; D006801:Humans; D019736:Prostheses and Implants; D013610:Tachycardia / Q000628:therapy*; D014693:Ventricular Fibrillation / Q000628:therapy*