THE IMPLANTABLE CARDIOVERTER DEFIBRILLATO R (ICD) - DEVELOPMENT TO PRESENT AND PERSPECTIVES FOR THE FUTURE/

The implantable cardioverter/defibrillator is gaining increasing signi ficance in the therapy of life-threatening ventricular arrhythmias. In dependently, the team of Mirowski and the team of Schuder started to d evelop experimental automatic implantable defibrillators in the sevent ies. In 1980, the first human implant of an automatic defibrillator wa s done by Levi Watkins together with the team of Mirowski in Baltimore , USA. Since 1989 implantable cardioverter/defibrillators exhibit mult iple functions among which are high energy defibrillation therapy, low energy cardioversion, antitachycardia pacing, permanent and post ther apy antibradycardia pacing, diagnostic counters, and device status par ameters. This offers a markedly improved technical device to the patie nts. Evaluation of the patient's diagnostic counters provide a detaile d overview about the patient's arrhythmia history and information for optimizing antitachycardia pacing therapy and additional antiarrhythmi c drug therapy. The availability of non-thoracotomy transvenous lead s ystems and biphasic shock forms allows the insertion of the device wit hout open chest surgery and even without subcutaneous leads resulting in low mortality rates and an exclusively transvenous system. Single-l ead unipolar devices are currently investigated in clinical trials. Fu ture development of atrial sensing lead systems may further reduce ina ppropriate shock therapy triggered by sinus tachycardia or atrial tach yarrhythmias, e.g. atrial fibrillation, and may be used for dual chamb er stimulation. Hemodynamic sensors for determining the severity of th e arrhythmia are currently under experimental evaluation. Possible pro gnostic indications of ICD therapy in patients without a history of ma lignant arrhythmias are currently studied in several prospective trial s. All new directions hold promise to expand and improve the use of IC Ds in patients at risk for sudden cardiac death.