[The implantable cardioverter/defibrillator (ICD). Developments up to the present time and future perspectives]

The implantable cardioverter/defibrillator is gaining increasing significance in the therapy of life-threatening ventricular arrhythmias. Independently, the team of Mirowski and the team of Schuder started to develop experimental automatic implantable defibrillators in the seventies. In 1980, the first human implant of an automatic defibrillator was done by Levi Watkins together with the team of Mirowski in Baltimore, USA. Since 1989 implantable cardioverter/defibrillators exhibit multiple functions among which are high energy defibrillation therapy, low energy cardioversion, antitachycardia pacing, permanent and post therapy antibradycardia pacing, diagnostic counters, and device status parameters. This offers a markedly improved technical device to the patients. Evaluation of the patient's diagnostic counters provide a detailed overview about the patient's arrhythmia history and information for optimizing antitachycardia pacing therapy and additional antiarrhythmic drug therapy. The availability of non-thoractomy transvenous lead systems and biphasic shock forms allows the insertion of the device without open chest surgery and even without subcutaneous leads resulting in low mortality rates and an exclusively transvenous system. Single-lead unipolar devices are currently investigated in clinical trials. Future development of atrial sensing lead systems may further reduce inappropriate shock therapy triggered by sinus tachycardia or atrial tachyarrhythmias, e.g. atrial fibrillation, and may be used for dual chamber stimulation. Hemodynamic sensors for determining the severity of the arrhythmia are currently under experimental evaluation. Possible prognostic indications of ICD therapy in patients without a history of malignant arrhythmias are currently studied in several prospective trials. All new directions hold promise to expand and improve the use of ICDs in patients at risk for sudden cardiac death.