Indications for implantable cardioverter defibrillator (ICD) therapy. Study Group on Guidelines on ICDs of the Working Group on Arrhythmias and the Working Group on Cardiac Pacing of the European Society of Cardiology

Last year was the 20th anniversary of the first defibrillator implantation in a human being. Since then, the number of new defibrillator implants has gradually increased following an exponential curve. In 1998, nearly 50 000 new ICD implants were carried out worldwide. This tremendous increase was due to technological improvements in the device and the effectiveness of ICD therapy. Technological improvements in devices and leads included a gradual reduction in the size of the device, the introduction of the endocardial approach in 1988, the biphasic waveform and antitachycardia pacing in 1991, pectoral implantation in 1995, inclusion of DDD pacing in 1996 and finally, inclusion of DDDR and also atrial defibrillation in 1998. Efficacy assessment started with observational studies. In 1985, FDA approval for ICD implantation was obtained. Results of prospective randomized studies, which assessed the effectiveness of ICDs, were obtained in the late 1990s. The first reported trial was essentially an analysis of cost-effectiveness, which compared ICD implantation as first-choice therapy vs conventional strategy starting with antiarrhythmic drugs in postinfarct sudden death survivors. If drugs failed, the patient was treated with endocardial resection or a late defibrillator implant. The cost-effectiveness ratio, defined as costs per day of life, was significantly in favour of early ICD implantation. However, because the number of patients was relatively small, total mortality showed only a trend in favour of early ICD implantation.