INDICATION AND CONTRAINDICATION OF THE TR EATMENT WITH IMPLANTABLE CARDIOVERTERS DEFIBRILLATORS/

Despite all advances in the diagnostic and therapy of cardiovascular d iseases the mortality from malignant ventricular tachyarrhythmias is s till a major health problem. In addition to established therapeutic st rategies in the prevention of sudden cardiac death such as antiarrhyth mic drug treatment, catheter ablation or antiarrhythmic surgery the im plantable cardioverter/defibrillator was introduced to clinical practi ce in 1980. The number of 50,000 overall implants reflects the current clinical status of the therapy with implantable cardioverters/defibri llators. Significant technical improvements in the defibrillator thera py may contribute to an increase in therapy acceptance. These advances include the introduction of nonthoracotomy lead systems, enhanced def ibrillation efficacy, full programmable devices providing tiered elect rical therapy, improved diagnostic Holter functions and enhanced arrhy thmia detection algorithms. The major present goals of defibrillator t herapy are, detection and termination of malignant ventricular tachyar rhythmias, reduction of sudden cardiac death, reduction in patient's m ortality and improvement in quality of life. The efficacy and safety o f defibrillator therapy to prevent sudden arrhythmic death has been pr oven in several large clinical investigations. The annual sudden cardi ac death mortality is <2% even in high-risk patient populations. Compa red to sudden cardiac death rate there is a much higher rate of overal l cardiac mortality because a defibrillator is not able to prevent non arrhythmic cardiovascular deaths. There is a clinical impression that cardiovascular mortality is lower in patients treated with an implanta ble cardioverter/defibrillator compared to patients treated with other therapies. However there are no results from controlled studies provi ding scientific evidence that defibrillator therapy can reduce overall cardiovascular mortality. The improvement of quality of life in patie nts with an implanted cardioverter/defibrillator is strongly associate d with technical device improvements, such as high specificity in arrh ythmia detection and tiered antitachycardia therapy. Currently the mai n role of defibrillator therapy is in patients with aborted sudden car diac death and in patients presenting drug-refractory hypotensive vent ricular tachyarrhythmias. Future indications in defibrillator therapy would in influenced by the results of ongoing clinical trials and by t he technological advances in device and lead technology. The presented clinical guidelines for the use of implantable cardioverters/defibril lators are focused on the present available scientific results and on the present technological status of device therapy.