Sudden cardiac death, implanted defibrillation, and clinical electrophysiology

A mere 25 years ago, the technique of external defibrillation became the starting point for the development of clinical electrophysiology by permitting routine use of endocavitary programmed electrical stimulation of the heart without undue risk. Major advances in knowledge of clinical arrhythmias and the understanding of their mechanisms were, thus, permitted. Mirowski's implanted defibrillator also constituted a major breakthrough therapeutically; unfortunately, however, some 10 years later, it has not yet induced similarly hoped for consequences in terms of progressing knowledge concerning lethal arrhythmias, largely due to the absence of Holter functions in the implanted devices. As a result of this, in our opinion, better established therapeutic indications are still needed. The reasons for the present situation, we believe, may be partly technical but are conceptual as well. The key point is that even the clear demonstration of the great practical efficacy of a therapeutic tool does not exempt us from the obligation of determining the mechanisms of this effect.