Automated implantable cardioverter defibrillator

Author(s): Luca Arioli

Sudden cardiac death (SCD) is defined as death from an abrupt pulseless condition due to a cardiac cause in a previously apparently healthy individual. More than 300,000 patients die suddenly each year in the US. Less than 20% of them meet the clinical criteria for the implantation of an automatic implantable cardioverter defibrillator (AICD) and, among these patients, only 20% will be saved by a shock from the AICD. Statistically speaking, we need to implant 20 patients with an AICD in order to save one’s life. It is therefore clear that the major unsolved question in cardiology and electrophysiology in particular, is why ventricular tachycardia (VT) or ventricular fibrillation (VF) occur in the first place. There is more to it than just a reduced ejection fraction or a well-timed ventricular extrasystole. The origin of fatal arrhythmias could be explained by a ventricular extrasystole which encounters a peculiar dynamic substrate. It is shown that the basis for the onset of VT or VF lies in the action potential duration dispersion which constitutes an arrhythmogenic spatially discordant repolarization ground regardless of the presence of ascar