Amplitude Spectrum Area to Predict the success of Defibrillation

Home Resuscitation Chapter Amplitude Spectrum Area to Predict the Success of Defibrillation Giuseppe Ristagno & Francesca Fumagalli Chapter First Online: 19 November 2013 2118 Accesses Abstract In victims of cardiac arrest due to ventricular fibrillation (VF) or pulseless ventricular tachycardia (VT), cardiopulmonary resuscitation (CPR) in conjunction with electrical defibrillation (DF) has the potential of re-establishing the return of spontaneous circulation (ROSC). During cardiac arrest, coronary blood flow ceases, accounting for a progressive and severe energy imbalance. Intra-myocardial hypercarbic acidosis is associated with depletion of high energy phosphates and correspondingly severe global myocardial ischemia [1, 2]. The ischemic left ventricle becomes contracted ushering in the stone heart [3, 4]. After onset of contracture, the probability of successful DF is remote. Early CPR, accounting for a partial restoration of coronary perfusion pressure (CPP) and myocardial blood flow, delays onset of ischemic myocardial injury and facilitates defibrillation [5]. Accordingly, VF is characterized by three time-sensitive electrophysiological phases: The electrical phase of 0–4 min; the circulatory phase of 4–10 min; and the metabolic phase of >10 min. During the electrical phase, immediate DF is likely to be successful. As ischemia progresses, the success of attempted DF diminishes without CPR.