title: Predicting the success of defibrillation by electrocardiographic analysis.
abstract: BACKGROUND
  We investigated an electrocardiographic signal analysis technique for predicting whether an electrical shock would reverse ventricular fibrillation (VF) in an effort to minimize the damaging effects of repetitive shocks during CPR.
  
  
  RESULTS
  An established model of CPR was utilized. VF was electrically induced in anesthetized 40 kg domestic pigs. Defibrillation was attempted after either 4 or 7 min of untreated VF. Failing to reverse VF, a 1 min interval of precordial compression and mechanical ventilation preceded each subsequent defibrillation attempt. The amplitude frequency spectrum of digitally filtered VF wavelets was computed with Fourier analysis during uninterrupted precordial compression from conventional right infraclavicular and left apical electrodes. Of a total of 34 electrical defibrillation attempts, 24 animals were restored to spontaneous circulation (ROSC). An amplitude spectrum analysis (AMSA) value of 21 mV Hz had a negative predictive value of 0.96 and a positive predictive value of 0.78.
  
  
  CONCLUSIONS
  AMSA predicted when an electrical shock failed to restore spontaneous circulation during CPR with a high negative predictive value. This method potentially fulfills the need for minimizing ineffective defibrillation attempts and their attendant adverse effects on the myocardium.
authors.affiliation: The Institute of Critical Care Medicine, 1695 North Sunrise Way, Building #3, Palm Springs, CA 92262-5309, USA.
authors.forename: Heitor P
authors.initials: HP
authors.lastname: Povoas
authors.forename: Max Harry
authors.initials: MH
authors.lastname: Weil
authors.forename: Wanchun
authors.initials: W
authors.lastname: Tang
authors.forename: Joe
authors.initials: J
authors.lastname: Bisera
authors.forename: Kada
authors.initials: K
authors.lastname: Klouche
authors.forename: Ann
authors.initials: A
authors.lastname: Barbatsis
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D016887:Cardiopulmonary Resuscitation; D004195:Disease Models, Animal; D004554:Electric Countershock; D004562:Electrocardiography; D011237:Predictive Value of Tests; D011379:Prognosis; D013552:Swine; D014693:Ventricular Fibrillation / Q000503:physiopathology / Q000628:therapy*