Analysing ventricular fibrillation ECG-signals and predicting defibrillation success during cardiopulmonary resuscitation employing N(α)-histograms

Mean fibrillation frequency may predict defibrillation success during cardiopulmonary resuscitation (CPR). N(alpha)-histogram analysis should be investigated as an alternative. After 4 min of cardiac arrest, and 3 versus 8 min of CPR, 25 pigs received either vasopressin or epinephrine (0.4, 0.4, and 0.8 U/kg vasopressin versus 45, 45, and 200 mug/kg epinephrine) every 5 min with defibrillation at 22 min. Before defibrillation, the N(alpha)-parameter histogramstart/histogramwidth and the mean fibrillation frequency in resuscitated versus non-resuscitated pigs were 2.9 +/- 0.4 versus 1.7 +/- 0.5 (P = 0.0000005); and 9.5 +/- 1.7 versus 6.9 +/- 0.7 (P = 0.0003). During the last minute prior to defibrillation, histogramstart/histogramwidth of greater than or equal to 2.3 versus mean fibrillation frequency ! 8 Hz predicted successful defibrillation with subsequent return of a spontaneous circulation for more than 60 min with sensitivity, specificity, positive predictive value and negative predictive value of 94 versus 82%, 96 versus 89%, 98 versus 93% and 90 versus 74%, respectively. We conclude, that N(alpha)-analysis was superior to mean fibrillation frequency analysis during CPR in predicting defibrillation success, and distinction between vasopressin versus epinephrine effects. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.