Abstract 2017: Prediction Of Successful Defibrillation In Human Victims Of Out Of Hospital Cardiac Arrest
Background. We sought to examine the efficacy of an electrocardiographic parameter, “amplitude spectrum area” (AMSA), for predicting the likelihood of whether an electrical shock would restore a perfusing rhythm during cardiopulmonary resuscitation in out-of-hospital cardiac arrest patients. We hypothesized that a threshold value of AMSA could be identified that would be applicable to the resuscitation of human victims of cardiac arrest.
Methods. Analysis was performed on a database of electrocardiographic records, representing lead 2 equivalent recordings from automated external defibrillators including 210 defibrillation attempts from 90 victims of out-of-hospital cardiac arrest. A 4.1 second interval of ventricular fibrillation or ventricular tachycardia, recorded immediately preceding the delivery of the shock, was analyzed using the AMSA algorithm. AMSA represents a numerical value based on the sum of the magnitude of the weighted frequency spectrum between 2 and 48 Hz.
Results. AMSA values were significantly greater in correspondence to successful defibrillation, with restoration of a perfusing rhythm, compared to unsuccessful defibrillation (p < 0.0001, Table⇓). An AMSA value of 12 mV-Hz was able to predict the success of each defibrillation attempt with a sensitivity of 0.91 and a specificity of 0.97.
Conclusion. AMSA analysis represents a clinically applicable method, which provides a real-time prediction of the success of defibrillation attempts. AMSA analysis is not invalidated by artifacts produced by chest compressions and thereby it can be performed during CPR. AMSA will also minimize the delivery of futile and detrimental electrical shocks.