Abstract 151: AMSA-Dependent Association Between Shock Energy and Shock Success
Purpose: Previous studies have demonstrated that quantitative analysis of ventricular fibrillation (VF) waveform has the potential to optimize the timing of defibrillation. However, the interaction between energy and the predictability of quantitative VF analysis is unknown. In the present study, we investigated the relationship between shock success and shock energy in the different amplitude spectrum area (AMSA) ranges and the possibility of using AMSA to guide the shock energy selection.
Materials and Methods: Digitized ECG recordings were analyzed from a registry data of out-of-hospital cardiac arrests. Current-based impedance compensation automated external defibrillators with an escalating defibrillation energy protocol from 120J to 150 and 200 J were used in this study. A waveform episode of 2.05 seconds (512 data points) ending at 0.5 second before each shock attempt was selected for analysis. Shock success was defined as an organized rhythm that was present for a minimum of 30 seconds, started within 60 seconds after the shock, and had a rate of 40 beats per minute or greater.
Results: A total of 1219 shocks from 536 patients with VF were analyzed. The shock success rate was increased with escalated energies when AMSA was greater than 12 mvHz (50.0% for 120J, 64.6% for 150J and 82.5% for 200J, p<0.05). When AMSA was low (<12 mvHz), escalated energies did not increase the shock success rate (9.3% for 120J, 12.4% for 150J and 10.4% for 200J, p:NS). Multivariable logistic regression demonstrated that the only independent predictor of shock success for low AMSA values was the AMSA (OR=1.494, 95% CI:1.362-1.638, p<0.001), while for high AMSA values, it was the shock energy (OR=1.011, 95% CI=1.004-1.018, p=0.003)
Conclusions: In this patient population, escalating energy protocol improved defibrillation success when AMSA was high. When AMSA was low the escalating energy protocol did not improve defibrillation success and a fixed low energy protocol may perform equally well as the escalating energy protocol. This may help to reduce myocardial damage associated with higher cumulative energy delivery. Real-time AMSA analysis during CPR could optimize not only the timing of defibrillation, but also provide robust energy selection for defibrillation.
Author Disclosures: Y. Li: None. B. Chen: None. M. He: None. G. Ristagno: None. W. Quan: Employment; Significant; Employee of ZOLL Medical Corporation. U. Herken: Employment; Significant; Employee of ZOLL Medical Corporation.
- © 2014 by American Heart Association, Inc.