Abstract 19090: Ventricular Fibrillation Waveform Analysis to Predict Defibrillation Success in Out-of-Hospital Cardiac Arrest: Can the Amplitude Spectrum Area Be Used Throughout the Entire Resuscitation?
Introduction: Characteristics of the ventricular fibrillation (VF) waveform have been studied to guide timing of defibrillation during out-of-hospital cardiac arrest (OHCA). The Amplitude Spectrum Area (AMSA) is regarded the most promising predictor of shock success, but it is unknown whether its predictive ability pertains throughout the entire course of the resuscitation. We therefore sought to investigate whether the AMSA is able to predict shock success during early (shock 1–2) and later stages of resuscitation (shocks > 2).
Methods: Paddle-ECG recordings of OHCA patients from the Nijmegen area (2008–2011) with VF as first observed rhythm were studied (n=108, 392 shocks). The AMSA was calculated from three-second chest compression free segments of VF prior to each shock. Univariate analysis and receiver operating characteristic curves were used to evaluate the association of the pre-shock AMSA with shock success (i.e. return of organized rhythm).
Results: For shock 1–2 (success 44%), the AMSA was significantly higher prior to successful compared to unsuccessful shocks. The discriminative value of the AMSA for shock success of shock 1 and 2 was 0.72 (p<0.001). The AMSA prior to shock 3–8 (success 53%) was slightly higher in successful than unsuccessful shocks, but did not reach statistical significance. Also, the discriminative value of the AMSA was lower (0.58, p=0.054) for these shocks.
Conclusion: The present analysis demonstrates that during OHCA, the predictive value of the AMSA for shock success is restricted to the early phase of resuscitation. This challenges the concept of continuous ECG waveform analysis for guidance of the entire resuscitation. As the shock success rate remains high in the later phases of the resuscitation, further research investigating predictive factors of late shock success seems warranted.
Author Disclosures: J. Nas: None. J.L. Bonnes: None. R. Starreveld: None. J. Thannhauser: None. G. Meinsma: None. P. van Grunsven: None. J.L. Smeets: None. M. de Boer: Consultant/Advisory Board; Modest; Prof De Boer is a member of the European advisory board on interventional cardiology of Medtronic. M.A. Brouwer: None.
- © 2016 by American Heart Association, Inc.