Abstract 210: Temporal Changes in Detrended Fluctuation Analysis (DFA) of Ventricular Fibrillation From Out-of-Hospital Cardiac Arrests in an Asian Community

Abstract

Introduction: Ventricular fibrillation (VF) is the most common arrhythmia causing out-of-hospital cardiac arrest (OOHCA) and electrical defibrillation remains the mainstay of its treatment. Successful defibrillation is linked to VF morphology characteristics, and is affected by VF duration, quality of cardiopulmonary resuscitation (CPR) and emergency medical service (EMS) responsiveness. This study aimed at comparing VF morphology characteristics between two study periods in an Asian community. Method: Electrocardiographic recordings of VF signals from automated external defibrillators (AEDs) were obtained from OOHCA subjects in Taipei city, a metropolitan with 2.65 million residents in 272km 2 . Root-mean-squared (RMS) amplitude, mean amplitude, amplitude spectrum analysis (AMSA), frequency analysis, and fractal measurements including scaling exponent (SE) and DFA were calculated and compared between early (2000-2001) vs. late (2006-2007) periods. Results: A total of 137 OOHCA subjects with VF, 61 in early and 76 in late period, were included for analysis. For patients converted to normal sinus rhythm (NSR) at 10 seconds after the first shock, DFAα2 was significantly lower in the late period (0.29±0.17 vs. 0.44±0.27, p=0.047). Similarly, for those converted to nonVF at 30 seconds after the first shock, the DFAα2 was lower in the late period (0.37±0.21 vs. 0.50±0.27, p=0.012). Differences in late vs. early period were not observed among any other parameters studied. Conclusions: DFAα2, but not AMSA or other VF waveform characteristics, decreased over time. This might reflect changes in EMS responses and community quality of CPR in different study time periods.