Prognostic Value of Ventricular Fibrillation Spectral Analysis in Sudden Cardiac Death

Up to 5-s long ventricular fibrillation segments will be extracted after segmentation and signal codification from artifact-free tracings. Signals will be band-pass filtered between 1.5 and 40 Hz. Averaged power spectral density will be obtained at each frequency using the non-parametric Welch method for using fast Fourier transform and normalized to the peak power in the 1.5-10 Hz band for each patient. Dominant frequency, HL-PSDR (the relative power between high and low frequency bands (cut-off: 3.9 Hz)) and HL-pKR ( relative number of spectral peaks above and below the 3.9 Hz threshold with power above 40% the frequency with the highest power), along with the number of DC shocks before ROSC, will be the variables used to obtain a model-derived risk score for outcome prediction.