Ventricular fibrillation frequency analysis: signatures of modes of death in a canine sudden cardiac death model

A sudden cardiac death (SCD) animal model of acute ischemia on top of an existing infarct was used to study SCD. An 8-channel radiotelemetry system was implanted for continuous monitoring of electrograms from 14 animals; 7 died spontaneously 24 to 72 hours after the initial surgery. In 2 of the spontaneous deaths bradycardia preceded ventricular fibrillation (VF). In the other 5 animals VF occurred following either sinus rhythm (n=2) or ectopic episodes (n=3). In all 7 SCD animals the spectral content of the VF over time was analyzed. The tachycardia and bradycardia deaths were completely separable by the centroid of their spectra. The various modes of death exhibited different spectral signatures over the first 30 seconds of VF and showed differing degrees of organization. The time-frequency analysis of the first 30 seconds of VF permitted differentiation between 3 modes of SCD