The apparent repetition frequency of ventricular fibrillation

Abstract

The auto power spectra of the recorded electrical activity of the heart during ventricular fibrillation (VF) strongly suggests that during VF action potentials occur at very regular time intervals. These intervals, however, are approximately twice as short as the shortest RR-intervals encountered in e.g. sinusrhythm during heavy exercise or ventricular tachycardia. A mathematical model of 1000 interconnected "cells" showed a persistent repetitive activity, with the rate of the modeL as a whole two times higher than the individuaL components. An analysis of the individual states of all 1000 "cells" indicated that approximateLy 30% of the "cells" were activated synchroneously and regularly, another 30% behaved in the same way, but with a shift of half a period compared to the first group, thus causing the two times higher frequency of the whole. Data from literature and our own bservations disclose that fibrillation as a sequel to tachycardia may indeed contain a repetition frequency approximately twice the frequency of the tachycardia.