Changes in the surface ECG frequency spectrum during the onset of ventricular fibrillation

Forty five recordings of ventricular fibrillation (VF) are analyzed and the changes in frequency spectrum accompanying the transition to VF are investigated. A rapid increase in signal power was observed in the 4-8-Hz band at the start of VF, rising to 75% in an average of 9.0 s for self-terminating VF (N=5), 5.8 s for recordings where VF was preceded by ventricular tachycardia (VT) (N=7), and 4.6 s for the remainder of VF records. (N=33). These findings have implications for VF detection. It is concluded that, during the onset of VF, a high proportion of signal power is concentrated in a relatively small frequency band; the maximum contribution to this band peaks early after the onset of VF