Organized Structure of Ventricular Fibrillation during Prolonged Heart Perfusion in Dogs

The aim of the study was to identify the organized ventricular fibrillation (VF) activity in the dog heart and characterize its quantitative parameters during prolonged heart perfusion.

A total of four experiments on isolated dog's hearts perfused with the blood of a supporting dog were performed. Episodes of VF were recorded in the form of an electrogram followed by a spectral analysis by the fast Fourier transform in the range of 0.5-15 Hz. The frequency, spectral power (amplitude), and relative weight (%) of the 1^st, 2^nd, and 3^rd highest amplitude oscillations were determined (frequency - mode; amplitude, relative weight - M±SEM; n=120).

In the perfused dog heart, VF was characterized by an organized activity, as evidenced by the dominant structure of the oscillation frequencies. Oscillations with a frequency of 9-10 Hz (occurring in 1/10 of the 0.5-15 Hz range) represent 42-44% of the spectral power and dominate the structure of the oscillation frequencies. The frequency and spectral power of the dominating oscillations proved to be stable thus indicating that under perfusion, VF did not cause disturbances in the heart organized activity.

Our experimentation with isolated perfused hearts revealed the patterns of VF that could not be revealed in situ under conditions complicated by nerve factors and ischemia in VF. The results of the work are protected with a patent which is applicable for VF diagnosis in implantable defibrillators.