Frequency spectrum of the intracardiac and body surface ECG during ventricular fibrillation - a computer model study

Recent findings indicate that stable organized centers of rapid activity (mother rotors) are the maintaining mechanism of ventricular fibrillation (VF). A computer model study was performed for understanding how intracardiac cellular activity is reflected at the body surface. The model contained a driving region of fast periodic activity (22 Hz). On the intracardiac layer the dominant frequency (DF) map revealed a constant DF of 22 Hz in the region of the mother rotor. A sharp drop of frequency (2 Hz - 12 Hz) occurred in the surrounding tissue of chaotic fibrillatory conduction. No organized pattern was observable on the body surface and the DF was reduced to 4.6 Hz -8.5 Hz. It was shown that wave propagation transforms the spatial low pass filtering of the thorax into a temporal low pass in the far field. It hampers the observation of intracardiac organization from the body surface. No RC low pass was included in the model.