Biophysics. Vol. 48, No 2, pp. 297-305, 2003
AUTOWAVE MECHANISMS OF ELECTROCARDIOGRAPHIC VARIABILITY DURING HIGH-FREQUENCY ARRHYTHMIAS: A STUDY BY MATHEMATICAL MODELING
*)Institute for Theoretical & Experimental Biophysics , Russian Academy of Sciences,
Pushchino, Moscow Region, 142290 Russia,
**)The University of Utrecht
The high-frequency cardiac arrhythmias represent the large danger, as they quite often lead to sudden cardiac death. Such high-frequency arrhythmias are frequently produced by rotating autowaves. In the given work, dynamics of a rotating three-dimensional excitation scroll wave, and influence of this dynamics on variability of the model electrocardiograms (ECGs) are simulated with the use of Aliev - Panfilov model  for both homogeneous, and heterogeneous excitable media. The model ECGs are obtained as a result of summing up local membrane potentials, while ECG variability is estimated numerically through the normalized variability analysis . In the homogeneous medium, the stability of the scroll wave to its filament perturbations is shown to be depended both on excitability of the medium and tension of the filament, while in the heterogeneous medium, the scroll is shown to be unstable. It is shown, that the scroll wave dynamics affects essentially the variability of the model ECGs, and the ECG variability increases as the excitation threshold value grows. It is revealed that the ECGs in heterogeneous media appear at some parameters more variable than in homogeneous media..
Keywords: autowaves, ECG variability, high-frequency arrhythmias, mathematical modeling.