Zusammenfassung
The onset of ventricular fibrillation (VF) has been associated with
steep action potential duration restitution in both clinical and
computational studies. Recently, detailed clinical restitution properties
in cardiac patients were reported showing a substantial degree of
heterogeneity in restitution slopes at the epicardium of the ventricles.
The aim of the present study was to investigate the effect of heterogeneous
restitution properties in a three-dimensional model of the ventricles
using these clinically measured restitution data. We used a realistic
model of the human ventricles, including detailed descriptions of
cell electrophysiology, ventricular anatomy, and fiber direction
anisotropy. We extended this model by mapping the clinically observed
epicardial restitution data to our anatomic representation using
a diffusion-based algorithm. Restitution properties were then fitted
by regionally varying parameters of the electrophysiological model.
We studied the effects of restitution heterogeneity on the organization
of VF by analyzing filaments and the distributions of excitation
periods. We found that the number of filaments and the excitation
periods were both dependent on the extent of heterogeneity. An increased
level of heterogeneity leads to a greater number of filaments and
a broader distribution of excitation periods, thereby increasing
the complexity and dynamics of VF. Restitution heterogeneity may
play an important role in providing a substrate for cardiac arrhythmias.
Nutzer