Electrical heterogeneity in ventricular arrhytmia – from cell to tissue
Alexander V.Panfilov*
Department of Theoretical Biology, Utrecht University, Utrecht, The Netherlands
In my talk I will first describe development of Utrecht anatomical model of the human heart. The model integrates our knowledge about electrophysiology of the human heart from a single cell to the whole organ and allows us to study mechanisms of cardiac arrhythmias in the human heart, where experimental interventions are very limited.
Next, I will present results of our study which aim was to investigate the effect of heterogeneous restitution properties in a 3D model of the ventricles. For these studies we used data from a recent clinical study by Nash et al. who has provided global epicardial restitution properties in 14 cardiac patients at 256 locations over the entire ventricular epicardial surface. For that studies we extended our human heart model by mapping the clinically observed epicardial restitution data to our anatomical 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 lead to a greater number of filaments and a broader distribution of excitation periods, thereby increasing the complexity and dynamics of VF.
We also show that in the case of substantial heterogeneity mother rotor VF can occur in the human heart. We compare the organization of these two different types of VF (the mother rotor and multiple wavelet) in terms of filament numbers and excitation periods.
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