Filters

2014 - 201912020 - 20211

More filters

2019 - 201912020 - 20221
Reset filters

Settings

Type: Report × Subject: Nonlinear dynamics ×

Search Results

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Cardiac contraction induces discordant alternans and localized block
    (Berlin : Weierstraß-Institut für Angewandte Analysis und Stochastik, 2014) Radszuweit, Markus; Alvarez-Lacalle, Enrique; Bär, Markus; Echebarria, Blas
    In this paper we use a simplified model of cardiac excitation-contraction coupling to study the effect of tissue deformation on the dynamics of alternans, i.e. alternations in the duration of the cardiac action potential, that occur at fast pacing rates and are known to be pro-arrhythmic. We show that small stretch-activated currents can produce large effects and cause a transition from in-phase to off-phase alternations (i.e. from concordant to discordant alternans) and to conduction blocks. We demonstrate numerically and analytically that this effect is the result of a generic change in the slope of the conduction velocity restitution curve due to electromechanical coupling. Thus, excitation-contraction coupling can potentially play a relevant role in the transition to reentry and fibrillation.
  • Thumbnail Image
    Item
    Analysis and simulation of a modified cardiac cell model gives accurate predictions of the dynamics of the original one
    (Berlin : Weierstraß-Institut für Angewandte Analysis und Stochastik, 2021) Erhardt, André H.; Solem, Susanne
    The 19-dimensional TP06 cardiac muscle cell model is reduced to a 17-dimensional version, which satisfies the required conditions for performing an analysis of its dynamics by means of bifurcation theory. The reformulated model is shown to be a good approximation of the original one. As a consequence, one can extract fairly precise predictions of the behaviour of the original model from the bifurcation analysis of the modified model. Thus, the findings of bifurcations linked to complex dynamics in the modified model - like early afterdepolarisations (EADs), which can be precursors to cardiac death - predicts the occurrence of the same dynamics in the original model. It is shown that bifurcations linked to EADs in the modified model accurately predicts EADs in the original model at the single cell level. Finally, these bifurcations are linked to wave break-up leading to cardiac death at the tissue level.