Regensburg 2007 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 25: Oscillatory Systems
BP 25.9: Vortrag
Donnerstag, 29. März 2007, 16:45–17:00, H44
Dynamics of Phase Singularities in Cardiac Tissue — •Amgad Squires1,2, Gisa Luther2, Robert Jr. Gilmour1, Eberhard Bodenschatz2, and Stefan Luther2 — 1Department of Biomedical Sciences, Cornell University, NY — 2Max Planck Institute for Dynamics and Self-Organization, Goettingen, Germany
Many spatially extended, nonlinear systems exhibit spatio-temporal chaos in terms of irregular wave fronts or turbulent spiral dynamics. Examples can be found in systems as diverse as Rayleigh-Bénard convection, liquid crystals and excitable media. An example of the latter is cardiac tissue. Here, spiral waves and subsequent wave breaks correspond to an electro-mechanical malfunction of the heart. Spiral wave cores and breakup correspond to phase singularities or defects. We investigate the dynamics of these objects using numerical simulations and arterially perfused canine wedge preparations.
We use an automated phase transformation method that can identify and track these objects from onset to termination of an arrhythmic episode. The system is robust to noise and can be used in vivo and in silico. It has been used to study various arrhythmias as well as a recently proposed far-field defibrillation protocol. Singularity detection and tracking allows us to analyze the interaction of singularities with each other and with external stimuli, in both space and time, and to characterize the complexity of spatiotemporal states. In light of these methods, we discuss current hypotheses of cardiac fibrillation.