Regensburg 2007 – scientific programme
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DY: Fachverband Dynamik und Statistische Physik
DY 24: Poster I
DY 24.31: Poster
Wednesday, March 28, 2007, 16:00–18:00, Poster D
Stabilizing chaotic behaviour in a model of ventricular fibrillation — •Zhuchkova Ekaterina1, Radnayev Boris2, and Loskutov Alexander2 — 1Institut of Theoretical Physics, Technical University Berlin, Germany — 2Physics Faculty, Moscow State University, Moscow, Russia
It is believed that lethal heart pathology - ventricular fibrillation (VF) is caused by re-entrant activity, which represents multiple rotating spiral waves in 2D and scroll waves in 3D. We have made a comparative analysis of the spatio-temporal complex patterns of activation during VF in the Fenton-Karma model by three methods: counting and tracking phase singularities (PSs) - tips of re-entrant waves, computing invariant characteristics used in the theory of dynamical systems and implementing compression algorithm sensitive to regularity (CASToRe). The processes in excitable media may be more complex than a given set of re-entrant waves. Hence counting singularities is not enough. To find an amount of order in the system (quantify complexity) and determine a possibility to predict the system's dynamics and suppress chaotic behaviour CASToRe is more appropriate.
Choosing quite complex spiral-wave dynamics for stabilizing, in contrast to defibrillation by pulses (single shocks) applied to an entire tissue or a quite large part of it we applied low-amplitude non-feedback periodic excitation of monophasic and biphasic shapes to a point (or a small group of points) of medium. We have found that under some conditions re-entrant waves can be eliminated by a mild stimulation by two-three orders of magnitude less than that used in clinical practice.