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DY: Fachverband Dynamik und Statistische Physik

DY 34: Nonlinear Dynamics, Synchronization and Chaos - Part II

DY 34.2: Vortrag

Mittwoch, 18. März 2015, 15:15–15:30, BH-N 128

Entraining and eliminating spiral waves in excitable media by secondary excitations — •T K Shajahan, Sebastian Berg, and Stefan Luther — Max Planck Institute for Dynamics and Self Organization, Am Fassberg, Göttinegn, Germany

Excitable media comprises of a wide variety of physical, chemical, and biological systems made of coupled networks of excitable elements. Heart is an example of an excitable medium; the individual cardiac myocytes have a characteristic response, the action potential, to an external stimulus. Such excitations in a two-dimensional medium can form traveling wave patterns including spiral waves and target waves. These patterns in a physiological system have implications for the healthy functioning of the system. For example, spiral waves of cardiac excitation waves in the heart can override the natural rhythm of the heart and lead to cardiac arrhythmias. We study control and elimination of spiral waves using secondary excitations in monolayers of cultured cardiac cells. Free spiral waves can be eliminated with a local electrode by stimulating the medium at a higher frequency than the spiral. But this method fails if the spiral is pinned to tissue heterogeneities. A pinned spiral wave can be controlled by electric field stimulus. Our theoretical and experimental studies indicate that periodic field stimuli at a frequency lower than the spiral frequency is more efficient to eliminate pinned spiral waves. I will discuss the implications of this result for low energy defibrillation.