title: Curvature-Dependent Excitation Propagation in Cultured Cardiac Tissue.
abstract: The geometry of excitation wave front may play an important role on the propagation block and spiral wave formation. The wave front which is bent over the critical value due to interaction with the obstacles may partially cease to propagate and appearing wave breaks evolve into rotating waves or reentry. This scenario may explain how reentry spontaneously originates in a heart. We studied highly curved excitation wave fronts in the cardiac tissue culture and found that in the conditions of normal, non-inhibited excitability the curvature effects do not play essential role in the propagation. Neither narrow isthmuses nor sharp corners of the obstacles, being classical objects for production of extremely curved wave front, affect non-inhibited wave propagation. The curvature-related phenomena of the propagation block and wave detachment from the obstacle boundary were observed only after partial suppression of the sodium channels with Lidocaine. Computer simulations confirmed the experimental observations. The explanation of the observed phenomena refers to the fact that the heart tissue is made of finite size cells so that curvature radii smaller than the cardiomyocyte size loses sense, and in non-inhibited tissue the single cell is capable to transmit excitation to its neighbors.
authors.affiliation: Institute for Integrated Cell-Material Sciences, Kyoto University, 60638501 Kyoto, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Kadota
authors.affiliation: Department of Electrical and Computer Engineering, George Washington University, 20052 Washington DC, USA.
authors.forename: M W
authors.initials: MW
authors.lastname: Kay
authors.affiliation: Institute for Integrated Cell-Material Sciences, Kyoto University, 60638501 Kyoto, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Magome
authors.affiliation: Institute for Integrated Cell-Material Sciences, Kyoto University, 60638501 Kyoto, Japan ; Research and Education Center Bionanophysics, Moscow Institute of Physics and Technology, Dolgoprudnyi, Moscow region, 141700 Russia.
authors.forename: K
authors.initials: K
authors.lastname: Agladze