title: Oblique propagation of activation allows the detection of uncoupling microstructures from cardiac near field behavior.
abstract: Wave fronts of cardiac activation, when propagating oblique to the fiber axis, reveal small fractionations and distortions in extracellular potential waveforms Phi(e) as well as in parameters derived from Phi(e) like dPhi(e)/dt and the gradient of Phi(e), the cardiac near field E. dPhi(e)/dt shows multiple deflections and E changes its morphology forming abnormal or even two or multiple subsequent loops. We analyze segments of such irregular loops of E obtained from in-vitro experiments and from computer simulation of a 2D-tissue sheet with a longitudinal oriented obstacle. In computer simulations we found that the individual sections of E reflect fairly well individual pathways of activation separated and delayed by the presence of a structural obstacle similar to connective tissue embedded longitudinally in heart tissue. Electrophysiological experiments with papillary muscles confirm this near field behavior.
authors.affiliation: Institute of Biophysics, Center for Physiological Medicine, Medical University Graz, A-8010 Graz, Austria. ernst.hofer@meduni-graz.at
authors.forename: Ernst
authors.initials: E
authors.lastname: Hofer
authors.forename: Thomas
authors.initials: T
authors.lastname: Wiener
authors.forename: Anton J
authors.initials: AJ
authors.lastname: Prassl
authors.forename: Thomas
authors.initials: T
authors.lastname: Thurner
authors.forename: Gernot
authors.initials: G
authors.lastname: Plank
mesh_terms: D000200:Action Potentials; D000818:Animals; D054849:Cardiac Electrophysiology; D003198:Computer Simulation; D006321:Heart / Q000502:physiology*; D006329:Heart Conduction System / Q000502:physiology*; D008955:Models, Cardiovascular; D010210:Papillary Muscles / Q000502:physiology; D011817:Rabbits