title: Period-doubling bifurcation to alternans in paced cardiac tissue: crossover from smooth to border-collision characteristics.
abstract: We investigate, both experimentally and theoretically, the period-doubling bifurcation to alternans in heart tissue. Previously, this phenomenon has been modeled with either smooth or border-collision dynamics. Using a modification of existing experimental techniques, we find a hybrid behavior: Very close to the bifurcation point, the dynamics is smooth, whereas further away it is border-collision-like. The essence of this behavior is captured by a model that exhibits what we call an unfolded border-collision bifurcation. This new model elucidates that, in an experiment, where only a limited number of data points can be measured, the smooth behavior of the bifurcation can easily be missed.
authors.affiliation: Department of Physics, Duke University, Durham, North Carolina 27708, USA.
authors.forename: Carolyn M
authors.initials: CM
authors.lastname: Berger
authors.forename: Xiaopeng
authors.initials: X
authors.lastname: Zhao
authors.forename: David G
authors.initials: DG
authors.lastname: Schaeffer
authors.forename: Hana M
authors.initials: HM
authors.lastname: Dobrovolny
authors.forename: Wanda
authors.initials: W
authors.lastname: Krassowska
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Gauthier
mesh_terms: D000200:Action Potentials; D006321:Heart; D006801:Humans; D008955:Models, Cardiovascular