title: Line-defect patterns of unstable spiral waves in cardiac tissue.
abstract: Spiral wave propagation in period-2 excitable media is accompanied by line defects, the locus of points with period-1 oscillations. Here we investigate spiral line defects in cardiac tissue where period-2 behavior has a known arrhythmogenic role. We find that the number of line defects, which is constrained to be an odd integer, is 3 for a freely rotating spiral, with and without meander, but 1 for a spiral anchored around a fixed heterogeneity. We interpret this finding analytically using a simple theory where spiral wave unstable modes with different numbers of line defects correspond to quantized solutions of a Helmholtz equation. Furthermore, the slow inward rotation of spiral line defects is described in different regimes.
authors.affiliation: Department of Applied Mathematics, University of Colorado, Boulder, Colorado 80309, USA. juanga@colorado.edu
authors.forename: Juan G
authors.initials: JG
authors.lastname: Restrepo
authors.forename: Alain
authors.initials: A
authors.lastname: Karma
mesh_terms: D001145:Arrhythmias, Cardiac / Q000503:physiopathology; D002462:Cell Membrane / Q000378:metabolism; D006321:Heart / Q000503:physiopathology*; D008954:Models, Biological; D009206:Myocardium / Q000166:cytology / Q000378:metabolism