title: Cardiac anisotropy: is it negligible regarding noninvasive activation time imaging?
abstract: The aim of this study was to quantify the effect of cardiac anisotropy in the activation-based inverse problem of electrocardiography. Differences of the patterns of simulated body surface potential maps for isotropic and anisotropic conditions were investigated with regard to activation time (AT) imaging of ventricular depolarization. AT maps were estimated by solving the nonlinear inverse ill-posed problem employing spatio-temporal regularization. Four different reference AT maps (sinus rhythm, right-ventricular and septal pacing, accessory pathway) were calculated with a bidomain theory based anisotropic finite-element heart model in combination with a cellular automaton. In this heart model a realistic fiber architecture and conduction system was implemented. Although the anisotropy has some effects on forward solutions, effects on inverse solutions are small indicating that cardiac anisotropy might be negligible for some clinical applications (e.g., imaging of focal events) of our AT imaging approach. The main characteristic events of the AT maps were estimated despite neglected electrical anisotropy in the inverse formulation. The worst correlation coefficient of the estimated AT maps was 0.810 in case of sinus rhythm. However, all characteristic events of the activation pattern were found. The results of this study confirm our clinical validation studies of noninvasive AT imaging in which cardiac anisotropy was neglected.
authors.affiliation: University for Health Sciences, Medical Informatics and Technology (UMIT), Hall in Tirol 6060, Austria. robert.modre@arcsmed.at
authors.forename: Robert
authors.initials: R
authors.lastname: Modre
authors.forename: Michael
authors.initials: M
authors.lastname: Seger
authors.forename: Gerald
authors.initials: G
authors.lastname: Fischer
authors.forename: Christoph
authors.initials: C
authors.lastname: Hintermüller
authors.forename: Dieter
authors.initials: D
authors.lastname: Hayn
authors.forename: Bernhard
authors.initials: B
authors.lastname: Pfeifer
authors.forename: Friedrich
authors.initials: F
authors.lastname: Hanser
authors.forename: Günter
authors.initials: G
authors.lastname: Schreier
authors.forename: Bernhard
authors.initials: B
authors.lastname: Tilg
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D018780:Body Surface Potential Mapping / Q000379:methods*; D003198:Computer Simulation; D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D006329:Heart Conduction System / Q000502:physiology*; D006801:Humans; D008955:Models, Cardiovascular; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016276:Ventricular Function