title: Dynamic approximate entropy electroanatomic maps detect rotors in a simulated atrial fibrillation model.
abstract: There is evidence that rotors could be drivers that maintain atrial fibrillation. Complex fractionated atrial electrograms have been located in rotor tip areas. However, the concept of electrogram fractionation, defined using time intervals, is still controversial as a tool for locating target sites for ablation. We hypothesize that the fractionation phenomenon is better described using non-linear dynamic measures, such as approximate entropy, and that this tool could be used for locating the rotor tip. The aim of this work has been to determine the relationship between approximate entropy and fractionated electrograms, and to develop a new tool for rotor mapping based on fractionation levels. Two episodes of chronic atrial fibrillation were simulated in a 3D human atrial model, in which rotors were observed. Dynamic approximate entropy maps were calculated using unipolar electrogram signals generated over the whole surface of the 3D atrial model. In addition, we optimized the approximate entropy calculation using two real multi-center databases of fractionated electrogram signals, labeled in 4 levels of fractionation. We found that the values of approximate entropy and the levels of fractionation are positively correlated. This allows the dynamic approximate entropy maps to localize the tips from stable and meandering rotors. Furthermore, we assessed the optimized approximate entropy using bipolar electrograms generated over a vicinity enclosing a rotor, achieving rotor detection. Our results suggest that high approximate entropy values are able to detect a high level of fractionation and to locate rotor tips in simulated atrial fibrillation episodes. We suggest that dynamic approximate entropy maps could become a tool for atrial fibrillation rotor mapping.
authors.affiliation: Centro de Bioingeniería, Universidad Pontificia Bolivariana, Medellín, Colombia.
authors.forename: Juan P
authors.initials: JP
authors.lastname: Ugarte
authors.affiliation: Centro de Bioingeniería, Universidad Pontificia Bolivariana, Medellín, Colombia.
authors.forename: Andrés
authors.initials: A
authors.lastname: Orozco-Duque
authors.affiliation: GI²B, Instituto Tecnológico Metropolitano, Medellín, Colombia.
authors.forename: Catalina
authors.initials: C
authors.lastname: Tobón
authors.affiliation: Czech Institute of Informatics, Robotics and Cybernetics, Czech Technical University in Prague, Prague, Czech Republic; Department of Cybernetics, Faculty of Electrical Engineering, Czech Technical University in Prague, Prague, Czech Republic.
authors.forename: Vaclav
authors.initials: V
authors.lastname: Kremen
authors.affiliation: Czech Institute of Informatics, Robotics and Cybernetics, Czech Technical University in Prague, Prague, Czech Republic.
authors.forename: Daniel
authors.initials: D
authors.lastname: Novak
authors.affiliation: I3BH, Universitat Politècnica de València, Valencia, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Saiz
authors.affiliation: Institute of Biomedical Engineering, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany.
authors.forename: Tobias
authors.initials: T
authors.lastname: Oesterlein
authors.affiliation: Medizinische Klinik IV, Staedtisches Klinikum Karlsruhe, Karlsruhe, Germany.
authors.forename: Clauss
authors.initials: C
authors.lastname: Schmitt
authors.affiliation: Medizinische Klinik IV, Staedtisches Klinikum Karlsruhe, Karlsruhe, Germany.
authors.forename: Armin
authors.initials: A
authors.lastname: Luik
authors.affiliation: Centro de Bioingeniería, Universidad Pontificia Bolivariana, Medellín, Colombia.
authors.forename: John
authors.initials: J
authors.lastname: Bustamante
mesh_terms: D001281:Atrial Fibrillation / Q000473:pathology* / Q000503:physiopathology*; D004562:Electrocardiography; D019277:Entropy; D006325:Heart Atria / Q000473:pathology* / Q000503:physiopathology*; D006801:Humans; D008953:Models, Anatomic