title: Turbulent electrical activity at sharp-edged inexcitable obstacles in a model for human cardiac tissue.
abstract: Wave propagation around various geometric expansions, structures, and obstacles in cardiac tissue may result in the formation of unidirectional block of wave propagation and the onset of reentrant arrhythmias in the heart. Therefore, we investigated the conditions under which reentrant spiral waves can be generated by high-frequency stimulation at sharp-edged obstacles in the ten Tusscher-Noble-Noble-Panfilov (TNNP) ionic model for human cardiac tissue. We show that, in a large range of parameters that account for the conductance of major inward and outward ionic currents of the model [fast inward Na(+) current (INa), L-type slow inward Ca(2+) current (ICaL), slow delayed-rectifier current (IKs), rapid delayed-rectifier current (IKr), inward rectifier K(+) current (IK1)], the critical period necessary for spiral formation is close to the period of a spiral wave rotating in the same tissue. We also show that there is a minimal size of the obstacle for which formation of spirals is possible; this size is ∼2.5 cm and decreases with a decrease in the excitability of cardiac tissue. We show that other factors, such as the obstacle thickness and direction of wave propagation in relation to the obstacle, are of secondary importance and affect the conditions for spiral wave initiation only slightly. We also perform studies for obstacle shapes derived from experimental measurements of infarction scars and show that the formation of spiral waves there is facilitated by tissue remodeling around it. Overall, we demonstrate that the formation of reentrant sources around inexcitable obstacles is a potential mechanism for the onset of cardiac arrhythmias in the presence of a fast heart rate.
authors.affiliation: Centre for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore, India; Laboratory of Experimental Cardiology, Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands;
authors.forename: Rupamanjari
authors.initials: R
authors.lastname: Majumder
authors.affiliation: Centre for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore, India; Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, India;
authors.forename: Rahul
authors.initials: R
authors.lastname: Pandit
authors.affiliation: Department of Physics and Astronomy, Gent University, Ghent, Belgium; and Moscow Institute of Physics and Technology (State University), Dolgoprudny, Moscow Region, Russia Alexander.Panfilov@ugent.be.
authors.forename: A V
authors.initials: AV
authors.lastname: Panfilov
mesh_terms: D000200:Action Potentials; D006321:Heart / Q000502:physiology*; D006801:Humans; D008955:Models, Cardiovascular; D009206:Myocardium / Q000378:metabolism*; D009431:Neural Conduction; D015221:Potassium Channels / Q000378:metabolism; D015222:Sodium Channels / Q000378:metabolism
chemical_list: D015221:Potassium Channels; D015222:Sodium Channels
keywords: cardiac arrhythmias; computer modeling; pacing; reentry; spiral waves