Spread of Excitation in a Myocardial Volume: Simulation Studies in a Model of Anisotropic Ventricular Muscle Activated by Point Stimulation.
Introduction: The purpose of this study was to present simulations of excitation wavefronts spreading through a parallelepipedal slab of ventricular tissue measuring 6.5 x 6.5 x 1.0 cm. Methods and Results: The slab incorporates the anisotropic properties of the myocardium including the transmural c...
| Published in: | Journal of Cardiovascular Electrophysiology Vol. 4; no. 2; pp. 144 - 161 |
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| Main Authors: | , , |
| Format: | Journal Article |
| Published: |
Wiley-Blackwell
Apr1993
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| Online Access: | View this record in EBSCOhost |
| fields | @attributes: recordID: 1 pdfLink: plink: https://search.ebscohost.com/login.aspx?direct=true&db=ccm&AN=106084438&site=ehost-live header: @attributes: shortDbName: ccm uiTerm: 106084438 longDbName: CINAHL Complete uiTag: AN controlInfo: bkinfo: dissinfo: jinfo: jid: 10453873 GSB jtl: Journal of Cardiovascular Electrophysiology issn: 10453873 maglogo: Y pubinfo: dt: Apr1993 vid: 4 iid: 2 pid: 480 pub: Wiley-Blackwell place: Malden, Massachusetts artinfo: ui: 106084438 2009404697 NLM8269287 106084438 ppf: 144 ppct: 17 formats: fmt: @attributes: type: P tig: atl: Spread of Excitation in a Myocardial Volume: Simulation Studies in a Model of Anisotropic Ventricular Muscle Activated by Point Stimulation. aug: au: Franzone PC Guerri L Taccardi B sug: subj: Computer Simulation Heart Physiology Cardiac Pacing, Artificial Heart Ventricle Purkinje Fibers Physiology ab: Introduction: The purpose of this study was to present simulations of excitation wavefronts spreading through a parallelepipedal slab of ventricular tissue measuring 6.5 x 6.5 x 1.0 cm. Methods and Results: The slab incorporates the anisotropic properties of the myocardium including the transmural counterclockwise fiber rotation from epicardium to endocardium. Simulations were based on an eikonal model that determines excitation times throughout the ventricular wall, which is represented as an anisotropic bidomain. Excitation was initiated by delivering ectopic stimuli at various intramural depths. We also investigated the effect of a simplified Purkinje network on excitation patterns. Excitation wavefronts in the plane of pacing, parallel to epicardial-endocardial surfaces, were oblong with the major axis approximately oriented along the local fiber direction, with bulges and deformations due to attraction from rotating fibers in adjacent planes. The oblong intersections of the wavefront with planes at increasing distance from pacing plane rotated clockwise or counterclockwise, depending on pacing depth, but wavefront rotation was always less than fiber rotation in the same plane. For all pacing depths, excitation returned toward the plane of pacing. Return occurred in multiple, varying sectors of the slab depending on pacing depth, and was observed as close as 6 mm to the pacing site. Conclusion: Curvature of wavefronts and collision with boundaries of slab markedly affected local velocities. Shape and separation of epicardial isochrones and spatial distribution of epicardial velocities varied as a function of site and depth of pacing. When the Purkinje network was added to the model, epicardial velocities revealed the subendocardial location of the Purkinje-myocardial junctions. Considerable insight into intramural events could be obtained from epicardial isochrones. If validated experimentally, results may be applicable to epicardial isochrones recorded at surgery. pubtype: Academic Journal doctype: Journal Article ougenre: Article language: English refInfo: holdings: @attributes: islocal: N |
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