title: Modulation of shock-end virtual electrode polarisation as a direct result of 3D fluorescent photon scattering.
abstract: Due to the large transmural variation in transmembrane potential following the application of strong electric shocks, it is thought that fluorescent photon scattering from depth plays a significant role in optical signal modulation at shock-end. For the first time, a model of photon scattering is used to accurately synthesize fluorescent signals over the irregular geometry of the rabbit ventricles following the application of such strong shocks. A bidomain representation of electrical activity is combined with finite element solutions to the photon diffusion equation, simulating both the excitation and emission processes, over an anatomically-based model of rabbit ventricular geometry and fiber orientation. Photon scattering from within a 3D volume beneath the epicardial optical recording site is shown to transduce differences in transmembrane potential within this volume through the myocardial wall. This leads directly to a significantly modulated optical signal response with respect to that predicted by the bidomain simulations, distorting epicardial virtual electrode polarization produced at shock-end. Furthermore, we show that this degree of distortion is very sensitive to the optical properties of the tissue, an important variable to consider during experimental mapping set-ups. These findings provide an essential first-step in aiding the interpretation of experimental optical mapping recordings following strong defibrillation shocks.
authors.affiliation: Computational Biology Group, University of Oxford, Oxford, UK.
authors.forename: M J
authors.initials: MJ
authors.lastname: Bishop
authors.forename: B
authors.initials: B
authors.lastname: Rodriguez
authors.forename: N
authors.initials: N
authors.lastname: Trayanova
authors.forename: D J
authors.initials: DJ
authors.lastname: Gavaghan
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D016477:Artifacts; D018780:Body Surface Potential Mapping / Q000379:methods*; D003198:Computer Simulation; D004566:Electrodes; D006329:Heart Conduction System / Q000502:physiology*; D008856:Microscopy, Fluorescence / Q000379:methods*; D008955:Models, Cardiovascular; D017785:Photons; D011817:Rabbits; D015203:Reproducibility of Results; D012542:Scattering, Radiation; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence / Q000379:methods*