Modulation of shock-end virtual electrode polarisation as a direct result of 3D fluorescent photon scattering

TY - CHAP

T1 - Modulation of shock-end virtual electrode polarisation as a direct result of 3D fluorescent photon scattering

AU - Bishop, Martin

AU - Rodriguez, B

AU - Trayanova, N

AU - Gavaghan, D J

PY - 2006

Y1 - 2006

N2 - 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.

AB - 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.

KW - Sensitivity and Specificity

KW - Heart Conduction System

KW - Animals

KW - Artifacts

KW - Computer Simulation

KW - Scattering, Radiation

KW - Spectrometry, Fluorescence

KW - Body Surface Potential Mapping

KW - Photons

KW - Reproducibility of Results

KW - Action Potentials

KW - Rabbits

KW - Microscopy, Fluorescence

KW - Models, Cardiovascular

KW - Electrodes

U2 - 10.1109/IEMBS.2006.259243

DO - 10.1109/IEMBS.2006.259243

M3 - Conference paper

C2 - 17946049

VL - 1

SP - 1556

EP - 1559

BT - Engineering in Medicine and Biology Society, 2006. EMBS '06. 28th Annual International Conference of the IEEE

PB - IEEE

CY - 1-4244-0032-5

ER -