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Optimisation of ionic models to fit tissue action potentials: application to 3D atrial modelling.

Al Abed A, Guo T, Lovell NH, Dokos S - Comput Math Methods Med (2013)

Bottom Line: A 3D model of atrial electrical activity has been developed with spatially heterogeneous electrophysiological properties.Membrane potentials of myocytes from spontaneously active or electrically paced in vitro rabbit cardiac tissue preparations were recorded using intracellular glass microelectrodes.The tissue-based optimisation of ionic models and the modelling process outlined are generic and applicable to image-based computer reconstruction and simulation of excitable tissue.

View Article: PubMed Central - PubMed

Affiliation: Graduate School of Biomedical Engineering, The University of New South Wales, Sydney, NSW 2052, Australia. amra@unsw.edu.au

ABSTRACT
A 3D model of atrial electrical activity has been developed with spatially heterogeneous electrophysiological properties. The atrial geometry, reconstructed from the male Visible Human dataset, included gross anatomical features such as the central and peripheral sinoatrial node (SAN), intra-atrial connections, pulmonary veins, inferior and superior vena cava, and the coronary sinus. Membrane potentials of myocytes from spontaneously active or electrically paced in vitro rabbit cardiac tissue preparations were recorded using intracellular glass microelectrodes. Action potentials of central and peripheral SAN, right and left atrial, and pulmonary vein myocytes were each fitted using a generic ionic model having three phenomenological ionic current components: one time-dependent inward, one time-dependent outward, and one leakage current. To bridge the gap between the single-cell ionic models and the gross electrical behaviour of the 3D whole-atrial model, a simplified 2D tissue disc with heterogeneous regions was optimised to arrive at parameters for each cell type under electrotonic load. Parameters were then incorporated into the 3D atrial model, which as a result exhibited a spontaneously active SAN able to rhythmically excite the atria. The tissue-based optimisation of ionic models and the modelling process outlined are generic and applicable to image-based computer reconstruction and simulation of excitable tissue.

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Rhythmic atrial simulation using optimised cSAN, pSAN, RA, LA, and PV ionic models and finite-thickness atrial wall geometry. (a) Snapshots of membrane potential across the surface of the atria at various times during one cardiac cycle. (b) Representative AP plots from various regions. The locations of points where the highlighted APs were sampled are shown in the inset. Data was sampled at 1 kHz.
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fig8: Rhythmic atrial simulation using optimised cSAN, pSAN, RA, LA, and PV ionic models and finite-thickness atrial wall geometry. (a) Snapshots of membrane potential across the surface of the atria at various times during one cardiac cycle. (b) Representative AP plots from various regions. The locations of points where the highlighted APs were sampled are shown in the inset. Data was sampled at 1 kHz.

Mentions: In simulations utilising the 3D atrial geometry with finite wall thickness, spontaneous periodic APs originated from the SAN and propagated to activate the atria (Figure 8). APs in both the cSAN and pSAN regions were initiated at the same time and it took slightly longer for APs to propagate through the pSAN compared to the cSAN. Atrial breakthrough occurred first at the RA followed by the CT, with the activation pattern being stable for each cycle. Intra-atrial conduction began at the BB followed by the septum, with the CS playing only a minor role. The superior PVs were activated before the inferior ones. The mean pacemaking CL was 779 ms.


Optimisation of ionic models to fit tissue action potentials: application to 3D atrial modelling.

Al Abed A, Guo T, Lovell NH, Dokos S - Comput Math Methods Med (2013)

Rhythmic atrial simulation using optimised cSAN, pSAN, RA, LA, and PV ionic models and finite-thickness atrial wall geometry. (a) Snapshots of membrane potential across the surface of the atria at various times during one cardiac cycle. (b) Representative AP plots from various regions. The locations of points where the highlighted APs were sampled are shown in the inset. Data was sampled at 1 kHz.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3713319&req=5

fig8: Rhythmic atrial simulation using optimised cSAN, pSAN, RA, LA, and PV ionic models and finite-thickness atrial wall geometry. (a) Snapshots of membrane potential across the surface of the atria at various times during one cardiac cycle. (b) Representative AP plots from various regions. The locations of points where the highlighted APs were sampled are shown in the inset. Data was sampled at 1 kHz.
Mentions: In simulations utilising the 3D atrial geometry with finite wall thickness, spontaneous periodic APs originated from the SAN and propagated to activate the atria (Figure 8). APs in both the cSAN and pSAN regions were initiated at the same time and it took slightly longer for APs to propagate through the pSAN compared to the cSAN. Atrial breakthrough occurred first at the RA followed by the CT, with the activation pattern being stable for each cycle. Intra-atrial conduction began at the BB followed by the septum, with the CS playing only a minor role. The superior PVs were activated before the inferior ones. The mean pacemaking CL was 779 ms.

Bottom Line: A 3D model of atrial electrical activity has been developed with spatially heterogeneous electrophysiological properties.Membrane potentials of myocytes from spontaneously active or electrically paced in vitro rabbit cardiac tissue preparations were recorded using intracellular glass microelectrodes.The tissue-based optimisation of ionic models and the modelling process outlined are generic and applicable to image-based computer reconstruction and simulation of excitable tissue.

View Article: PubMed Central - PubMed

Affiliation: Graduate School of Biomedical Engineering, The University of New South Wales, Sydney, NSW 2052, Australia. amra@unsw.edu.au

ABSTRACT
A 3D model of atrial electrical activity has been developed with spatially heterogeneous electrophysiological properties. The atrial geometry, reconstructed from the male Visible Human dataset, included gross anatomical features such as the central and peripheral sinoatrial node (SAN), intra-atrial connections, pulmonary veins, inferior and superior vena cava, and the coronary sinus. Membrane potentials of myocytes from spontaneously active or electrically paced in vitro rabbit cardiac tissue preparations were recorded using intracellular glass microelectrodes. Action potentials of central and peripheral SAN, right and left atrial, and pulmonary vein myocytes were each fitted using a generic ionic model having three phenomenological ionic current components: one time-dependent inward, one time-dependent outward, and one leakage current. To bridge the gap between the single-cell ionic models and the gross electrical behaviour of the 3D whole-atrial model, a simplified 2D tissue disc with heterogeneous regions was optimised to arrive at parameters for each cell type under electrotonic load. Parameters were then incorporated into the 3D atrial model, which as a result exhibited a spontaneously active SAN able to rhythmically excite the atria. The tissue-based optimisation of ionic models and the modelling process outlined are generic and applicable to image-based computer reconstruction and simulation of excitable tissue.

Show MeSH
Related in: MedlinePlus