DOI: 10.5281/zenodo.10726485
title: In Silico Local Electrical Impedance Measurements in the Atria

description: This document describes a dataset provided in the context of the manuscript “In Silico Study of Local Electrical Impedance Measurements in the Atria - Towards Understanding and Quantifying Dependencies in Human” [1].

 

Authors: Unger LA, Anton CM, Stritt M, Wakili R, Haas A, Kircher M, Dössel O, Luik A

 

The dataset contains in silico simulation setups and results from forward electrical impedance simulations with EIDORS. Geometrical models include the commercially available ablation catheters IntellaNav MiFi and IntellaNav StPt catheter measuring local impedance (LI). 

Catheter geometries were embedded in different surrounding conditions of clinical importance. Catheter tissue interaction with and without scar, the insertion of the catheter into a pulmonary vein (PV), the withdrawal into a transeptal sheath, and catheter irrigation were modeled to quantify the respective effect on LI measurements. In vitro and clinical data used for validation purposes are included in the dataset as well.

 

Abbreviations: 

LI: local impedance, all numbers are given in Ohms

MiFi: IntellaNav MiFi catheter

PV: pulmonary vein

StPt: IntellaNav StPt catheter

 

 

Simulation results, in vitro measurements and clinically measured traces are provided in the following MATLAB files in the subdirectory „results_LI“:

 

• impConductivities.mat

In vitro measurements and simulation results for MiFi and StPt in NaCl solutions of different concentrations as described in section III A  of the related publication [1]. The struct "impedance" includes the following fields:

⁃ conc: concentration of NaCl solutions from in vitro measurements in weight percentages

⁃ cond: conductivities of the NaCl solutions from in vitro measurements in S/m

⁃ temp: interpolated temperature curves from in vitro measurements in °C

⁃ condSim: different conductivities of the NaCl solutions from in silicon experiments in S/m

⁃ LI_MiFi_iV: 41x9 matrix with interpolated in vitro LI measurements with the MiFi catheter in 9 different NaCl solutions and at 41 interpolated temperature values

⁃ LI_StPt_iV: 41x9 matrix with interpolated in vitro LI measurements with the StPt catheter in 9 different NaCl solutions and at 41 interpolated temperatures values

⁃ LI_MiFi_iV_RT: LI values for different NaCl solutions at  room temperature interpolated from in vitro MiFi measurements

⁃ LI_MiFi_iV_BT: LI values for different NaCl solutions at  body temperature interpolated from  in vitro MiFi measurements

⁃ LI_StPt_iV_RT: LI values for different NaCl solutions at  room temperature interpolated from  in vitro StPt measurements

⁃ LI_StPt_iV_BT: LI values for different NaCl solutions at body temperature  interpolated from  in vitro StPt measurements

⁃ LI_MiFi_sim: LI extracted from simulations with the MiFi catheter for different NaCl solutions

⁃ LI_StPt_sim: LI extracted from simulations with the StPt catheter for different NaCl solutions

 

• impSheath.mat

Simulation results and clinical measurements of LI with MiFi and StPt for different overlaps with a transeptal sheath as described in section III B of the related publication [1]. The struct „impSheath“ contains the following fields:

⁃ distance: vertical distance between catheter tip and distal edge of the sheath in mm. Negative distances describe an insertion of the catheter into the sheath

⁃ LI_MiFi_sim: LI extracted from simulations with the MiFi catheter for different vertical distances between catheter tip and distal edge of the sheath corresponding to the field distance

⁃ LI_StPt_sim: LI extracted from simulations with the StPt catheter for different vertical distances between catheter tip and distal edge of the sheath corresponding to the field distance

⁃ LI_MiFi_cd: 281x2 matrix containing clinical LI measurements with the MiFi catheter in the second column and corresponding time steps in the first column

⁃ LI_StPt_cd: 301x2 matrix containing clinical LI measurements with the StPt catheter in the second column and corresponding time steps in the first column

 

• impTissue.mat

Simulation results for MiFi and StPt with variable distance and angle between catheter and tissue as described in section III C of the related publication [1]. The struct „impTissue“ contains the following fields:

⁃ distance: 25 different distances between catheter tip and endocardial surface in mm

⁃ distanceSel: 5 selected distances between catheter tip and endocardial surface in mm

⁃ angle: 13 different angles between catheter and endocardial tissue surface in degrees

⁃ LI_MiFi_d_alpha: 5x13 matrix with simulated LI values for the MiFi catheter at 5 selected distances (distanceSel) and 13 angles between catheter and tissue.

⁃ LI_MiFi_d_90: 25 simulated LI values for the MiFi catheter for different distances between catheter tip and endocardial surface corresponding to the field “distance” for orthogonal catheter placement

⁃ LI_StPt_d_alpha: 5x13 matrix with simulated LI values for the StPt catheter at 5 selected distances (distanceSel) and 13 angles between catheter and tissue.

⁃ LI_StPt_d_90: 25 simulated LI values for the StPt catheter different distances between catheter tip and endocardial surface corresponding to the field “distance” for orthogonal catheter placement

 

• impTissueScar.mat

Simulation results for MiFi and StPt interacting with tissue in the presence of scar as described in section III C of the related publication [1]. The struct „impTissueScar“ contains the following fields:

⁃ distance: vertical distance between catheter tip and endocardial surface for all simulation setups in mm

⁃ centerX: horizontal distance between the catheter tip and the center of the line of scar for all simulation setups in mm

⁃ LI_MiFi3mm: simulated LI for the MiFi catheter for all combinations of horizontal and vertical distances with a central line of scar of 3mm width

⁃ LI_StPt3mm: simulated LI for the StPt catheter for all combinations of horizontal and vertical distances with a central line of scar of 3mm width

⁃ LI_MiFi6mm:  simulated LI for the MiFi catheter for all combinations of horizontal and vertical distances with a central line of scar of 6mm width

⁃ LI_StPt6mm:  simulated LI for the StPt catheter for all combinations of horizontal and vertical distances with a central line of scar of 6mm width

 

• impPV.mat

Simulation results for MiFi and StPt insertion into a pulmonary vein (PV) as described in section III D of the related publication [1]. The struct „impPV“ includes the following fields:

⁃ distance: vertical distance between catheter tip and tissue surface in mm. Negative distances describe an insertion of the catheter into the vein.

⁃ radius: inner radius of the PV in mm

⁃ thickness: thickness of the PV tissue in mm

⁃ LI_MiFi_d_r_th: 31x4x4 matrix containing the LI simulation results for the MiFi catheter for all combinations of 31 distances, 4 radii, and 4 thicknesses.

⁃ LI_StPt_d_r_th: 31x4x4 matrix containing the LI simulation results for the StPt catheter for all combinations of 31 distances, 4 radii, and 4 thicknesses.

 

• impFlush.mat

Simulation results for MiFi and StPt flush with NaCl at different flow rates as described in section III E of the related publication [1]. The struct „impFlush“ includes the following fields:

⁃ radius: radius of the NaCl spheres at the irrigation holes in mm

⁃ LI_MiFi_NaCl: LI extracted from simulations with MiFi catheter for NaCl irrigation spheres of different sizes corresponding to the respective radius

⁃ LI_StPt_NaCl: LI extracted from simulations with StPt catheter for NaCl irrigation spheres of different sizes corresponding to the respective radius

 

Additionally, exemplary geometrical setups and results are provided as VTK files in the subdirectory „selectedGeometriesAndSimResults“:

 

Each VTK file contains the following data fields:

⁃ Ids (point data): integer specifying the Id of the respective vertex

⁃ Voltage (point data): electric potential of the respective vertex with respect to a reference potential in mV

⁃ Conductivity (cell data): conductivity of the material of the respective cell in S/mm

⁃ Current (cell data): current density of the respective cell in nA/mm^2

⁃ Ids (cell data): integer specifying the Id of the respective cell

⁃ Material (cell data): integer specifying the material of the respective cell (for MiFi setups: 1: distal ring electrode, 2: middle ring electrode, 3: proximal ring electrode, 4: tip electrode, 5: outer insulator, 6: inner insulator, 7: mini electrode 1, 8: insulator mini electrode 1, 9: mini electrode 2, 10: insulator mini electrode 2, 11: mini electrode 3, 12: insulator mini electrode 3, 13: tissue, 14: blood, 15: sheath, 16:NaCl, 17: scar tissue; for StPt setups: 1: distal ring electrode, 2: middle ring electrode, 3: proximal ring electrode, 4: tip electrode, 5: outer insulator, 6: inner insulator, 7: tissue, 8: blood, 9: NaCl, 10: scar tissue)

 

• mifi.vtk: MiFi catheter in blood 

• stpt.vtk: StPt catheter in blood

• mifiTissue_dist000_angle0000.vtk: MiFi catheter positioned in 0mm distance to the endocardial tissue at an angle of 0°

• mifiTissue_dist000_angle0450.vtk: MiFi catheter positioned in 0mm distance to the endocardial tissue at an angle of 45°

• mifiTissue_dist000_angle0900.vtk: MiFi catheter positioned in 0mm distance to the endocardial tissue at an angle of 90°

• mifiTissue_dist000_angle1350.vtk: MiFi catheter positioned in 0mm distance to the endocardial tissue at an angle of 135°

• mifiTissue_dist000_angle1800.vtk: MiFi catheter positioned in 0mm distance to the endocardial tissue at an angle of 180°

• mifiTissueScar_dist0000_angle0900_centerX0000_line3mm.vtk: MiFi catheter positioned centrally and orthogonally at a line of scar tissue of 3mm width

• mifiTissueScar_dist0000_angle0900_centerX0000_line6mm.vtk: MiFi catheter positioned centrally and orthogonally at a line of scar tissue of 6mm width

• mifi_PV_d0060_r030_th20.vtk: MiFi catheter 6mm above the endocardial surface with a PV of 3 mm radius and 2mm PV tissue thickness

• mifi_PV_d-070_r030_th20.vtk: MiFi catheter inserted into a PV of 3 mm radius and 2mm PV tissue thickness; insertion depth = 7mm

• mifi_flush_050-0.50.vtk: MiFi catheter within blood with NaCl spheres of 0.5mm radius at irrigation holes

• mifi_sheath_0100.vtk: MiFi catheter within transeptal sheath extracted by 10mm

 

[1] Unger LA, Anton CM, Stritt M, Wakili R, Haas A, Kircher M, Dossel O, Luik A. In Silico Study of Local Electrical Impedance Measurements in the Atria - Towards Understanding and Quantifying Dependencies in Human. IEEE Trans Biomed Eng. 2023 Feb;70(2):533-543. doi: 10.1109/TBME.2022.3196545. Epub 2023 Jan 19. PMID: 35925848.