<abstract xmlns="http://www.w3.org/1999/xhtml">Volume measurement is beneficial in left ventricular assist device (LVAD) therapy to quantify patient demand. In principle, an LVAD could provide a platform that allows bioimpedance measurements inside the ventricle without requiring additional implants. Conductance measured by the LVAD can then be used to estimate the ventricular radius, which can be applied to calculate ventricular volume. However, established methods that estimate radius from conductance require elaborate individual calibration or show low accuracy.
This study presents two analytical calculation methods to estimate left ventricular radius from conductance using electric field theory. These methods build on the established method of Wei, now considering the dielectric properties of muscle and background tissue, the refraction of the electric field at the blood-muscle boundary, and the changes of the electric field caused by the measurements.
The methods are validated in five glass containers of different radius. Additional bioimpedance measurements are performed in in-vitro models that replicate the left ventricle’s shape and conductive properties. The proposed analytical calculation methods estimate the radii of the containers and the in-vitro models with higher accuracy and precision than Wei’s method. The lead method performs excellently in glass cylinders over a wide range of radii (bias: 1.66%–2.48%, limits of agreement &lt; 16.33%) without calibration to specific geometries.</abstract>

Volume measurement is beneficial in left ventricular assist device (LVAD) therapy to quantify patient demand. In principle, an LVAD could provide a platform that allows bioimpedance measurements inside the ventricle without requiring additional implants. Conductance measured by the LVAD can then be used to estimate the ventricular radius, which can be applied to calculate ventricular volume. However, established methods that estimate radius from conductance require elaborate individual calibration or show low accuracy.
This study presents two analytical calculation methods to estimate left ventricular radius from conductance using electric field theory. These methods build on the established method of Wei, now considering the dielectric properties of muscle and background tissue, the refraction of the electric field at the blood-muscle boundary, and the changes of the electric field caused by the measurements.
The methods are validated in five glass containers of different radius. Additional bioimpedance measurements are performed in in-vitro models that replicate the left ventricle’s shape and conductive properties. The proposed analytical calculation methods estimate the radii of the containers and the in-vitro models with higher accuracy and precision than Wei’s method. The lead method performs excellently in glass cylinders over a wide range of radii (bias: 1.66%–2.48%, limits of agreement < 16.33%) without calibration to specific geometries.

Improved estimation of left ventricular volume from electric field modeling

Journal of Electrical Bioimpedance

This work is licensed under the Creative Commons Attribution 4.0 International License.

{"article-title":"Improved estimation of left ventricular volume from electric field modeling"}

Volume measurement is beneficial in left ventricular assist device (LVAD) therapy to quantify patient demand. In principle, an LVAD could provide a platform...

Improved estimation of left ventricular volume from electric field modeling

Published Online: Dec 27, 2021

Page range: 125 - 134

Received: Jun 16, 2021

DOI: https://doi.org/10.2478/joeb-2021-0015

Keywords
Left ventricular volume, Electric field distribution, LVAD

© 2021 Leonie Korn, Stephan Dahlmanns, Steffen Leonhardt and Marian Walter, published by Sciendo

This work is licensed under the Creative Commons Attribution 4.0 International License.

Improved estimation of left ventricular volume from electric field modeling

Published Online: Dec 27, 2021

Page range: 125 - 134

Received: Jun 16, 2021

DOI: https://doi.org/10.2478/joeb-2021-0015

KeywordsLeft ventricular volume, Electric field distribution, LVAD

© 2021 Leonie Korn, Stephan Dahlmanns, Steffen Leonhardt and Marian Walter, published by Sciendo

This work is licensed under the Creative Commons Attribution 4.0 International License.

Keywords
Left ventricular volume, Electric field distribution, LVAD