Real time pressure-volume loops in mice using complex admittance: Measurement and implications

Anil T.G. Kottam, John Porterfield, Karthik Raghavan, Daniel Fernandez, Marc D. Feldman, Jonathan W. Valvano, John A. Pearce

Research output: Chapter in Book/Report/Conference proceedingConference contribution

12 Scopus citations

Abstract

Real time left ventricular (LV) pressure-volume (P-V) loops have provided a framework for understanding cardiac mechanics in experimental animals and humans [1]. Conductance measurements have been used for the past 25 years to generate an instantaneous left ventricular (LV) volume signal. The standard conductance method yields a combination of blood and ventricular muscle conductance; however, only the blood signal is used to estimate LV volume. The state of the art techniques like hypertonic saline injection and IVC occlusion, determine only a single steady-state value of the parallel conductance of the cardiac muscle. This is inaccurate, since the cardiac muscle component should vary instantaneously throughout the cardiac cycle as the LV contracts and fills, because the distance from the catheter to the muscle changes. The capacitive nature of cardiac muscle can be used to identify its contribution to the combined conductance signal. This method, in contrast to existing techniques, yields an instantaneous estimate of the parallel admittance of cardiac muscle that can be used to correct the measurement in real time. The corrected signal consists of blood conductance alone. We present the results of real time in vivo measurements of pressure - admittance and pressure - phase loops inside the murine left ventricle. We then use the magnitude and phase angle of the measured admittance to determine pressure volume loops inside the LV on a beat by beat basis. These results may be used to achieve a substantial improvement in the state of the art in this measurement method by eliminating the need for hypertonic saline injection.

Original languageEnglish (US)
Title of host publication28th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS'06
Pages4336-4339
Number of pages4
DOIs
StatePublished - Dec 1 2006
Event28th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS'06 - New York, NY, United States
Duration: Aug 30 2006Sep 3 2006

Publication series

NameAnnual International Conference of the IEEE Engineering in Medicine and Biology - Proceedings
ISSN (Print)0589-1019

Other

Other28th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS'06
CountryUnited States
CityNew York, NY
Period8/30/069/3/06

ASJC Scopus subject areas

  • Signal Processing
  • Biomedical Engineering
  • Computer Vision and Pattern Recognition
  • Health Informatics

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    Kottam, A. T. G., Porterfield, J., Raghavan, K., Fernandez, D., Feldman, M. D., Valvano, J. W., & Pearce, J. A. (2006). Real time pressure-volume loops in mice using complex admittance: Measurement and implications. In 28th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS'06 (pp. 4336-4339). [4029432] (Annual International Conference of the IEEE Engineering in Medicine and Biology - Proceedings). https://doi.org/10.1109/IEMBS.2006.259407