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 language | English (US) |
|---|---|
| Title of host publication | Annual International Conference of the IEEE Engineering in Medicine and Biology - Proceedings |
| Pages | 4336-4339 |
| Number of pages | 4 |
| DOIs | |
| State | Published - 2006 |
| Event | 28th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS'06 - New York, NY, United States Duration: Aug 30 2006 → Sep 3 2006 |
Other
| Other | 28th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS'06 |
|---|---|
| Country | United States |
| City | New York, NY |
| Period | 8/30/06 → 9/3/06 |
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ASJC Scopus subject areas
- Bioengineering
Cite this
Real time pressure-volume loops in mice using complex admittance : Measurement and implications. / Kottam, Anil T G; Porterfield, John; Raghavan, Karthik; Fernandez, Daniel; Feldman, Marc D; Valvano, Jonathan W.; Pearce, John A.
Annual International Conference of the IEEE Engineering in Medicine and Biology - Proceedings. 2006. p. 4336-4339 4029432.Research output: Chapter in Book/Report/Conference proceeding › Conference contribution
}
TY - GEN
T1 - Real time pressure-volume loops in mice using complex admittance
T2 - Measurement and implications
AU - Kottam, Anil T G
AU - Porterfield, John
AU - Raghavan, Karthik
AU - Fernandez, Daniel
AU - Feldman, Marc D
AU - Valvano, Jonathan W.
AU - Pearce, John A.
PY - 2006
Y1 - 2006
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=34047155638&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=34047155638&partnerID=8YFLogxK
U2 - 10.1109/IEMBS.2006.259407
DO - 10.1109/IEMBS.2006.259407
M3 - Conference contribution
C2 - 17946238
AN - SCOPUS:34047155638
SN - 1424400325
SN - 9781424400324
SP - 4336
EP - 4339
BT - Annual International Conference of the IEEE Engineering in Medicine and Biology - Proceedings
ER -