Assessment of cardiac function during mechanical circulatory support: The quest for a suitable clinical index

Antonio L. Ferreira, Yajuan Wang, John Gorcsan, James F. Antaki

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

4 Scopus citations

Abstract

A new index to assess left ventricular (LV) function in patients implanted with continuous flow left-ventricular assist devices (LVADs) is proposed. Derived from the pump flow signal, this index is defined as the coefficient (k) of the semiloga-rithmic relationship between pseudo-ejection fraction (pEF) and the volume discharged by the pump in diastole, (V d). pEF is defined as the ratio of the pseudo-stroke volume (pSV) to V d. The pseudo-stroke volume is the difference between V d and the volume discharged by the pump in systole (V s), both obtained by integrating pump flow with respect to time in a cardiac cycle. k was compared in-vivo with others two indices: the LV pressure-based index, M TP, and the pump flow-based index, I Q. M TP is the slope of the linear regression between the triple-product and end-diastolic pressure, EDP. The triple-product, TP LV SP.dP/dt max. HR, is the product of LV systolic pressure, maximum time-derivative of LV pressure, and heart rate. I Q is the slope of the linear regression between maximum time-derivative of pump flow, dQ/dt max, and pump flow peak-to-peak amplitude variation, Q P2P. To test the response of k to contractile state changes, contractility was altered through pharmacological interventions. The absolute value of k decreased from 1.3540.25 (baseline) to 0.6850.21 after esmolol infusion. The proposed index is sensitive to changes in inotropic state, and has the potential to be used clinically to assess contractile function of patients implanted with VAD.

Original languageEnglish
Title of host publication33rd Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS 2011
Pages223-226
Number of pages4
DOIs
StatePublished - 2011
Event33rd Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS 2011 - Boston, MA, United States
Duration: Aug 30 2011Sep 3 2011

Publication series

NameProceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS
ISSN (Print)1557-170X

Conference

Conference33rd Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS 2011
CountryUnited States
CityBoston, MA
Period08/30/1109/3/11

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