Method and system for determining cardiac performance

Inactive Publication Date: 2010-06-17
CARDIAC PROFILES
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Benefits of technology

[0020]According to one embodiment of the invention, the methods and associated algorithms for determining cardiac and/or cardiovascular performance (CP) are based on at least one cardiac function determinant that is associated with or at least in part, reflective of preload, contractility and afterload.
[0021]In one embodiment of the invention, cardiac performance is accordingly determined and, hence, represented by the following equation
[0022]In accordance with another embodiment of the invention, the methods a

Problems solved by technology

While each of the prior art methods can be employed to provide an estimate of cardiac output, as discussed in detail below, the accuracy of the estimated cardiac output is limited by virtue of various methodological constraints, including the limited number of cardiac hemodynamic variables (or cardiac performance determinants) employed in th

Method used

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  • Method and system for determining cardiac performance
  • Method and system for determining cardiac performance
  • Method and system for determining cardiac performance

Examples

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example 1

[0200]Referring now to Equation 7, there is shown a general empirical relationship of the invention that can be employed to derive an accurate estimation of cardiac stroke index (SI), i.e.

SI=α*LVET / PEP*((1−β)*(dv / dte,s) / (dv / dtf,s)*((dv / dte,s) / (dv / dte,d)))  Eq. 7

where:[0201]LVET=left ventricular ejection time;[0202]PEP=pre-ejection period;[0203]α and β=variable constants that are measurement system-specific;[0204]dv / dte,s=the maximal systolic upslope of the plethysmogram signal obtained at the ear;[0205]dv / dtf,s=the maximal systolic upslope of the plethysmogram signal obtained at the finger; and[0206]dv / dte,d=the maximal diastolic down slope of the plethysmogram signal obtained at the ear.

[0207]In this example, the Stroke Index (SI) is determined (via Equation 7) by the product of three terms or determinants: (i) the ratio of ejection time from onset at the max change of systolic upslope to the max change of rate of slope in the diastolic down-slope divided by pre-ejection period, (i...

example 2

[0216]A primary, uncorrected estimate of strength of contraction is obtained from the systolic upstroke interval as the difference of amplitudes between 75% and 25% divided by the maximal systolic amplitude; the derived strength of contraction serving as variable (dv / dte,s) in Eq. 7, above.

example 3

[0217]An equivalent measure for strength of contraction as upstroke interval (as described in Example 1) is obtained by calculating the time difference of the QRS component to 75% of systolic upstroke and QRS component to 25% of systolic upstroke. This time measure of contraction is normalized by the ejection period (EP), as measured from onset of systolic upstroke, and defined as maximal rate of amplitude increase to the indication of dichrotic notch, as measured and defined as the maximal rate of amplitude decrease on the diastolic side; the derived strength of contraction similarly serving as variable (dv / dte,s) in Eq. 7, above.

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Abstract

Methods and associated algorithms for determining cardiac and/or cardiovascular performance that are based on at least one cardiac function determinant associated with or at least in part, reflective of preload, contractility and afterload.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims the benefit of U.S. Provisional Application No. 61 / 133,876, filed Jul. 2, 2008.FIELD OF THE PRESENT INVENTION[0002]The present invention relates generally to methods and systems for determining cardiac function. More particularly, the invention relates to a method for determining cardiac performance as a function of multiple cardiac parameters.BACKGROUND OF THE INVENTION[0003]A clinical and scientific goal for many years has been to accurately and non-invasively determine myocardial or cardiac output of a patient or subject. Indeed, there is a vast array of methods for determining cardiac output in the prior art. While each of the prior art methods can be employed to provide an estimate of cardiac output, as discussed in detail below, the accuracy of the estimated cardiac output is limited by virtue of various methodological constraints, including the limited number of cardiac hemodynamic variables (or cardiac perf...

Claims

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Application Information

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IPC IPC(8): A61B5/02
CPCA61B5/029
Inventor STERLING, BERNHARD B.LAWRENCE, ANDREW R.VOSS, GREGORY I.PERRY, JAMES M.CLINTON, III, RANKIN A.
Owner CARDIAC PROFILES
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