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. 2008:2:28-30.
doi: 10.2174/1874192400802010028. Epub 2008 Apr 25.

Calculation of left ventricular relaxation time constant-Tau in patients with aortic regurgitation by continuous-wave Doppler

Xufang Bai  1
Affiliations

Calculation of left ventricular relaxation time constant-Tau in patients with aortic regurgitation by continuous-wave Doppler

Xufang Bai. Open Cardiovasc Med J. 2008.

Abstract

Left ventricular relaxation time constant, Tau, is the best index to evaluate left ventricular diastolic function. The measurement is only available traditionally in catheter lab. In Echo lab, several methods of non-invasive measurement of Tau have been tried since 1992, however almost all the methods are still utilizing the same formula to calculate Tau as in catheter lab, which makes them inconvenient, time-consuming and sometimes not very accurate. A simple method to calculate Tau in patients with mitral regurgitation has been developed just based on Weiss' formula and simplified Bernoulli's equation. Similarly, formulas are developed here by pure mathematical derivative to calculate Tau by continuous-wave Doppler in patients with aortic regurgitation.

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Figures

Fig. (1)
Fig. (1)
Schematic description of aortic regurgitation spectrum. AVC is aortic valves closure, MVO is mitral valves opening, MVC is mitral valves closure and AVO is aortic valves opening.
Fig. (2)
Fig. (2)
The curve derived from Eq. (9) shows the relation of (t3-t1)/(t2-t1) and ADP.
Fig. (3)
Fig. (3)
The curve derived from Eq. (10) shows the relation of Tau/(t3-t1) and ADP.
See this image and copyright information in PMC

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References

    1. Weiss JL, Frederiksen JW, Weisfeldt ML. Hemodynamic determinants of the time-course of fall in canine left ventricular pressure. J Clin Invest. 1976;58:751–60. - PMC - PubMed
    1. Chen C, Rodriguez L, Levine RA, Weyman AE, Thomas JD. Noninvasive measurement of the time constant of left ventricular relaxation using the continuous-wave Doppler velocity profile of mitral regurgitation. Circulation. 1992;86:272–78. - PubMed
    1. Nishimura RA, Schwartz RS, Tajik AJ, Holmes DR Jr. Noninvasive measurement of rate of left ventricular relaxation by Doppler Echocardiography.Validation with simultaneous cardiac catheterization. Circulation. 1993;88:146–55. - PubMed
    1. Chen C, Rodriguez L, Lethor JP, et al. Continuous wave Doppler echocardiography for noninvasive assessment of the left ventricular dP/dt and relaxation time constant from mitral regurgitant spectra in patients. J Am Coll Cardiol. 1994;23:970–76. - PubMed
    1. Scalia GM, Greenberg NL, McCarthy PM, Thomas JD, Vandervoort PM. Noninvasive assessment of the ventricular relaxation time constant in humans by Doppler Echocardiography. Circulation. 1997;95:151–55. - PubMed

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