Calculation of Left Ventricular Relaxation Time Constant-Tau in Patients With Aortic Regurgitation by Continuous-Wave Doppler

Bai Xufang *
Henderson Research Center, McMaster University, Hamilton, Ontario, L8V 1C3, Canada

Article Metrics

CrossRef Citations:
Total Statistics:

Full-Text HTML Views: 945
Abstract HTML Views: 482
PDF Downloads: 271
Total Views/Downloads: 1698
Unique Statistics:

Full-Text HTML Views: 497
Abstract HTML Views: 275
PDF Downloads: 198
Total Views/Downloads: 970

Creative Commons License
Bentham Open.

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestrictive use, distribution, and reproduction in any medium, provided the original work is properly cited.

* the Henderson Research Center, McMaster University, Hamilton, Ontario, L8V 1C3, Canada; E-mail


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.