Non-invasive determination of left ventricular relaxation time constant by transthoracic Doppler echocardiography

Wen Chung Yu, Kuan Rau Chiou, Yao Ping Lin, Wen Hsin Lee, Wen Bin Huang, Chen Huan Chen

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


Background. Left ventricular (LV) relaxation time constant (Tau) is a relatively load-independent index of diastolic function in the evaluation of heart failure. However, the requirement of high-fidelity intraventricular pressure recording limits its clinical utility. In the present study, we investigated whether Tau could be estimated noninvasively. Methods. Thirty-seven patients indicated for cardiac catheterization were recruited for study. Echocardiography and cardiac catheterization with high-fidelity LV pressue recording were performed sequentially within 1 hour. The non-invasive Taud,Dopp was derived from the formula: TauDopp = IVRTDopp/ [ln(Ps) - ln(10)], where IVRT is the isovolumic relaxation time measured by Doppler echocardiography and Ps is systolic blood pressure measured during the echocardiographic examination. The invasive TauLM was determined by non-linear least-square parameter estimate technique, using the exponential equation: Pv = P0e-t/Tau + b, where Pv is the instantaneous LV pressure, P0 is LV pressure at minimal dP/dt, and b is the theoretical asymptote. The difference between TauDopp and TauLM was compared using paired t-test, and their relation was evaluated using simple correlation and intra-class correlation coefficient. Results. IVRTDopp was significantly correlated with the invasively derived IVRT (r = 0.42, p = 0.012). The completely non-invasive TauDopp was significantly correlated with the direct curve-fitted TauLM (r = 0.41; p = 0.013), and the intraclass correlation coefficient was 0.29 (p 0.04). In addition, TauDopp was significantly smaller than TaULM (36 ± 6 ms vs. 57 ± 15 ms,p < 0.001). Conclusions. Tau can be estimated noninvasively by transthoracic Doppler echocardiographic method with limited accuracy. The clinical utility of TauDopp remains to be determined.

Original languageEnglish
Pages (from-to)317-322
Number of pages6
JournalJournal of the Chinese Medical Association
Issue number7
Publication statusPublished - Jul 1 2004
Externally publishedYes


  • Diastolic function
  • Diastolic heart failure
  • Doppler echocardiography
  • Isovolumic relaxation time
  • Pressure-volume loop study

ASJC Scopus subject areas

  • Medicine(all)


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