Estimation of time constant of left ventricular relaxation.
نویسندگان
چکیده
منابع مشابه
Estimation of time constant of left ventricular relaxation.
When the fall in left ventricular pressure during isovolumic relaxation is treated as a monoexponential the rate of relaxation can be measured by a time constant. Though an empirical measurement, the time constant has been used extensively to study relaxation. It can be accepted, however, as a valid measurement only if isovolumic pressure fall approximates very closely to a monoexponential in a...
متن کاملEstimation of the left ventricular relaxation time constant tau requires consideration of the pressure asymptote.
The left ventricular isovolumic pressure decay, obtained by cardiac catheterization, is widely characterized by the time constant tau of the exponential regression p(t)=Pomega+(P0-Pomega)exp(-t/tau). However, several authors prefer to prefix Pomega=0 instead of coestimating the pressure asymptote empirically; others present tau values estimated by both methods that often lead to discordant resu...
متن کاملThe time constant of left ventricular relaxation: extrication from load dependence and overestimation of functional abnormality.
Left ventricular (LV) diastolic dysfunction induces the increase of LV diastolic pressure and subsequently of left atrial and pulmonary capillary pressures independent of systolic function, resulting in the onset of heart failure. In the early 1990s, several clinical studies demonstrated that diastolic dysfunction is an independent prognostic factor in patients with heart failure with reduced e...
متن کاملNon-invasive determination of left ventricular relaxation time constant by Transthoracic Doppler echocardiography.
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...
متن کاملCalculation of Left Ventricular Relaxation Time Constant-Tau in Humans by Continuous-Wave Doppler
Left ventricular relaxation time constant, Tau, is the best index to evaluate left ventricular diastolic function, but 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...
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ژورنال
عنوان ژورنال: Heart
سال: 1983
ISSN: 1355-6037
DOI: 10.1136/hrt.49.3.250