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1976年,Weiss等发现在等容舒张期(IRP)中左室压力(P)服从指数下降规律:P=exp(-t/T+C),t为时间,e是自然对数的底,C是常数,T是左室压力下降的时间常数。T可作为评价左室等容舒张功能的指标。然而,测定T的方法是创伤性的,不易在临床推广。鉴于心尖搏动图(ACG)中含有压力和容积的信息,其波形、时间、高度和斜率都与左室压显著相关,ACG的一阶导数与心室压的一阶导数在时间和波形上也极相似。为此,我们提出了一个无创伤性的新指标——ACG幅度下降时间常数(Ta),拟用其代替T对心舒功能进行估测。
In 1976, Weiss et al found that left ventricular pressure (P) obeys an exponential declining pattern during isobolographic diastole (IRP): P = exp (-t / T + C), t is time, e is the base of natural logarithm, C is a constant and T is the time constant of left ventricular pressure drop. T can be used as an index to evaluate LV diastolic function. However, the method of determining T is traumatic, not easy to promote in the clinic. In view of the pressure and volume information contained in the apical beating chart (ACG), the waveform, time, height and slope are significantly correlated with left ventricular pressure. The first derivative of ACG and the first derivative of ventricular pressure are also very time and waveform similar. To this end, we propose a new non-invasive index - amplitude decay time constant (Ta), to be used instead of T to estimate cardiac function.