无创性估测左室心肌松弛时间常数的新方法

New approach for noninvasive assessment of left ventricular relaxation time constant

目的 探讨无创性估测左室心肌松弛时间常数的新方法。方法 在３０ 例二尖瓣返流患者中，应用返流压差法测量左室松弛时间常数（Ｔ） ，应用脉冲波多普勒测量二尖瓣瓣尖及瓣下１ ｃｍ 、２ ｃｍ 及３ｃｍ 取样点的Ｅ 波流速、瓣下各点与瓣尖Ｅ 波流速比值，各点心电图Ｒ 波顶峰至Ｅ 波顶峰的时间（ ＲＥ） 、瓣下各点与瓣尖ＲＥ０ 时间比值。结果 在各项指标中，ＲＥ２／ＲＥ０ 和ＲＥ３／ ＲＥ０ 两项指标与Ｔ 值相关最佳（ｒ ＝ ０ ．８７ 和ｒ ＝ ０ ．８９ ， Ｐ ＜ ０ ．００１） 。结论 左室松弛减退可导致Ｅ 波传播时间的延长，而左室中部与二尖瓣瓣尖ＲＥ 比值为无创性估测Ｔ 值提供了一个新的方法。

Objectives To find a new method for evaluating the left ventricular relaxation time constant noninvasively.Methods The time constants (Tau) were measured by computer from the mitral regurgitation spectra in 30 patients with mitral regurgitation,Mitral peak flow velocity E at mitral tip level(E 0) and at 1 cm,2 cm and 3 cm below mitral tip toward the apex (E 1,E 2,E 3) and the interval from ECG peak of R to the peak of velocity E(R E 0,R E 1,R E 2,R E 3) were recorded by pulsed Doppler.The E 1,E 2,E 3 to E 0 ratios (E 1/E 0,E 2/E 0,E 3/E 0) and R E 1,R E 2,R E 3 to R E 0 ratios(R E 1/R E 0,R E 2/R E 0,R E 3/R E 0) were measured simulataneously.Results R E 3/R E 0,R E 2/R E 0 correlated well with Tau (r= 0.87 and r= 0.89 ,P< 0.001 ).Conclusions Impaired relaxation of left ventricle may lead time delay to reach peak velocity E,R E ratio between mid left ventricle and mitral tip provide a new method in the noninvasive evaluation of the time constant.