Kupari M, Koskinen P
Division of Cardiology (First Department of Medicine), Helsinki University Central Hospital, Finland.
Am J Cardiol. 1993 Nov 15;72(15):1172-8. doi: 10.1016/0002-9149(93)90989-p.
It is a common but unsubstantiated belief that blood flows through the left ventricular outflow tract (LVOT) with a spatially uniform velocity. Doppler echocardiography was performed to study in an apically obtained view of the LVOT the profile of subaortic velocities in 79 subjects free of clinical heart disease. The systolic velocities and time intervals were determined in the medial and lateral margins and the center of the LVOT. Peak systolic velocity measured 98 +/- 16 cm/s (mean +/- SD) in the medial margin of the LVOT close to the subaortic ventricular septum, 89 +/- 14 cm/s in the midline of the LVOT, and 79 +/- 14 cm/s in the lateral margin of the LVOT close to the base of the mitral valve (p < 0.001). The respective means of the velocity-time integrals were 19 +/- 3, 17 +/- 3 and 14 +/- 3 cm (p < 0.001). Systolic time intervals determined from the flow signals differed also statistically significantly across the recording sites in the LVOT. The velocity measurements obtained in the center of the LVOT were nearly identical with the values averaged over all measurements across the LVOT. It is concluded that the systolic flow velocity profile in the LVOT is not flat, as has been assumed, but skewed toward faster flow along the subaortic ventricular septum. Measurements made in the center of the LVOT can be used as surrogate for the spatial average velocities.
人们普遍认为血液以空间均匀的速度流经左心室流出道（LVOT），但这一观点缺乏依据。本研究采用多普勒超声心动图，在经心尖获得的LVOT视图中，对79例无临床心脏病的受试者的主动脉瓣下速度分布进行了研究。测定了LVOT内侧缘、外侧缘及中心的收缩期速度和时间间期。LVOT靠近主动脉瓣下室间隔的内侧缘处，收缩期峰值速度为98±16cm/s（均值±标准差）；LVOT中线处为89±14cm/s；LVOT靠近二尖瓣瓣环的外侧缘处为79±14cm/s（p<0.001）。速度-时间积分的相应均值分别为19±3、17±3和14±3cm（p<0.001）。根据血流信号测定的收缩期时间间期在LVOT各记录部位之间也存在统计学显著差异。在LVOT中心获得的速度测量值与LVOT所有测量值的平均值几乎相同。结论是，LVOT的收缩期血流速度分布并非如假设的那样平坦，而是沿主动脉瓣下室间隔向更快的血流方向倾斜。在LVOT中心进行的测量可作为空间平均速度的替代值。
