Evaluation of left ventricular function based on simulated systolic flow dynamics computed from regional wall motion.
Evaluation of left ventricular function based on simulated systolic flow dynamics computed from regional wall motion.
复制标题
根据局部室壁运动计算出的模拟收缩期血流动力学评估左心室功能。
DOI：
10.1016/0021-9290(94)90201-1
复制
发表时间：
1994
影响因子：
2.4
通讯作者：
Ray,G
中科院分区：
文献类型：
--
作者：
Schoephoerster,RT;Silva,CL;Ray,G
左心室（LV）腔室流量无疑会受到LV壁随时间变化的局部运动的影响。为了获得基于左心室血流的诊断参数，我们计算了两个右前斜（RAO）心室造影的左心室腔、二维收缩期速度和压力分布：一个正常，一个缺血性冠状动脉疾病，以及几个规定的异常室壁运动模拟。流场是通过求解二维粘性不可压缩非定常流的Navier-Stokes方程得到的。这些解决方案用作两个LV评估参数的基础：（1）LV壁附近的局部压力梯度，以及（2）中心射血区域（CER），定义为获得的速度场矢量与LV长轴对齐±5°的流域区域。根据CER在LV腔内的位置和方向导出的CER系数R被定义为：对于不产生CER的心脏，R =0;对于沿着整个RAO LV轮廓沿着完全均匀收缩的心脏，R =1。计算的局部压力梯度在缺血心脏近顶壁区域相比，在正常心脏计算。还表明心尖区压力梯度的幅度可观察到降低，以增加异常室壁运动的严重程度。然而，规定的异常室壁运动模拟在异常室壁运动区域和正常区域中也产生降低的压力梯度。因此，局部壁压梯度可能不适用于冠状动脉闭塞的定位，而仅适用于疾病的存在。正常心脏的时间平均CER系数为0.709，病变心脏的时间平均CER系数为0.453。CER向室壁运动异常区移动，CER系数随室壁运动异常程度增加而降低。CER系数提供了局部室壁运动分析无法提供的全局功能的定性和定量测量，并且是对局部和时间异常敏感的参数，以及无法通过全局参数检测到的由此产生的代偿动作。
Left ventricular (LV) chamber flow is undoubtedly influenced by the time-dependent regional motion of the LV wall. In an attempt to obtain diagnostic parameters based on LV chamber flow, we computed the LV chamber, two-dimensional systolic velocity and pressure distribution for two right anterior oblique (RAO) ventriculograms: one normal, one with ischemic coronary artery disease, and several simulations with prescribed abnormal wall motion. The flow fields are obtained by solving the discretized two-dimensional Navier-Stokes equations for viscous, incompressible unsteady flow using the finite analytic method. These solutions were used as a basis for two LV assessment parameters: (1) local pressure gradient near the LV wall, and (2) the central ejection region (CER), defined as the region of flow domain in which the obtained velocity field vectors are aligned ±5° from the LV long axis. A CER coefficient,R, derived from the location and orientation of the CER within the LV cavity, is defined such thatR=0 for a heart which produces no CER, andR=1 for a heart whose contraction is perfectly even along the entire RAO LV outline. The computed local pressure gradients in the ischemic heart near the apical wall region were reduced compared with those computed in the normal heart. An observable decrease in magnitude of the pressure gradients in the apical region for increasing severity of abnormal wall motion was also indicated. However, the prescribed abnormal wall motion simulations generated reduced pressure gradients in regions of abnormal wall motion and normal regions as well. Therefore, the local wall pressure gradient may not be suitable for localization of coronary occlusion but for presence of disease only. The time-averaged CER coefficient was 0.709 for the normal heart and 0.453 for the diseased heart. The CER shifted toward the region of LV wall which exhibits the abnormal motion, and the CER coefficient decreased with increasing severity of abnormal wall motion. The CER coefficient provides a qualitative and quantitative measure of global function that regional wall motion analysis cannot provide, and is a parameter which is sensitive to regional and temporal abnormalities and the resulting compensatory actions which cannot be detected by global parameters.