Moon-Grady A J, Taylor D, Bennett S H, Hornberger L K, Tacy T A
Department of Pediatrics, University of California Davis, Sacramento, San Francisco, CA, USA.
Ultrasound Obstet Gynecol. 2008 May;31(5):535-41. doi: 10.1002/uog.5303.
Color M-mode propagation velocity (Vp) is a measure of diastolic function in adults and, when combined with early diastolic inflow velocity (E), the ratio E/Vp reflects ventricular filling pressure. Early detection of diastolic compromise may benefit fetal patients at risk for developing heart failure. The objectives of this study were to measure values for Vp and inflow peak E in a group of normal fetuses, to analyze age-dependent alterations in these measurements, and to evaluate the interobserver and intraobserver variability of the measurements.
Thirty-two normal fetuses at between 20 and 35 weeks' gestation underwent echocardiography. Color M-mode Vp was measured from the four-chamber view for the right (RV) and left (LV) ventricles, and mitral and tricuspid inflow velocities were determined by pulsed-wave Doppler ultrasound. The values obtained were compared with previously reported findings in adults.
Adequate tracings were obtainable in 23 patients for the RV and 29 for the LV. Mean Vp values for the RV (15.3 +/- 3.2 cm/s) and LV (20.8 +/- 5.6 cm/s) were lower than normal adult values, and Vp values were significantly lower for the RV than the LV (P < 0.001). Applying Bazett's heart rate correction, values for RV (23.4 +/- 4.8 cm/s) and LV (31.9 +/- 8.7 cm/s) remained lower than normal adult values. There was a linear correlation of Vp with gestational age for the RV (R = 0.69, P < 0.001), and the ratio of E/Vp corrected for heart rate for the RV (1.51 +/- 0.26) remained constant throughout gestation. Interobserver bias was high but intraobserver bias low, at 19 and 1.1%, respectively.
Vp is lower in fetal than in adult life. Vp for the RV changes in a manner indicative of improving diastolic function throughout normal gestation, providing insight into the alterations in diastolic function with gestation that contribute to increases in cardiac output. The use of Vp to assess diastolic function disturbance in fetuses is feasible, but high interobserver variability is problematic.
彩色M型传播速度（Vp）是评估成人心室舒张功能的一项指标，与舒张早期血流速度（E）相结合时，E/Vp比值可反映心室充盈压。早期发现舒张功能受损可能使有发生心力衰竭风险的胎儿患者受益。本研究的目的是测量一组正常胎儿的Vp值和流入峰值E，分析这些测量值随年龄的变化，并评估测量值在观察者间和观察者内的变异性。
对32例妊娠20至35周的正常胎儿进行超声心动图检查。从四腔心切面测量右心室（RV）和左心室（LV）的彩色M型Vp，并通过脉冲波多普勒超声测定二尖瓣和三尖瓣的血流速度。将获得的值与先前报道的成人结果进行比较。
23例患者可获得右心室的合适描记图，29例可获得左心室的合适描记图。右心室（15.3±3.2cm/s）和左心室（20.8±5.6cm/s）的平均Vp值低于正常成人值，且右心室的Vp值显著低于左心室（P<0.001）。应用巴泽特心率校正后，右心室（23.4±4.8cm/s）和左心室（31.9±8.7cm/s）的值仍低于正常成人值。右心室的Vp与胎龄呈线性相关（R=0.69，P<0.001），且右心室经心率校正后的E/Vp比值（1.51±0.26）在整个妊娠期保持恒定。观察者间偏差较高，但观察者内偏差较低，分别为19%和1.1%。
胎儿期的Vp低于成人期。右心室的Vp在整个正常妊娠期以表明舒张功能改善的方式变化，这有助于深入了解妊娠期舒张功能的改变对心输出量增加的影响。使用Vp评估胎儿舒张功能障碍是可行的，但观察者间变异性较高是个问题。
