多普勒超声心动描记术检测胎儿机械性QT间期

Doppler echocardiography in measurement of mechanical QT interval of the fetal heart

目的探讨多普勒超声心动描记术在测量胎儿机械性QT间期中的应用价值。方法对胎儿心脏无异常的早孕期、中孕期和晚孕期孕妇各100名行胎儿多普勒超声心动描记术检查。记录左心室流入道及流出道血流频谱,测量机械性QT间期,即自二尖瓣舒张期A峰结束至下一个舒张期E峰开始的时间,同时测量胎儿心率。结果胎儿机械性QT间期和心率呈正态分布,早孕、中孕和晚孕组胎儿机械性QT间期均值的95%可信区间分别为225.25～231.21ms、241.21～248.79ms和253.23～259.45ms;不同孕期组间胎儿机械性QT间期和心率的差异均有统计学意义(P均<0.01);胎儿机械性QT间期与孕周呈正相关(r=0.499,P<0.01),胎儿心率与孕周呈负相关(r=-0.628,P<0.01)。结论应用多普勒超声心动描记术检测胎儿机械性QT间期简便易行,图像清晰且重复性好,可为临床诊断胎儿心律失常提供重要依据。

Objective To explore the value of Doppler echocardiography in measurement of mechanical QT interval of the fetal heart.Methods Totally 300 pregnant women with normal fetuses at the first,the second and the third trimester（each n=100） underwent fetal Doppler echocardiography.The blood flow spectrum of left ventricular inflow and outflow tract were recorded.The mechanical QT interval,i.e.the time interval from the end of mitral A wave to the onset of the mitral E wave was measured.In addition,the heart rate of the fetus was recorded.Results QT interval of the fetus distributed in normal fashion with 95% confidence interval of 225.25—231.21 ms in the first trimester group,241.21—248.79 ms in the second trimester group and 253.23—259.45 ms in the third trimester group,and so was the heart rate.There were significant differences in mechanical QT interval and heart rate among different trimester groups（all P0.01）.The mechanical QT interval was positively correlated（r=0.499,P0.01） and the heart rate was negatively correlated（r=-0.628,P0.01） with gestational week.Conclusion Doppler echocardiography is convenient and reproducible with clear images in measurement of mechanical QT interval of the fetal heart,which may provide important diagnostic standard for fetal arrhythmia.