二尖瓣环位移对正常胎儿左心功能的定量研究

Quantitative study of left ventricular function in the normal fetuses by mitral annular displacement

目的探讨M型超声心动图测量中晚孕期正常胎）L2尖瓣环位移（MAD）与常规方法评价胎儿左心功能参数之间的关系。方法用M型超声心动图测量155例孕龄在19～38周的正常胎儿的MAD，脉冲多普勒（PW）测量房室瓣口血流频谱的舒张早期峰值流速（E），组织多普勒（TDI）测量房室瓣环处心肌运动频谱的舒张早期峰值流速（Era）及两者的比值（E／Em），定量分析MAD与孕周及常规胎儿左心功能参数之间的相关性。结果正常胎儿MAD值为（7．05±1．17）mm。MAD与孕周呈显著正相关（r=0．82，P〈0.01），与其他评价左心功能的指数E、A、Em、Am、Sm呈正相关（r值分别为0．25、0．24、0．32、0．29、0．40，P值均〈O．01），但与E／A、E／Em、左室射血分数（LVEF）、左室短轴缩短率（LVFS）无显著相关性（P值均〉O．05）。MAD在任何孕周均小于三尖瓣环位移。结论MAD是评价胎儿长轴方向左室功能有价值的参考标准，正常中晚孕胎儿MAD值随孕周增加而增长，其评价胎儿左室功能与PW二尖瓣口E、A峰值流速及TDI二尖瓣瓣环Em、Am、Sm等传统左室功能评价参数有良好的相关性，与传统方法相比具有更好的简便性及可重复性。

Objective To measure mitral annual displacement （MAD） by M-mode echocardiography in normal second and third trimester fetuses,and assess relationships between MAD and gestational age and routine echocardiographic parameters for evaluation of left ventricular function. Methods One hundred fifty-five normal fetuses from 19 to 38 weeks of gestation were recruited in the study. MVD and tricuspid annual displacement （TAD） were measured. Early diastolic inflow velocities （E） of the atrioventricular valves were assessed by pulsed-wave Doppler（PW） ,and early diastolic velocities （Em） of the mitral annular were estimated by pulsed-wave tissue Doppler imaging （TDI）. The ratio of E/Era was calculated. Results In normal fetuses,the MAD was （7.05 ± 1.17） mm. There was significant positive correlation between the fetal MAD and advancing gestational age （ r = 0.82, P d0.01） ,and between MAD and E,A,Em,Am or Sm （ r = 0. 25,0. 24,0. 32,0. 29 and 0.40 respectively, P 〈0.01）. There was no correlation between fetal MAD and E/A,E/Em,LVEF or LVFS. The left MAD was significantly lower than the right TAD （ P〈 0.01）. Conclusions MAD of fetuses from 19 to 38 weeks of gestation can be quantitatively measured by Mmode echocardiogram. The measurement of MAD provides a reliable quantitative standard to estimate long axis ventricular function of fetuses,which may be clinically useful in prenatal detecting early cardiac failure.