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Objective:To measure mitral annual displacement (MAD) by M-mode echocardiography in normal second and third trimester fetuses. The relationships between MAD and gestational age and routine echocardiographic parameters for evaluation of left ventricular function were assessed.Methods:One hundred fifty-five normal fetuses from19to38weeks 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/Em 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<0.01), and between MAD and E, A, Em, Am or Sm (r=0.25,0.24,0.32,0.29and0.40respectively; P<0.01). There was no correlation between fetal MAD and E/A, E/Em, EF or FS. The left MAD was significantly lower than the right TAD (P<0.01). Conclusions:MAD of fetuses from19to38weeks of gestation can be quantitatively measured by using M-mode echocardiogram. The reference ranges provide a reliable quantitative standard to estimate long axis ventricular function of fetuses, which may be clinically useful in prenatal detecting early cardiac failure.
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