Preliminary Study On Left Ventricular Torsion In Normal Fetal Left Ventricular With Velocity Vector Imaging

ObjectiveThe purpose of this study was to detect the rotation and twist parameters of endocardial and epicardial of five groups normal fetal left ventricular with velocity vector imaging(VVI) quantitatively and to establish nomogram in different gestational age fetuses. Observed the characteristics of rotation and twist in normal fetal left ventricular and the trends with increasing gestational age. Investigated the feasibility and clinical value of fetal left ventricular twist using VVI.Materials and methodsThe total of 150 cases of pregnant women who were referred for routine prenatal ultrasound examination at FuZhou General Hospital between August 2009 and September 2010 were enrolled as research subjects. Maternal age ranged from 21 to 43 years(mean,29.3±3.0 years). Gestational ages ranged from 20⁺⁰ to 39⁺¹ weeks (mean,29.6±5.6). The fetal heart rate mean was (145±10)bpm. Pregnant women are healthy, the fetuses of mothers without the history of smoking and alcoholism, chronic disease such as hypertension, diabetes mellitus, heart, liver and kideney diseases, reproductive history and family history of congenital heart disease, were excluded.All of them were singleton pregnancies. Growth and development indicators were appropriate for gestational age. The obstetric, routine prenatal ultrasound examination and fetal echocardiography examination were showed normal.All fetuses were divided into five groups according to their gestational age:20⁺⁰～23⁺⁶ week group(n=32), 24⁺⁰～27⁺⁶ week group(n=33), 28+0～31+6 week group(n=29), 32⁺⁰～35⁺⁶ week group(n=28), 36+0～39⁺¹week group(n=28).Using Siemens Sequoia C512 ultrasound diagnostic apparatus, the probe was 8v3, frequencies were 4.0 6.0MHZ, using VVI processing software. Result97 cases out of 150 fetus were analyzed successfully, which obtained satisfactory clear endocardium and epicardium of left ventricular apical and base short axis and left ventricular fractional VVI dynamic images.The successful rate was about 65.3%,whereas 53 cases out of 150 fetus failed to be analyzed with VVI, because of fetal movement, maternal respiration et al result in unclear endocardium and epicardium.Establish five groups nomogram of the endocardial and epicardial of normal fetal left ventricular rotation and twist parameters with VVI in the different gestational age fetuses. The study found that base and apex of normal fetal left ventricular rotation and twist direction were opposite,the rotation in one direction to the maximum in the systolic period and the rotation in one opposite direction in the diastolic period.Endocardial and epicardial, the apex velocity peak and angle peak of rotation and torsion were higher than the base,with statistically significant(P <0.05). Base and apex, the endocardial rotation and twist velocity peak and angle peak were higher than the epicardium,with statistically significant(P <0.05). Either endocardium or epicardium, base or apex, systolic and diastolic period,rotation and twist velocity peak and angel peak were not increases with the increasing of gestational age, without statistically significant(P> 0.05).ConclusionThis study establish nomogram of the endocardial and epicardial of normal fetal left ventricular rotation and twist parameters with VVI in the different gestational age fetuses.Base and apex of normal fetal left ventricular rotation and twist direction were opposite.In the systolic period,rotation of fetal left ventricular in one direction to the maximum, in the opposite direction to a relaxation of the helicase.Either endocardial or epicardial, the apex of absolute value of rotation velocity peak is higher than the base. Either base or apex, the endocardial rotation velocity peak and rotation velocity peak are higher than the epicardium.It reminds us that from the second trimester of fetal children and adults already have similar twist of left ventricular. Either endocardium or epicardium, base or apex, systolic and diastolic rotation velocity peak and rotation veloctiy peak are not increases with the increases of gestational age. VVI is a effective technology for evaluation the endocardial and epicardial rotation and twist of normal fetal left ventricular. Anatomical M -mode can accurately distinguish systolic and diastolic of fetal heart.