Comparison Study Of Fetal Heart Conduction Time By Pulmonary Artery And Vein Complex And Left Ventricular Inflow And Outflow Tract With Pulse Doppler

Objectives By comparing the observed pulse doppler in left ventricular inflow outflow and Pulmonary arteriovenous complex measurement of fetal heart atrioventricular conduction time,To evaluate the clinical application of pulmonary arteriovenous complex in measuring normlal fetal atrioventricular conduction time with pulse Doppler, and analyze of the relationship between fetal atrioventricular conduction time and gestational age as well as fetal heart rate.Methods 1 Object 231 cases of normal singleton pregnant women who underwent routine prenatal ultrasound and fetal echocardiography were selected randomly from October 2015 to January 2016. Inclusion criteria as follow: pregnant women with no cardiovascular malformations and diseases of the immune system were selected. 15 fetuses of them were excluded for cardiac abnormalities and persistent arrhythmia after being examed by fetal echocardiography. The other 216 normal fetuses were selected as study subjects, pregnant women aged 20~39 years old, averaged(27.04±2.13) years old, gestational age were 20~40 weeks, averaged(26.93±5.31) weeks. 2 Routine examination: Routine obstetric examination as follow: pregnant women took supine or left lateral position, opened the obstetric procedures, firstly made sure fetal position in the uterus by detecting fetal spinal and head foot, and determined fetal left and right. Estimated gestational age through measurement of abdominal circumference, biparietal diameter, humerus length, head circumference, femur length and so on. Determined apical direction and the right or left sides of the heart according to the position of the fetus, stomach, spine, ovale valve direction; Fetal echocardiography examnation as follow: including fetal four chamber view of the heart, three vessels and trachea view, abdominal transverse section, long axis view of aortic arch and ductus arteriosus arch axis section, left and right ventricular outflow tract long axis view, pulmonary arteriovenous complex section, superior and inferior vena cava long section and so on. 3 Measurement of parameters: After fetal bottom or oblique four chamber heart standard section were showed, the enhanced display type flow imaging(e-Flow) and color Doppler flow imaging(CDFI) were applied to show the left and right pulmonary artery and vein complex, and fetal heart conduction time spectrum were obtained by adding superimposed pulse Doppler(PD). After left ventricular inflow and outflow tract views were displayed on the heart or the apical five chamber view of the heart, sampling line were placed on the left ventricular inflow tract and outflow tract junction, and then Amplified sample volume and obtained fetal heart conduction time spectrum with pulse doppler. Sampling line should be in the direction of blood flow as parallel as possible or included angle <15°. 4 the research objects were divided into 3 groups according to the heart rate(heart rate<140 times/min, 140~150 times/min, heart rate>150 times/min), and four groups according to fetal age(20~22 weeks, 23~ 26 weeks, 27~32 weeks, 33~40 weeks). The AV values(from the atrial to ventricular conduction time), VA value(onset of ventricular contraction to a cardiac cycle the onset of atrial contraction time and heart rate were measured. 5 T test was used to compare the difference of two methods in measuring fetal heart conduction time. The relationship between fetal heart conduction time and fetal age as well as heart rate were analyzed by linear correlation analysis. The fetal heart conduction times of different gestational weeks were compared by single factor analysis of variance. P<0.05 was thought to show the significance statistically. All data was analyzed by SPSS19.0 statistical package.Results 1 Result of fetal heart and heart conduction time examination: None of the 216 cases of fetal examined had abnormal cardiac structure and persistent arrhythmia. The AV value and VA value were successfully obtained in the section of the pulmonary artery and vein and the left ventricular inflow and outflow tract. The successful rates of measurements with the two methods have no significantly different. 2 Results of heart conduction times of pulmonary arteriovenous complex and left ventricular inflow and outflow tract views: AV values of pulmonary arteriovenous complex was(131.61±13.56) ms, VA value was(274.89± 22.54) ms; AV value of left ventricular inflow outflow tract was(120.99 ±10.33) ms, VA value was(28.617 ±24.36) ms. After AV values and VA values measured by two sections were compared, the difference had statistically significant(AV: t=9.156, P<0.01; VA: t=4.995, P<0.01). AV values of pulmonary artery and vein complex were longer than that of the left ventricular outflow tract, and the VA value of the pulmonary artery and vein complex section was shorter than that of the left ventricular outflow tract. The result indicates that heart conduction time of the pulmonary artery and vein complex can not be replaced by that of the left ventricular outflow tract. 3 The correlation of between AV value, VA value and gestational age as well as heart rate: AV value, VA value showed positive correlation with gestational age, and negative correlation with heart rate. All of the correlations had statistically significance. the correlations between VA and the fetal heart rate was more closer, and R value reaches more than 0.8, but R values of other correlations were less than 0.5. 4 Normal value range of heart conduction time in pulmonary arteriovenous complex and left ventricular inflow and outflow tract views: According to the normality test analysis, AV, VA values were in accord with normal distribution, so the normal distribution method could be taken, namely x±1.96 S to calculate normal value range of heart conduction time of them. The normal AV value range of pulmonary arteriovenous complex was(129.65~133.60) ms, that of VA was(271.69~278.25) ms.Conclusions 1 In pulse doppler fetal pulmonary arteriovenous complex edge detected fetal cardiac conduction time, with the traditional left ventricular inflow/outflow section measuring value comparison, the AV value increases, the VA value decreased, but are in complete accord with gestational age and the relationship of the heart rate. That with the increase of gestational age, cardiac conduction time increased; The faster the heart rate, cardiac conduction time is shorter. 2 This study established the normal values of fetal heart conduction time. Fetal cardiac conduction time of pulmonary arteriovenous complex has its own reference range. Namely 20~32 weeks,that is AV: 102.40~155.10 ms, VA: 232.07~312.38 ms, 33~40 weeks, that is AV: 113.67~164.43 ms, VA: 222.88~339.03 ms.