Clinical application of mechanical PR interval of Doppler ultrasound in fetal cardiac
多普勒超声检测胎儿心脏机械性PR间期的临床意义研究

Objective To explore the application of mechanical PR interval of Doppler ultrasound measurement in fetal heart, and to analyze the test results and the clinical significance of a group of abnormal fetuses. Methods A total of 83 cases of abnormal group detected by fetal echocardiography were classified as congenital heart disease and arrhythmia. The healthy control group consisted of 100 cases in medium-term and late gestation. The pulse Doppler sample volume guided by color Doppler recorded the blood flow spectrum of left ventricular inflow tract / outflow tract and measured the conduction time from the beginning of the diastolic mitral A peak to the beginning of aortic systolic ejection （PR interval） and from the beginning of aortic systolic ejection to the beginning of mitral A peak （VA interval）. Results The eighty-three cases of abnormal group（69 cases of congenital heart disease and 12 cases of arrhythmia）included 54 cases of Doppler ultrasound measurement of PR interval prolongation （131-220 ms）. One hundred cases of normal control group had no autoimmune disease, which was ruled out by ultrasound of fetal congenital heart disease, arrhythmia and other fetal anomalies, whose Doppler ultrasound measurement of PR interval value was not less than 130 ms. The comparison PR interval versus VA interval had the most significant discriminating power （P 〈 0.01 ）. Conclusion The results of this study showed the pregnant women suffering from auto- immune diseases can lead to damage of fetal conduction system. In addition, the vulnerability of sinus node and atrioventricular node in the fetuses of congenital heart disease, arrhythmiawas significantly higher than normal group. The relevance between their pathogenic factors with abnormal anatomical structure of the cardiac dysplasia conduction system should be further studied.