Diagnostic study of fetal first degree atrioventricular block by tissue Doppler imaging
GUO Min1, ZHU Qi2
1. Hospital of University of Electronic Science and Technology of China, Chengdu 611731, China; 2. Department of Ultrasound, West China Second University Hospital, Sichuan University, Chengdu 610041, China
Abstract:Objective: To confirm the suitable index and critical value in diagnosing the fetal first degree atrioventricular block. Methods: Sixty-two pregnant women in third trimester(≥38 week) of our out-patient clinic were erolled. TDI-derived AV intervals were measured as the intervals from atrial contraction(Aa) to isovolumic contraction(IV) and from Aa to ventricular systole(Sa). Their neonatal ECG were performed and the correlation between the neonatal PR intervals and fetal TDI values was analysed by linear regression. Receiver operator characteristic(ROC) curve was established to compare the diagnostic value of Aa-IV and Aa-Sa and to determine the most suitable critical value to screen the fetal first degree atrioventricular block. Results: Aa-IV correlated significantly better with neonatal PR intervals than did Aa-Sa. The ROC showed secondary diagnostic value of Aa-IV and only little diagnostic value of Aa-Sa. The point(Aa-IV=93.7 ms) of Aa-IV curve with sensitivity 100% and specificity 51%, was confirm to screen the first degree atrioventricular block. Conclutions: TDI-derived Aa-IV can assess the fetal atrioventricular time interval more accurately than did Aa-Sa. The point(Aa-IV=93.7 ms) should be used as the critical value to screen the fetal first degree atrioventricular block.