采用3种多普勒超声检查方法：上腔静脉/升主动脉脉冲多普勒同步记录法（SVC/AAO）、二尖瓣环组织多普勒法（TDI）及肺动/静脉脉冲多普勒同步记录法（PA/PV）分别创建中晚孕期胎儿心脏房室传导时间（AV）正常值参考范围，并分析AV值与孕周、胎儿心率及心脏面积的相关性。

选取2019年6月至12月在浙江大学医学院附属邵逸夫医院接受胎儿超声心动图检查的正常胎儿227例入选本研究，孕周为16~41周，根据孕周分为5组，采用SVC/AAO法、TDI法及PA/PV法分别测量AV值，分析3种方法的测量成功率；并获得不同孕周组AV值的正常范围；采用单因素方差分析及多重比较（LSD-t法）对不同方法获得AV值的差异进行分析，对AV值与孕周、胎儿心率及胎儿心脏面积之间进行Pearson相关分析；采用组内相关系数（ICC）评估每种方法检查者内和检查者间重复性。

3种方法均取得了较高的测量成功率，SVC/AAO法为94.58%；TDI法为100%；PA/PV法为95.83%；测得AV值正常范围：AV-SVC/AAO为（115.94±6.67）ms；AV-TDI为（117.69±6.43）ms；AV-PA/PV为（123.70±6.42）ms，AV-PA/PV最大，AV-SVC/AAO最小，两两比较差异均具有统计学意义（t=-2.843、-12.662、-9.819，P=0.005、＜0.001、＜0.001）；所有AV值与孕周均呈正相关（r=0.677~0.680，P＜0.001），与胎儿心脏面积均呈正相关（r=0.648~0.654，P＜0.001），与胎儿心率均呈负相关（r=-0.568~-0.581，P＜0.001）。观察者内及观察者间重复性检验显示3种多普勒超声检查方法测量的重复性均良好（ICC均＞0.80）。

3种多普勒超声检查方法用于测量胎儿心脏AV可行且重复性好；中晚孕期正常胎儿AV值受孕周、胎儿心脏面积及胎儿心率影响，且不同方法所测得AV值存在差异；因此，应选择一种合适的方法测量胎儿心脏AV，同时，需要认识到不同的方法所得测量值之间的差异性，这在临床工作中具有重要意义。

To establish the normal range of fetal atrioventricular (AV) time intervals during the second and third trimesters assessed by three different pulsed-wave Doppler techniques [superior vena cava and ascending aorta (SVC/AAO) method, tissue Doppler imaging (TDI), and pulmonary artery and pulmonary vein (PA/PV) method and analyze the correlation of AV value with gestational age, fetal heart rate, and heart area.

From June to December 2019, 227 normal fetuses who underwent echocardiography at the Sir Run Run Shaw Hospital of Zhejiang University College of Medicine were selected. The gestational age was 16 to 41 weeks. They were divided into five groups according to gestational age. Pulsed-wave Doppler methods including SVC/AAO, TDI, and PA/PV were applied to measure AV, respectively. The measurement success rate and the normal range of AV values in different gestational weeks were obtained. Single-factor analysis of variance and multiple comparisons (LSD-t method) were used to analyze the differences in AV values obtained by different methods. Pearson correlation analysis was performed to examine the correlation of AV values with gestational age, fetal heart rate, and fetal heart area. Intraclass correlation coefficient (ICC) was used to evaluate the in-observer and inter-observer repeatability of each method.

All the three Doppler methods achieved a high measurement success rate: SVC/AAO, 94.58%; TDI, 100%; PA/PV, 95.83%. The normal range of AV values was: AV-SVC/AAO, (115.94±6.67) ms; AV-TDI, (117.69±6.43) ms; AV-PA/PV,(123.70±6.42 )ms; the difference between them was statistically significant (t=-2.843, -12.662, -9.819; P=0.005, ＜0.001, ＜0.001). All AV values were positively correlated with gestational age (r=0.677~0.680, P＜0.001) and fetal heart area (r=0.648~0.654, P＜0.001), but negatively correlated with fetal heart rate (r=-0.568~-0.581, P＜0.001). In-observer and inter-observer repeatability tests showed that the three Doppler methods had good repeatability (ICC＞0.80).

All the three Doppler methods are feasible and reproducible in measuring fetal heart AV values; normal fetal AV values in the second and third trimesters are affected by gestational age, fetal heart area, and fetal heart rate, and there are differences in AV values measured by different methods. Therefore, choosing an appropriate method to measure the fetal AV time and understanding the difference between the measured values by different methods are very important in clinical work and have very important significance.