应用二维斑点追踪技术（2D-STE）定量正常中晚孕期胎儿右心房应变，评估正常胎儿右心房功能，并分析胎儿右心房应变的可能影响因素及与左心房应变的关联性。

选取2021年11月至2022年3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中晚孕胎儿261例，采集标准四腔心观动态图像，脱机应用2D-STE离线分析软件测量胎儿心房整体纵向应变，得出应变曲线及参数。分析胎儿左、右心房应变曲线及应变参数获得情况，正常胎儿右心房应变参数、心率与孕龄的相关性以及应变参数显示率与孕龄、心率、帧频等的关系，并对右心房应变与左心房应变进行比较及相关性分析。

261例胎儿中244例（93%，244/261）成功获得右心房应变曲线。其中131例（54%，131/244）胎儿可识别右心房储存期应变（RASr）、管道期应变（RAScd）及收缩期应变（RASct），并计算管道期与储存期应变之比（RAratio），113例（46%，113/244）胎儿仅识别RASr，未能识别RAScd及RASct。RASr、RASct与孕龄呈弱负相关（r=-0.205，P=0.001；r=-0.235，P=0.007），RAratio与孕龄呈弱正相关（r=0.178，P=0.042）。显示RASct组胎儿的心率低于未显示RASct组[（146.34±8.83）次/min vs（149.67±7.49）次/min，P<0.05]。右心房的3个时相应变值均高于左心房（P均<0.05），且RASr与左心房储存期应变（LASr）（r=0.581，P<0.001），RAScd与左心房管道期应变（LAScd）（r=0.258，P=0.004），RASct与左心房收缩期应变（LASct）（r=0.413，P<0.001）均呈正相关性。

2D-STE在正常胎儿右心房功能评估中具有良好的可行性和可重复性，正常胎儿右心房功能与左心房相似，存在3个时相，并与孕龄存在弱相关性。

To quantify the right atrial strain of normal fetuses in the second and third trimester of pregancy by using two-dimensional speckle tracking echocardiography (2D-STE) to evaluate the normal fetal right atrial function, and to analyze the possible influencing factors of fetal right atrial strain and its correlation with left atrial strain.

A total of 261 normal second- and third-trimester fetuses who underwent fetal echocardiography at Sir Run Run Shaw Hospital, Zhejiang University College of Medicine from November 2021 to March 2022 were selected. The standard four-chamber views were collected. 2D-STE offline analysis software was used to measure the global longitudinal strain of the fetal atrium, and the strain curves and parameters were obtained. The acquisition of fetal left and right atrial strain curves and parameters was analyzed. The correlation between fetal right atrial strain, heart rate, and gestational age, as well as the relationship between the display rate of strain and gestational age, heart rate, and frame rate, was analyzed. The comparison and correlation between right and left atrial strain was analyzed.

Right atrial strain curves were successfully obtained in 244 (93%, 244/261) of the 261 fetuses included. Among them, 131 (54%,131/244) fetuses had detectable right atrial reservoir strain (RASr), conduit strain (RAScd), and contraction strain (RASct), and the ratio of conduit strain to reservoir strain (RAratio) was calculated. In 113 cases (46%, 113/244) fetuses, only RASr, but not RAScd and RASct, could be identified. RASr and RASct had a weak negative correlation with gestational age (r=-0.205, P=0.001; r=-0.235, P=0.007), and RAratio had a weak positive correlation with gestational age (r=0.178, P=0.042). The fetal heart rate in the RASct group was lower than that in the non-RASCT group [(146.34±8.83) beats/min vs (149.67±7.49) beats/min, P<0.05]. The three-phase strain values of the right atrium were higher than those of the left atrium (P<0.05 for all). RASr was positively correlated with left atrial reservoir strain (LASr) (r=0.581, P<0.001), RAScd was positively correlated with left atrial conduit strain (LAScd) (r=0.258, P=0.004), and RASct was positively correlated with left atrial contraction strain (LASct) (r=0.413, P<0.001).

2D-STE has good feasibility and repeatability in assessing right atrial function in normal fetuses. The function of the right atrium in normal fetuses is similar to that of the left atrium, with three phasic strains. Right atrial strain has a weak negative correlation with gestational age.