Department of Obstetrics and Gynecology, Máxima Medical Center, Veldhoven, The Netherlands.
Eindhoven MedTech Innovation Center (e/MTIC), Eindhoven, The Netherlands.
PLoS One. 2021 Dec 16;16(12):e0256115. doi: 10.1371/journal.pone.0256115. eCollection 2021.
A fetal anomaly scan in mid-pregnancy is performed, to check for the presence of congenital anomalies, including congenital heart disease (CHD). Unfortunately, 40% of CHD is still missed. The combined use of ultrasound and electrocardiography might boost detection rates. The electrical heart axis is one of the characteristics which can be deduced from an electrocardiogram (ECG). The aim of this study was to determine reference values for the electrical heart axis in healthy fetuses around 20 weeks of gestation.
Non-invasive fetal electrocardiography was performed subsequent to the fetal anomaly scan in pregnant women carrying a healthy singleton fetus between 18 and 24 weeks of gestation. Eight adhesive electrodes were applied on the maternal abdomen including one ground and one reference electrode, yielding six channels of bipolar electrophysiological measurements. After removal of interferences, a fetal vectorcardiogram was calculated and then corrected for fetal orientation. The orientation of the electrical heart axis was determined from this normalized fetal vectorcardiogram. Descriptive statistics were used on normalized cartesian coordinates to determine the average electrical heart axis in the frontal plane. Furthermore, 90% prediction intervals (PI) for abnormality were calculated.
Of the 328 fetal ECGs performed, 281 were included in the analysis. The average electrical heart axis in the frontal plane was determined at 122.7° (90% PI: -25.6°; 270.9°).
The average electrical heart axis of healthy fetuses around mid-gestation is oriented to the right, which is, due to the unique fetal circulation, in line with muscle distribution in the fetal heart.
在妊娠中期进行胎儿异常扫描，以检查是否存在先天性异常，包括先天性心脏病（CHD）。不幸的是，40%的 CHD 仍然会被漏诊。超声和心电图的联合使用可能会提高检测率。心脏电轴是可以从心电图（ECG）中推断出的特征之一。本研究旨在确定健康胎儿在妊娠 20 周左右的心脏电轴参考值。
在妊娠 18 至 24 周期间携带健康单胎的孕妇中，在进行胎儿异常扫描后，对胎儿进行非侵入性胎儿心电图检查。将 8 个粘性电极贴在孕妇腹部，包括一个接地电极和一个参考电极，产生 6 个双极电生理测量通道。去除干扰后，计算胎儿心向量图，然后根据胎儿方位进行校正。从这个正常化的胎儿心向量图中确定心脏电轴的方位。对正常化笛卡尔坐标进行描述性统计，以确定额面的平均心脏电轴。此外，还计算了异常的 90%预测区间（PI）。
在进行的 328 次胎儿心电图中，有 281 次纳入分析。额面的平均心脏电轴确定为 122.7°（90%PI：-25.6°；270.9°）。
健康胎儿在妊娠中期的平均心脏电轴向右，这与独特的胎儿循环有关，与胎儿心脏中的肌肉分布一致。
