Intrathoracic cardiac position in the fetus

Abstract

In a 4-year period, 83 fetuses have been noted to have an abnormal fetal heart position within the thorax on fetal echocardiography. In 55 cases where the heart lay in the right chest, this was due to the presence of a left-sided diaphragmatic hernia; in one case, the heart was abnormally far into the left chest because of a left-sided diaphragmatic hernia. Of the remaining 27 cases, the heart lay in the right chest in 16 cases. In seven of those 16, there was a congenital heart malformation; in six, there were lung anomalies; a hiatus hernia was present in one; both congenital heart disease and lung abnormality were present in one and one fetus had isolated dextrocardia. In nine cases, the heart lay in the center of the chest and in three, the heart lay further to the left than normal. Congenital heart disease was found in nine of these 12. Chromosomal anomalies were found in four of the 27 cases with an abnormal heart position but an intact diaphragm. In summary, it is important to be familiar with the normal cardiac orientation within the thorax and to investigate abnormalities of position. A diaphragmatic hernia will be the most common underlying cause but, where the diaphragm is intact, other explanations must be sought in order to counsel correctly or plan appropriate perinatal management. Lung disorders, congenital heart disease and chromosomal anomalies will be the principal differential diagnoses.

Fetal Cardiac Axis and Congenital Heart Defects in Early Gestation

“…[14][15][16] This observation supports the earlier proposed theory that fetal cardiac axis establishes its position by the 12th week of gestation and remains unchanged during pregnancy. 17,18 Studies performed in the second and third trimesters have differed slightly with regard to the definition of an abnormal cardiac axis. The very first study by Comstock 13 suggested an abnormal cardiac axis as greater than 65°or less than 25°.…”

Prenatal echocardiographic diagnosis of cardiac right/left axis and malpositions according to standardized Cordes technique

“…Generally, intrinsic congenital heart diseases cause abnormal cardiac axis (17,18). In addition, extracardiac malformations are often responsible for the abnormal location of the heart in the thorax due to mediastinal shift (19). In our study among 20 cases with cardiac malposition, 16 had congenital heart disease, and four had extracardiac malformation.…”

Antenatal sonographic findings of right pulmonary agenesis with ipsilateral microtia: a possible new laterality association

“…This may include the use of color Doppler¯ow and vaginal sonography to detect any additional laterality patterns or associated malformations. Fetal karyotyping is also recommended since chromosomal abnormalities have been found in 4/27 cases with abnormal position of the heart and intact diaphragm (Allan and Lockhart, 1993).…”

“…Thus in cases of unilateral right pulmonary agenesis this will result in secondary dextrocardia in situs solitus. Other indirect signs include cystic structure in the chest or an abnormal upper abdomen (Allan and Lockhart, 1993;Yancey and Richards, 1993). However, a more reliable direct sign for this pathology is the lack of branching of the pulmonary artery (Kalache et al, 1997).…”