Comparing levocardia and dextrocardia in fetuses with heterotaxy syndrome: prenatal features, clinical significance and outcomes.

BACKGROUND: To investigate the differences in cardiovascular disease, extracardiac anomalies and outcomes between fetuses with levocardia and dextrocardia. METHODS: Clinical demographics, prenatal features, postnatal characteristics and the outcomes of fetuses with levocardia or dextrocardia were recorded and analyzed. RESULTS: Sixty-five fetuses with dextrocardia and thirty-eight fetuses with levocardia were enrolled. Right ventricle outlet obstruction, atrioventricular septal defect and intestinal malrotation were common in both groups. Univentricular physiology, transposition of the great arteries and esophageal atresia were more frequent in fetuses with levocardia, whereas abnormal pulmonary venous connection, double outlet of right ventricle, left ventricle outlet obstruction and brain abnormalities were more frequent in the dextrocardia group. The accuracy of evaluating cardiac malformations was high, but the sensitivity in assessing extracardiac abnormalities was low. CONCLUSIONS: Although the disorders have certain overlapping features, there are several differences between fetuses with levocardia and dextrocardia. These findings might improve patient counseling and perinatal management.

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

OBJECTIVE: The aim of this study was to evaluate distinguishing the right/left side of the fetus, cardiac axis and position according to the standardized Cordes technique in 20 cases with cardiac malposition. METHODS: We studied retrospectively 1536 cases whose fetal echocardiographic examinations were performed between 1999 and 2006 in prenatal cardiology unit. Among these, cardiac malpositions were determined in 20 cases. The cardiac axis and position were determined according to the Cordes technique. All cases were followed-up by serial fetal echocardiograms until birth or intrauterine death occurred. In cases of intrauterine death, an autopsy was performed. After birth, physical and echocardiographic examinations were done and prenatal and postnatal diagnoses were compared. RESULTS: Of 1536 fetal echocardiograms performed, 144 revealed congenital heart diseases (9.4%), among these cases 20 were diagnosed with cardiac malposition. Of cases with cardiac malposition, 16 had congenital heart disease, and four had extracardiac malformation. There were six cases of isolated dextrocardia, three cases of situs inversus totalis, six cases of situs ambiguous, and one case of situs inversus with isolated levocardia. Of four cases with extracardiac malformations, two cases had mesoposition, one had dextroposition, and one had extreme levoposition. In six cases the autopsy findings were the same as that their prenatal echocardiographic findings. When postnatal echocardiographic results of the remaining cases with cardiac malposition due to congenital heart disease were compared with prenatal diagnoses, the same echocardiographic findings were verified. CONCLUSION: The fetal right/left axis must be determined correctly for the accurate diagnosis of cardiac malpositions. Therefore, we recommend that Cordes technique provides a simple and reliable determination of the fetal right/left axis and fetal situs.

Arrangement of the systemic and pulmonary venous components of the atrial chambers in hearts with isomeric atrial appendages.

BACKGROUND: The morphological definition of atrial chambers, and the determination of atrial laterality, are based on analysis of the structure of the atrial appendages. The systemic and pulmonary venous connections to the heart, nonetheless, are important in the management of patients having isomeric appendages. In this study, therefore, we analysed the morphology of the postero-superior walls of the atrial chambers so as to provide evidence concerning the morphogenetic background of those hearts, and to improve operative management. METHODS: We reviewed 15 autopsied specimens with isomeric right appendages, and 10 with isomeric left appendages, paying particular attention to the morphology of the systemic and pulmonary venous connections. The postero-superior walls of the atrial chambers can be made up of the atrial body, the systemic venous components, or the pulmonary venous component. We analysed the contributions made by each of these components. RESULTS: The postero-superior walls of the atrial chambers were markedly variable, but could be grouped into five patterns. Bilaterally well-developed systemic venous components and absence of the pulmonary venous component within the hypoplastic atrial body were present in 9 hearts with extracardiac pulmonary venous connections in the setting of right isomerism. Bilaterally well-developed systemic venous components, and a hypoplastic pulmonary venous component within the hypoplastic atrial body, were present in 5 hearts with intracardiac pulmonary venous connections in right isomerism. Bilaterally well-developed systemic venous components, and a hypoplastic pulmonary venous component within the sizable atrial body, were present in 1 heart with an intracardiac pulmonary venous connection in right isomerism. A well-developed pulmonary venous component within the atrial body, and hypoplasia of one systemic venous component, were present in 7 hearts with left isomerism. A well-developed pulmonary venous component within the atrial body, and hypoplasia of bilateral systemic venous components, were present in 3 hearts with left isomerism. CONCLUSIONS: The postero-superior walls of the atrial chambers in hearts with isomeric atrial appendages can be analysed on the basis of a compound structure made of bilateral systemic venous components, a central pulmonary venous component, and the body of the atrium. Hearts with isomeric right appendages have absence or hypoplasia of the pulmonary venous component, while hearts with isomeric left appendages have hypoplastic systemic venous components.

A case of malrotation and situs ambiguus.

Isolated levocardia is a rare condition in which intestinal malrotation may be encountered. The case herein reported is particularly uncommon and raises a number of questions about the development of abdominal symmetry.

Control of vertebrate left-right asymmetry by a snail-related zinc finger gene.

A gene encoding a zinc finger protein of the Snail family, cSnR, is expressed in the right-hand lateral mesoderm during normal chick development. Antisense disruption of cSnR function during the hours immediately preceding heart formation randomized the normally reliable direction of heart looping and subsequent embryo torsion. Implanted ectopic sources of intercellular signal proteins that are involved in establishing normal left-right information randomized the handedness of heart development and also altered the asymmetry of cSnR expression. cSnR thus appears to act downstream of these signals, or perhaps in parallel with the latest expressed of them, the Nodal protein, in controlling the anatomical asymmetry.