Antenatal Assessment of Topsy-Turvy Heart With Crisscross Inlet.

Rare cardiac malpositions are faced with diagnostic challenges and may not follow set rules. The presence of more than one pathology simultaneously makes diagnosis challenging. The present case report describes antennal diagnosis topsy-turvy heart with crossed ventricular inlets. (Level of Difficulty: Intermediate.).

Topsy-turvy heart (TTH) is an extremely rare cardiac anomaly characterized by abnormal position of the heart in the mediastinum where the origin of great arteries is shifted in the postero-inferior direction. Crisscross heart (CCH) and superior-inferior ventricles are 2 other closely related anomalies and each have unique differentiating features. There are a few case reports of antenatal diagnosis of TTH. This case report describes a fetal heart that has this rare abnormality along with crisscross axis of atrioventricular valves (1, 2, 3, 4, 5, 6, 7). To the best of our knowledge, this is the first description of TTH with CCH.

Learning Objectives

To understand fatal cardiac anatomy in a case of TTH.

To demonstrate crisscross ventricular inlets in the fetal heart.

To understand limitations and scope of counselling for parents after fetal cardiac diagnosis.

History of Presentation

A 32-year-old multigravida was referred for fetal echocardiography for suspected cardiac anomaly (gestational age 22 weeks and 6 days). Of 5 previous pregnancies, 3 males had neonatal death; the details were not available. The remaining 2 were healthy females. Marriage was not consanguineous. The woman was conscious and oriented. Her pulse was 90 beats/min and her blood pressure was 110/70 mm Hg in her right upper arm. Cardiovascular system and systemic examination were unremarkable except for palpable gravid uterus of 20 to 22 weeks.

Medical History

The patient did not have any systemic illness, such as diabetes mellites, systemic hypertension, thyroid abnormality, and autoimmune syndromes. She was receiving only iron and folic acid supplements and was not receiving any other medication in the recent past. Nuchal thickness scan (12 weeks and 2 days) and triple marker (15 weeks and 5 days) were within normal limits. Anomaly scan (at 21 weeks) showed a small left ventricle (LV), however, there were no extra cardiac anomalies.

Differential Diagnosis

Abnormal anomaly scan put her at high risk of fetal cardiac anomaly. Chances of aneuploidy was low but could not be entirely ruled out (nuchal translucency scan and triple marker).

Investigations

Fetal 2-dimensional echocardiography showed the following anatomy. The cardiac mass was in the left hemi-thorax and situs was solitus. The superior and inferior vena cava were draining into right atrium (Figure 1). The right side of the heart was dominant (Video 1). The major mass of the right atrium was against the diaphragm (Figure 2). The left atrium was very small and received pulmonary veins. Atrioventricular connections were concordant. The right ventricle (RV) was dominant and the LV was small. Inlets of both ventricles were not parallel to each other in any plane. When the tricuspid valve could be seen in long axis, mitral was seen enface and vice versa (Videos 2 and 3). The RV was placed more cranially (superiorly) and the LV was close to the diaphragm (Figure 3). This arrangement gave an impression that the heart was moved along its long axis and the cardiac axis was in an anterior and superior direction.

Figure 1

Superior and Inferior Vena Cava Draining Into the Right Atrium

Figure 2

Orientation of RA, RV With Outlet, and MPA Connection Between Ao and MPA

RA is facing diaphragm and liver. Ao = aorta; MPA = main pulmonary artery; RA = right atrium; RV = right ventricle.

Figure 3

RV Giving Rise to MPA and Its Continuation in a Descending Aorta and Abdominal Aorta

RV is cranial and LV is close to diaphragm. LV = left ventricle; other abbreviations as in Figure 2.

Ventriculoarterial connections were concordant (Figures 3 and 4, Videos 4, 5 and 6). The main pulmonary artery was dilated and the aorta was small. The origin of the great arteries was shifted posteriorly and inferiorly very close to the diaphragm. Just after the origin, the great arteries had a large aortopulmonary window (APW) and they were continuing as descending thoracic aorta. The origin of carotid and subclavian arteries was in the posterior mediastinum (Figure 5). Great arteries were descending on the left side of the trachea. Due to this orientation, stomach bubble, right pulmonary artery, and APW were seen in one plane (Figure 6). The arterial duct was not seen. Branch pulmonary arteries were confluent. Thus, after the origin, the entire course of the great arteries was in the posterior mediastinum and there were no arches of the great arteries.

Figure 4

LV Giving Rise to Ao and its Continuation

Note venous duct (VD). Abbreviations as in Figure 2.

Figure 5

Origin of Neck and Head Vessels in Posterior Mediastinum

Neck vessels (arrows).

Figure 6

Stomach Bubble, Confluence of AO/MPA, Atrium, and RPA Seen in 1 Plane

RPA = right pulmonary artery; other abbreviations as in Figure 2.

Management

Possible post-natal outcomes were discussed with the parents, which included cardiac surgery for APW, management of trachio-bronchial compression from abnormal vessel anatomy, and chances of development of hypoplastic left heart syndrome.

Discussion

CCH, superior-inferior ventricle, and TTH are the result of twisting, tilting, and rotational anomalies along the long axis of the heart, respectively. CCH is characterized by crossed ventricular inlet that is independent of atrioventricular connections. The interventricular septum in the horizontal plane is the feature of the superior-inferior ventricle. Not all CCHs have superior-inferior ventricles and vice versa is also true. However, both of the conditions have normal origin and course of great arteries but, in the case of TTH, they are shifted in the posterior inferior direction (6,7).

Typical cases of TTH have superior-inferior ventricles and parallel atrioventricular valve axis, thus all 4 chambers can be seen in one plane (3, 4, 5). However, in the present case, all 4 chambers could not be shown in the same plane and the axis of the atrioventricular valve was perpendicular to each. The right atrium was inferior and along the diaphragm. These findings are similar to CCH. Other features, like posterior inferior origin and course of great vessels, were consistent with TTH. Thus, the present heart had more than one pathology, i.e., twisting (CCH) and rotation (TTH) (1, 2, 3, 4, 5, 6, 7). APW is a well-described feature of TTH (4). Because TTH is an extremely rare anomaly (<10 to 15 cases reported in the literature), it is impossible to make any generalization about possible diagnostic criteria and associated defects.

Difficulty of prediction of growth of small LV and little literature about long-term outcome of TTH made parent counselling challenging. Possible interventions in natural history include APW closure and palliation for airway compression, but the chance of development of hypoplastic left heart is the most contentious issue. There was no possible hemodynamic reason for same.

Another major challenge faced in the management of this case was the difficult bi-caval and aortic canulation during corrective cardiac surgery for APW because the aorta was posterior to the mediastinal structure (8). Recurrent left lung collapse from left main bronchus compression may need translocation of the aorta and stent dilatation of the left bronchus (9).

Genetic evaluation would have been very useful to determine possible causation because there were recurrent neonatal deaths of male siblings in this particular case. However, results will be only speculative because there is paucity of cross-sectional data. It can be useful for hypothesis generation.

Follow-Up

The parents obtained medical termination of pregnancy. Autopsy and genetic evaluation were denied despite persuasion.

Conclusions

Fetal diagnosis of a very rare cardiac malposition is challenging. It is the responsibility of the treating doctor to specify what is known and what is yet to be known. The scope of genetic evaluation and pathological autopsy should be explored whenever possible. Parents’ wishes about treatment choices should be respected.

Funding Support and Author Disclosures

The authors have reported that they have no relationships relevant to the contents of this paper to disclose.