Pre natal evaluation of heterotaxy syndrome by fetal echocardiography and correlating with autopsy

Heterotaxy syndrome/ isomerism is characterized by an abnormal symmetry of the viscera that are normally dissimilar due to abnormal lateralization of thoracic and abdominal viscera and is frequently associated with complex cardiac anomalies. Isomerism may be of right or left.

This article describes the morphological characteristics of heterotaxy and suggests an approach in evaluating the spectrum of abnormalities associated with this syndrome. This study is based on 12 cases diagnosed on antenatal ultrasound as heterotaxy syndrome. Results of the examinations were re-evaluated and compared by fetal autopsy.

Based on the following echocardiographic criteria, a diagnosis of left isomerism was made if there was viscerocardiac heterotaxy associated with an interruption of inferior vena cava or with bilateral finger-like atrial appendages or if it was associated with heart block. If there was evidence of viscerocardiac heterotaxy with complex cardiac anomalies then it was diagnosed as right atrial isomerism or visceral heterotaxy syndrome. We diagnosed 6/12 as left isomerism and rest of the cases as right isomerism/visceral heterotaxy syndrome. In Autopsy we evaluated visceral situs and morphology of the lungs and the main bronchi, the state of the liver, spleen, bowel, and the precise anatomy of the heart and confirmed 4/12 as left isomerism 4/12 as right isomerism and two cases as visceral heterotaxy syndrome (VHS). Rest of the two cases were included in the study despite missing autopsy data, as the combination of abnormal situs with interrupted inferior vena cava, and cardiac malformation allowed a diagnosis of left isomerism with high probability.

In this study, we aimed to find common features of heterotaxy syndrome on prenatal ultrasound as well as on fetal autopsy. This syndrome should be accurately diagnosed in the prenatal period in order to allow appropriate counseling of parents.