Cardiovascular manifestations of heterotaxy and related situs abnormalities assessed with CT angiography

Abstract

Heterotaxy and situs abnormalities describe an abnormal arrangement of visceral organs in the thoracoabdominal cavity across the normal left–right axis of the body. It is associated with a high occurrence of congenital heart and abdominal defects, including anomalous pulmonary venous connections, systemic venous abnormalities, asplenia, and intestinal malrotation. Without proper diagnosis and surgical intervention, the prognosis of patients with heterotaxy syndrome and associated congenital defects is extremely poor. Complex intracardiac and extracardiac lesions are common in heterotaxy and can be difficult to assess by echocardiography. CT angiography (CTA) is a useful tool in this setting to accurately assess intracardiac and extracardiac abnormalities in this population for medical or surgical management. The intention of this pictorial essay is to review the most common cardiovascular defects involved with heterotaxy syndrome in addition to emphasizing the utility of CTA in the identification and classification of anomalies seen in these patients. This review briefly defines most common terminology used in situs abnormalities as well as presents CT images and 3-dimensional reconstructions of common anomalies associated with situs abnormalities. In summary, this review should prepare radiologists and pediatric cardiologists to describe heterotaxy and situs abnormalities in addition to recognizing the utility of CTA in these patients.

Heterotaxy Polysplenia Syndrome in Adulthood: Focused Review and a Case Report

“…From a cardiological standpoint, left isomerism, the sinus and atrioventricular nodes are right atrial structures. These patients often have sinus node dysfunction or congenital heart block [9]. Our patient did present with mild cardiac anomalies, but none of which were significant.…”

“…Our patient also presented with an interrupted IVC with azygos continuation and polyspenia. Polysplenia is noted in 2.5:100,000 live births and it is present in 55% of patients with left isomerism [9,10]. It is often seen in conjunction with an interrupted IVC with azygos vein such as this particular case.…”

An atypical journey during a “typical” EP case

“…Heterotaxy with right atrial isomerism, known as asplenia syndrome, is characterized by duplication of right-sided structures and absence of left-sided structures. As such, there are bilateral right atrial appendages and bilateral trilobed lungs with bronchi that branch over the pulmonary arteries (eparterial bronchi) and absence of the spleen, rendering these patients immunocompromised and at risk of sepsis 1 . Because of the bilateral morphologic right atria, this type of isomerism is often associated with bilateral SVCs, 2 distinct sinoatrial nodes presenting with competing “sinus” rhythms with an alternating P-wave axis corresponding to their respective atria and absence of the coronary sinus 2 .…”

Cardiovascular CT in Cyanotic Congenital Heart Disease

“…Some single ventricle disease occurs in the setting of heterotaxy syndrome, in which the laterality of structures within the thorax and abdomen is arranged abnormally, with highly variable duplication of left-or right-sided structures known as isomerism. In these patients, CT can assess not only intracardiac and extracardiac abnormalities but can also identify bilateral left or right atrial appendages and assess the situs of the lungs and abdominal viscera [87].…”