Heterotaxy

Define • Known as situs ambiguous, is defined as the abnormal and

disorganised arrangement of organs and vessels within the abdominal cavity

Differential diagnosis • This is in contrast to the orderly arrangement that occurs in situs

inversus or situs solitus

2 Categories • situs ambiguous with polysplenia• Left isomerism• Bilateral left-sidedness• Midline position of the abdominal

organs and multiple spleens/splenules• Lower prevalence of congenital

heart disease (50–90%)• Less severe defects than

• Situs ambiguous with asplenia• Right isomerism • Complex CHD

Left isomerism: No cyanosis • Many spleen • Bilaterally symmetrical liver• Bilateral bi-lobed lungs• Bilateral hypo-arterial bronchi (left isomerism)• Bilateral SVC• Intrahepatic interruption of the IVC with azygous or hemi-azygous continuation• Common atrium • AVCD• Hypoplasia or absence of one ventricle• LVOT/RVOT obstruction • DORV• 50% dextrocardia• Kartagener’s syndrome

Right isomerism :Cyanosis• No left atrium to receive pulmonary venous drainage(TAPVC) • Venous drainage into a systemic vein is seen in > 50%• Infancy • Transposition of the great arteries• AVCD• Ventricular hypoplasia or single ventricle physiology• Pulmonary atresia• Pulmonary vein obstruction• 80%-90% die in the first year

Easy to follow • http://www.ncbi.nlm.nih.gov/p

mc/articles/PMC3116098/