Right atrial isomerism, also called Asplenia syndrome, is one of the heterotaxy syndromes. It is a failure to differentiate into the right/left sidedness of the body, involving all internal organs. The cardiac anatomy can be very variable, with abnormal venous return, both systemically and pulmonary (total anomalous pulmonary venous drainage TAPVD), conduction problems with two sinus nodes with atrial tachyarrhythmias, frequently complete atrio-ventricular septal defect with a common atrio-ventricular valve, pulmonary stenosis or atresia, etc. Anaesthetic management depends on the details of the lesion.