Introduction
Described initially as “Ivemark syndrome”, there is still no agreement as how best to segregate individuals with jumbled-up thoracic and abdominal organs.1-4 Usually considered under the overarching term “heterotaxy”, 2-7 two specific subsets exist within the overall group.2-7 The existence of an isomeric arrangement of the lungs and bronchial tree was long since established as a discriminating feature, but arguments have raged as to whether isomerism might exist within the heart.5-15 It has now been shown that, when assessed on the basis of the extent of the pectinate muscles relative within the atrial appendages relative to the atrial vestibules, cardiac isomerism is a real entity.13 The two subsets thus identified encompass a wide range of anatomical variants, characterized by complex systemic and pulmonary venous connections, and complicated intracardiac anatomy. The strategies for treating these patients remain equally complicated. To date, most publications assessing the significance of the isomeric arrangements have been based on necropsy studies, case reports, or small case series.8-13 Only limited large scale clinical studies have emphasized the potential significance of the isomeric features.14-22 With all of this in mind, we have assessed the published clinical and necropsy data to determine the influences of right as opposed left isomerism on the surgical outcomes, including re-interventions.