Heterotaxy Isomerism 2018-05-05T18:12:17Z Isomerism in the context of the congenitally malformed heart is defined as a situation where some paired structures on opposite sides of the left-right axis of the body are, in morphologic terms, symmetrical mirror images of each other. The word isomerism is also derived from the Greek: iso-meaning equal and meros-meaning part. Isomerism refers to structures that are themselves mirror-imaged. When used in the area of the congenitally malformed heart, the term isomerism has become the conventional description for the situation in which morphologically right structures or morphologically left structures are found on both sides of the body in the same individual.