Hypoplastic Left Heart Syndrome

Abstract

An embryonic heart and a fetal heart are different from the neonatal heart. The heart of the human embryo when 10 mm from crown to rump, it is symmetrical in the sense that the septa formation is in the middle of atria and ventricles. The plane of septa extends from the anterior part of the anterior interventricular sulcus to the posterior part of the atrial septum. In congenital heart defects (CHDs), the position of the heart has a different appearance when seen through ultrasonographic guidance. Such as when the right ventricle is underdeveloped, the cardiac apex has an anterior position, while in the hypoplasia of the left ventricle, the cardiac axis is found to be posterior. Moreover, anatomically and functionally, a left heart is different from the right. The tissues forming the left atrium are smoother, refined, and comprised of narrow and tubular appendages. Similarly, trabeculae carneae of the left ventricle is comprised of a thin and smoother layer, while the fibrous continuum exists in the bicuspid and aortic valves. In the fetal heart, the left atrium is in situ posterior chamber, while the pulmonary vein exists inferiorly and shifts cranially by the start of the 12th week of gestation. It affects 1–8% of all the CVMs. The disease is fatal without surgical intervention, and even in the case of survival, the data and research lack a definite answer on the life span and other associated comorbidities of these patients. Nonetheless, HLHS even after the surgical interventions the survival chances are only 65% until the age of 5 and 55% at the age of 10. This chapter provides a comprehensive overview regarding the anatomy, etiology, epidemiology, genealogy, morphology, pathogenesis, management, and surgical intervention of HLHS.