The term hypoplastic left heart syndrome (HLHS) contains a spectrum of complex congenital malformations of the heart involving varying degrees of underdevelopment of the left-sided heart
structures including aortic or mitral valve stenosis atresia and coarctation of the aorta. There is a significant obstruction to blood flow and the inability of the left heart to support the systemic circulation. Without surgical intervention, the vast majority of infants born with HLHS will die within the first few weeks of life. Early initiation of continuous intravenous prostaglandin E1 infusion to maintain ductal patency is key to initial survival. The percentage of children with HLHS who are diagnosed antenatally is increasing, due to the widespread establishment of adequate ultrasound screening programmes over the past twenty years. Clinicians should give to detailed information about staged surgical palliation, the potential for unplanned cardiac reinterventions, and the potential need to consider cardiac transplantation at any point during the child’s life. Survival has improved in the present era and is likely due to improved surgical and hibrid techniques, and intensive care management.