Unrepaired Most Severe Form of HLHS in Adulthood: A Case Report of Late Diagnosis and Long-Term Follow-up

Background Hypoplastic left heart syndrome (HLHS) is a rare, severe congenital heart disease (CHD) characterised by underdevelopment of the left-sided cardiac structures, typically necessitating neonatal surgical intervention. Survival beyond infancy without surgical palliation is exceptionally uncommon. Case summary We report the case of an 18-year-old woman with a late diagnosis of unrepaired HLHS, comprising mitral and aortic atresia, a hypoplastic ascending aorta, and a rudimentary left ventricle. Cardiac imaging provided a comprehensive anatomical assessment. Remarkably, despite the absence of surgical intervention, the patient remained clinically stable over a ten-year follow-up under exclusive medical management. Discussion This case illustrates extraordinary natural survival in unrepaired HLHS and emphasises the importance of specialised CHD centres in long-term management, clinical surveillance, and imaging-based evaluation of complex univentricular physiology.