Hypoplastic Left Ventricle: Definition, Morphology, and Classification of the Cardiac Phenotypes.

A prior manuscript provided information about hypoplastic left heart syndrome (HLHS) and related malformations, including definitions, morphology, and classification, based on the 2021 International Paediatric and Congenital Cardiac Code (IPCCC) and the Eleventh Revision of the International Classification of Diseases (ICD-11). This manuscript provides information about the related cardiac phenotypes associated with "hypoplastic left ventricle" that might be suitable for biventricular repair, including definitions, morphology, and classification of the cardiac phenotypes of the following four congenital cardiac malformations that can all include a hypoplastic left ventricle: (1) hypoplastic left heart complex (HLHC), (2) critical aortic stenosis with left ventricular hypoplasia, (3) aortic atresia + ventricular septal defect, and (4) hypoplastic left ventricle with severely unbalanced atrioventricular septal defect.