[HYPOPLASTIC LEFT HEART SYNDROME: MORPHOGENESIS OF PATOMORPHOLOGICAL TYPES OF THE LEFT VENTRICLE]

The purpose of the study was to investigate the morphogenesis of the left ventricle in the hypoplastic left heart syndrome (HLHS). There are five types of hypoplastic left ventricles were identified: with a slit-like shape and hypoplasia of LV wall, with a slit-like cavity shape and wall hypertrophy and types with endocardial fibroelastosis (with a cylindrical cavity shape, with lacunar cavities and lacunar-cylindrical cavity of the left ventricle), as a result of differences in the wall structure, cavity shape, presence or absence of endocardial fibroelastosis. The analysis of morphometric data of pathomorphological types of the left ventricle in the HLHS revealed the possible ways of their morphogenesis. Left displacement of interventricular septum in embryogenesis at 4-5 weeks of intrauterine development is associated with the occurrence of atresia of the left atrioventricular orifice and aortic valve and the appearance of a slit-like shape and hypoplasia of LV wall in the HLHS. The displacement of only the conotruncus septum leads to the appearance of a slit-like shape of cavity and hypertrophy of LV wall in the HLHS. The pathomorphological types with endocardial fibroelastosis in the HLHS depends on the stage of embryogenesis of myocardium at which fibroelastosis appears: before the myocardial compaction (up to 4th week of gestation) - the lacunar shape of LV cavity with thin compact layer of myocardium; during the compaction of myocardium (5-6th week of gestation) - the lacunar-cylindrical shape of LV cavity and after compaction (after 7-8th week of fetal development) - a cylindrical shape of LV cavity.