Publication Details
Abstract
Congenital heart defects (CHD) represent structural abnormalities of the heart and great vessels that develop during embryogenesis (3–8 weeks of gestation). In infants, the morphological pattern depends on the type of defect, the severity of hemodynamic disturbances, the degree of hypoxia, and the progression of heart failure. The prevalence of congenital heart defects in the Republic of Uzbekistan demonstrates certain variability; approximately 8.7% of all cases are attributed to Tetralogy of Fallot.The conducted morphological study of Tetralogy of Fallot revealed pronounced structural alterations in the myocardium, predominantly affecting the right ventricle. Hypertrophic and dystrophic changes of right ventricular cardiomyocytes were observed, whereas the left ventricle showed mainly atrophic and sclerotic processes. In addition to alterations in the contractile myocardium, disturbances of the cardiac conduction system were identified. Both quantitative and qualitative transformations of fiber bundles originating from the sinoatrial node were noted, along with heterogeneous hypertrophic and atrophic changes in various branches of the intraventricular conduction system. In defects associated with valvular abnormalities and ventricular septal defects, a predominance of His bundle fibers directed toward the right ventricle was observed, with a relatively reduced distribution to the left ventricle.Alterations of the microcirculatory bed were also detected. Myocardial hypertrophy led to disruption of capillary histoarchitecture, deformation of vascular lumina, and disorganization of the capillary network. These structural changes were accompanied by local hemodynamic disturbances, reduced capillary perfusion efficiency, and increased vascular permeability, contributing to the development of interstitial edema and aggravation of hypoxic processes in the myocardium.