The monograph discusses the prognostic value of genetic markers for early diagnosis of endothelial dysfunction in patients with chronic heart failure. Particular attention is paid to clinical studies on the relationship between the severity of the clinical course of the disease and indicators of endothelial dysfunction depending on polymorphisms T786C and Glu298Asp of endothelial NO synthase gene. Taking into consideration the regional factors in patients with CHF of Uzbek nationality the determination of the role of polymorphisms of genes T786C and Glu298Asp of endothelial NO synthase in increasing the quality of diagnostics and treatment of this disease gains particular importance.The monograph is intended for general practitioners, cardiologists, therapists, masters and clinical residents.