Based on many years of clinical experience of the authors and the latest literature data, the book systematizes modern information on pathogenesis, pathological physiology, diagnosis, and differential diagnosis of the main diseases of the cardiovascular system. The issues of treatment of patients from the standpoint of modern medical practice are considered in detail. The focus is on the most significant sections of practical cardiology: circulatory failure, ischemic myocardial damage, stable and unstable angina, pathogenetic justification of the treatment of myocardial infarction at the beginning of its development, mechanisms of formation and therapy of arterial hypertension. A peculiar chapter is devoted to the importance of studying sinus rhythm in the clinic.