The significant incidence of hypertensive disease among the Ukrainian population makes the search for new methods of management and treatment of patients suffering from this pathology a matter of high priority. Our research is focused on study of changes of some biochemical parameters in patients suffering from hypertensive disease as well as patients suffering from hypertensive disease and coexistent extrasystoles. Arterial hypertension leads to different structural and functional changes in the cardiovascular system. In many patients these changes may result in rhythm disorders. 120 patients have been examined (42 men and 78 women) between the ages of 27 to 81 (average 59.8) suffering from hypertensive disease of the II stage as defined by the Ukrainian Association of Cardiologists and from extrasystoles (more than 30 episodes per hour of research) of different topography and 30 persons (13 men and 17 women) suffering from hypertensive disease of the II stage between the ages 30 to 76 (average 56.4) without rhythm disturbance). The first clinical group was formed by 54 (45%) patients suffering from repeated supraventricular extrasystoles (SE) (average 62 ± 2 SE per hour of research). The second clinical group was formed by 42 (35%) patients suffering from repeated ventricular arhythmia (VA) (average 37 ± 2 VA per hour of research). The third group was formed by 24 (20%) patients suffering from both repeated SE and VA (average 48 ± 3 SE and 32 ± 3 VA per hour of research). We conducted 24 hours’ monitoring of blood pressure and electrocardiography using the “Dia Card”-system (“Solvaig”, Ukraine) for all patients. This revealed that ventricle extrasystoles and combined extrasystoles in patients with essential hypertension, II stage are associated with more unfavourable changes in 24 hours’ profile of blood pressure. The paper analyses the cardiac arhythmia structure of heart rate variability in patients with arterial hypertension (AH) and extrasystoles. The findings confirmed the presence of desynchronization in the activity of the neurohnmoral system. Thus, different mechanisms of arhythmogenesis were revealed in patients with arterial hypertension. In the results, frequent ventricular and combined extrasystoles were associated with an unfavourable blood pressure profile during 24-hours monitoring as well as higher end-diastolic left ventricular volume, diastolic dysfunction, aortic valve fibrosis, aorta remodeling, endothelial dysfunction and more prominent lipid disorders. Supraventricular extrasystoles were associated with hypertriglyceridemia, left ventricular diastolic dysfunction and left atrium enlargement.