Рostural orthostatic tachycardia syndrome

Introduction. Postural orthostatic tachycardia syndrome (SPOT) is a heterogeneous clinical syndrome characterized by an excessive increase in heart rate (HR) in the standing position in the absence of orthostatic hypotension.Aim. To study the change in hemodynamic parameters, heart rate variability (HRV) during the tilt test, as well as to evaluate the indicators of Holter monitoring in patients with SPOT and patients without.Materials and methods. From the patients examined for the presence of disorders of the autonomic nervous system (ANS) associated with orthostasis intolerance, fainting in the anamnesis, persons aged 18 to 40 years were selected. According to the results of the tilt test, the following groups were formed: 1 group – patients with episodes of syncopal states and a negative tilt test, 2 group – patients with a pattern of postural tachycardia (PPT), 3 group – control. All patients underwent standard electrocardiography, Holter monitoring, 24-hour blood pressure monitoring and a long-term passive orthostatic test in accordance with the Westminster Protocol.Results. No deviations were found in all groups based on ECG results, daily ECG monitoring data and blood pressure. Sinus normosystole and normative values of the duration of intervals and ECG waves were observed, the subjects demonstrated normal HRV and SAD and DAD indicators throughout the day. In the first group, an increase in heart rate was observed without a decrease in blood pressure. When assessing HRV during the tilt test, a decrease in the tone of the parasympathetic system was observed in the second group. HRV indicators were analyzed during the day to assess the state of the ANS in the groups. When studying the dynamics of RR intervals, an increase in all HRV indicators at night was recorded.Conclusions. The results indicate a violation of the vegetative response to vertical position in patients with PT, which correlates with orthostatic intolerance and indicates violations of heart rate regulation and an imbalance between sympathetic and parasympathetic activity.