BACKGROUND: Yearly, 200–300 new spinal cord injuries (SCI) happen in the Czech Republic. Some of thesepatients suff er from autonomic disturbances, especially concerning their cardiovascular and genito-urinary systems.Autonomic disturbances markedly decrease quality of life in patients with SCI. It is important to assess the severityof the autonomic nervous system (ANS) involvement in these subjects.OBJECTIVE: The main aim of this study was to assess the spectral analysis of heart rate variability as a markerof cardiovascular autonomic regulation in patients with spinal cord injury and to compare it with fi ndings in healthycontrols.METHODS: Ten paraplegics (with a mean age of 53.1 ± 15.8 years, seven males and three females) participatedin this study. There were fi ve patients with incomplete and fi ve patients with complete spinal cord injury. The ASIA –American Spinal Injury Association, the modifi ed Ashworth scale and the Questionnaire on Autonomic Functionswere used. Autonomic reactivity was evaluated by means of the spectral analysis of heart rate variability (SAHRV)method (short-term registration) using the supine-sitting-supine test. Diagnostic system VarCor PF7, which is an in-novation of the VarCor PF6 system, was used. Twenty four healthy subjects (with a mean age of 51.9 ± 9.4 years) wereenrolled as a control group.RESULTS: A marked decrease of the reactivity of the autonomic nervous system as a response to orthostaticchanges was found in patients after SCI (paraplegics). In particular, characteristic responses of low frequency (LF)and high frequency (HF) spectral components during the body position changes were suppressed in these patients incomparison with healthy controls. Furthermore, a signifi cant decrease in the spectral power of the LF and HF com-ponents was found in patients after SCI. The value of the spectrum’s total power (TP) was signifi cantly lower in thegroup of paraplegics in comparison with healthy volunteers, both in the fi rst and in the repeated supine positions. A sig-nifi cant degree of orthostatic hypotension was registered only in two paraplegics in a sitting position. A lower increasein the LF/HF ratio was registered in a sitting position in a group of paraplegics in comparison with healthy subjects.CONCLUSIONS: A decrease in the reactivity of the autonomic nervous system to orthostatic changes, whichevidences disturbances of cardiovascular regulation, was found in patients after spinal cord injury (paraplegics). Thereduction of the low-frequency component (LF) of the spectral analysis of heart rate variability refl ects a loweredsympathetic activity in these patients in a sitting position. It refl ects ortostatic disturbances in situations with bodyposition changes associated with a modifi ed orthostatic load. Blood pressure measurement and SAHRV contributeto a more precise assessment of the autonomic dysfunction in patients after SCI.
展开▼
