Orthostatic dysregulation (OD) has been identified as a kind of autonomic failure, however few studies have evaluated the autonomic dysfunction in patient with OD. Also the treatment of patients with OD has not been also necessarily standardized. We therefore investigated the cardiovascular autonomic function of 12 dizziness patients with OD using heart rate variability analysis (HRV) during the shellong test, and compared the findings with those of sex and aged-match healthy subjects. In addition, we discussed the clinical efficiency of cardiovascular α-adrenoreceptor stimulators or β-adrenoreceptor blockers for dizziness patients with OD.
There was no significant difference in LF (low frequency power), HF (high frequency power) or LF/HF of HRV analysis between patients with OD and healthy subjects. However, the intersubject variation of the LF/HF value in patients with OD in supine and upright positions was apparently larger than that of the healthy adults, and some patients with OD showed extremely high values of LF/HF when upright.
The cardiovascular α-adrenoreceptor stimulators improved dizziness symptoms in 4 of 8 patients that showed the lower values (<4.2) of LF/HF when upright. β-adreno-receptor blockers diminished dizziness symptoms in 3 of 5 patients that showed higher values (>4.2) of LF/HF value when upright. These results suggested that some dizziness patients with OD have an imbalance of sensitivity between α-adrenoreceptor and β-adrenoreceptor functions in the cardiovascular system. However, the cardiovascular autonomic function of OD patients requires further investigation.
