The orthostatic dysregulation of blood pressure in dizzy patients

OBJECTIVES: A number of animal studies have confirmed that the otolith organs may contribute to the maintenance of blood pressure during positional change; however, the contribution of such organs remains to be elucidated in humans. METHODS: This study investigated whether acute dizzy patients (n = 11) with an abnormal deviation of the subjective visual vertical (SVV) show an abnormality in the orthostatic regulation of blood pressure in comparison to acute dizzy patients with a normal deviation of the SVV (n = 11) and control subjects (n = 11). RESULTS: The average change in the systolic blood pressure (SBP) at 1 minute after active standing in comparison to that at baseline in dizzy patients with an abnormal deviation of the SVV was -6.8 +/- 3.0 mmHg. The change was significantly lower than that in the control subjects (2.1 +/- 2.6 mmHg, p < 0.05), while the change in dizzy patients with a normal deviation of the SVV (2.6 +/- 2.2 mmHg) was not significantly different from that in the control subjects (p > 0.05). Active standing significantly increased the heart rate (HR) in all participants (p < 0.01) and there was no significant difference in the change of the HR among the 3 groups (p > 0.05). CONCLUSIONS: These results suggest that dizzy patients in the acute phase of recovery from vestibular dysfunction have an orthostatic dysregulation of the blood pressure, thus resulting in such patients suffering from orthostatic intolerance.