Involvement of autonomic disorders

Patients with orthostatic dysregulation (OD)-associated disease may show autonomic disorders more frequently as compared with patients with other types of dizziness. However, the pathological mechanisms of OD remain unclear. We examined the cardiovascular autonomic function in dizzy patients with postural orthostatic tachycardia syndrome (POTS) or chronic orthostatic intolerance (OI) in order to evaluate the contribution of the autonomic disorders to the occurrence of dizziness. Heart rate variability analysis during the Schellong test showed that patients with POTS have hypo-parasympathetic function and relative hyper-sympathetic function, and that some patients with OI also have hypo-parasympathetic function. In our clinic, single therapy with a β1-blocker (Atenolol) for patients with POTS or single therapy with an a- agonist for patients with OI relieved orthostatic symptoms in 60% of the patients with POTS and OI. Further clinical studies on OD-associated disease to evaluate methods for accurate diagnosis and appropriate combined physical and pharmacotherapy may improve the outcomes in patients with OD-associated disease.