Postural tachycardia syndrome (POTS) is a relatively common condition affecting mostly
otherwise healthy young women. These patients have high heart rate and disabling symptoms
during standing. Quality of life may be poor. The sympathetic nerves in the autonomic nervous
system help to maintain normal blood pressures and heart rates during activities of daily
life.
The purpose of this study is to determine the importance of sympathetic activation as a cause
of orthostatic symptoms. The investigators will assess the effects of a blood pressure
medication (Moxonidine) on the symptoms during standing. Moxonidine lowers sympathetic
activity. The investigators believe patients with high resting sympathetic activity might
benefit from Moxonidine. It might reduce high heart rate and improve symptoms during
standing. This study should help clinicians and the growing population of patients with POTS
gain a better understanding of this disorder and find more personalized treatment.