The present study is designed to test the hypothesis that muscarinic autoantibody-mediated parasympathetic dysfunction contributes to the pathogenesis of POTS, and that parasympathetic (vagal) stimulation improves POTS symptoms, autoimmunity and inflammation.~Define and determine the prevalence, burden, and clinical significance of muscarinic autoantibodies in a well-phenotyped cohort of POTS patients with and without gastroparesis and a matched cohort of healthy control subjects.~Evaluate the impact of vagal stimulation on antibody suppression, inflammatory inhibition, and symptom improvement in POTS patients. Non-invasive transcutaneous stimulation of the auricular branch of the vagus nerve (tragus stimulation) will be used to increase parasympathetic activity.
The purpose of this study is to test the hypothesis that an antibody-mediated autoimmune reaction will cause symptoms of autonomic dysfunction in some patients with postural tachycardia syndrome (POTS). The investigators further hypothesize that electrical stimulation of the vagus nerve will improve POTS symptoms, autoimmunity and inflammation.