Postural Tachycardia Syndrome (POTS) is a form of dysautonomia characterized by an abnormal cardiovascular response to orthostatic challenges. Individuals afflicted with POTS typically exhibit a heart rate increase of more than 30 beats per minute (bpm) within 10 minutes of assuming an upright posture from a supine or sitting position. This abnormal response is often accompanied by symptoms, such as orthostatic intolerance, dizziness, weakness, fatigue, and, in certain instances, syncope. Lately, there is revived interest in POTS, as it has been quite frequently reported as a manifestation of autonomic dysfunction among patients with long COVID. POTS primarily affects the younger demographic, particularly women, and its pathophysiology appears to be multifactorial, involving autonomic neuropathy, hyperadrenergic state, and inadequate blood volume regulation. Diagnostic criteria commonly include a sustained heart rate increase without significant orthostatic hypotension. The pathophysiological mechanisms of POTS are complex and not fully elucidated. Management strategies encompass lifestyle modifications, exercise programs, and pharmacotherapy, but their efficacy is modest.
Transcutaneous auricular vagus nerve stimulation (tVNS) is an emerging therapeutic modality in cardiovascular diseases. tVNS has been shown to exert antiadrenergic and anti-inflammatory effects in humans. Recently, tVNS has been tested in experimental and human POTS, leading to improved autonomic function, reduction of anti-autonomic autoantibodies and inflammatory cytokines. However, the exact patient characteristics that would identify a patient likely to respond to tVNS as well as further mechanistic and clinical endpoints with tVNS have not been explored.
The aim of this study is to assess and characterize in detail the effect of tVNS in patients with POTS. This is a prospective crossover study in patients with POTS. The expected study duration is approximately 15 months from the time the first subject is enrolled to study termination. Patient enrollment is planned to take place at 3-4 major centers in Greece.