Auricular Vagal Neuromodulation Therapy (AVNT) in Postural Tachycardia Syndrome: A Randomised Clinical Trial

Abstract

Effectiveness of Nurosym Auricular Vagus Nerve Therapy (AVNT) in alleviating symptoms of postural tachycardia syndrome (POTS) was measured. Conducted as a double-blind, placebo-controlled trial, patients underwent daily stimulation sessions for two months. Results showed a 40% reduction in postural tachycardia in the active group, significant decreases in α1-AR and β1-AR autoantibodies, and reduced inflammatory cytokines. Additionally, heart rate variability improved without any adverse effects. The findings suggest that Nurosym is a safe and effective non-pharmacological treatment for POTS, offering antiarrhythmic and anti-inflammatory benefits.

Background and aims

The aim of the study was to evaluate the effectiveness of AVNT in alleviating the symptoms of postural tachycardia syndrome (POTS) in patients with confirmed clinical history. POTS is characterised by persistent symptoms of orthostatic intolerance, including an abnormal increase in heart rate after assuming an upright posture, as well as associated indications ranging from fatigue to gastrointestinal symptoms. These symptoms are often linked with autonomic dysfunction, particularly involving excessive parasympathetic withdrawal and sympathetic overdrive during orthostatic stress. The vagus nerve, due to its wide connectivity, has the potential to address fundamental pathophysiological mechanisms by exerting parasympathomimetic and antiadrenergic effects on the heart and producing anti-inflammatory effects. Therefore, treatment with Nurosym by active stimulation of the vagus nerve may offer a non-pharmacological method targeting physiological causes, thus providing multi-level relief.

Methods

The study employed a prospective, double-blind, placebo-controlled, randomised clinical trial design. Patients were randomised 1:1 using block randomization to ensure balance between both groups over time. Active neuromodulation targeted the tragus innervated by the auricular branch of the vagus nerve, while placebo stimulation was applied to the earlobe deprived of vagal innervation. Patients were unaware of which sites provided active stimulation. They conducted stimulation sessions for an hour every day for a period of two months. Assessments were performed at baseline and two months later, including measurements of blood pressure and heart rate in the supine and standing positions for 25 minutes, an ECG to analyse heart rate variability, a blood draw for analysis of autoantibodies and inflammatory cytokines, and a subjective health questionnaire.

Results

In a study focusing on key parameters in POTS, Nurosym has proven to be an effective therapeutic intervention in alleviating autonomic dysregulation and associated inflammatory responses. Particularly, it has demonstrated efficacy in modulating the activity of autoantibodies associated with dysregulation in sympathetic nervous system activity and reducing heart rate (HR) connected with stress index and heart palpitations. Importantly, throughout the study duration, no adverse effects related to the Nurosym device were observed, indicating its safety profile in this context.

In the study on the Nurosym device, after two months of therapy, a noticeable reduction in postural tachycardia (HR) was observed by approximately 40% in the active group compared to the placebo group.

The level of anti autonomous autoantibodies, especially α1-adrenergic receptor (α1-AR) and β1-adrenergic receptor (β1-AR), was significantly lower (p<0.05) in the active group. Moreover, the study showed a reduction in inflammatory cytokines while improving heart rate variability (HRV).

Conclusion

Transcutaneous neuromodulation with the Nurosym device showed activation of the auricular branch of the vagus nerve located in the tragus, which led to noticeable antiarrhythmic and anti-inflammatory effects. Mechanistically, this effect is related to a reduction in anti-adrenergic autoantibodies and inflammatory cytokines, combined with an improvement in cardiac autonomic tone. Study results suggest that Nurosym is a beneficial and non-invasive treatment option for postural tachycardia syndrome (POTS).