# Non-invasive Vagus Nerve Stimulation as an Adjunct Treatment for Inappropriate Sinus Tachycardia

## TL;DR

Non-invasive vagus nerve stimulation may help treat inappropriate sinus tachycardia, a heart condition causing rapid heart rate and symptoms like dizziness.

## Contribution

This is the first report of low-level non-invasive vagal nerve stimulation being used to treat inappropriate sinus tachycardia.

## Key findings

- A 30-year-old woman with IST experienced near-complete symptom relief after two months of non-invasive vagal nerve stimulation.
- The patient had minimal improvement with β-blocker therapy but showed significant improvement with n-VNS.
- This case suggests n-VNS could be a promising treatment for IST, warranting further clinical studies.

## Abstract

Inappropriate sinus tachycardia (IST) is a type of cardiovascular autonomic dysfunction (CVAD) that mainly affects young women and has a prevalence of 1%–2%. IST is characterized by a sinus heart rate of >100 bpm at rest with a mean 24-h heart rate of >90 bpm associated with distressing symptoms such as palpitations, dizziness, and syncope. Here, we discuss a case of a 30-year-old woman who presented with complaints of tachycardia and associated symptoms, including dizziness, diaphoresis, and sudden loss of consciousness. The 24-h Holter monitoring was consistent with the diagnosis of IST. The patient had minimal improvement on β-blocker therapy. Due to persistent symptoms consistent with IST, she was started on non-invasive vagal nerve stimulation (n-VNS) therapy. Following 2 months of n-VNS applied twice daily over the carotid artery, the patient noted near-complete relief of her tachycardia and other debilitating symptoms. While n-VNS has recently been reported as a possible treatment for postural orthostatic tachycardia syndrome, another type of CVAD, to the best of our knowledge, this is the first report of low-level n-VNS as a treatment for IST. Our case study highlights the need for further clinical studies on the benefits of n-VNS in treating IST.