Wang et al. (2025)
- Authors: Zhuo Wang, Tongjian Zhu, Xuping Li, Xin Lai, Mingxian Chen.
- Institutes: Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, Hubei, China; Department of Cardiology, Institute of Cardiovascular Diseases, Xiangyang Central Hospital, Afliated Hospital of Hubei University of Arts and Science, Xiangyang, Hubei, China; Department of Cardiology, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China.
- Publisher: Clinical Cardiology
- Link: DOI
Summary
This research provides evidence for a non-drug, non-invasive treatment for POTS, a form of dysautonomia common in post-viral illnesses like Long COVID and sometimes seen in ME/CFS. The study suggests that stimulating the vagus nerve with a simple ear clip device can rebalance the autonomic nervous system, leading to a significant and lasting reduction in the excessive heart rate upon standing that defines POTS. By demonstrating improvements in objective markers like heart rate variability and neuropeptide Y, this study points towards a safe potential therapy that directly targets the underlying autonomic dysfunction.
What was researched?
This study investigated the potential therapeutic benefits of a non-invasive nerve stimulation technique, called low-level tragus stimulation (LL-TS), for patients experiencing Postural Orthostatic Tachycardia Syndrome (POTS) following a COVID-19 infection. Researchers examined the effect of this treatment on heart rate, heart rate variability (HRV), and levels of plasma neuropeptide Y (NPY).
Why was it researched?
POTS, a form of dysautonomia characterized by an excessive heart rate increase upon standing, is frequently reported in Long COVID. Current treatments for POTS have limited effectiveness and can have significant side effects. The researchers hypothesized that LL-TS, which stimulates the vagus nerve, could help rebalance the autonomic nervous system by increasing parasympathetic (“rest-and-digest”) activity and reducing sympathetic (“fight-or-flight”) over-activity, thereby improving POTS.
How was it researched?
This was a prospective, randomized, and controlled clinical trial involving 57 participants with confirmed post-COVID POTS. Patients were divided into two groups: 31 received genuine LL-TS via an ear clip device, and 26 received a sham (fake) stimulation. The treatment was administered for one hour twice daily for a month. Key measurements, including heart rate changes upon standing, HRV, and plasma NPY levels, were taken at the start of the study, after one month of treatment, and at a one-year follow-up.
What has been found?
The study found that one month of LL-TS 💊 significantly reduced the excessive heart rate increase that patients experienced upon standing. This improvement was sustained at the one-year follow-up. The treatment also rebalanced the autonomic nervous system, as shown by improved HRV metrics (increased high-frequency power and decreased low-frequency power) during a standing test. Furthermore, LL-TS significantly lowered plasma levels of NPY, a neuropeptide associated with sympathetic nerve activity.
Discussion
The authors acknowledged several limitations of the study. The sample size was relatively small, which may limit the generalizability of the results. The study focused on physiological measurements like heart rate and did not directly assess the broader range of clinical POTS symptoms (e.g., cognitive impairment, headache). Additionally, the absence of a control group of healthy individuals or Long COVID patients without POTS makes it difficult to ascertain if the observed effects are specific to the POTS condition.
Conclusion & Future Work
The authors conclude that LL-TS is a promising, non-invasive therapeutic approach for improving autonomic imbalance in individuals with POTS after a COVID-19 infection. They recommend that future research should involve larger, more diverse patient populations to confirm these findings. Subsequent studies should also directly assess the impact on clinical symptoms to provide a more comprehensive understanding of the treatment’s potential.