Transcutaneous vagus nerve stimulation in postural orthostatic tachycardia syndrome: A systematic search and narrative synthesis of three clinical studies

Postural orthostatic tachycardia syndrome is a chronic autonomic disorder with limited effective treatment therapy. Non-invasive transcutaneous vagus nerve stimulation has emerged as a promising intervention that improves autonomic balance and has anti-inflammatory properties. This systematic search and narrative synthesis brings together all available clinical evidence including landmark studies from 2025 to 2026 unavailable to all prior reviews and advances novel arguments to guide future trial design. We searched in 5 databases (PubMed, Embase, Cochrane, Scopus and Web of science) from inception to March 2026 to extract studies evaluating the role of tVNS in treatment of POTS following the PRISMA 2020 guidelines. Because of the small number of clinically and methodologically heterogeneous studies, findings were combined by narrative synthesis rather than meta-analysis, and reported in line with the Synthesis Without Meta-analysis (SWiM) guideline. A total of 105 patients with POTS from 3 primary studies (Stavrakis et al. (2024), Wang et al. (2025), Shiffer et al. (2026) were included in this review. Across the studies, tVNS consistently reduced orthostatic tachycardia and improved multiple autonomic parameters, with reductions in GPCR autoantibodies, inflammatory markers, and the emerging biomarker NPY. Patient-reported symptoms improved in two studies that reported them. These outcomes sustained up to 1-2 years. In this systematic review, we found that tVNS is safe, non-invasive and consistently effective in reducing the orthostatic tachycardia and improving autonomic indices in POTS patients and may contribute to disease modification.