Effects of Transcutaneous Auricular Vagus Nerve Stimulation Combined With Slow-Paced Diaphragmatic Breathing on Postural Tachycardia Syndrome: A Randomized Controlled Trial
Trial Snapshot
- Phase
- Not Applicable
- Status
- Not yet recruiting
- Sponsor
- Enrollment
- 100
- Primary Endpoint
- Change in Heart Rate From Supine to Standing (Delta HR) After 12 Weeks of Daily taVNS With or Without Slow-Paced Breathing in Individuals With POTS
Study Overview
Brief Summary
This study investigates a non-pharmacological treatment approach for Postural Orthostatic Tachycardia Syndrome (POTS), a disorder of the autonomic nervous system characterized by an excessive increase in heart rate upon standing. POTS is commonly associated with symptoms such as dizziness, fatigue, cognitive difficulties, sleep disturbances, as well as anxiety and depression, which significantly impair quality of life.
This randomized, controlled clinical trial aims to evaluate whether combining transcutaneous auricular vagus nerve stimulation (taVNS) with slow-paced diaphragmatic breathing (at 0.1 Hz) provides greater therapeutic benefit compared to taVNS alone or sham stimulation.
A total of 100 participants will be recruited and randomly assigned to one of four groups (25 per group):
taVNS with slow-paced breathing,
taVNS with spontaneous (normal) breathing,
sham taVNS with slow-paced breathing, or
sham taVNS with spontaneous breathing.
Participants will perform the intervention daily at home for a duration of 12 weeks. Medical and psychological assessments will be conducted before and after the intervention, including measurements of heart rate, inflammatory cytokines, and patient-reported outcomes on sleep, mood, and quality of life.
The study is conducted at the Center for Public Health, Medical University of Vienna, and is open to individuals diagnosed with POTS, including those with coexisting Post-COVID-19 syndrome.
Detailed Description
Postural Orthostatic Tachycardia Syndrome (POTS) is a disorder of the autonomic nervous system characterized by an excessive increase in heart rate (≥30 bpm) within 10 minutes of standing, without a significant drop in blood pressure. Affected individuals frequently suffer from fatigue, dizziness, palpitations, cognitive dysfunction ("brain fog"), anxiety, depression, and sleep disturbances. These symptoms significantly impair daily functioning and quality of life.
Conventional pharmacological treatments often yield limited benefit and can lead to adverse effects, especially in individuals with complex autonomic dysregulation. Non-pharmacological approaches that target the autonomic nervous system more holistically and with fewer side effects are gaining increasing scientific interest.
This randomized, controlled clinical trial aims to investigate the effects of combining transcutaneous auricular vagus nerve stimulation (taVNS) with slow-paced diaphragmatic breathing at 0.1 Hz (six breaths per minute) as an integrative therapeutic strategy for individuals with POTS.
A total of 100 participants diagnosed with POTS will be randomly assigned (1:1:1:1) into four groups (25 per group):
taVNS combined with slow-paced diaphragmatic breathing (0.1 Hz)
Study Design
- Study Type
- Interventional
- Allocation
- Randomized
- Intervention Model
- Parallel
- Primary Purpose
- Treatment
- Masking
- Double (Participant, Outcomes Assessor)
Eligibility Criteria
- Ages
- 18 Years to 65 Years (Adult, Older Adult)
- Sex
- All
- Accepts Healthy Volunteers
- No
Inclusion Criteria
- •Formal diagnosis of Postural Orthostatic Tachycardia Syndrome (POTS), confirmed by clinical criteria: a sustained increase in heart rate (HR) of ≥30 bpm within 10 minutes of standing, without orthostatic hypotension.
- •History of POTS diagnosis for at least 6 months.
- •Participants with Post-acute COVID-19 syndrome may be included if they meet the formal POTS criteria. These participants will be stratified based on the presence or absence of Post-Exertional Malaise (PEM).
- •Stable medication for POTS (same dosage/class) for at least 4 weeks before enrollment.
- •Willingness and ability to provide informed consent.
- •Screening of Undiagnosed Participants:
- •Suspected POTS based on clinical symptoms (e.g., dizziness, fatigue, syncope, brain fog, palpitations, exercise intolerance) persisting ≥6 months.
- •Preliminary Schellong test by study team.
- •If criteria are met, referral to a specialist (neurology or cardiology) for diagnostic confirmation.
- •Inclusion only after specialist-confirmed POTS diagnosis.
Exclusion Criteria
- •Significant hypertension (BP >150/100 mmHg supine or standing).
- •Orthostatic hypotension: drop in BP >20 mmHg systolic or >10 mmHg diastolic upon standing.
- •Recent stroke or myocardial infarction (within 6 months).
- •Significant immunological or hematological disorders.
- •Severe anemia (hematocrit <28%).
- •History of vagotomy.
- •Pregnancy or lactation.
- •Inability or unwillingness to provide informed consent.
Arms & Interventions
TVNS + Slow-Paced Breathing (TVNS+SDB)
Participants receive active transcutaneous auricular vagus nerve stimulation (taVNS) using electrodes placed at the cymba conchae, combined with guided slow-paced diaphragmatic breathing (0.1 Hz). The intervention is performed daily at home for 12 weeks, with each session lasting 60 minutes.
Intervention: TVNS + Slow-Paced Breathing (TVNS+SDB) (Device)
TVNS without Breathing Training (TVNS+NB)
Participants receive active transcutaneous auricular vagus nerve stimulation (taVNS) using electrodes placed at the cymba conchae, combined with spontaneous breathing (no guided breathing exercises). The intervention is performed daily at home for 12 weeks, with each session lasting 60 minutes.
Intervention: TVNS without Breathing Training (TVNS+NB) (Device)
Sham TVNS + SDB
Participants receive transcutaneous auricular vagus nerve stimulation using a sham protocol via electrodes placed at the cymba conchae, combined with guided slow-paced diaphragmatic breathing (0.1 Hz). The intervention is performed daily at home for 12 weeks, with each session lasting 60 minutes.
Intervention: Sham TVNS + SDB (Device)
Sham TVNS + NB
Participants receive transcutaneous auricular vagus nerve stimulation using a sham protocol via electrodes placed at the cymba conchae, combined with spontaneous breathing (no guided breathing exercises). The intervention is performed daily at home for 12 weeks, with each session lasting 60 minutes.
Intervention: Sham TVNS + NB (Device)
Outcomes
Primary Outcomes
Change in Heart Rate From Supine to Standing (Delta HR) After 12 Weeks of Daily taVNS With or Without Slow-Paced Breathing in Individuals With POTS
Time Frame: Change in Heart Rate (Delta HR) from Supine to Standing at Baseline and Week 12
Heart rate (HR) is continuously recorded via 12-lead ECG during a standardized Tilt test. Participants lie supine for 25 minutes and then stand upright for 10 minutes. The average HR from the last 10 minutes supine and the 10-minute standing phase is calculated. The primary outcome, Delta HR, is defined as the difference between upright and supine HR. This measure reflects autonomic cardiovascular response and is assessed before and after the 12-week intervention phase.
Secondary Outcomes
No secondary outcomes reported
Investigators
Ali Kapan
Principal Investigator
Medical University of Vienna