The Effect of Different Low-Level Tragus Stimulation Parameters On Autonomic Nervous System Function (LLT-SPANS)

Low level transcutaneous vagus nerve stimulation (LLTS) involves delivery of electrical impulses transcutaneously at the auricular branch of vagus nerve and it has been shown to have anti-inflammatory and anti-arrhythmic effects. In previous studies from our laboratory, we found that LLTS significantly suppressed atrial fibrillation (AF) inducibility and decreased AF duration. The anti-arrhythmic effects of LLTS were similar to those delivered to the cervical VN trunk. LLTS for just one hour significantly shortened the AF duration and decreased inflammatory cytokines. We have also shown that LLTS leads to favorable heart rate variability (HRV) changes and cardiac mechanics in patients with diastolic dysfunction. These results support the use of LLTS as a novel non-pharmacological, non-ablative treatment modality for AF and possibly other inflammatory conditions. However, the optimal stimulation parameters of LLTS remain to be determined.

In this study, we aim to examine the effect of 2 different frequencies (5Hz and 20Hz) and 2 different amplitudes (50% below the pain threshold and 1mA below the pain threshold) of LLTS on heart rate variability with deep breathing (HRVdb), mental arithmetic stress test (MAST), frequency domain measures of heart rate variability (HRV) and brain stem evoked potentials (BSEVP) in healthy volunteers and patients with AF or heart failure with preserved ejection fraction (HFpEF). HRV is a marker of vagus nerve activity and can be easily measured by software calculating the distance between consecutive R waves on the ECG. BSEVP are a surrogate for the central projections of the vagus nerve. Patients will be randomized into 4 groups in a 2x2 factorial design. LLTS will be delivered through a transcutaneous electrical nerve stimulation (TENS) device for 15 minutes. HRVdb, HRV and BSEVP will be measured before and after LLTS and compared.

Study Overview

• Status: Recruiting
• Conditions: Atrial Fibrillation; Heart Failure, Diastolic
• Intervention / Treatment: Device: Parasym

• Study Type: Interventional
• Enrollment (Estimated): 90
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Karrie Meeks; Phone Number: 4052714742; Email: karrie-meeks@ouhsc.edu

Study Locations

• United States
  • Oklahoma
    • Oklahoma City, Oklahoma, United States, 73104
      • Recruiting
      • University of Oklahoma Health Sciences Center
      • Contact: Brittany Karfonta, RN; Phone Number: 405-271-2229; Email: brittany-karfonta@ouhsc.edu
      • Principal Investigator: Stavros Stavrakis, MD, PhD

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 21 years to 90 years (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

1. Male and female patients older than 21 year old
2. Healthy volunteers free from diagnosis of AF, heart failure, coronary artery disease or diseases that affect the autonomic nervous system.
3. Patients with Paroxysmal Atrial Fibrillation
4. Patients with Heart Failure with Preserved Ejection Fraction (HFpEF)

Exclusion Criteria:

1. Recent (<6 months) stroke
2. Recent (<6 months) myocardial infarction
3. Heart failure (NYHA class III or IV)
4. Left ventricular ejection fraction <50%
5. Recurrent vaso-vagal syncopal episodes
6. Unilateral or bilateral vagotomy
7. Pregnancy or breast feeding
8. Uncontrolled diabetes or hypertension
9. Inability or unwillingness to understand and/or sign informed consent
10. Any serious disease that affects autonomic nervous system function
11. Any medications that affect autonomic nervous system function

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Triple

Number of Arms

4

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Frequency 20Hz; amplitude 1mA below discomfort threshold; Patients will receive tragus stimulation for 15 minutes using the following settings: Frequency 20Hz; amplitude 1mA below discomfort threshold. Continuous ECG will be recorded to assess heart rate variability.	Device: Parasym; Tragus stimulation
Active Comparator: Frequency 5Hz; amplitude 1mA below discomfort threshold; Patients will receive tragus stimulation for 15 minutes using the following settings: Frequency 5Hz; amplitude 1mA below discomfort threshold. Continuous ECG will be recorded to assess heart rate variability.	Device: Parasym; Tragus stimulation
Active Comparator: Frequency 20Hz; amplitude 50% below discomfort threshold; Patients will receive tragus stimulation for 15 minutes using the following settings: Frequency 20Hz; amplitude 50% below discomfort threshold. Continuous ECG will be recorded to assess heart rate variability.	Device: Parasym; Tragus stimulation
Active Comparator: Frequency 5Hz; amplitude 50% below discomfort threshold; Patients will receive tragus stimulation for 15 minutes using the following settings: Frequency 5Hz; amplitude 50% below discomfort threshold. Continuous ECG will be recorded to assess heart rate variability.	Device: Parasym; Tragus stimulation

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Heart rate variability	Heart rate variability is a marker of vagus nerve activity and can be easily measured by PC-based ECG software calculating the distance between consecutive R waves on the ECG. Both time domain [standard deviation of normal-to-normal intervals (SDNN), root mean square of successive differences of the normal-to-normal intervals (RMSSD)] and frequency domain [low frequency (LF; 0.04-0.15 Hz), high frequency (HF; 0.15-0.4 Hz), and LF/HF ratio] measures will be analyzed.	15 minutes
Mental arithmetic stress test	Mental arithmetic stress test is a measure of sympathetic activity and will be performed by asking the patient to consistently subtract 7 from 500 for a period of 2 minutes. Blood pressure will be measured before and after the test, before and during stimulation and the maximum blood pressure during the test will be the outcome of interest.	15 minutes

Collaborators and Investigators

• Sponsor: University of Oklahoma
• Investigators: Principal Investigator: Stavros Stavrakis, MD, PhD, University of Oklahoma

Study record dates

Study Major Dates

• Study Start (Actual): November 30, 2021
• Primary Completion (Estimated): October 1, 2024
• Study Completion (Estimated): February 1, 2025

Study Registration Dates

• First Submitted: December 8, 2020
• First Submitted That Met QC Criteria: December 18, 2020
• First Posted (Actual): December 24, 2020

Study Record Updates

• Last Update Posted (Estimated): February 21, 2024
• Last Update Submitted That Met QC Criteria: February 19, 2024
• Last Verified: February 1, 2024

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Pathologic Processes; Heart Diseases; Cardiovascular Diseases; Arrhythmias, Cardiac; Heart Failure; Atrial Fibrillation; Heart Failure, Diastolic
• Other Study ID Numbers: 12708

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: Yes