Vagus Nerve Stimulation for Autonomic Modulation After Coronary Artery Bypass Graft Surgery

NCT07853222 | Completed DMC

• 3 other identifiers: 2025-033890487825.4.1001.53277.780.341
• Study Type: interventional
• Target: 58
• Locations: 1 country
• Sites: 2

Brief Summary

The objective of this randomized clinical trial is to investigate whether transcutaneous auricular vagus nerve stimulation (taVNS) can improve the recovery of patients undergoing coronary artery bypass grafting (CABG) through autonomic modulation, while also evaluating the safety of the intervention. The main questions this study aims to answer are:

• Does taVNS improve autonomic modulation, as assessed by heart rate variability, in patients undergoing CABG?
• Does taVNS reduce the inflammatory response and pain intensity while improving quality of life and functional capacity during the postoperative period?
• Is taVNS a safe and well-tolerated intervention during recovery after CABG? The researchers will compare taVNS with a control group (sham stimulation/placebo) to determine whether the intervention leads to better clinical and functional outcomes in patients undergoing coronary artery bypass grafting. Participants will:
• Receive sessions of transcutaneous auricular vagus nerve stimulation (taVNS) or sham stimulation (placebo), according to the study randomization.
• Undergo assessments of autonomic modulation using heart rate variability before and after the intervention.
• Be evaluated for inflammatory markers, pain intensity, quality of life, and functional capacity at different time points during the postoperative period.

Conditions

Coronary Artery Bypass Grafting (CABG) Surgery; Vagus Nerve Stimulations

Keywords

Vagus Nerve Stimulation; Myocardial Revascularization; Autonomic Nervous System

Outcome Measures

Primary Outcomes (1)

• Heart rate variability (HRV) assessed before and after each stimulation session until hospital discharge

  Heart rate variability (HRV) measured immediately before and immediately after each daily stimulation session until hospital discharge.

  Postoperative day 1 through hospital discharge. Stimulation will begin on postoperative day 1. HRV will be assessed immediately before and immediately after each daily stimulation session, from the first postoperative stimulation session until hospital

Secondary Outcomes (6)

• Quality of life assessed using the 36-Item Short Form Health Survey (SF-36).

  At hospital discharge following CABG.

• Hospital complications (arrhythmias)

  From postoperative day 1 (POD 1) until hospital discharge.

• Inflammatory Markers (C-Reactive Protein [CRP])

  From postoperative day 1 (POD 1) until hospital discharge, with daily measurements.

• Pain Assessed Using the Visual Analog Scale (VAS)

  From postoperative day 1 (POD 1) until hospital discharge, with daily assessments.

• Functional Capacity Assessed by the Six-Minute Walk Test (6MWT)

  At hospital discharge following coronary artery bypass grafting (CABG).

Study Arms (2)

Intervention Group

ACTIVE COMPARATOR

Transcutaneous auricular stimulation of the auricular branch of the vagus nerve with daily 30-minute sessions until hospital discharge. A transcutaneous electrode will be positioned on the concha, and the other electrode on the left earlobe. In this manner, we will stimulate the vagus nerve at the concha and the great auricular nerve at the earlobe. These sites were selected based on the innervation of the ear, technical feasibility for electrode placement, and to standardize the treatment protocol. In our study, the device used will be the EL-30 (NKL Produtos Eletrônicos, Brusque, SC, Brazil), with the following stimulation parameters: pulse width of 250 μs, intensity below the pain threshold, 5 seconds at 2 Hz / 5 seconds at 15 Hz. Recent studies have demonstrated that low frequencies have a greater effect on reducing sympathetic activity, whereas frequencies in the range of 10-25 Hz produce effective parasympathetic modulation. We selected a mixed mode, using both low (2 Hz) and me

Device: Transcutaneous auricular vagus nerve stimulation

Control Group

PLACEBO COMPARATOR

The same device and electrodes used in the intervention group will be applied. No actual electrical current will be delivered. The session duration will be 30 minutes, with the same electrode placement and application positioning as the intervention group.

Device: Transcutaneous auricular vagus nerve stimulation

Interventions

Transcutaneous auricular vagus nerve stimulation DEVICE

Transcutaneous auricular vagus nerve stimulation (taVNS) will be performed daily for 30 minutes until hospital discharge. One electrode will be placed on the auricular concha to stimulate the auricular branch of the vagus nerve, and the other electrode will be positioned on the left earlobe to stimulate the great auricular nerve. The stimulation will be delivered using the EL-30 device (NKL Produtos Eletrônicos, Brusque, SC, Brazil), with a pulse width of 250 μs, intensity below the pain threshold, and alternating frequencies of 2 Hz for 5 seconds and 15 Hz for 5 seconds. The stimulation sites were selected based on auricular innervation, technical feasibility, and treatment standardization.The control group will use the same device; however, no active electrical current will be delivered (placebo stimulation).

Control Group; Intervention Group

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may not qualify if:

• History of severe cardiac arrhythmias or recent electrical instability, including permanent atrial fibrillation, tachyarrhythmias, or the presence of an implantable cardioverter-defibrillator (ICD).
• Presence of a pacemaker or other implanted electronic devices.
• Severe neurological or psychiatric disorders, such as epilepsy, schizophrenia, or recent stroke (within the past 6 months).
• Active chronic inflammatory or autoimmune diseases that may interfere with inflammatory markers (e.g., systemic lupus erythematosus or rheumatoid arthritis).
• Acute infection or fever at the time of screening.
• History of ear surgery or ear injury that would preclude the application of transcutaneous auricular vagus nerve stimulation (taVNS).
• Confirmed or suspected pregnancy (for female participants of childbearing potential).

Sponsors & Collaborators

• Hospital de Clinicas de Porto Alegre: lead
• Hospital de Clinicas de Ijuí: collaborator

Study Sites (2)

Hospital de Clinicas de Ijuí

Ijuí, Rio Grande do Sul, 98700000, Brazil

Location

Hospital de Clinicas de Porto Alegre

Porto Alegre, Rio Grande do Sul, 90035-903, Brazil

Location

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Study Officials

• Ricardo Stein

  Hospital de Clínicas de Porto Alegre (HCPA)

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: PARTICIPANT
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: September 18, 2026
• First Posted: October 1, 2026
• Study Start: August 31, 2025
• Primary Completion: June 15, 2026
• Study Completion: June 30, 2026
• Last Updated: October 1, 2026

Record last verified: 2026-09

Data Sharing

• IPD Sharing: Will not share

Locations

BR (2)