TREAT AF (Transcutaneous Electrical Vagus Nerve Stimulation to Suppress Atrial Fibrillation): A Randomized Clinical Trial

Stavros Stavrakis, Julie A Stoner, Mary Beth Humphrey, Lynsie Morris, Adrian Filiberti, Justin C Reynolds, Khaled Elkholey, Isma Javed, Nicholas Twidale, Pavel Riha, Subha Varahan, Benjamin J Scherlag, Warren M Jackman, Tarun W Dasari, Sunny S Po, Stavros Stavrakis, Julie A Stoner, Mary Beth Humphrey, Lynsie Morris, Adrian Filiberti, Justin C Reynolds, Khaled Elkholey, Isma Javed, Nicholas Twidale, Pavel Riha, Subha Varahan, Benjamin J Scherlag, Warren M Jackman, Tarun W Dasari, Sunny S Po

Abstract

Objectives: This study was a sham-controlled, double-blind, randomized clinical trial to examine the effect of chronic low level tragus stimulation (LLTS) in patients with paroxysmal AF.

Background: Low-level transcutaneous electrical stimulation of the auricular branch of the vagus nerve at the tragus (LLTS) acutely suppresses atrial fibrillation (AF) in humans, but the chronic effect remains unknown.

Methods: LLTS (20 Hz, 1 mA below the discomfort threshold) was delivered using an ear clip attached to the tragus (active arm) (n = 26) or the ear lobe (sham control arm) (n = 27) for 1 h daily over 6 months. AF burden over 2-week periods was assessed by noninvasive continuous electrocardiogram monitoring at baseline, 3 months, and 6 months. Five-minute electrocardiography and serum were obtained at each visit to measure heart rate variability and inflammatory cytokines, respectively.

Results: Baseline characteristics were balanced between the 2 groups. Adherence to the stimulation protocol (≤4 sessions lost per month) was 75% in the active arm and 83% in the control arm (p > 0.05). At 6 months, the median AF burden was 85% lower in the active arm compared with the control arm (ratio of medians: 0.15; 95% confidence interval: 0.03 to 0.65; p = 0.011). Tumor necrosis factor-alpha was significantly decreased by 23% in the active group relative to the control group (ratio of medians: 0.77; 95% confidence interval: 0.63 to 0.94; p = 0.0093). Frequency domain indices of heart rate variability were significantly altered with active versus control stimulation (p < 0.01). No device-related side effects were observed.

Conclusions: Chronic, intermittent LLTS resulted in lower AF burden than did sham control stimulation, supporting its use to treat paroxysmal AF in selected patients. (Transcutaneous Electrical Vagus Nerve Stimulation to Suppress Atrial Fibrillation [TREAT-AF]; NCT02548754).

Keywords: atrial fibrillation; neuromodulation; randomized clinical trial.

Copyright © 2020 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Figures

Figure 1.
Figure 1.
Representative examples of active (A) and sham control (B) stimulation. For active stimulation, the ear clip was attached to the tragus, which is innervated by the auricular branch of the vagus nerve (A). For sham control stimulation, the ear clip was attached to the ear lobe, which is devoid of vagal innervation (B). A schematic representation of the study design and timeline of events is shown in (C).
Figure 2.
Figure 2.
Flow diagram of participant recruitment and follow-up
Figure 3.
Figure 3.
Comparison of atrial fibrillation (AF) burden between the 2 groups. The data are presented as median values and interquartile range. The p-value is based on a comparison of median AF burden levels at the 6-month time point after adjusting for baseline measures.
Figure 4.
Figure 4.
Patient-level data on atrial fibrillation (AF) burden change in the 2 groups. Patients whose AF burden decreased by >75% at follow up were categorized as responders. The proportion of responders was significantly larger in the active compared to the sham control group (47% vs. 5%, respectively, p=0.003). B = baseline; 3M = 3 months; 6M = 6 months.
Figure 5.
Figure 5.
Linear regression of the change in AF burden at follow up (Δ AF burden) as a function of the respective change in low frequency to high frequency ratio (Δ LF/HF) in the active (n=13; r=−0.51, p=0.077) and sham control group (n=11; r=−0.14, p=0.67).
Central illustration.
Central illustration.
Noninvasive neuromodulation using low level tragus stimulation (LLTS) significantly decreased atrial fibrillation (AF) burden and decreased tumor necrosis factor (TNF)-α levels. The potential mechanisms of this effect are shown. Also shown are the neural pathways involved in this effect. LLTS targets the auricular branch of the vagus nerve, an afferent nerve (blue arrows) which relays information to central vagal projections in the brain stem. The signal undergoes processing in the brain stem and in higher centers (green arrows), which in turn provide the efferent neural signal to the heart (red arrows), which reaches the target organ through the vagus nerve.

References

    1. Uthman BM, Reichl AM, Dean JC et al. Effectiveness of vagus nerve stimulation in epilepsy patients: a 12-year observation. Neurology 2004;63:1124–6.
    1. Deuchars SA, Lall VK, Clancy J et al. Mechanisms underpinning sympathetic nervous activity and its modulation using transcutaneous vagus nerve stimulation. Exp Physiol 2018;103:326–331.
    1. Frangos E, Ellrich J, Komisaruk BR. Non-invasive Access to the Vagus Nerve Central Projections via Electrical Stimulation of the External Ear: fMRI Evidence in Humans. Brain Stimul 2015;8:624–36.
    1. Yakunina N, Kim SS, Nam EC. BOLD fMRI effects of transcutaneous vagus nerve stimulation in patients with chronic tinnitus. PLoS One 2018;13:e0207281.
    1. Lehtimaki J, Hyvarinen P, Ylikoski M et al. Transcutaneous vagus nerve stimulation in tinnitus: a pilot study. Acta Otolaryngol 2013;133:378–82.
    1. Hamer HM, Bauer S. Lessons learned from transcutaneous vagus nerve stimulation (tVNS). Epilepsy Res 2019;153:83–84.
    1. Clancy JA, Mary DA, Witte KK, Greenwood JP, Deuchars SA, Deuchars J. Non-invasive Vagus Nerve Stimulation in Healthy Humans Reduces Sympathetic Nerve Activity. Brain Stimul 2014;7:871–7.
    1. Huston JM, Gallowitsch-Puerta M, Ochani M et al. Transcutaneous vagus nerve stimulation reduces serum high mobility group box 1 levels and improves survival in murine sepsis. Crit Care Med 2007;35:2762–8.
    1. Stavrakis S, Humphrey MB, Scherlag BJ et al. Low-level transcutaneous electrical vagus nerve stimulation suppresses atrial fibrillation. J Am Coll Cardiol 2015;65:867–75.
    1. Yu L, Huang B, Po SS et al. Low-Level Tragus Stimulation for the Treatment of Ischemia and Reperfusion Injury in Patients With ST-Segment Elevation Myocardial Infarction: A Proof-of-Concept Study. JACC Cardiovasc Interv 2017;10:1511–1520.
    1. Stavrakis S, Nakagawa H, Po SS, Scherlag BJ, Lazzara R, Jackman WM. The role of the autonomic ganglia in atrial fibrillation. JACC Clin Electrophysiol 2015;1:1–13.
    1. Chen PS, Chen LS, Fishbein MC, Lin SF, Nattel S. Role of the autonomic nervous system in atrial fibrillation: pathophysiology and therapy. Circ Res 2014;114:1500–15.
    1. Li S, Scherlag BJ, Yu L et al. Low-level vagosympathetic stimulation: a paradox and potential new modality for the treatment of focal atrial fibrillation. Circ Arrhythm Electrophysiol 2009;2:645–51.
    1. Sha Y, Scherlag BJ, Yu L et al. Low-level right vagal stimulation: anticholinergic and antiadrenergic effects. J Cardiovasc Electrophysiol 2011;22:1147–53.
    1. Sheng X, Scherlag BJ, Yu L et al. Prevention and reversal of atrial fibrillation inducibility and autonomic remodeling by low-level vagosympathetic nerve stimulation. J Am Coll Cardiol 2011;57:563–71.
    1. Yu L, Scherlag BJ, Li S et al. Low-level vagosympathetic nerve stimulation inhibits atrial fibrillation inducibility: direct evidence by neural recordings from intrinsic cardiac ganglia. J Cardiovasc Electrophysiol 2011;22:455–63.
    1. Yu L, Scherlag BJ, Li S et al. Low-level transcutaneous electrical stimulation of the auricular branch of the vagus nerve: a noninvasive approach to treat the initial phase of atrial fibrillation. Heart Rhythm 2013;10:428–35.
    1. Shen MJ, Shinohara T, Park HW et al. Continuous low-level vagus nerve stimulation reduces stellate ganglion nerve activity and paroxysmal atrial tachyarrhythmias in ambulatory canines. Circulation 2011;123:2204–12.
    1. Aviles RJ, Martin DO, Apperson-Hansen C et al. Inflammation as a risk factor for atrial fibrillation. Circulation 2003;108:3006–10.
    1. Hu YF, Chen YJ, Lin YJ, Chen SA. Inflammation and the pathogenesis of atrial fibrillation. Nat Rev Cardiol 2015;12:230–43.
    1. Chavan SS, Pavlov VA, Tracey KJ. Mechanisms and Therapeutic Relevance of Neuroimmune Communication. Immunity 2017;46:927–942.
    1. Koopman FA, Chavan SS, Miljko S et al. Vagus nerve stimulation inhibits cytokine production and attenuates disease severity in rheumatoid arthritis. Proc Natl Acad Sci U S A 2016;113:8284–9.
    1. Peuker ET, Filler TJ. The nerve supply of the human auricle. Clin Anat 2002;15:35–7.
    1. Heart rate variability: standards of measurement, physiological interpretation and clinical use. Task Force of the European Society of Cardiology and the North American Society of Pacing and Electrophysiology. Circulation 1996;93:1043–65.
    1. Tran N, Asad Z, Elkholey K, Scherlag BJ, Po SS, Stavrakis S. Autonomic Neuromodulation Acutely Ameliorates Left Ventricular Strain in Humans. J Cardiovasc Transl Res 2019;12:221–230.
    1. Freeman R Assessment of cardiovascular autonomic function. Clin Neurophysiol 2006;117:716–30.
    1. Rosenberg MA, Samuel M, Thosani A, Zimetbaum PJ. Use of a noninvasive continuous monitoring device in the management of atrial fibrillation: a pilot study. Pacing Clin Electrophysiol 2013;36:328–33.
    1. Qian Y, Kang Z, Liu C, Li X. IL-17 signaling in host defense and inflammatory diseases. Cell Mol Immunol 2010;7:328–33.
    1. Tanaka T, Narazaki M, Kishimoto T. IL-6 in inflammation, immunity, and disease. Cold Spring Harb Perspect Biol 2014;6:a016295.
    1. Chen LY, Chung MK, Allen LA et al. Atrial Fibrillation Burden: Moving Beyond Atrial Fibrillation as a Binary Entity: A Scientific Statement From the American Heart Association. Circulation 2018;137:e623–e644.
    1. Go AS, Reynolds K, Yang J et al. Association of Burden of Atrial Fibrillation With Risk of Ischemic Stroke in Adults With Paroxysmal Atrial Fibrillation: The KP-RHYTHM Study. JAMA Cardiol 2018;3:601–608.
    1. Liu L, Nattel S. Differing sympathetic and vagal effects on atrial fibrillation in dogs: role of refractoriness heterogeneity. Am J Physiol 1997;273:H805–16.
    1. Andrus EC, Carter EP, With an Appendix by Harold A. Wheeler PD. The Refractory Period of the Normally-Beating Dog’s Auricle; with a Note on the Occurrence of Auricular Fibrillation Following a Single Stimulus. J Exp Med 1930;51:357–67.
    1. Zhang Y, Ilsar I, Sabbah HN, Ben David T, Mazgalev TN. Relationship between right cervical vagus nerve stimulation and atrial fibrillation inducibility: therapeutic intensities do not increase arrhythmogenesis. Heart Rhythm 2009;6:244–50.
    1. Ardell JL, Nier H, Hammer M et al. Defining the neural fulcrum for chronic vagus nerve stimulation: implications for integrated cardiac control. J Physiol 2017;595:6887–6903.
    1. Chinda K, Tsai WC, Chan YH et al. Intermittent left cervical vagal nerve stimulation damages the stellate ganglia and reduces the ventricular rate during sustained atrial fibrillation in ambulatory dogs. Heart Rhythm 2016;13:771–80.
    1. Verlinden TJ, Rijkers K, Hoogland G, Herrler A. Morphology of the human cervical vagus nerve: implications for vagus nerve stimulation treatment. Acta Neurol Scand 2016;133:173–82.
    1. Stavrakis S, Humphrey MB, Scherlag B et al. Low-Level Vagus Nerve Stimulation Suppresses Post-Operative Atrial Fibrillation and Inflammation: A Randomized Study. JACC Clin Electrophysiol 2017;3:929–938.
    1. Pavlov VA, Chavan SS, Tracey KJ. Molecular and Functional Neuroscience in Immunity. Annu Rev Immunol 2018;36:783–812.
    1. Gomes-Osman J, Indahlastari A, Fried PJ et al. Non-invasive Brain Stimulation: Probing Intracortical Circuits and Improving Cognition in the Aging Brain. Front Aging Neurosci 2018;10:177.
    1. Ashton JL, Burton RAB, Bub G, Smaill BH, Montgomery JM. Synaptic Plasticity in Cardiac Innervation and Its Potential Role in Atrial Fibrillation. Front Physiol 2018;9:240.
    1. Huffman WJ, Subramaniyan S, Rodriguiz RM, Wetsel WC, Grill WM, Terrando N. Modulation of neuroinflammation and memory dysfunction using percutaneous vagus nerve stimulation in mice. Brain Stimul 2019;12:19–29.
    1. Lombardi F, Tarricone D, Tundo F, Colombo F, Belletti S, Fiorentini C. Autonomic nervous system and paroxysmal atrial fibrillation: a study based on the analysis of RR interval changes before, during and after paroxysmal atrial fibrillation. Eur Heart J 2004;25:1242–8.
    1. Byku M, Mann DL. Neuromodulation of the Failing Heart: Lost in Translation? JACC Basic Transl Sci 2016;1:95–106.

Source: PubMed

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