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. 2023 Mar 23:17:1149449.
doi: 10.3389/fnhum.2023.1149449. eCollection 2023.

Afterload reduction after non-invasive vagus nerve stimulation in acute heart failure

Michiaki Nagai  1 , Keigo Dote  1 , Masaya Kato  1 , Shota Sasaki  1 , Noboru Oda  1 , Carola Y Förster  2
Affiliations

Afterload reduction after non-invasive vagus nerve stimulation in acute heart failure

Michiaki Nagai et al. Front Hum Neurosci. .

Abstract

Introduction: While central blood pressure (BP) has been recognized as a major indicator of left ventricular (LV) afterload, the reduction of central pressure decreases LV afterload and may prevent heart failure (HF) decompensation. Non-invasive transcutaneous vagus nerve stimulation (tVNS) was shown to improve cardiac function in HF patients. In this study, the relationship between active tVNS and reduction of central BP was investigated in patients with acute HF (AHF).

Methods: The 22 patients hospitalized for AHF after initial stabilization (median 80 yrs, males 60%) were randomly assigned to active or sham group. For 1 h daily over 5 days, low-level transcutaneous electrical stimulation (LLTS) (20 Hz, 1 mA) was performed after attaching an ear clip to the tragus (active group) or the earlobe (sham control group). Before and after stimulation, central aortic systolic pressure (CASP), brachial systolic BP (SBP), diastolic BP (DBP) as well as heart rate (HR) were noninvasively measured.

Results: No significant differences in baseline characteristics were observed between the active and sham groups. In the active group, CASP, SBP, DBP, and HR each decreased significantly after stimulation (all p < 0.05), whereas in the sham group, CASP, SBP, DBP, and HR each increased significantly after stimulation (all p < 0.05). All the changes in CASP, SBP, DBP and HR before and after stimulation were also significantly different between active and sham groups (all p < 0.01). There were no device-related side effects.

Conclusion: In this study, the left tragus tVNS resulted in an acute afterload reduction in the elderly AHF patients. Non-invasive LLTS may be useful and safe for reducing afterload in AHF.

Clinical trial registration: ClinicalTrials.gov, identifier UMIN000044121.

Keywords: acute heart failure; afterload; central aortic systolic pressure; low-level transcutaneous electrical stimulation; transcutaneous vagus nerve stimulation.

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Conflict of interest statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Figures

FIGURE 1
FIGURE 1
Transcutaneous electrical vagus nerve stimulation. (A) The device used for stimulation (Parasym, London, UK). (B) For active stimulation, the ear clip was attached to the left tragus, which is innervated by the auricular branch of the vagus nerve. (C) For sham control stimulation, the ear clip was attached to the left ear lobe, which is devoid of vagal innervation.
FIGURE 2
FIGURE 2
Flow diagram of participant screening and enrollment of patients.
FIGURE 3
FIGURE 3
A schematic representation of the study design and timeline of hemodynamic measurements. tVNS, transcutaneous vagus nerve stimulation; CASP, central aortic systolic pressure; SBP, systolic blood pressure; DBP, diastolic blood pressure; HR, heart rate.
FIGURE 4
FIGURE 4
Effect of active vs sham tVNS on measures of central aortic systolic pressure. (A) Active stimulation. (B) Sham stimulation. tVNS, transcutaneous vagus nerve stimulation.
FIGURE 5
FIGURE 5
Effect of active vs sham tVNS on measures of brachial systolic blood pressure. (A) Active stimulation. (B) Sham stimulation. tVNS, transcutaneous vagus nerve stimulation.
FIGURE 6
FIGURE 6
Effect of active vs sham tVNS on measures of brachial diastolic blood pressure. (A) Active stimulation. (B) Sham stimulation. tVNS, transcutaneous vagus nerve stimulation.
FIGURE 7
FIGURE 7
Effect of active vs sham tVNS on measures of heart rate. (A) Active stimulation. (B) Sham stimulation. tVNS, transcutaneous vagus nerve stimulation.
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