Background:
Autonomic imbalance, characterized by suppressed vagal activity and increased sympathetic activity
significantly contribute to the development and progression of cardiovascular diseases. A noninvasive neuromodulation technique that may influence the cardiac autonomic nervous system
(CANS) and restore autonomic imbalance is transcutaneous vagus nerve stimulation (tVNS). This
thesis focuses on a novel cervical tVNS device (Pulsetto) which targets the vagus nerve through the
neck. The aim of this research is to investigate the efficacy of this new device and provide insights into
how cervical tVNS influences the CANS.
Methods:
Two experiments were conducted: the first explored cervical tVNS in 8 atrial fibrillation (AF) patients,
while the second involved 40 healthy participants, randomly assigned to either a stimulation group
(n=30) or a sham group (n=10). Participants in the stimulation group received 10 minutes of
stimulation. Heart rate variability (HRV) and cardiac conduction were measured via a 3-lead ECG, with
data analysis focusing on HRV parameters, conduction intervals, and wave amplitude detection.
Results:
Significant HRV changes were observed during stimulation compared to pre-stimulation. Cervical
tVNS significantly decreased mean HR (P<0.001) and LF/HF (P=0.038), while significantly increasing
RMSSD (P=0.001), PNN50 (P=0.001) and HF power (P=0.003). Additionally, the QT interval and Twave amplitude significantly increased (P=0.001 and P=0.030 respectively) in the stimulation group.
None of these parameters changed in the sham group.
Conclusion:
This thesis provides evidence that cervical tVNS can modulate cardiovascular autonomic control in
healthy participants by increasing parasympathetic activity. Additionally, it is the first study to observe
an increased T-wave amplitude during cervical tVNS, suggesting a novel effect on ventricular
conduction. These insights indicate that cervical tVNS holds great potential for treating arrhythmias
and other cardiovascular diseases.
