Impact of Subthreshold Transcutaneous Auricular Vagus Nerve Stimulation on the Heart Rate Variability and Atrial Arrhythmias

Dysfunction of cardiac intrinsic autonomic nervous system could be one of possible triggers for atrial fibrillation. Different studies show that it is possible to modulate the cardiac intrinsic autonomic activity with electrical stimulation through the skin in the ear, innervated by auricular branch of the vagus nerve (tVNS). The aim of our study was to determine, weather tVNS reduces the burden of atrial arrhythmias in patients with paroxysmal atrial fibrillation. A randomised double-blind study, with one-hour daily subthreshold tVNS, over three-day blocks of sham or true stimulation, was performed. A continuous single-channel ambulatory ECG was recorded. Significant technical assistance to computer-based ECG interpretation was necessary for highest possible interpretation quality. The obtained results were compared between periods with true and sham stimulation to discover eventual differences. We have successfully validated the designed methodology. The subthreshold tVNS has a detectable impact on heart rate variability. However, there was no significant impact of tVNS on the burden of atrial arrhythmias. A 3-day tVNS is probably too short for such evaluation.