Acupuncture at the auricular branch of the vagus nerve enhances heart rate variability in humans: An exploratory study

Abstract Background Recent animal and human studies have shown antiarrhythmic effects inhibiting inducibility of atrial fibrillation (AF) through low-level transcutaneous electrical stimulation at the auricular branch of the vagus nerve (ABVN). Objective The present study investigated effects of acupuncture at the ABVN on autonomic cardiac nervous system (ACNS) in humans through analysis of heart rate and heart rate variability (HRV) parameters. Methods We enrolled 24 healthy male volunteers and compared acupuncture at the ABVN to placebo-acupuncture performed at Ma-35 point (an acupuncture point used in Traditional Chinese Medicine to treat pain caused by gonarthrosis). An additional measurement without acupuncture served as control. We analyzed heart rate and heart rate variability parameters (Standard Deviation of Normal-to-Normal Intervals (SDNN), Root Mean Square of Successive RR interval Differences (RMSSD), High-Frequency (HF), Low-Frequency (LF), LF/HF ratio). Results In comparison to placebo acupuncture, acupuncture at the ABVN led to a significant reduction in heart rate (approximately 4 to 6%, P Conclusion Acupuncture of the region innervated by the ABVN may activate the parasympathetic nervous system as suggested by reduction in heart rate and increase in SDNN. However, given the lack of clear significant changes in other HRV parameters, this effect seems modest and its evaluation requires further investigation. (word count: 248)