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 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 the autonomic cardiac nervous system 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 the 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 the following heart rate and HRV parameters: standard deviation of normal-to-normal intervals (SDNN), root mean square of successive R-R 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%–6%, P < .05) and an increase in overall HRV demonstrated by SDNN (approximately 19%, P < .05). RMSSD and power spectral density parameters (HF, LF, LF/HF) showed statistical trends ( P < .1) induced by auricular acupuncture in favor of vagal tone. No relevant difference was shown between control and placebo group. 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.

Heart Rate Variability during Auricular Acupressure at Heart Point in Healthy Volunteers: A Pilot Study

“…In our study, if we compare the LF value at each stage, including before, during, and after acupressure, the difference is not statistically significant ( p > 0.05) in both the experimental and control groups ( Table 4 ). This result is similar to the studies of Shen et al [ 24 ] and Lee et al [ 10 ], but different from that of Gao et al [ 7 , 8 , 15 ]. In the study of Gao, LF value was increased in both stages of stimulating the heart point with electroacupuncture (electric vibrating pen) and auricular needling (stimulating the acupuncture point with a needle).…”

“…When surveying RMSSD through each stage, we noted that RMSSD was different with no statistical significance ( p > 0.05) between both groups, which was also observed by Andreas et al [ 15 ].…”

“…In our study, the SDNN change was not statistically significant ( p > 0.05) at the study stages and in both the experimental group and the control group. Nevertheless, in the study of Boehmer et al [ 15 ], SDNN increased after performing auricular acupuncture. To clarify this difference, it is important to compare the inclusion criteria and methods of the two studies.…”

“…This result is similar to the study of Gao et al on healthy volunteers. When performing stimulated acupressure of the vagus nerve in the ear, the heart rate was reduced [ 8 , 15 – 17 ]. The decrease in heart rate is a precedent for further research on heart rate variability.…”

“…This can be both an unwanted reaction and a beneficial effect. If this method is applied to patients with insomnia at the right time, there will be therapeutic benefits [ 15 , 25 , 26 ].…”