Focus on Alternative and Complementary Therapies
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Focus Alternat Complement Ther©2005 Pharmaceutical Press
Focus Altern Complement Ther 2003; 8: 477–8
Previous studies have yielded divergent findings regarding effects of acupuncture on the autonomic nervous system. Conflicting results might be explained by variations in physiological responses to needle stimulation among individuals or groups. This study examined whether cardiac parasympathetic response to acupuncture varies as a function of preceding, basal vagal control among migraine patients.
Aspects of cardiovascular autonomic control can be investigated by measurement of heart rate variability (HRV) derived from spectral analysis. The high-frequency component, or respiratory sinus arrhythmia (RSA), has been shown predominantly to reflect cardiac vagal tone. We monitored the ECG and respiration before, during and after acupuncture sessions in 30 patients with migraine. Patients were randomised into two groups: 15 patients received a standardised verum acupuncture treatment, whereas the other 15 patients underwent sham acupuncture (superficial needling of non-acupoints). Data were analysed by multivariate analysis of variance.
In the verum acupuncture group, patients with high pretreatment levels of vagal tone showed a significant decrease of vagal control during treatment. In contrast, patients with low levels of vagal tone preceding treatment manifested no vagal changes during treatment. In the sham acupuncture group, there was no relation between pretreatment levels of RSA and treatment response.
These findings suggest that physiological responses to verum acupuncture may depend upon baseline pretreatment levels of cardiac vagal control. Additionally, sham acupuncture appears not to evoke cardiac vagal responses at all.
