Bailey J R, Fitzgerald D M, Applegate R J
Section of Cardiology, Bowman Gray School of Medicine, Wake Forest University, Winston-Salem, North Carolina 27157, USA.
Am J Physiol. 1996 Jun;270(6 Pt 2):H2081-7. doi: 10.1152/ajpheart.1996.270.6.H2081.
Heart rate variability is used to assess cardiac autonomic tone. We bought to determine the relationship of graded direct stimulation of efferent cardiac autonomic nerves on heart rate variability in an anesthetized canine model. Time and frequency domain variables were measured at denervated baseline and during electrical stimulation of the vagi and ansae subclaviae over a wide range of frequencies. Vagal and ansae stimuli produced significant changes in heart rate that correlated with the intensity of stimulation. Vagal stimulation resulted in small increases in time domain indexes of heart rate variability and in the power spectrum from 0.04 to 0.40 Hz, but with no correlation between stimulus intensity and changes in these indexes. By contrast, ansae stimulation had no effect on time or frequency domain measures. In the absence of central modulation of autonomic outflow, indexes of heart rate variability reflect the presence of vagal input but do not correlate with the level of vagal tone and are unaffected by changes in mean sympathetic tone.
心率变异性用于评估心脏自主神经张力。我们旨在确定在麻醉犬模型中，分级直接刺激传出性心脏自主神经对心率变异性的影响。在去神经支配的基线状态以及在广泛频率范围内对迷走神经和锁骨下袢进行电刺激期间，测量时域和频域变量。迷走神经和锁骨下袢刺激引起心率的显著变化，且与刺激强度相关。迷走神经刺激导致心率变异性时域指标以及功率谱在0.04至0.40赫兹范围内小幅增加，但刺激强度与这些指标变化之间无相关性。相比之下，锁骨下袢刺激对时域或频域测量无影响。在自主神经输出无中枢调节的情况下，心率变异性指标反映了迷走神经输入的存在，但与迷走神经张力水平无关，且不受平均交感神经张力变化的影响。
