Blaber A P, Bondar R L, Freeman R
Centre for Advanced Technology Education, Ryerson Polytechnic University, Toronto, Ontario, Canada.
Am J Physiol. 1996 Oct;271(4 Pt 2):H1555-64. doi: 10.1152/ajpheart.1996.271.4.H1555.
We examined heart rate and blood pressure variability (HRV and BPV) during graded tilt (5 min in each position: supine, -10 degrees, 10 degrees, 30 degrees, 60 degrees, -10 degrees, supine) in autonomic failure patients and age-matched controls. Heart rate was not different between patients and controls and increased with tilt (P < 0.001). Total HRV was reduced in patients (P < 0.03). Patients had reduced low-frequency (0-0.15 Hz) HRV and BPV (P < 0.005). With tilt, low-frequency BPV increased in controls, whereas high-frequency (> 0.15 Hz) BPV increased in patients. The slope of the fractal component (beta) for HRV and BPV was not different between patients and controls. HRV-beta increased (1.5-1.9, P < 0.01) with tilt, but BPV-beta (approximately 1.8) was unaffected. Values of beta close to 1 indicate high signal regulatory complexity, and values of beta close to 2 indicate low complexity. HRV and BPV provide clear evidence of impaired sympathetic and parasympathetic autonomic nervous system response to tilt with autonomic failure. The similarity in signal complexity with reduced fractal and harmonic spectral power, in patients compared with controls, suggests unchanged cardiovascular neural input and integration with reduced output in autonomic failure.
我们在自主神经功能衰竭患者和年龄匹配的对照组中，对分级倾斜（每个体位5分钟：仰卧位、-10度、10度、30度、60度、-10度、仰卧位）过程中的心率和血压变异性（HRV和BPV）进行了检查。患者和对照组之间的心率无差异，且随倾斜度增加（P<0.001）。患者的总HRV降低（P<0.03）。患者的低频（0 - 0.15Hz）HRV和BPV降低（P<0.005）。随着倾斜度增加，对照组的低频BPV增加，而患者的高频（>0.15Hz）BPV增加。患者和对照组之间HRV和BPV的分形成分（β）斜率无差异。HRV-β随倾斜度增加（1.5 - 1.9，P<0.01），但BPV-β（约为1.8）未受影响。β值接近1表明信号调节复杂性高，β值接近2表明复杂性低。HRV和BPV提供了明确证据，表明自主神经功能衰竭时交感和副交感自主神经系统对倾斜度的反应受损。与对照组相比，患者信号复杂性相似，但分形和谐波频谱功率降低，这表明自主神经功能衰竭时心血管神经输入不变，但输出减少。
