Gulli G, Fattor Bruno, Marchesi Mario
Institute for Cardiovascular Research, University of Leeds, Worsley dental Building, Leeds LS2 9JT, UK.
Clin Auton Res. 2005 Apr;15(2):92-8. doi: 10.1007/s10286-005-0247-x.
Cardiovascular autonomic neuropathy in diabetes is associated with a high risk of mortality, which makes its early identification clinically important. An easy method for identification of subjects with autonomic dysfunction would be of clinical benefit. We evaluated the autonomic function in 28 diabetic patients and 21 control subjects recording 12 min time series of heart period (RR) and systolic arterial pressure (SAP, Finapres) during supine rest and 60 degrees head-up tilt. The power of the high (respiratory) and low (LF approximately 0.1 Hz) frequency oscillations was quantified by spectral analysis. The central frequency of the LF oscillations (LF_freq), phase shift, and the transfer function gain between RR interval and SAP fluctuations were provided by cross-spectral analysis, and measured at the point of maximal coherence. In the supine position 15 patients (LF-) displayed atypical LF variability with the LF_freq being shifted towards lower frequencies (about 0.06 Hz). They also showed larger phase angle, lower values or even absence of coherence and smaller transfer function gain between RR and SAP fluctuations. 13 patients (LF+) and the controls showed the LF_freq around 0.1 Hz, higher coherence and transfer function gain values. The orthostatic maneuver induced the expected changes in the spectral parameters (increase in the LF components of both RR and SAP and decrease in the HF variability of RR) into the LF+ patients and all the control subjects and abnormal response in the other 15 LF-patients. These findings indicate that diabetic subjects with uncharacteristic response to the orthostatic test present abnormal LF variability already in the supine position. Crossspectral parameters while supine may be used for the identification of these subjects.
糖尿病中的心血管自主神经病变与高死亡风险相关，这使得其早期识别具有重要的临床意义。一种识别自主神经功能障碍患者的简便方法将具有临床益处。我们评估了28例糖尿病患者和21例对照受试者的自主神经功能，记录了仰卧休息和60度头高位倾斜期间12分钟的心动周期（RR）和收缩期动脉压（SAP，Finapres）时间序列。通过频谱分析对高频（呼吸）和低频（LF约0.1Hz）振荡的功率进行量化。通过互谱分析提供LF振荡的中心频率（LF_freq）、相移以及RR间期与SAP波动之间的传递函数增益，并在最大相干点进行测量。在仰卧位时，15例患者（LF-）表现出非典型的LF变异性，LF_freq向较低频率（约0.06Hz）偏移。他们还表现出更大的相角、更低的值甚至缺乏相干性以及RR与SAP波动之间更小的传递函数增益。13例患者（LF+）和对照组的LF_freq约为0.1Hz，具有更高的相干性和传递函数增益值。直立位动作在LF+患者和所有对照受试者中引起了频谱参数的预期变化（RR和SAP的LF成分增加以及RR的HF变异性降低），而在其他15例LF-患者中引起了异常反应。这些发现表明，对直立试验反应异常的糖尿病受试者在仰卧位时就已经存在异常的LF变异性。仰卧位时的互谱参数可用于识别这些受试者。
