Byrne E A, Porges S W
Institute for Child Study, University of Maryland, College Park 20742.
Psychophysiology. 1993 Jul;30(4):397-404. doi: 10.1111/j.1469-8986.1993.tb02061.x.
Filter characteristics of the peak-valley respiratory sinus arrhythmia estimation method are described. To identify filter characteristics of this method, models were generated that combined signals of different frequencies with trends of varying slopes. These models simulate the influence of trend and changing respiratory frequency on the accuracy of peak-valley estimates. The transfer function of the peak-valley method, unlike that of other time domain filters, is not solely dependent upon signal frequency. Two factors interact to determine the relative accuracy of the peak-valley method: (a) slope of the signal component and (b) slope of the underlying trend. Combinations of these factors may result in significant distortion to the input signal. The direction of error is a function of the direction of the trend (i.e., overestimation with deceleration and underestimation with acceleration). In many situations when respiratory sinus arrhythmia amplitude is low in special populations (e.g., cardiovascular disorders, high-risk infants, or human fetuses) or under conditions that greatly reduce respiratory sinus arrhythmia amplitude (e.g., exercise, drugs, pharmacological manipulations), use of the peak-valley method may result in significant measurement error. The use of this method to evaluate respiratory sinus arrhythmia over short epochs (i.e., less than 2 min) or to quantify changes in respiratory sinus arrhythmia due to discrete stimulation (e.g., breath by breath) may result in inconsistent measurement error. Recommendations are made for detrending heart rate data prior to application of the peak-valley method.
描述了峰谷呼吸性窦性心律不齐估计方法的滤波特性。为了确定该方法的滤波特性，生成了将不同频率信号与不同斜率趋势相结合的模型。这些模型模拟了趋势和呼吸频率变化对峰谷估计准确性的影响。与其他时域滤波器不同，峰谷法的传递函数不仅仅取决于信号频率。有两个因素相互作用来决定峰谷法的相对准确性：(a)信号分量的斜率和(b)潜在趋势的斜率。这些因素的组合可能会导致输入信号的显著失真。误差方向是趋势方向的函数（即减速时高估，加速时低估）。在许多情况下，当特殊人群（如心血管疾病、高危婴儿或胎儿）的呼吸性窦性心律不齐幅度较低时，或在大大降低呼吸性窦性心律不齐幅度的条件下（如运动、药物、药理操作），使用峰谷法可能会导致显著的测量误差。在短时间段（即小于2分钟）内使用该方法评估呼吸性窦性心律不齐，或量化由于离散刺激（如逐次呼吸）导致的呼吸性窦性心律不齐变化，可能会导致测量误差不一致。建议在应用峰谷法之前对心率数据进行去趋势处理。
