Kelsey R M, Guethlein W
Center for the Study of Behavioral and Social Aspects of Health, State University of New York, Buffalo 14260.
Psychophysiology. 1990 Jan;27(1):24-33. doi: 10.1111/j.1469-8986.1990.tb02173.x.
The ensemble averaged impedance cardiogram was evaluated during rest and during vocal mental arithmetic stress in samples of female (n = 17) and male (n = 40) undergraduates. Measures of myocardial performance determined from ensemble averaged signals were compared to those determined by simple beat-to-beat averaging over 60-s and 20-s sampling intervals. In addition, the influence of cardiac interval variability on dZ/dt amplitude measures was assessed. As expected, measures derived by the two averaging techniques corresponded closely, with correlations ranging from r = 0.882 to r = 1.000 for the 60-s sampling intervals, and from r = 0.726 to r = 1.000 for the 20-s sampling intervals. Inverse relationships of comparable magnitude were found between cardiac interval variability and dZ/dt amplitude measures determined by both averaging techniques, suggesting that these relationships did not result simply from artifacts introduced by the ensemble averaging technique. The results support the validity of ensemble averaging as a method for deriving impedance cardiographic measures of myocardial performance.
在17名女大学生和40名男大学生样本中，对静息状态和发声心算应激状态下的总体平均阻抗心动图进行了评估。将根据总体平均信号确定的心肌性能指标与在60秒和20秒采样间隔内通过简单逐搏平均确定的指标进行比较。此外，还评估了心脏间期变异性对dZ/dt幅度测量的影响。正如预期的那样，两种平均技术得出的指标密切相关，60秒采样间隔的相关性范围为r = 0.882至r = 1.000，20秒采样间隔的相关性范围为r = 0.726至r = 1.000。两种平均技术确定的心脏间期变异性与dZ/dt幅度测量之间发现了相当程度的反比关系，这表明这些关系并非仅仅由总体平均技术引入的伪影导致。结果支持总体平均作为一种获取心肌性能阻抗心动图测量方法的有效性。
