Pfeiffer K P, Kenner T, Schaefer J
Cardiovasc Res. 1984 Feb;18(2):80-98. doi: 10.1093/cvr/18.2.80.
To study the influence of the sequence of stimulation intervals on cardiac performance indices the relationship between properties of succeeding arrhythmic aortic pressure pulses of patients with atrial fibrillation has been analysed by methods of correlation and regression analysis. There are high correlations between properties of succeeding pulses and it can be shown that the pressure amplitude of one pulse correlates to the properties (diastole, diastolic pressure, pressure amplitude) of up to five preceding pulses. Furthermore, the diastolic pressure is also highly correlated with properties of more than one preceding pulse whereas the duration of the diastole and the RR-interval is independent of preceding pulse properties. We, therefore, conclude that there is no beat to beat regulation of intervals during atrial fibrillation. The relations between properties of succeeding pressure pulses have been summarised in a transfer function model, which allows the description of pulse properties from preceding pulse properties without lack of it. The parameters of the transfer function models are estimated from a sequence of arrhythmic pressure pulses and a parameter selection procedure was developed which identifies the optimal number of input variables (= properties of preceding pulses) required to describe the time course of one pulse property. In order to obtain informations about the presence of possible interval dependent potentiation effects, the transfer function model was used to stimulate the behaviour of the aortic pressure for different stimulation sequences, which have been used in the literature to study potentiation effect experimentally. From typical sequences of potentiation phenomena in the stimulated pulse sequence we conclude that frequency potentiation effects exist in the human myocardium.
为了研究刺激间隔序列对心脏性能指标的影响，采用相关性和回归分析方法，对心房颤动患者连续心律失常主动脉压力脉冲的特性之间的关系进行了分析。连续脉冲的特性之间存在高度相关性，并且可以表明，一个脉冲的压力幅度与多达五个前序脉冲的特性（舒张期、舒张压、压力幅度）相关。此外，舒张压也与多个前序脉冲的特性高度相关，而舒张期持续时间和RR间期与前序脉冲特性无关。因此，我们得出结论，心房颤动期间不存在逐搏的间期调节。连续压力脉冲特性之间的关系已总结在一个传递函数模型中，该模型允许从前序脉冲特性描述脉冲特性而不缺失。传递函数模型的参数根据一系列心律失常压力脉冲进行估计，并开发了一种参数选择程序，该程序可确定描述一个脉冲特性的时间过程所需的最佳输入变量数量（=前序脉冲的特性）。为了获得有关可能存在的间期依赖性增强效应的信息，使用传递函数模型来模拟主动脉压力在不同刺激序列下的行为，这些序列已在文献中用于实验研究增强效应。从刺激脉冲序列中典型的增强现象序列，我们得出结论，人类心肌中存在频率增强效应。
