Meijer Jan H, Boesveldt Sanne, Elbertse Eskeline, Berendse H W
Department of Physics and Medical Technology, VU University Medical Center, Amsterdam, The Netherlands.
Physiol Meas. 2008 Jun;29(6):S383-91. doi: 10.1088/0967-3334/29/6/S32. Epub 2008 Jun 11.
The time difference between the electrocardiogram and impedance cardiogram can be considered as a measure for the time delay between the electrical and mechanical activities of the heart. This time interval, characterized by the pre-ejection period (PEP), is related to the sympathetic autonomous nervous control of cardiac activity. PEP, however, is difficult to measure in practice. Therefore, a novel parameter, the initial systolic time interval (ISTI), is introduced to provide a more practical measure. The use of ISTI instead of PEP was evaluated in three groups: young healthy subjects, patients with Parkinson's disease, and a group of elderly, healthy subjects of comparable age. PEP and ISTI were studied under two conditions: at rest and after an exercise stimulus. Under both conditions, PEP and ISTI behaved largely similarly in the three groups and were significantly correlated. It is concluded that ISTI can be used as a substitute for PEP and, therefore, to evaluate autonomic neuropathy both in clinical and extramural settings. Measurement of ISTI can also be used to non-invasively monitor the electromechanical cardiac time interval, and the associated autonomic activity, under physiological circumstances.
心电图与阻抗心动图之间的时间差可被视为心脏电活动与机械活动之间时间延迟的一种度量。这个以射血前期（PEP）为特征的时间间隔与心脏活动的交感自主神经控制有关。然而，PEP在实际中很难测量。因此，引入了一个新参数——初始收缩期时间间隔（ISTI），以提供一种更实用的度量方法。在三组人群中评估了使用ISTI而非PEP的情况：年轻健康受试者、帕金森病患者以及一组年龄相仿的老年健康受试者。在两种条件下研究了PEP和ISTI：静息状态和运动刺激后。在这两种条件下，三组人群中PEP和ISTI的表现大致相似，且显著相关。得出的结论是，ISTI可作为PEP的替代指标，因此可用于临床和院外环境中评估自主神经病变。测量ISTI还可用于在生理情况下无创监测心脏机电时间间隔及相关的自主神经活动。
