Kizakevich P N, Teague S M, Nissman D B, Jochem W J, Niclou R, Sharma M K
Research Triangle Institute, Biomedical Engineering Program Office, Research Triangle Park, NC 27709.
Biol Psychol. 1993 Aug;36(1-2):51-61. doi: 10.1016/0301-0511(93)90080-r.
Measurements of systolic ejection dynamics by impedance cardiography were compared with simultaneous Doppler echocardiography in normal subjects and coronary artery disease patients. Patients with chest pain admitted for elective coronary angiography were monitored by simultaneous impedance cardiography and Doppler echocardiography before, during, and after treadmill exercise. Ensemble-averaged ECG, impedance cardiogram (ICG), the first derivative of ICG (dZ/dt), and Doppler waveforms were analyzed to identify systolic ejection variables. The timing of aortic valve opening was well correlated (r = 0.78) the timing of peak ejection velocity was very well correlated (r = 0.86), and the timing of aortic valve closure was moderately correlated (r = 0.69 and r = 0.73) in these subjects. The thoracic electrical impedance acceleration and normalized impedance acceleration indices were moderately correlated with Doppler model acceleration (r = 0.74, r = 0.79). The impedance cardiogram waveforms are of complex origin and are related to both aortic blood velocity and aortic blood acceleration. Users of dZ/dt timing features for determining aortic valvular events might consider alternative impedance features to improve ejection time accuracy.
在正常受试者和冠状动脉疾病患者中，通过阻抗心动图测量收缩期射血动力学，并与同步多普勒超声心动图进行比较。因胸痛入院接受择期冠状动脉造影的患者，在跑步机运动前、运动期间和运动后，通过同步阻抗心动图和多普勒超声心动图进行监测。对平均心电图、阻抗心动图（ICG）、ICG的一阶导数（dZ/dt）和多普勒波形进行分析，以确定收缩期射血变量。在这些受试者中，主动脉瓣开放时间相关性良好（r = 0.78），射血峰值速度时间相关性非常好（r = 0.86），主动脉瓣关闭时间相关性中等（r = 0.69和r = 0.73）。胸电阻抗加速度和标准化阻抗加速度指数与多普勒模型加速度中度相关（r = 0.74，r = 0.79）。阻抗心动图波形起源复杂，与主动脉血流速度和主动脉血流加速度均有关。使用dZ/dt时间特征来确定主动脉瓣事件的用户，可能会考虑使用其他阻抗特征来提高射血时间的准确性。
