Stark G, Huber U, Hofer E, Tritthart H A
Institute of Medical Physics and Biophysics, University of Graz.
Basic Res Cardiol. 1987 Sep-Oct;82(5):437-44. doi: 10.1007/BF01907091.
The present paper describes a method by which it is possible to continuously detect early atrial and His-bundle activity from the surface of intact Langendorff-perfused guinea-pig hearts, by appropriate placement of two electrodes and the use of a custom designed instrumentation-amplifier. In some experiments the surface ECG recordings were compared with intracardiac ECG recordings. No difference in ECG durations could be observed between intracardiac and extracardiac measurements. In further experiments changes in ECG durations and heart rate were measured for 2 h. After 30 min equilibration time, no changes in heart rate and conduction time could be observed. In order to locate the best surface electrode positions to detect His-bundle activity, vector ECG recordings were taken at high gain. This vector ECG signal contained a His-loop which was split into a larger and a smaller part. The main and initial vector was directed to the left and the smaller to the right ventricle. The best recordings of the His-bundle activity could be observed when the electrodes were positioned as follows; one in a posterior position, near the valve plane and the other one in the opposite position near the initial part of the anterior interventricular artery and in the direction of the large His-loop. We conclude that the ECG surface recordings are a valuable tool for measuring impulse propagation through various segments of the cardiac conduction system in preparations of guinea-pig hearts, perfused by the Langendorff method.
本文描述了一种方法，通过适当放置两个电极并使用定制设计的仪器放大器，可以从完整的Langendorff灌注豚鼠心脏表面连续检测早期心房和希氏束活动。在一些实验中，将表面心电图记录与心内心电图记录进行了比较。在心内和心外测量之间未观察到心电图持续时间的差异。在进一步的实验中，测量了2小时内心电图持续时间和心率的变化。在30分钟的平衡时间后，未观察到心率和传导时间的变化。为了确定检测希氏束活动的最佳表面电极位置，以高增益进行了矢量心电图记录。该矢量心电图信号包含一个希氏环，该希氏环被分为一个较大部分和一个较小部分。主矢量和初始矢量指向左心室，较小矢量指向右心室。当电极按以下方式放置时，可以观察到希氏束活动的最佳记录：一个位于后位，靠近瓣膜平面，另一个位于相反位置，靠近前室间动脉起始部并沿大希氏环方向。我们得出结论，在Langendorff法灌注的豚鼠心脏标本中，心电图表面记录是测量冲动在心脏传导系统各节段中传播的有价值工具。
