Hori M
Jpn Circ J. 1978 May;42(5):539-51. doi: 10.1253/jcj.42.539.
The relationship between the difference in the action potential duration in the myocardium and the T wave investigated by a mathematical model of the electrical activity of the heart. In this study we constructed an eccentric spherical model which duplicates the ventricles except for the interventricular septum. Our model is assumed to be composed of the working myocardium and the excitation conduction system which is uniformly distributed on the endocardial surface. The ventricular gradient was defined as a linear decrease (beta msec/cm) of the duration of the action potential from the endocardium to the epicardium according to the concept proposed by Wilson. Theoretical analysis based on this model strongly suggest that the ventricular gradient of 10-40 msec/cm accounts for the normal QRS-T angle since vectorcardiographic analysis have revealed that the QRS-T angle closely correlates with the angle (theta) between the directions of the propagation waves of depolarization and repolarization. The QRST waves in the standard limb and chest leads were calculated from the sum of the time-varying dipoles derived from the action potential, assuming that the heart was in a homogenous conducting medium. Simulated QRS-T waves were compatible with the clinically observed electrocardiograms not only under normal conditions but also with changes in the spacial position of the heart and the wall thickness. Positive T waves were obtained in the left precordial leads when the ventricular gradient was more than 20 msec/cm and when the amplitude of T wave increased with the transmural gradient. Our model also indicates that differences in the velocities of the excitation wave in the conduction system and the working myocardium may affect the polarity of the T wave.
通过心脏电活动的数学模型研究了心肌动作电位持续时间差异与T波之间的关系。在本研究中，我们构建了一个偏心球模型，该模型除室间隔外复制了心室。我们的模型假定由工作心肌和均匀分布于心内膜表面的兴奋传导系统组成。根据Wilson提出的概念，心室梯度定义为动作电位持续时间从心内膜到心外膜的线性下降（β毫秒/厘米）。基于该模型的理论分析强烈表明，10 - 40毫秒/厘米的心室梯度解释了正常的QRS - T角，因为向量心电图分析表明QRS - T角与去极化和复极化传播波方向之间的角度（θ）密切相关。假设心脏处于均匀导电介质中，标准肢体导联和胸导联中的QRST波由动作电位导出的时变偶极子之和计算得出。模拟的QRS - T波不仅在正常情况下与临床观察到的心电图相符，而且与心脏的空间位置和壁厚的变化也相符。当心室梯度大于20毫秒/厘米且T波振幅随透壁梯度增加时，在左胸前导联获得正向T波。我们的模型还表明，传导系统和工作心肌中兴奋波速度的差异可能影响T波的极性。
