層封電説知見補遺 : 刺戟傳逹時間について

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Accoding to the "Chain-Doublet Theory" of Maekawa, it is defined that the time of arrival of activation to the muscle region underlying electroded to lead is represented by the point where zero-line crosses the downward deflection following initial positive peak in clinical ECG. For the theoretical ground of this finding there is minute interpretation by Hayase. According to his report the polyphasic curve obtainable out of tissue membrane is just going down near the zero-line when the initial positive deflection of monophasic curve within tissue membrane reaches its maximum value, and the initial positive peak of monophasic curves is able to be assumed as the representative point indcating the arrival of excitation wave. But such phenomenon as reported by Hayase is the result obtained from ideal straight muscle strip, and it is supposed that there may be different correlations between them under various conditions of muscle strip. So we tried mathermatical analysis of potential variations in up-, mid- and down-streams in various conditions of tissue membrane capacitance and of excitation process. As the results of these analyses we found that the correlation between the initial positive peak of monophasic curve and corresponding point to it in polyphasic curve is variable according to the value of membrane capacitance (C_m), membrane resistance (R_m) and electric conductivity (1/R) of volume conductor and to the condition of excitation process. For example, if we assume the potential variation within the tissue membrane as a single sine wave, namely φ(t)E=sin(ωt), the potential variation φ(t) without the tissue membrane will vary according to the value of C_m, R_m, R and frequency of φ(t). When the φ(t) is a high frequent sine wave, the peak of φ(t) coincides with the peak of φ(t), and when it is a low frequent sine wave, it coincides with the cross point of φ(t) with the zero-line. If we assume that the time of arrival of activation in mid-stream like Hayase's model is represented by initial positive peak of φ(t), the corresponding point to it in φ(t) will be represented by any point in the downward deflection from peak to zero-line. Next, when we suppose the excitation process, in which the front of activation of each muscle fiber is preceded gradually in deeper layers, the monophasic tracing in mid-stream arrived at negative side beyond the zero-line at that instant, when the activation of outer layer has involved the muscle region just under the electrode. Consequently, the poly phasic curve φ(t) at that instant records also the negative deflection. Namely, in the "Chain-Doublet Theory," the time of arrival of activation in ECG can be reperesented by any point in duration of downward deflection from initial positive peak to following negative peak. These findings coincided very well with our experimental results obtained by simultaneous record of contiguous bipolar lead and unipolardirect lead from the toad heart. It is concluded that the point where downward deflection following initial positive peak crosses the zero-line can not be defined as the representative point indicating the arrival of activation. It must be noted this point is dcceptable merely for clinical convenience as Maekawa also says.
社団法人日本循環器学会の論文
1954-04-20

層封電説知見補遺 : 刺戟傳逹時間について

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