Abstract
On the isolated toad heart the author studied the relationships between the QT interval and the heart work, comparing before with after the addition of various medicaments (Digitalis, Sekigaigoseishi-kiso, Chloralum hydratum, Aethylalkohol, Bile of toad, 1/2 Ca Ringer's Solution and 2K 1/2 Ca Ringer's Solution).(1) When the heart work was increased after the addition of the medicament, the QT interval was prolonged, unchanged or shortened according to the kind and the concentration of the medicament.(2) When the heart work was unchanged after the addition of the medicament, the QT interval was prolonged or shortened after the addition.(3) When the heart work was decreased after the addition of the medicament, the QT interval after the addition was shortened in the majority of cases, but prolonged in some cases.(4) From the above-mentioned data, it may be concluded as follows. Namely, (i) on the toad heart under the action of the medicament to influence the heart function, the QT interval and the heart work are not uniformally related. (ii) Consequently, under the action of the medicament to influence the heart function, not only the QT interval, but also another factor (the electric quantity in unit time), as considered from "Chaindoublets Theory (Maekawa)", have to be taken into consideration in order to judge the change in the heart work.
