Abstract
In order to record the mechanical movements of heart and aorta, an apparatus for rheography was originated for trial by our research group. Having examined this apparatus and method. we made studies on the rheograms of the healthy and of the arrhythmic patients followed by considerations of its clinical significances. 1) On rheography the A.C. bridge has been used as a transducer, i.e. one electrode is placed on the anterior chest wall and another on the back, positioning so that the heart or aorta to become in between them, connecting both to one arm of A.C. bridge, and 40 KC more or less frequency A.C. was transmitted. This apparatus is possible to record the mechanical movements of heart or aorta by the fluctuation of unbalanced current of A.C. bridge caused through the changes of impedance between the both electrodes. 2) An impedance equivalent to that of human body has been measured and have noticed that the values of phase angles of human body impedance are constantly negative and its absolute values decrease in accordance with the frequency increase. Hence, it became known that this A.C. bridge requires relatively simple composition : i.e. the arm of fixed impedance value is necessary for resistance only, and the other arm for adjustment may be joined in series both resistance and capacitance. 3) Having studied the characteristics of the A.C. bridge as a transducer, we have also noticed that the fluctuation of unbalanced current of the A.C. bridge is in proportion to the human body, in case the arm impedance fluctuation joined to body compared to the electrodes impedance, is negligibly small. Theoretically and from the results of our experimental researches, the bridge with equal absolute value of impedance on every arm was found to be most sensitive and advantageous for this experiment, from the viewpoint of this apparatus structure. On the other hand, through the outcome of our examination on the convergent loci of the A.C. bridge, the A.C. bridge as a transducer has been also recognized as most sensitive in case used in the slightly unbalanced state. Whereas, when recording the rheograms of heart or aorta, we have arrived at the conclusion that it is most advantageous to be recorded in the unbalanced state of slightly increased resistance and capacitance (from the balanced state). 4) We have devised a calibrating method to calibrate the fluctuation of impedance between the 2 electrodes as a vector; That is, the determination of vector value induced from the deviated curve which is caused by changing resistance and capacitance of the arm for adjustment respectively in the course of recording. 5) The A.C. distribution in a piece of fish-flesh was examined. Also we further studied the wave forms of rheograms by placing electrodes on several parts of human body. From these experiments in case a small electrode is uesd, we have recognized that the current density of the place adjacent to the electrode was greatest.
