Apexcardiogramの臨床的応用,ならびに,Electrokymogramとの関連性について
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概要
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From the results in the simultaneous polygraphy of electrocardiography, phonocardiography, carotid sphygmography and absolute apexcardiography by means of the "Infraton Abnehmer" registered in recumbency on the supine as well as on the left-side, there were examined the cardiodynamical time relationship, atrial contraction wave, besides sphape and magnitude of the lateral movement of systolic waves. The cardio-dynamical values gained by the analysis of apexcardiograms were compared with those obtained by Blumberger-Holldack's method. On the other hand, recording electrokymogram and apexcardiogram in sitting position were compared each other. The cardiodynamical values were examined in normal health, hypertension, ischemic heart diseases, myocardial infarction and high output, total 131 cases. The electrokymogram and apexcardiogram registered in sitting position were compared in normal health, high blood pressure, and myocardial infarction, total in 54 cases. Furthermor electrokymogram and apexcardiogram were simultaneously recorded and analyzed in mitral valvular diseases in which 24 electrokymograms and 21 apexcardiograms were available. The interval Q-C (from Q, electrocardiogam to C in apexcardiogram) supposed to express the electro-mechanical latent time, is prolonged in hypertension and in ischemic heart diseases, but shortened in high output failure. While the interval Q--E (from Q in electrocardiogram to E in apexcardiogram) corresponds to the tension time ASZ in the sense of Holldack; the point E is later ranging from 35 to 40 msec for the initiation of the ejection time ATZ, that is, the end of ASZ. The Q-E interval is, however, pararell to ASZ with the difference of the abovementioned range; this interval is prolonged in high blood pressure complicated with pressure load and in myocardial infarction, but is diminished in high output with volume load. As the point E is later for the onset of ATZ, the interval E-II (from E in apexcardiogram to aortic component of the second heart sound) is shorter than ATZ, yet these two values are propostinate each other with the almost constant difference. From apexcardiogram and carotid sphygmogram, the isometric contraction period can be determined. The point C on apexcardiogram is assumed to closely agree with the initiation of the ventricular systole, and the duration from the point C to the end of ASZ, i.e., the time difference between ASZ and QC interval is regarded as the isometric contraction period. The mean value of the isometric contration period is found proplonged in hypertension and diminished in high output disorders, that is, volume load respectively. Beyond author's expectation in myocardial in faction there remains the mean value of the isometric contraction period within normal range. Among those patients the point C is, however, not rarely found later for the onset of the 1st heart sound so that it may be in need of further study to estimate the isometric contraction period by this method. The point 0 on apexcardiogram is assumed to coincide with the time point of the atrio-ventricular valvular opening, accordingly, the interval II-0 suggests the isovolemic relaxation period. The interval II-O is prolonged in arterial hypertension and ischemic heart disease including myocardial infarction; in addition, there exists a tendency that the interval II-0 is usually found longer in older group than in younger group. The facts mentioned above enable to suggest the existence of the pressure-elevation of the ventricular diastole as well as the reduced distensibility of the myocardium. The interval 0-F (from the point 0 on apexcardiogram to its foot) shows the rapid filling period and there exists a tendency to be more or less reduced in each of the diseased groups. On this occasion, it is necessary to study, taking the ventricular inflow throughout diastole, above all, the contour of the diastolic a-wave into due consideration. The inflow volume and its velocity during the rapid filling period can be regarded as the indicators for the estimation of the ventricular tonus. In the cases of atrial fibrillation, the rapid filling period is measured fairly constant ranging from 600 to 1300 msec, whereas the slow filling period varies in proportion to the cardiac cycle length. From these results, it follows that a tachycardia within a certain extent maintains the adequate inflow during the rapid filling due to augmentation of the cardiac output. On the other hand, the change in the inflow during whole cardiac cycle is dependent chiefly upon the length of the slow filling period. The appearance rate of the a wave on the normal apexcardiogram according to this method remains not so large; in hypertension and ischemic heart diseases including myocardial infarction, the a wave increase, however, the appearance rate and magnitude on an average. Especially, the a wave is seen prominent in myocardial infarction, though this finding can not be yet regarded as a special feature of so-called ventricular aneurysma. Systolic waves on the apexcardiogram are divided into the 1st type (the rapid internal movement during ejection), the 2nd type (the small internal movement during ejection and the return to the original level after the completion of ejection) and the 3rd type (the internal movement during ejection and the occurrence of bulge) respectively. In hypertension and ischemic heart diseases including myocardial infarction, the appearance rates of the 2nd and 3rd types increase in their number. When the registration site is exchanged, the 2nd and 3rd types increase in their appearance rates in the recumbence on the left side, on the other hand, their appearance rates are reduced in sitting position. There takes place a prominent cave-in of the systolic wave in the posterior infarction. The 3rd type of the systolic elevation can be found not only in so-called ventricular aneurysma, but also not rarely in cardiac hypertrophy. The time lags between the electrokymogram and apexcardiogram are ranged from 50 to 60 msec. The onset (Latenzzeit) of the rapid internal movement due to ejection seen on electrokymogram and the interval Q-E coincides with those of the electrokymogram resistered in the vicinity of the apex, taking the time lag of electrokymogram into account. In the cranial portion of the electrokymogram, socalled "Latenzzeit" is shorter than the Q-E interval. As to the onset of the diastolic external movement among most of the cases, there can not be found any constant relationship between electrokymogram and apexcardiogram, and the onset of the diastolic external movement on electrokymogram is, as usual, earlier than that of the point 0 on the apexcardiogram. Respecting the contour of the systolic wave, there exists no definite relationship between the both-sided movements in electrokymogram and the pulsation in apexcardiogram. The mode of the pulsation on electrokymogram registered in the oblique position becomes, however, one of the clues to interpret various sorts of electrokymograms, thus simultaneously utilizing apexcardiogram and electrokyomography, it may be possible to make clear the mode of pulsation to the transversal as well as sagittal directions The analysis of the diastolic portion of apexcardiogram in mitral valvular disease enables the differentiation between mitral stenosis and insufficiency, while in the mitral stenosis, the rapid filling wave disappears or becomes hazy, in mitral insufficiency this wave becomes prominent and steeper, moreover the wave F appears not rarely. The filling angle elucidates also the above-mentioned differenciation by the correction with the whole amplitude of apexcardiogram ; while in the mitral stenosis, the filling angle is smaller than the total angle, the mitral insufficiency the former is larger than the latter. The a wave is found larger in m. s. than in normal health; this suggests the dominant influence of the right ventricle; in the registration of the absolute pulsation may elucidate one of the characteristic availability of this method. From the observation upon the external diastolic movement in the electrokymogram of the left IV cardiac margins in mitral stenosis, one of the features of mitral insufficiency is assumed to consist in the steepness of both apical and cranial portions suggesting the increase in inflow. This external movement of electrokymogram is also more precipitous in m.s. than in normal health, showing the possibility of the predo minant influence of the right ventricle in m.s.. Apexcardiogram enables to analyze not only several time-segments of diastole, but also those of systole, for example, the time-point of the systolic arise and so on. Thus the apexcardiogram has some of superiority to other non-blooded polygraphy, above all, this method proves useful to the after-care of the surgery of m. s. On the other hand, such usual clinical events as the diastolic elevation of apexcardiogram which can occur even when the apex beats are prominently palpated or as the palpatory interpretation of the large a-wave and so on, are all easily diagnosed.