Seventy cases of ICM including 8 HOCM, 20 familiar cardiomyopathies and 3 heart diseases with collagen disease were examined by ACG, Scintigram of the heart using ¹³¹Cs and the measurement of the plasma hydroxyproline containing collagen-like protein comparing with coronary heart disease. The results were evaluated as a useful technique for the diagnosis of ICM. 1. Prominent "a" wave and bulging in ACG is observed in ICM frequently and its utility as a routine test was emphasized, especially with pharmacological test with amyl nitrite for the mild case, and with nitroglycerin for the differential diagnosis to the coronary heart disease, be-cause nitroglycerin improves ACG findings in coronary heart disease while not in ICM. 2. On ICM scintigram of the heart showed sparse defect and low uptake of ¹³¹Cs into the heart which is reported as an uptake index in this study. 3. Some of the cases of ICM including old case showed high level of plasma hydroxyproline containing collagen-like protein over 8.0μg/ml such as seen in fresh myocardial infarction, while normal value was less than 7.0μg/ml in this study. The elevated level of plasma HOP suggests the active process of the fibrosis in the heart of ICM and of continuous fibroplastic mechanism in the heart of ICM was discussed.

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1. By utilizing the endomyocardial biopsy, such diseases as myocarditis, myocardial sarcoidosis or giant cell myocarditis, and glycogen storage disease could be excluded as secondary myocardial disease. Those cases of clinically diagnosed primary myocardial disease were classified into three major groups according to their histopathological patterns. They are 1)Myocardial hypertrophy, 2) Myocardial degeneration or fibrosis, and 3) Endocardial thickening. 2. Accordingly, 125 biopsied cases which were diagnosed as primary myocardial disease could be differentiated into our classification. A: I) Familial, II') Suspected familial, III) Nonfamilial B: I) Endocardial fibroelastosis, II) Idiopathic cardiomyopathy a. Myocardial hypertrophy. b. Myocardial degeneration or fibrosis. c. Endomyocardial disease. d. Undetermined. III) Postpartal heart disease. IV) Suspected secondary cardiomyopathy. 3. Studies in each groups disclosed the following results (a) In the hypertrophic group; high incidence (37.7%) of the proven and those of strongly suspective familial occurrence was noteworthy. In high percentage, electrocardiographic evidences of hypertrophy, ST.T change, and abnormal Q waves were also noted. The cases could be divided into obstructive and non-obstructive form according to their hemodynamic features. How-ever, 7 cases were considered to be intermediate form because of the variability of the hemodynamic and angiocardiographic findings. The biopsies from the obstructive and intermediate form often revealed abnormally hypertrophic myocardial fibers with abundant glycogen. It is considered that the obstructive cardiomyopathy is not a different disease but one of the extreme form of the hypertrophic type cardiomyopathy and cannot be clearly differentiated from those of non-obstructive form. It is suggested that the hypertrophic type is that of endogenous nature. (b) In cases of degenerative or fibrotic type; rather lower incidence (10.6%) of familial occurrance, and high incidence of electrocardiographic conduction disturbances and of ST.T changes were noteworthy. It is speculated that this group may be of exogenous nature. (c) In those cases in which endocardial thickening was pre-dominant, it was assumed that they are secondarily developed lesions to either hypertrophic or degenerative or fibrotic type cardiomyopathy. Clinical pictures were those of mixted type of the two. Infantile endocardial fibroelastosis was considered to be of different nature. It is concluded that the application of the endomyocardial biopsy will give a potential value in making a more detailed clinical diagnosis of primary myocardial disease as well as recognizing the disease process. This study was supported by Asahi Shinbun academic research grant (Asahi Gakuzyutsu Shourei-kin) in the year of 1969-1970.

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Based on the clinical observations of some 50 patients with idiopathic cardiomyopathy, an infectious-immune theory for etiology or pathogenesis of the disease was brought up and discussed. Viral antibody titers in the patients suggest a possibility of the previous virus infections in many of the patient. Among many viruses studied Coxsackie B group viruses may be most incriminated. With our current immunofluorescent techniques on the biopsied specimens of the myocardium the viral antigens are failed to be demonstrated in many instances. But this does not eliminate a possibility of previous viral infection no longer reflected by the presence of viral antigen in the myocardium as an etiologic factor. The findings of positive fluorescence in some of the nuclear region in the myocardial cells stained with the FITC-labeled anti-human IgM-globulin appears to support the role of an autoimmune mechanism for pathogenesis in some of the patients with idiopathic cardiomyopathy.

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Three cases of endocardial fibroelastosis, seven cases of acute nonspecific myocarditis, two cases of obscure cardiomyopathy and one autopsied case of idiopathic hypertrophic subaortic stenosis with Nielsen's syndrome were described. Development of myocardial hypertrophy along the course after the acute stage of nonspecific myocarditis in certain cases was suggested. For clarifying the possible correlation between idiopathic cardiomyopathy and nonspecific myocarditis further investigation is considered to be necessary.

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Twenty-six patients with idiopathic cardiomyopathy of hypertrophic type were divided angiographically into three types. Fifteen patients (57.7 per cent) showed obvious obstruction in the outflow tract of the left ventricle (type I). Seven subjects (26.9 per cent) should prominent hypertrophy in the lower septum without distinct obstruction (type II) and 4 patients (15.4 per cent) had diffuse hypertrophy with slight dilation (type III). Type I and type II were proved to have familial form with high incidence of 54.5 per cent and 83.3 per cent respectively. Those two types were found to be identical etiologically in view of our results. Because of absence of obstruction, type II did not demonstrated such specific hemodynamics as in type I. In type III, etiological discrepancy with the former two types was suggested.

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Spatial velocity ECG is a record of the speed of inscription of spatial vector loops on the linear time scale. There was definite pattern in normal spatial velocity ECG in spite of the wide varieties of configurations of VCG loops. High incidences of abnormalities were observed on the initial portions of QRS waves of spatial velocity ECG in old myocardial infarctions, even in the cases whose conventional ECG did not satisfy the criteria of abnormal Q waves. Thus the spatial velocity ECG was considered as a useful supportive measure in diagnosing old myocardial infarctions.

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Angiotensin I converting enzyme was purified from rabbit plasma by means of ammonium sulfate fractionation, DEAE-Sephadex A-50 column chromatography and Sephadex G-200 gel filtration. The purified material was separated from angiotensinase, carboxypeptidase and L-leucyl-β-naphthylamidase, but could not be separated from di- or tri-peptidases. The specific activity of the enzyme was elevated 63 fold by the purification method. The purified material produced angiotensin II, His-Leu, histidine and leucine when incubated with angiotensin I at 37°C, pH 7.2 for 20 hours. This fact suggests that the enzyme hydrolyses the Phe-His bond of angiotensin I. The enzyme activity was inhibited by the addition of 10^-3M EDTA. Optimum pH of the enzyme was about pH 7.2.

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Effects of glucagon, prostaglandin El and dibutyryl cyclic 3', 5'-AMP upon the transmembrane action potential and the myocardial contractile force were investigated by using the isolated, perfused guinea pig heart by Langendorff's technique. The positive chronotropic and inotropic actions were observed by administering these agents into perfusion-cannula, and these effects were not blocked by propranolol. All of these agents produced shortening of the repolarization phase 2 (plateau phase) and increased the membrane resting potential in magnitude. The possible mechanisms underlying these changes is discussed in the light of cardiac cellular physiology and of the action of cyclic 3', 5'-AMP in the two messenger system.

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No significant elevation of blood pressure was observed in control Wistar rats parabiotically united with spontaneously hypertensive rats (SHR). SHR showed a slight lowering of blood pressure when they were united with control Wistar rats, but such a lowering effect was not obvious in SHR united w:th unilaterally nephrectomized Wistar rats. The blood pressure of the partner of SHR parabiotics maintained hypertension for 10 days after bilateral nephrectomy. These results showed that SHR had no humoral transmissible pressor substance and that the kidney of SHR had no positive role in maintaining hypertension.

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1. Various kinds of the parameters for estimating the cardiac function or contractility have been advocated and their usefulness has been experimentally and clinically investigated by a number of investigators. The author has appreciated that Isometric Time-Tension Index (dp/dt/IIT) is one of the parameters of use for estimating the cardiac contractility. This parameter can be promptly and accurately obtained by means of an on-line real-time system, and which can not be affected by pre-load or after-load upon the ventricle. In this parameter dp/dt is the maximal value of a differentiated ventricular pressure (max dp/dt), and IIT is the total integrated systolic isometric pressure. Isometric systolic time is set 1.5 times Δt that is the time from the peak of the R wave of the ECG to the point of max dp/dt. 2. The AC apparatus (Type I) devised by the author for measuring dp/dt/IIT by an on-line real-time system was equipped with three-ply filters to remove noises mixed from a power source ; without filters the time constant is zero and infinite in a differentiator and integrator, respectively. the time constant of the remolded apparatus (Type II) operated by a direct current is 4.5 msec in the differentiator and 2.2 sec in the integrator. Both types of the apparatus can start integral calculation simultaneously with the triggering R wave of the ECG, while they are regulatable to stop calculation at any time. Calibration of differentiated value to the power input is done in the inside of the apparatus. For an accurate measurement of dp/dt/IIT, the time constant should ideally be zero in the differentiator and infinite in the integrator. The apparatus devised by the author apparently satisfies these requirements. 3. For an aim of studying the effects of the technique of pressure sampling upon the pressure curve and the differentiated one, the author used different 3 types of conduit : a blood transfusion needle, a Cournand's cardiac catheter F 10 or a polyethylene tube (120 cm long, inner diameter 1.6 mm). Every conduit was connected to the same transducer (Statham SP-37 Needle Type) and the apparatus Type II was used. This preliminary experiment revealed that a blood transfusion needle connected Statham SP-37 Needle Type best functioned as the technique of pressure sampling.

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During ventricular diastole of the cardiac cycle, coronary blood flow reaches the maximum rate with the relative lack of flow in the forward direction in the aortic root. When a contrast medium is injected into the aortic root during cardiac diastole, it is minimally diluted with blood and selectively reaches the coronary arteries at a higher concentration. On the basis of this principle, Nagata, a co-worker of the author, reported the experimental and clinical studies on coronary arteriography using three successive diastolic injections of a contrast medium in synchronization with the cardiac cycle with the satisfactory results. However, the pump used by Nagata as a phasic injector was a Davol Heart Pump devised primarily for circulatory assist, the maximum output of which is only about 10 ml for 0.4 sec of the injecting time, and it was considerable difficult to secure a proper timing for diastolic injection with a Davol Heart pump. Thus, a recent review of his report revealed that excellent opacification of the coronary artery system was achieved only in the experimental animal with a smaller aortic root or in the clinical case with a smaller aortic root or in the clinical case with considerable bradycardia. Accordingly, the author has devised a new injector, with which a pump output of more than 10 ml and an accurate timing for diastolic injection can be easily attained even during a short period of cardiac diastole in a tachycardiac patient. The newly designed device is composed of a control unit and an injector of ventricular type. The actuator and the tubings have been reformed according to the computation from the theoretical considerations and the actual surveys so that filling and ejection of the pump ventricle may be smoothly carried out.

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