In 30 patients with nocturnal angina, the night-time ECGs were continuously recorded, and the time and duration of attack, cyclic character of attacks, the relation of chest pain to ischemic ECG changes and arrhythmias during attack were compared between 18 cases with ST elevation and 12 cases with ST depression during attack. In cases with ST elevation, 1) attacks occurred between 2:00 and 8:00 a.m., being most frequent between 4:00 and 5:00 a.m., 2) the duration of attack measured from the duration of ischemic ECG changes was less than 5min in 88% of the attacks, 3) the attack often recurred with intervals less than 30min and ECG changes were often unaccompanied bt chest pain, 4) the attack was complicated with various kinds of arrhythmias. These features were in marked contrast to the cases with ST depression, in which attacks were evenly distributed over the night-time, of longer duration, sporadic in occurrence and far less complicated with arrhythmias.
These data suggest that the difference of mechanisms causing attacks between both groups.

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The new system of cardiac wall kymography was proposed based on the results with our modified device. The cardiac wall motion kymography taken from a portion of the precordial area was examined for its ability to detect wall motion abnormalities. Furthermore, the 3 dimensional graphic display of the cardiac wall kymogram map was attempted by computer. This new approach looks promising because of the enhanced ability to recognize cardiac wall motion abnormalities in myocardial infarction.

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(1) Frank vectorcardiographic P loops of 25 healthy males were recorded at deep inspiration and expiration by using a minicomputer system with an averaging technique. Respiratory changes in 21 P parameters were quantitatively investigated.
(2) The maximal left component of the P loop, the magnitude of the horizontal maximal vector and the magnitude of the P polar vector significantly decreased at deep inspiration as compared with those at expiration. The frontal and the spatial maximal vectors were significantly deviated vertically at deep inspiration as compared to those at expiration.
(3) It was considered to be better to obtain P loops at a particular phase of respiration or to use those obtained by an averaging technique in order to analyse P loop in detail in various heart diseases, especially in the exercise stress test associated with rapid deep respiration.
(4) The mechanism of respiratory P loop changes was discussed.

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Frank vectorcardiographic P loops with satisfactory signal-to-noise ratio were obtained from 44 patients with ostium secundum atrial septal defect (OSASD), confirmed at operation, by using computer-averaging technique of 8 successive beats. Morphological and quantitative analyses of the P loop were made in order to reveal those characteristics of the P loop in OSASD which seemed most typically to show volumetric or diastolic overloading of the right atrium. Twenty-three automatically measured parameters of the P loop were compared with hemodynamic variables such as the systolic right ventricular pressure (s-RVP) and the left-to-right shunt ratio.
A majority of the maximal P-vector directions in 3 projection planes and the P duration were within normal 95 percentile ranges. The magnitude of the maximal horizontal, the magnitude of mean polar and the magnitude of the maximal spatial P-vector increased above the 97.5 percentile values considered as the upper limit of normality in 66%, 55%, and 50% of the cases, respectively. These findings seem to suggest that the vectorcardiographic analysis of the P loop with computer-averaging technology is a valuable screening tool of right atrial diastolic overloading.
Although the horizontal P loop of normal subjects showed many different patterns, the horizontal P loop of OSASD could be divided morphologically into 3 groups (Type A, Type B, and Type C). Thirteen cases (30%) out of 44 were of Type A, 22 cases (50%) Type B, and 9 cases (20%) Type C. There was a significant age difference between the individual mean values in the 3 groups (p<0.01), and there was a significant difference between the mean values in the shunt ratio of groups 'Type A and Type B' and group 'Type C' (p<0.01). The horizontal P loop pattern seems to be very important in the vectorcardiographic diagnosis of the presence and degree of the right atrial diastolic overloading.
There was a significant correlation between 5 P-loop parameters and s-RVP, and between 3 of the parameters and the shunt ratio. The correlation between magnitude of the maximal horizontal P vector (XmV) and the shunt ratio (Y%) was the highest of all (r=0.426, p<0.01), the regression equation being Y=130.7X+49.8 (SEE=11.5%). These findings seem to suggest that the horizontal P loop can provide valuable information for the vectorcardiographic diagnosis of the presence of right atrial diastolic overloading and for estimating the degree of its severity.

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Results of measurements of systolic time intervals (STI) in 32 patients of chronic severe anemia, before and after treatment, were studied. The patients were all without any clinical, radiological, or electrocardiographic evidence of cardiac decompensation. Data from an equal number of normal age and sex matched control subjects were also analysed. STI in individual patients showed a wide variation which precluded specific diagnostic utility. As a group, however, anemic patients showed significant differences from normal control subjects. Significant differences between pre-treatment and post-treatment values also suggest that chronic severe anemia adversely affects cardiac contractile function. Of the various STI measurements, PEP and PEP/LVET ratio were found useful parameters to be studied.

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Six subjects performed a breathholding maneuver during facial cooling and immersed their foot in cold water, without drugs and after the intravenous administration of propranolol plus atropine (P+A). Cardiac interval (INT), mean interval for longest consecutive 5 cycles (L5INT/5); systolic time intervals including electromechanical systole (EMS), left ventricular ejection time (LVET), pre-ejection period (PEP), and PEP/ LVET; and systolic (SP) and diastolic pressures (DP) were monitored during supine rest, during apnea with a plastic bag of ice water on the face, and from 16-30th and 46-60th sec of 1-min periods of foot immersion in 4°C water. P+A administration induced reduction in INT, L5INT/5, and LVET and increase in PEP, PEP/LVET, and DP. INT, L5INT/5, PEP, SP, and DP increased during facial cooling without drugs. Only the increases in INT and L5INT/5 were abolished by P+A and thus considered to result from reflexes mediated by vagal or sympathetic outflow to the heart. Reductions in TNT, L5INT/5, EMS, PEP, and PEP/LVET at 16-30sec of foot immersion without drugs were not observed after P+A; 46-60sec responses neared resting values, however, with and without P+A. These results indicate an initial cardiac reflex response to foot immersion may be overpowered by the ventricular afterload and the baroreceptor response due to the increased arterial pressure.

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In a study of 14 patients (11 Japanese and 3 white North Americans) with aldosterone-producing tumor carried out within 2 to 4 weeks after unilateral adrenalectomy, both plasma renin activity (PRA) and plasma aldosterone concentration (PAC) increased almost normally with short-term sodium depletion and upright posture. Aldosterone excretion rate (AER) also increased significantly with sodium depletion, and was normally suppressed by sodium loading. Highly significant correlations were observed between PRA and PAC (r=0.89, p<0.001) or AER (r=0.88, p<0.001) ater operation, whereas there had been no such correlation before operation. Either physiological or laboratory findings were normalized or markedly improved in all cases although pathohistological diagnosis was made as adenomatous hyperplasia in 10 out of 11. These results indicate that within 4 weeks of operation PRA and the remaining adrenal gland can almost normally respond to stimuli such as sodium depletion and upright posture regardless of the amount of spironolactone given preoperatively.

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At the Niigata University Hospital, various kinds of prosthetic valves such as the Starr-Edwards noncloth- and cloth-covered, Bjork-Shiley tilting disc, and Carpentier-Edwards porcine valves, have been used from September, 1965 to March, 1979 for replacement of diseased valves on 176 patients.
The patients with Starr-Edwards noncloth- and cloth-covered ball valves showed survival rates of 90 and 84% over a period of 5 years, and 87 and 81% for 8 years. Those with Carpentier-Edwards porcine and Bjork-Shiley tilting disc valves exhibited a survival rate of 93% for 1 and 3 years respectively.
Since 1973, regarding postoperative thromboembolic complications, patients who could not be maintained within a suitable therapeutic range using Warfarin, were given Bucolome also. For the patients with the Starr-Edwards cloth-covered valve, the 6-year major thromboembolism-free rate was 92% in those operated before 1973 and 96% for those operated since 1973. The minor episodes were free in 85 and 100%, respectively.
The actuarial reoperation rate at 7 years was 7% for the patients with Starr-Edwards noncloth-covered and 1% for those with cloth-covered valves. However, there was only one death among 7 patients. No reoperation was carried out for the other valves.
In conclusion, the actuarial survival curve for the Starr-Edwards ball valves showed a good survival rate when the patients age at the operation was taken into account. The use of the Bjork-Shiley tilting disc and Carpentier-Edwards porcine valves is also justified within the constraint of the short follow-up period.

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The purpose of this study is to evaluate the left ventricular contractility and diastolic compliance in experimental chronic volume overloading. After cardiac catheterization studies obtaining control data, dogs were divided into 2 groups. An infrarenal aorto-caval fistula was created in 14 dogs (Group I) and a left subclavian arterial-left atrial shunt was constructed in 7 dogs (Group II). These 2 groups were further divided into 7 subgroups according to the time of data acquisition.
Results in both groups showed that the left ventricular end-diastolic pressure (LVEDP), end-diastolic volume (LVEDV), and end-diastolic volume index (LVEDVI) increased in the postshunt groups compared with the preshunt groups. In a subgroup (Group Ic) in which data were obtained 58±11 days after creation of the infrarenal aorto-caval fistula, the max dP/dt, maximal contractile element velocity at zero load (Vmax), peak measured contractile element velocity (Vpm), ejection fraction (EF), and mean velocity of circumferential fiber shortening (mean VCF) decreased significantly from 3680mmHg/sec, 1.08ML/sec, 0.90ML/sec, 0.65 and 2.52circ/sec in the preshunt group to 2970mmHg/sec, 0.94ML/sec, 0.70ML/sec, 0.57 and 1.74circ/sec, respectively. On the other hand, values of these indices did not decrease but increased in animals of the left subclavian arterial-left atrial shunt in the postshunt groups (Groups IIb, IIc), although the differences revealed no statistical significance.
Since no single index of ventricular compliance has been accepted as standard, left ventricular distensibility was assessed by using 5 formulae. ΔV/ESV/ΔP decreased significantly from 0.056mmHg-1 in the preshunt group (Group Ia) to 0.027 and 0.025mmHg-1 in postshunt groups (Groups Ic, Id). Although the diastolic compliance decreased in Group I, it showed no variation in Group II.

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Micro-electrode studies in 13 excised rabbit preparations were done to determine the site of S-A block. Previously the fastest S-A conduction occurred in the area connecting the sinus node and the right branch of the crista terminalis. When a small cut was made in this area, 5 of the 13 hearts showed the first degree S-A block. Two hearts exhibited the second degree S-A block of the Wenckebach phenomenon and 3 showed the third degree block after cutting the same area. All blocks were transient and, within 1 hour after cutting, they were of the first degree. When the caval area was subsequently cut in these 10 hearts, all of them developed the complete S-A block. Three other hearts showed the complete S-A block by cutting only the connectable area of the sinus node with the right branch of the crista terminalis. The first cutting of the caval area surrounding the sinus node excepting the above mentioned connection did not change the S-A conduction time. Conclusions from these experiments reveal that the dominant sino-atrial conduction occurs through the connectable area of the sinus node with the right branch of the crista terminalis. Functional impairment to this region is essential and necessary to the development of any degree of S-A block.

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The conduction system of bovine heart was studied to clarify the characteristics of its energy metabolism. Results showed that its mitochondrial oxygen uptake was much lower than that of ordinary heart muscle with succinate as substrate but similar to that of ordinary heart muscle with glutamate+malate as substrate. The activity of succinate dehydrogenase was lower than that in ordinary heart muscle. The total activity of isozymes of lactate dehydrogenase was lower in the specialized heart muscle than in ordinary heart muscle. The main isozyme of lactate dehydrogenase in the specialized heart muscle was LDH 1 (H₄). The cytoplasmic NAD⁺/NADH ratio was much higher in the specialized heart muscle than in ordinary heart muscle. These results suggest that in the specialized heart muscle energy is mainly derived from aerobic metabolism.

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Relationship of renal function and plasma renin level to a spontaneous diuresis in an advanced stage of hypertension was examined in the stroke-prone spontaneously hypertensive rats (SHRSP). For a comparison, it was also investigated in 2 kidney 1 clip (1CR) and 2 kidney 2 clip (2CR) models of renovascular hypertensive rats. The spontaneous diuresis was usually associated with an elevation of plasma renin level and an impairment of renal function in SHRSP and 1CR. In SHRSP, renal plasma flow showed an inverse correlation to the plasma renin level. The diuresis, however, is not prerequisite to the increase in plasma renin or to the renal impairment, since the latter changes were not always accompanied by diuresis. No correlations were found between these factors in 2CR. Remittent diuresis was observed in many 2CRs and 2 SHRSPs with normal renal function, indicating that renal damage underlies the continuous progression of the diuresis observed in most cases of SHRSP and 1CR. Both sodium and potassium balances tended to be negative in 1CR and 2CR in the diuretic phase, whereas potassium alone showed this tendency in SHRSP. The negative balances, if any, were not due to an excessive loss of the electrolytes but attributed mainly to a decrease in intake. The critical level of blood pressure for the spontaneous diuresis was highest in SHRSP and lowest in 1CR. It is probable that an interaction and cooperation between high blood pressure, impaired renal function and high plasma renin participate in the mechanism of the spontaneous diuresis during the development of malignant phase of hypertension of the rat.

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The effects of butropium on chronotropic and isotropic activity were investigated in 10 isolated atrial preparations which were suspended in a bath and perfused with arterial blood led from a carotid artery of a heparinized support dog. Butropium injected into the cannulated sinus node artery in a dose range of 3 to 100μg produced a dose-dependent positive chronotropic and inotropic effect. At relatively higher doses above 30μg, slight and brief initial negative chronotropic and inotropic effect followed by a long-lasting positive effect was observed. The positive effect of butropium was markedly suppressed by propranolol or carteolol, but it was not affected by tetrodotoxin or desmethylimipramine.
From these results, a large amount of butropium may induce positive chronotropic and inotropic effect through cholinergic blockade and in part stimulation of adrenergic beta-receptors.

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By means of the least square method, the motion of an equivalent electric dipole which simulates electric activity of the heart was traced from body surface potentials. In normal case, this equivalent dipole was a good approximation.

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