Frank vectorcardiographic P loops with satisfactory signal to noise ratio were obtained from 28 patients with pure mitral stenosis by using computer-averaging technique of eight successive beats. Twenty-three parameters of the P loop automatically measured were compared with the mean pulmonary artery wedge pressure (m^^- PAW) and the maximal left atrial volume (max. LAV) calculated from biplane angiocardiogram by the area-length method. There was a significant correlation between the m^^- PAW and four P loop measurements. The positive amplitude in lead Z (the posterior component) showed the highest correlation with the m^^- PAW (r = 0.54, p<0.01). In the multiple regression analysis, the predicted m^^-PAW using eight P loop measurements and the measured m^^- PAW showed a high significant correlation (r = 0.86, p<0.01). There were significant correlations between the max. LAV and fourteen P loop measurements. The magnitude of spatial maximal P-vector showed the highest correlation with the max. LAV (r = 0.86, P<0.01). In the multiple regression analysis, the predicted max. LAV using four P loop measurements out of 23 showed the best correlation with the measured max. LAV (r = 0.94, P<0.01).

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Mean systemic pressure (MSP) and mean pulmonary pressure(MPP), which are mean driving pressures for venous return in the natural heart, were studied in 11 calves in which the natural heart had been replaced with a total artificial heart (TAH). They were measured simply by stopping the artificial heart pumping. Although blood translocation from the arterial to the venous side was not performed, the eventual right and left atrial pressures reached six to eight seconds after stopping the TAH would represent MSP and MPP with reasonable accuracy. The MSP varied from nine to 35 mmHg (20±6 mmHg), whereas the MPP varied from nine to 39 mmHg (22±7 mmHg). The MSP varied in close relation to the right atrial pressure prior to cessation of the TAH (r = 0.9124). Increases in RAP and MSP were mainly attributed to an increase in circulating blood volume. In the performance of the TAH, MSP (or MPP), proper diastolic duration and vacuum application during diastole was of prime importance in determining the end-diastolic ventricular volume.

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The hypotensive effect of fusaric acid calcium salt (Calcium salt of 5-butylpicolinic acid) was examined clinically in 10 elderly hypertensive patients by the long-term administration of this agent and the following results were obtained. 1) The means of the systolic and/or diastolic blood pressures of each patient were significantly lower during the first year of the trial period than those during the one year's control period in all patients. 2) The means of the systolic and/or diastolic blood pressures of each patient were significantly lower during the second year of the trial period than those during the one year's control period, in whom administration of fusaric acid calcium salt was continued throughout two years. A significant reduction of the systolic blood pressure was observed in 3 out of 6 patients and that of the diastolic blood pressure was observed in 5 out of 6 patients. 3) Comparison was made between the means of the systolic and diastolic blood pressures during the one year's control period and those during the six months' placebo period after two year's administration of fusaric acid calcium salt. During the placebo period, both systolic and diastolic blood pressures showed a tendency of returning to the levels during the control period, confirming the hypotensive effect of this agent. 4) Laboratory findings after one year's administration of fusaric acid calcium salt showed no adverse effect of this agent.

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The hemodynamic effect of fusaric acid calcium salt (calcium salt of 5-butylpicolinic acid), an inhibitor of dopamine β-hydroxylase, was studied in long-term administration of this agent in 10 elderly hypertensice patients. The hemodynamic items were measured by dye-dilution method before and 3 months, 6 months and one year after administration of fusaric acid calcium salt. The main hemodynamic changes observed were as follows: 1) Heart rate did not show any consistent change. 2) Systolic, diastolic and mean blood pressure decreased. The mean values of these pressures after fusaric acid calcium salt administration were significantly lower than the mean values before administration of this agent. 3) Total peripheral vascular resistance index decreased. The mean values of this index at 3 months, 6 months and one year after fusaric acid calcium salt administration were significantly lower than the mean value before administration of this agent. 4) Cardiac index showed various changes throughout administration of fusaric acid calcium salt. The changes in this index might be secondary following the changes in total peripheral vascular resistance index, an inverse correlation being existed between them. 5) Stroke volume index showed almost a similar pattern of change as observed in cardiac index. An inhibitory action of fusaric acid calcium salt on the inotropism of the heart could be hardly found. 6) Plasma volume showed no tangible changes after fusaric acid calcium salt administration throughout one year. It might be concluded that fusaric acid calcium salt elicited the hypotensive response primarily through the reduction of total peripheral vascular resistance index.

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The urinary norepinephrine excretion during fusaric acid calcium salt administration was examined in 5 elderly hypertensive patients by double blind cross-over method. The average daily excretion of the last 5 days during fusaric acid calcium salt or placebo administration of 5 weeks' duration was compared in each patient. In 4 patients except for one, the average daily urinary excretion of norephinephrine during fusaric acid calcium salt administration showed an increase, being highly significant (p<0.01) statistically, when compared with that during placebo administration, the latter being essentially unchanged. In the one patient, however, the average daily urinary excretion of norepinephrine was significantly higher during placebo administration than that during fusaric acid calcium salt administration. The relationship between the changes in the average daily urinary excretion of norepinephrine and those in blood pressures seemed to be not consistent. The mechanism which brought about an increased norepinephrine excretion in the urine of the hypertensive patients is not obscure at present.

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Recently attention is directed on myocardial disease which has such clinical significance as cardiac enlargement and intractable congestive heart failure and such pathological findings as myocardial degeneration, atrophy, hypertrophy and fibrosis. A number of terms other than idiopathic cardiomyopathy have been used in denote this condition, they include primary myocaridal disease, idiopathic myocardial hypetrophy and others. Idiopathic cardiomyopathy (ICM) have been classified inseveral ways by Lowler, Mattingly and Sega, but there is no agreement as to what classification and terminology should be given to the heart disease in this group. For the purpose of communication, however some designation is necessary, thus, this group is referred in the study to congestive cardiomypathy and hypertrophic nonobstructive cardiomyopathy according to Goodwin's classification. 1. CLINICAL OBSERVATION AND COMMENTS Subjects of hit study consisted of 30 patients (14 males 16 females) admitted or consulted to our clinic from 1962 to 1972. 12 of these patients died during observation period.

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The results of epidemiological studies on ischemic heart diseases in recent years have called for attention to the concept of coronary risk factors, and there are several papers on relations of the grade of significance of each risk factor to coronary heart diseases. These risk factors, however, are correlated with one anorher, and some factor, in association with some other factor or factors, exerts untoward effects, making evaluation of each factor difficult. Therefore, coronary heart diseases are now studied in terms of multivariate cause-and-effect relationship. In a study on quantitative prediction of the onset of myocardial infarction in terms of combinations of risk factors, an attempt was made at estimating the grade of significance of each one of the risk factors in there correlations by means of (I) the maximum likelihood method and (II) discrimination analysis; and a few interesting findings obtained in the study on the method of predicting the onset of myocardial infarction are presented hereunder. (I) STUDY BY MAXIMUM LIKELIHOOD METHOD Materials and Method: A total of 11, 188 materials, consisting of inpatients, outpatients and the people admitted to the human dock at the author s hospital, were followed up, and 862 materials whose prognosis was known and whose data on five factors were available weer selected as the subjects. These subjects were classed to the myocardial infarction group which comprised 94 subjects (77 males and 17 females), and the control group which comprised 768 subjects (556 males and 212 females), including 53 patients of angina pectoris without the onset of myocardial infarction during the follow-up period of not less than one year. The average age of the myocardial infarction group was 60.3 years, and that of the control group 52.6 years.

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The impairment of cardiac function resulted from acute pulmonary embolization (PE) is very important to the determination of the patient s treatment and prognosis. But, the current state of knowledge of it s mechanism is obscure. The purpose of this study is to obtain the information on the mechanism of irreversible cardiac failure and the augmentation of coronary blood flow by acute PE. Changes of ventricular function of the both ventricles and left and right coronary blood flow were observed under right ventricular loading from the normal up to possible maximum strain. Materials and Methods Thirty-three anesthetized (pentobarbital soda 30 mg/kg) adult mongrel dogs, weighing 12 to 28 kirograms, were used. A bilateral thoractomy was performed in the fourth intercostal space under positive pressure air ventilation and the heart was suspended in a pericardial cradle. Aortic pressure (AoP) (via the right carotid artery), main pulmonary arterial pressure (PAP) (via the pulmonary arteria trunk), right ventricular pressure (RVP) (via the free wall) and left ventricular pressure (LVP) (via the apex) were measured through short polyethylene catheters connected directly to the pressure transducers (Nihon Kohden MPU 0.5). The zero level of the pressures were determined at the midpoint of the right auricle. The first derivatives of the ventricular pressures (dp/dt) were obtained by using matched RC differentiating circuits. Aortic blood flow (AF), left circumflex coronary blood flow (LCF) and right coronary blood flow (RCF) were measured with electromagnetic flowmeters (Nihon Kohden) placed around the vessles.

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