Mode of left ventricular contraction was studied by cine left ventriculography in 22 cases with mitral valve diseases and 7 control cases. In rheumatic mitral valve diseases, local hypokinesis of the left ventricular wall and poor contraction of the mitral annulus were observed frequently, at various location and to various extent. Transient asynergic motion of local wall was also seen either during systole or during diastole. Local hypokinesis was seen even in normal-sized left ventricles, and was associated with decreased cardiac pump performance, when its localization was extensive. Severe mitral regurgitation of rheumatic nature was always associated with poor contraction of the mitral annulus, although the reverse was not true.

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A total of 14 cases of papillary muscle dysfunction have been observed in Ehlers Danlos syndrome. Five patients had clinically identifiable syndrome of prolapsing mitral leaflets. This form of rare interesting cardiovascular abnormality in Ehlers Danlos syndrome is discussed. The relevant literature is reviewed.

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The systematic nonlinearity exhibited in a comparison of 2 commonly used electrocardiographic lead-systems, when the net QRS axis-angle from one system is plotted against the other, is quantitatively analyzed. A family of nonlinear correlation curves is implemented using the ratio of 2 correction factors, f_c/f_o, as a parameter. Such curves, replacing linear regression lines, provide a more realistic representation of the actual problem of this type.
Between the Frank and the 12-lead systems, the value of f_c/f_o is found to be 0.53 for the frontal plane from a sample of 1, 000 subjects. The combination of correction factors, f_c=1.155 and f_o=2.18, is a possibility among countless others to make up the same f_c/f_o of 0.53. Appreciable improvement in axis correlation is demonstrated after the data are corrected by such factors.

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Arterial pressure, cardiac output, and total peripheral resistance were compared between spontaneously hypertensive rats (SHR) and normotensive control rats (NCR) at 4, 7, and 12 months of age.
The rats were anesthetized with pentobarbital sodium, thoracotomized and kept under positive pressure respiration. Cardiac output was measured with an electromagnetic flowmeter probe placed at the ascending aorta. On all the age groups, arterial pressure and total peripheral resistance were significantly higher in SHR than in NCR, while cardiac output per body weight was not different. However, the significant differences in pressure and resistance at each age disappeared after ganglion blockade with hexamethonium bromide. Total peripheral resistance was not higher in SHR than in NCR even after cardiac output, which had once been diminished by blockade, was restored to the pre-blockade level by dextran infusion. Phenoxybenzamine, an alpha adrenergic receptor blocker, also equalized arterial pressure and total peripheral resistance between SHR and NCR, both aged about 10 months, without decrease in cardiac output. It is concluded that, in both young and old SHR's, the hypertensive state is maintained by an increase in total peripheral resistance ascribable to sympathetic activity.

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The effect of electrical stimulation of the efferent cardiac sympathetic nerves on activity of afferent cardiac fibers in the sympathetic nerves and coronary hemodynamics of anesthetized dogs has been examined. During partial constriction of the coronary artery, a brief stimulation of the efferent cardiac sympathetic nerves resulted in sustained excitation of the afferent fibers and a sustained decrease in blood flow of the con-stricted artery which were associated with systolic bulge of the left ven-tricle and elevation of the ST segment of electrocardiogram. These changes were not produced without constriction. Pretreatment with phentolamine suppressed excitation of the afferent fibers, development of systolic bulge and elevation of the ST segment. Also, the decrease in coronary blood flow induced by stimulation was replaced by an in-crease after the administration of the agent. Propranolol suppressed excitation of the fibers, systolic bulge and elevation of the ST segment, but could not eliminate the decrease in blood flow. The results indicate that sympathetic stimulation caused a decrease in coronary blood flow through excitation of the α-adrenergic receptors while increasing cardiac work load and energy requirements through excitation of the β-adre-nergic receptors, leading to more severe myocardial ischemia and excita-tion of the afferent fibers.

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Hemodynamic effects of dopamine were studied on 30 open-chest dogs with experimental myocardial infarction. These dogs were divided into 3 groups. Three different doses of intravenous dopamine, 5, 10, and 20μg/Kg/min, were administered for 30min. Heart rate and myocardial contractility were increased dose-dependently. Total peripheral vascular resistance was reduced with 5 or 10μg/Kg/min of dopamine. With 20μg/Kg/min of dopamine, it became the lowest 5min after the initiation of infusion but increased above the control value 20min after the start of administration. Renal vascular resistance was decreased with 5μg/Kg/min of dopamine but increased with 20μg/Kg/min.
These results suggested that this drug would be useful for treatment of shock state.

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The aorta of SHR was thickened with hyperplasia and hypertrophy of medial cells and with the increase of elastic component after the development of hypertension. The aorta of stroke-prone SHR, in spite of the similar thickening to that of stroke-resistant SHR, was obviously less elastic than the latter. The stress-elongation diagrams which showed that the former aorta succumbed into a ductile failure to lesser stress than the latter were suggestive of the brittleness of the vasculature in stroke-prone SHR, although it was not yet determined whether the fragility was due to the primary or secondary defects.
(The authors acknowledge the advice and instruction of Prof. J. Takamura and Dr. N. Narita, Faculty of Technology, Kyoto University. This study was supported by Science and Technology Agency of Japanese Government, the Ministry of Education and Japan Society for the Promotion of Science.)

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Hypertensive vascular changes of arterioles and small arteries were electron microscopically examined comparing the findings with those of normalWistar rats. Among the various changes of vessels in SHR, which were not found in Wistar rats, the following findings seem to be of particular importance for understanding the pathogenesis of hypertensive vascular changes.

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(1) Not only SHR after the development of hypertension but also SHR in the prehypertensive stage showed acute arterial ring-like fat deposition when fed on the hypercholesterolemic diet. This finding substantiated the view of the importance of disposition in the mechanism of acute arterial fat deposition.
(2) The ring-like fat deposition corresponded to the region of the increased permeability, which was indicated by the preponderant distribution of peroxidase reaction products.
(3) The localized increase of vascular permeability was likely related to vasoconstriction and dilatation, mainly noted in the latter regions.
(4) The degenerated vessel walls with fat deposition were easily dilated with further increase in vascular permeability which accelerated the fat deposition and aggravated the vascular lesions.
(5) Such functional phenomena as arterial spasm and dilatation were assumed to cause medial damage following the increased permeability and to accelerate the acute fatty deposition under the existence of hypercholesterolemia and finally to lead irreversible atherogenetic changes.

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Quantitative analysis of spontaneous movement revealed that SHR moved somewhat more than WK during the day time, when they were exposed to environmental stimuli more frequently than at night, and that SHR showed a greater increase in movement than WK when exposed to hypoxia.
Consequently, SHR appeared to be more reactive to environmental alteration. Diurnal variation of the spontaneous movement became irregular in stroke-prone SHR (SHRSP) when they showed some alterations in the character some time before they died with cerebrovascular lesions. The transient episode of repetitive movement possibly related to hypertensive encephalopathy was detected by continuous recording of spontaneous movement. Saltloading accelerated the appearance of these abnormal behaviors in SHRSP.
Raphe-lesioned SHR showed a hyperkinetic or hyperresponsive state which appeared to be affected by the alteration of brain serotonin level, and the possible relationship between brain monoamine metabolism and the hyperreactive character in SHR was discussed.

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Bilateral carotid artery ligation may cause the more severe hemodynamic changes in SHR than in NR, resulting in cerebral ischemic damage to be pronounced in the former rats. The lower limit of cerebral autoregulation shifted to the higher level is necessary to explain the mechanism of hemodynamic crisis following carotid occlusion in SHR.

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Neuropathological study with light and electron microscopy was performed in SHR and NR following BCAL. SHR showed early death due to cerebral infarction, while NR with BCAL did not show cerebral death. The posterior communicating arteries connecting the carotid and basilar systems were well developed in SHR as well as NR. Because of paucity of vascular changes in the experimental animals, the cerebral lesions in SHR were attributed to the hemodynamic difference in the both groups.

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The precise predilection sites of stroke in nearly 1, 000 cases of stroke-prone SHR (SHRSP) were morphologically studied and statistical analysis showed that the first and second predilection sites were the cortical region and basal ganglia. Our microangiographical studies on these predilection sites and comparative analysis on the angioarchitecture of these regions between rats and man threw light on the pathogenetic importance of "recurrent branchings" which were noted in the cortical region in rats as well as in the basal ganglia of both rat and human brains. Two other angioarchitectural characteristics common to these predilection sites both in rat and man were confirmed to be "hypovascularity" and "boundary zone". Our present findings substantiated the view that these 3 angioarchitectural "minor loci" and the cerebral circulatory disturbance subsequently caused by these organic weak points were the main local factors of stroke common in the rat and human brains.
Now that the cortical lesions characteristic in SHRSP are supposed to be caused by the same mechanism as the most frequent lesions of the basal ganglia in man, SHRSP can be regarded as a good pathogenetic model for the studies on stroke in man.

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We devised the methods by which we could observe the ring-like fat deposition in the circle of Willis" as a whole" in SHR on HFCD.
This ring-like fat deposition is a good indicator for increased permeability in the vascular wall and this increased permeability seems to be related to vasospasm in cerebrovascular system in SHR. Further, we detected the increased permeability of intracerebrovascular system.
Our analysis of the factors affecting the fat deposition in the circle of Willis, obviously indicated the importance of hypertension and the acceleratory influence of increased salt intake. The possible involvement of some other factors affecting the arterial fat deposition still remained for the furtherstudy in SHR in contrast to EHR, in which hypertension itself seemed to be a main decisive factor for the fat deposition.

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An increased permeability of the cerebral blood vessels caused by a chronic hypertensive state or sequential anoxia proved to play the important role in the developement of certain cerebrovascular lesion especially certain subcortical necrosis with cyst formation in SHR.

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1. The β-adrenergic receptor blocker (propranolol) does not affect the blood pressure and heart weight of SHR fed with common diet.
2. Propranolol lowers the level of blood pressure, decreases the heart weight and heart rate in SHR fed with high-salt, high-carbohydrate, and low-protein diet. The lowered level of blood pressure in SHR fed with above mentioned diet and propranolol is similar to the level of SHR fed with common diet.
3. The blood pressure of SHR with high salt diet is higher than the SHR with common diet and is lower than the SHR fed with high-salt, high-carbohydrate, and low-protein diet.

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Two cases of hypertensive pulmonary vascular disease with Raynaud's phenomenon are reported. One is a 32-year-old housewife of primary pulmonary hypertension with some immunological disorders and the other is a 28-year-old female of systemic lupus erythematosus. It may be considered that some immunological process could play a role in the etiology of some cases of primary pulmonary hypertension and the relationship of pathogenesis between these 2 cases was discussed.

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