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Biomedical subjects

Y Nimura

Publications and source records attributed to Y Nimura.

At least 433 records · Page 24Linked to original sources
PubMed1981

[Mechanism of the systolic anterior motion of the mitral valve and site of the intraventricular pressure gradient in hypertrophic obstructive cardiomyopathy (author's transl)].

The mechanism of the systolic anterior motion (SAM) of the mitral valve and the relationship between SAM and the intraventricular pressure gradient in hypertrophic cardiomyopathy were analyzed. The subjects were 15 cases, in which SAM was observed on the M-mode echocardiograms. Real-time two-dimensional echocardiography was performed at the time of cardiac catheterization and the measurement of left ventricular pressure was made with observing the spatial relationship between the tip of of the catheter and the surrounding intracardiac structures. There were two modes of the systolic anterior motion of the mitral valve in cases with SAM as follows: (1) The hypertrophied papillary muscle protruded into the left ventricular cavity in systole and it caused the displacement of the chordae tendineae, but also the tips of both anterior and posterior mitral leaflets were anterosuperiorly pulled up by the enlarged papillary muscles and the leaflets seemed apparently to intersect the left ventricular outflow tract (type II). These two types seem to make a continuous spectrum. Seven of the 15 cases examined exhibited type I and 8 cases exhibited type II or the intermediate condition. In the cases of type I, the pressure gradient was noted at the level of the tip of the papillary muscles. The inflow tract and the suprapapillary of the outflow tract exhibited a low pressure, while the apical cavity exhibited a high pressure. It is suggested that the enlarged papillary muscles make the ventricular cavity much more narrowly, resulting in the development of pressure gradient at their level. In the cases of type II, the pressure gradient was noted across the anterior and posterior mitral leaflets perpendicular to the outflow tract (subaortic area). The inflow tract exhibited a high pressure in contrast to that in the cases of type I. It is suggested that the anterosuperiorly pulled anterior and posterior leaflets dam up the ventricular cavity, resulting in the development of pressure gradient across them. Here, it should be emphasized that not only the anterior mitral leaflet, but also the posterior leaflet participates to yield the SAM and the intraventricular pressure gradient.

Adult↗
PubMed1981

[Echocardiographic features of the eustachian valve and its clinical significance (author's transl)].

The detailed informations and clinical significance of the Eustachian valve have not yet been elucidated. Real-time two-dimensional echocardiography has enabled one to investigate the Eustachian valve non-invasively. The valve was usually very small. The larger valve was a few cm in length and moved with heart beat. Its motion was analyzed with M-mode echocardiography. In the cases with sinus rhythm, the valve opened gradually in systole, and opened further in rapid filling phase,. followed by the rapid closing at the time of atrial contraction. In the cases of atrial fibrillation with severe tricuspid regurgitation, the valve remained at the semi-closed position throughout systole and opened in rapid filling phase. In one case of tricuspid regurgitation the valve was observed to flutter in systole. After the surgical repair of the tricuspid valve, systolic opening of the valve was noted, though atrial fibrillation persisted.

Adolescent↗
PubMed1981

[Evaluation of tricuspid regurgitation by the ultrasonic pulsed Doppler technique from a transcutaneous approach (author's transl)].

Severity of tricuspid regurgitation was assessed by using a combined system of the ultrasonic pulsed Doppler technique and two-dimensional echocardiography from a transcutaneous approach. The study group comprised 47 patients with various heart diseases, who were clinically presumed to have tricuspid regurgitation, and 10 healthy subjects. 1) Pansystolic abnormal flow signal was detected in an area from the tricuspid valve into the right atrial cavity in 43 patients including 8 patients without definitive signs of tricuspid regurgitation. Such abnormal flow had never been detected in healthy subjects and was considered to represent tricuspid regurgitant flow. Tricuspid regurgitant flow usually exhibited a wide band spectrum of velocity component indicating a disturbed flow. In 4 patients with clinical signs of severe tricuspid regurgitation, a laminar flow was detected in the right atrial cavity, which was considered to indicate a regurgitant jet in the central part of tricuspid regurgitant flow. 2) The area where tricuspid regurgitant flow was detected was interpreted as revealing the main direction and spread of tricuspid regurgitant flow. Based on this finding, severity of TR was classified into 4 grades by the assessment on the basis of the distance reached by tricuspid regurgitant flow in the right atrium. Severity of tricuspid regurgitation was also classified into 4 grades by right ventriculography. The grade of tricuspid regurgitation assessed by Doppler technique was nearly consistent with that assessed by right ventriculography. Severity of tricuspid regurgitation was also classified into 4 grades on the basis of the extent of the area where the regurgitant flow spread, and nearly the same results were obtained as those described above. 3) Thus, the combined use of Doppler flowmetry and two-dimensional echocardiography proved to be useful for detecting tricuspid regurgitant flow and assessing the severity of tricuspid regurgitation.

Doppler Effect↗
PubMed1981

[Blood flow analysis with pulsed echo Doppler cardiography in valvular pulmonary stenosis (author's transl)].

Blood flows in the main pulmonary artery, right pulmonary artery and right ventricular outflow tract were analyzed in 11 cases of valvular pulmonary stenosis and 10 healthy subjects by pulsed echo Doppler cardiography (two-dimensional) with the parasternal and suprasternal approaches. 1) The systolic flow in the right pulmonary artery was detected in 7 cases of valvular pulmonary stenosis, in which the flow of both right and main pulmonary arteries was detected in only one case. The flows seemed to be turbulent. These abnormal signals were never detected in healthy subjects and considered to be caused by the narrowing of the pulmonic orifice. 2) Abnormal flow signals were also detected in the right ventricular outflow tract in patients of pulmonary stenosis. Their features were as follows: (1) A systolic turbulent flow was detected in a case with severe hypertrophy of the wall and narrowing of the lumen of the right ventricular outflow tract. (2) A/S ratio, which is a ratio of the peak velocity in atrial contraction (A) to the peak velocity in systole (S), was larger in cases with pulmonary stenosis than in healthy subjects (p less than 0.05). It was considered that the atrial component in the right ventricular filling was augmented in pulmonary stenosis. (3) The PEP/ET (pre-ejection period/ejection time) of the right ventricle was smaller in cases with pulmonary stenosis than in healthy subjects (p less than 0.05). The ratio exhibited a reverse correlation with the pressure gradient between the right ventricle and pulmonary artery (r = 0.74, p less than 0.025). (4) Acceleration time index, a ratio of the time interval between the upstroke and the peak velocity of ejection flow to the ejection time, as a parameter indicating the time delay of the peak velocity exhibited a significant correlation with the pressure gradient between the right ventricle and pulmonary artery (r = 0.67, p less than 0.05). (5) No correspondence was revealed between the time interval of Q-peak velocity in systole and that of Q-peak intensity of the murmur during systole. It was remained to be clarified.

Adult↗
PubMed1980

Mitral cleft in ostium primum atrial septal defect assessed by cross-sectional echocardiography.

We attempted to detect mitral deformities in ostium primum atrial septal defect using real-time cross-sectional echocardiography. Transverse sections of the anterior mitral leaflet echo were examined in 11 patients with this malformation who subsequently received surgical treatment. The section for observing the transverse view of te anterior leaflet was along the sagittal plane of the body, because of the deformity of the mitral annulus. Each echocardiographic finding was compared with the surgical and angiographic findings. On the echocardiogram, the superior and inferior parts of the anterior mitral leaflet separated into two parts during diastole in all patients with mitral cleft. Thin linear echoes connected the ridges of the cleft and the ventricular septum in seven patients in whom the accessory chordae at that area were revealed at surgery. The systolic configuration of the anterior leaflet echo varied among the patients. The severity of the miral regurgitation seemed to relate not only to the size of the cleft but also to the systolic configuration of the anterior mitral leaflet. After surgery, diastolic separation of the anterior leaflet echo was no longer observed. However, the abnormal systolic configuration of the anterior leaflet was unchanged.

Adolescent↗
PubMed1978

Pancreatic internal fistula to the left pleural cavity.

A case of recurrent pancreaticopleural effusion is presented. The pleural effusion with high enzyme and protein contents resulted from a pancreatic internal fistula to the left pleural cavity. A sinus tract passing through esophageal hiatus was demonstrated by the endoscopic retrograde pancreatography (ERP). Surgical intervention afforded complete relief of abdominal pain and elimination of the pleural effusion.

Fistula↗