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Biomedical subjects

Y Shimazaki

Publications and source records attributed to Y Shimazaki.

At least 253 records · Page 14Linked to original sources
PubMed1981

[Determination of right ventricular volume by subxiphoid two-dimensional echocardiography (author's transl)].

To establish the measurement method of right ventricular (RV) volume by two-dimensional (2-D) echocardiography, a comparative study was performed in respect to the quantitative evaluations of the RV areas or volumes obtained by biplane 2-D echographic and angiographic methods. At first, a preliminary investigation was performed to define the optimum tracing of the endocardial surface on the 2-D echogram by using a fresh mongrel dog heart. It was revealed that the 2-D echographic views of the ventricular surface contained some artifact echoes inside the true echo of the endocardium. As a result, the optimum line for tracing was considered to be in external margin of the echo which seemed to represent the endocardium. This technique was then applied to 10 patients with congenital heart disease who were followed by cardiac catheterization. Ages ranged from 9 months to 5 years with an average of 2 years and 4 months. The RV was imaged by a subxiphoid approach. The RV apex, pulmonary valve (PV) and mid-portion of the tricuspid valve were showed in a frontal view, which allowed to measure the frontal RV area (f). In a sagittal plane, the RV wall and the PV were imaged, and then the lateral area (l) and the RV long axis (d) were measured. From the biplane cineangiography, the frontal RV area (f') lateral area (l'), RV long axis (d') and RV end-diastolic volume (EDV) by arealength method were calculated. The f and l were correlated with the f' (r = 0.90) and with the l' (r = 0.86), respectively. However, the values by the echocardiographic measurement were smaller than those by the cineangiographic ones. The f was also well correlated with the RVEDV (r = 0.94). The f.l/d, considered to represent a variable of echography measurement of the RV volume by area-length method, was well correlated with the RVEDV (r = 0.84). Although there are still some problems related to the imaging technique and sharpness of the echogram, further improvement to establish a echocardiographic measurement of RV volume is expected with the advance of the techniques.

Animals↗
PubMed1980

Ventricular volume characteristics of single ventricle before corrective surgery.

With use of biplane cineangiocardiograms, ventricular cavity volume measurements were determined in 17 patients with single ventricle, before total correction. There were 4 patients with a single left and 13 with a single right ventricle. Atrioventricular (A-V) valve regurgitation was evident in 6 of 13 patients with a common A-V valve. End-diastolic volume index ranged from 72 to 282 ml/m2 (average 131 ml/m2), and these values ranged from 71 to 206 percent (average 110 percent) of the sum of the normal left and right ventricular end-diastolic volumes. Ejection fraction averaged 0.55. There was no significant difference in ventricular cavity volume characteristics and ventricular function between patients with single and and single right ventricle. The single ventricle ejects blood to both the systemic and the pulmonary circulatory beds. There was a high correlation of end-diastolic volume index with pulmonary to system flow ratio (r = +0.89, p less than 0.001). This observation indicates that the major factor affecting ventricular cavity volume in single ventricle is pulmonary blood flow and a systemic to pulmonary arterial shunt should increase the ventricular cavity volume. Ventricular function of single ventricle was depressed. The ejection fraction of patients with A-V valve regurgitation averaged 0.49, which was significantly lower than that (0.58) of patients without regurgitation (p less than 0.05). A-V valve regurgitation was also a factor that increased ventricular cavity volume, although the ventricular function became more depressed.

Adolescent↗
PubMed1980

Angiographic volume estimation of right ventricle. Re-evaluation of the previous methods.

Previous angiographic methods for volume estimation of the right ventricle were re-evaluated by ten cast studies as far as the positions of the right ventricular casts were concerned. The spatial orientation of the right ventricular chamber cavity varies clockwise or counterclockwise, in the normal heart. For right ventricular volume estimation, it is important to analyze the right ventricular casts with rotated positions. The casts were studied by biplane cineangiocardiograms with four clockwise rotated positions, which were 0 degrees, 30 degrees, 40 degrees, 45 degrees, and 60 degrees. Simpson's rule and the area-length methods were used for angiocardiographic determination of the right ventricular volume. In four positions, four linear regression equations comparing true volumes with calculated volumes had similar values to each other in the two methods. Regression equation comparing true volumes with calculated volumes which contained a total of 40 casts in four positions, yielded a high correlation coefficient (r = +0.98, p less than 0.001) and small errors in both Simpson's rule and the area-length methods. This study indicates that the right ventricular chamber volume can be accurately estimated with only one regression equation from biplane cineangiocardiograms, even when the right ventricular cavity would have been rotated clockwise or counterclockwise.

Adolescent↗
PubMed1980

Severe mitral regurgitation due to coronary arteritis of mucocutaneous lymph node syndrome. A new surgical entity.

Case histories are reported of three patients, 1 to 4 years of age, with severe mitral regurgitation that occurred as a sequela of mucocutaneous lymph node syndrome (MCLS). These patients were found among 12 patients with coronary artery lesions such as aneurysms, narrowings, and obstructions. One of them with multiple coronary aneurysms and also severely impaired left ventricular function died of congestive heart failure in the 2 years and 7 months' follow-up period after the acute illness. The second patient, 1 year of age, had multiple coronary aneurysms and mitral regurgitation. Because of the difficulty in treating coronary artery lesions at this patient's age and also because of medically controllable mitral regurgitation at present, this patient is now under careful observation. The third patient, whose condition was complicated by inferior wall myocardial infarction due to occlusion of the right coronary artery, underwent mitral valve replacement for intractable heart failure and cardiac cachexia. This patient had slow but definite improvement postoperatively. Mitral regurgitation secondary to MCLS usually is complicated by the associated difficult coronary artery lesions and impaired left ventricular function. Although this fact causes an extra-difficult situation, mitral regurgitation consequent to MCLS is amenable to surgical treatment and this disease should now be considered as a new surgical entity.

Aneurysm↗