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Biomedical subjects

H Kunishige

Publications and source records attributed to H Kunishige.

33 records · Page 2Linked to original sources
PubMed1985

[Differences in left ventricular systolic performance during exercise in patients with hypertrophic cardiomyopathy and systemic hypertension].

To evaluate differences in systolic global and regional performances of the left ventricle during exercise, multi-stage submaximal exercise echocardiography was used for 21 patients with hypertrophic cardiomyopathy (HCM) and 14 patients with systemic hypertension (HT), whose interventricular septa (IVS) were nearly the same in thickness (HCM; 16.5 +/- 2.4 mm, HT; 15.4 +/- 1.7 mm, NS). The data were compared with those of 18 normal subjects (N). During exercise, end-diastolic dimension (EDD) was increased in all three groups; however, there was no statistical differences among the three groups either at rest or during exercise. End-systolic dimension (ESD) was significantly decreased during exercise in HT (29.3 +/- 5.8 at rest to 28.1 +/- 5.8 mm at the peak exercise, p less than 0.05) and N (from 30.3 +/- 3.3 to 25.7 +/- 3.0 mm, p less than 0.001). On the other hand, ESD of HCM at rest, which was less than those of the other two groups, did not decrease with exercise (from 25.1 +/- 4.5 to 25.6 +/- 4.6 mm, NS), and rather they increased (more than 2 mm) during exercise in seven patients. The % shortening fraction (%SF) increased from rest to exercise both in HT (35.6 +/- 7.9% to 40.1 +/- 9.6%, p less than 0.001) and in N (from 35.1 +/- 4.2 to 45.9 +/- 4.7%, p less than 0.001). However, in the HCM group, the %SF, which was significantly greater at rest than in the other two groups, did not increase during exercise (42.5 +/- 6.8 to 42.5 +/- 8.8%, NS). In addition, in seven of 21 patients with HCM, the %SF increased more than 5% at the peak exercise. At rest, systolic wall thickening (%WT) of the IVS equally reduced both in HCM and HT. It increased in HT from 20.8 +/- 9.3% at rest to 24.6 +/- 12.7% at the peak exercise (p less than 0.05), but did not change in HCM (from 16.6 +/- 9.6% to 16.3 +/- 7.0%, NS). At rest, %WT of the left ventricular posterior wall (LVPW) was significantly greater in HCM than in HT. During exercise, it increased in HT (from 43.1 +/- 15.9% to 61.9 +/- 20.5%, p less than 0.01), but did not increase in HCM (from 81.0 +/- 27.7% to 85.5 +/- 29.6%, NS).(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1984

Simultaneous changes of left ventricular and left atrial size and function in normal subjects during exercise.

We performed dual M-mode exercise echocardiography, which records left ventricular (LV) and left atrial (LA) echocardiograms simultaneously, in 10 normal subjects to investigate mechanisms of cardiac adaptation to dynamic exercise. The LV end-diastolic dimension (EDD) increased significantly as exercise increased from mild to moderate (3-5%, p less than 0.05 and 0.001). At peak exercise the EDD was slightly increased, but it returned to the baseline during recovery. The LV end-systolic dimension (ESD) showed a progressive decrease with the severity of exercise (5-13%, p less than 0.05 and 0.001). It decreased further immediately after exercise (17-20%) and then returned to the resting value. The LV stroke dimension and fractional shortening increased as exercise changed from mild to moderate and reached a plateau at peak exercise. During recovery, they showed a transient increase and then decreased. By contrast, the LA dimensions, both maximum and minimum, increased significantly as exercise changed from mild to moderate (15-16% and 16-19%, p less than 0.01 and 0.001, respectively), but they were lower at peak exercise (12 and 14%). They returned rapidly to the resting values immediately after exercise. Thus, during exercise, LV function is augmented by the Frank-Starling mechanism in combination with increased contractility, while the LA is enlarged to receive the increased venous return accompanying dynamic exercise. These exercise-induced changes in LV performance return gradually to the resting state, but LA size recovers rapidly after the cessation of exercise.

Adolescent↗
PubMed1983

Left ventricular size and performance during graded supine exercise in normal subjects.

To investigate left ventricular size and performance during graded submaximal exercise, 14 normal subjects with a mean age of 21 years exercised in a supine position to achieve the target heart rate. Using two-dimensional echocardiography, we recorded and analysed the left ventricular (LV) cross-sectional area and internal dimension at the level of the tips of the mitral valve at rest and during mild, moderate and severe exercise. The heart rate and systolic blood pressure increased substantially from rest to peak exercise (71 +/- 11 to 162 +/- 10 beats/min, 122 +/- 10 to 204 +/- 22 mmHg). The end-diastolic cross-sectional area and internal dimension (EDA & EDD) increased by 1.1-2.2 cm2 (7-13%) and 0.2-0.3 cm (4-7%), respectively, from mild to moderate exercise, (p less than 0.05-0.001). At peak exercise, however, these decreased and showed no statistically significant difference from the values at rest. The end-systolic cross-sectional area and internal dimension (ESA & ESD) decreased by 1.1 to 1.6 cm2 (14-20%) and 0.2-0.3 cm (7-10%), respectively, from moderate to severe exercise (p less than 0.01-0.001). However, the end-systolic values during mild exercise were not significantly different from those at rest. The stroke area (EDA-ESA) and dimension (EDD-ESD) increased by 1.6-2.6 cm2 (19-31%) and 0.2-0.6 cm (25-38%), respectively, during all levels of graded exercise (p less than 0.05-0.001). The percent change of LV cross-sectional area and internal dimension during systole increased gradually from rest to moderate exercise (51.0 +/- 7.1 to 61.9 +/- 4.4%, 35.4 +/- 3.9 to 45.0 +/- 3.7%), respectively, and showed no further increase during peak exercise. The mean circumferential fiber shortening velocity increased sharply from rest to peak exercise (1.27 +/- 0.14 to 2.25 +/- 0.21 circ/sec). These results suggest that the Frank-Starling mechanism operates during mild to moderate exercise, and contractility increases markedly at moderate to severe exercise levels as cardiac performance is augmented during graded submaximal exercise.

Adolescent↗
PubMed1983

[Quantitative evaluation of thallium-201 exercise myocardial scintigraphy and its display on the two-dimensional view of the left ventricular wall as the functional image].

We developed a new method for the quantitative evaluation of 201T1 exercise myocardial scintigraphy. Final diagnostic images obtained by this method were displayed on the two-dimensional views of the left ventricular wall. Five projection images obtained 10 min and 3 hrs after exercise were recorded respectively in the magnetic disk. Each image was divided into seven fan-shaped segments utilizing the apical image as the reference which was placed in the middle. The corrected uptake indices were examined in 20 normal controls and served as the normal data. Each segment was then judged to be intact or ischemic or infarcted by matching the segmental uptakes of the images given 10 min and 3 hrs after exercise. The results were displayed on the computer-assisted color monitor as the two-dimensional view of the left ventricular wall. In order to evaluate its diagnostic usefulness in coronary artery disease, comparative coronary angiography was performed in 25 patients. The present technique proved to have high sensitivity and specificity both in left anterior descending artery and right coronary artery diseases (88 and 78%, respectively in the former and 83 and 89%, respectively in the latter).

Coronary Disease↗
PubMed1981

[Analysis of left to right ventricular stroke count ratio by gated radionuclide angiocardiography: detection and quantitation of valvular regurgitation and shunts (author's transl)].

The stroke count ratio (SC ratio: SCL/SCR) for left to right ventricular enddiastolic-endsystolic count differences was obtained from LAO multi-gated cardiac blood pool scintigrams for quantitative assessment of valvular regurgitation and shunts. SC ratio, 1.48 +/- 0.24 (mean +/- S.D.) in 21 normal subjects, was decreased in 7 patients with atrial septal defects (ASD) and in one with isolated tricuspid regurgitation (TR), and increased in 15 patients with aortic regurgitation (AR) and in 6 with mitral regurgitation (MR). In post-surgical reassessment of 3 patients, the ratio was restored in normal range. Comparison between SC ratio and angiographic estimates of regurgitation revealed good agreement. Regurgitant fraction (RF) in AR or MR and shunt ratio (SR) in ASD were calculated by the formula: RF = 1-1.48/SC ratio, and SR = 1-SC ratio/1.48, respectively. These were derived by assuming that an excess of stroke counts was due to regurgitant or shunt flow and that the coefficient in counting ventricular radioactivity was 1.48. Agreement was found between RF or SR measured by this formula and by the invasive method. This method permits noninvasive quantitation in patients with valvular regurgitation and shunts without complicated computer procedures.

Aortic Valve Insufficiency↗
PubMed1979

Use of digitised left ventricular echocardiograms in assessment of mitral stenosis.

In order to establish a new echocardiographic index of the severity of mitral stenosis, left ventricular echocardiograms were digitised using manual tracing and a computer. The instantaneous left ventricular dimension was measured in 15 patients with mitral stenosis. The peak rate of change of left ventricular dimension (peak dD/dt) and the normalised peak rate (peak dD/dt/D) during early diastole were significantly lower in mitral stenosis than in normal subjects. Also, the time between the second heart sound and peak dD/dt was significantly shorter in patients with mitral stenosis than in normal subjects. Correlation between the mitral valve area calculated from the Gorlin formula and peak dD/dt/D was good, while valve area was poorly correlated with the EF slope of the anterior mitral leaflet echo. It is suggested that by continuous measurement of left ventricular dimension and of its first derivative, the reduced atrioventricular blood flow in mitral stenosis can be shown, and that peak dD/dt/D during early diastole is a possible index of its severity.

Adult↗
PubMedDate not supplied

Abnormal myocardial uptake and clearance of 123I-labeled metaiodobenzylguanidine in patients with chronic renal failure and autonomic dysfunction.

BACKGROUND: Patients with chronic renal failure were evaluated with 123I-labeled metaiodobenzylguanidine (MIBG) myocardial scintigraphy to investigate the relationship between abnormal findings on MIBG scintigrams and autonomic dysfunction. METHODS AND RESULTS: Eleven control subjects and 20 patients with chronic renal failure (CRF) (serum creatinine level > 8 mg/dl) were evaluated by MIBG myocardial scintigraphy and power spectral analysis (PSA) of the R-R fluctuations of the electrocardiogram. Subjects with CRF were divided into two groups: without (CRF1; nine patients) or with (CRF2; 11 patients) autonomic neuropathy. From MIBG images, the heart/mediastinum mean count rate, defect score, which was scored visually, and clearance rate were calculated. Percent low-frequency power and high-frequency power were obtained from PSA. MIBG scintigrams showed decreased heart/mediastinum mean count rate, a high defect score in both initial and delayed images, and rapid clearance rate in the CRF2 group. PSA showed an abnormally low percent low-frequency power and high-frequency power in the CRF2 group. In addition, there was a weak but significant inverse correlation between percent low-frequency power and defect score. CONCLUSION: Alterations in MIBG scintigrams are seen in patients with autonomic dysfunction in CRF and may be useful for evaluating cardiac sympathetic dysfunction in those patients.

3-Iodobenzylguanidine↗