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Biomedical subjects

H Katsume

Publications and source records attributed to H Katsume.

At least 73 records · Page 4Linked to original sources
PubMed1987

[Right ventricular systolic and diastolic functions assessed by 81mKr scintigraphy and relation to ventricular septal ischemia].

Right ventricular (RV) systolic and diastolic functions were assessed in patients with previous anteroseptal myocardial infarction to ascertain the influence of interventricular septal ischemia on RV function. Gated right ventriculography with continuous infusion of krypton-81 m was performed in 12 normal subjects and 28 patients with infarction but without significant stenosis of the right coronary artery. Furthermore, RV contractile reserve by postextrasystolic potentiation was evaluated by gated radionuclide ventriculography with 99mTc-HSA. The patients with anteroseptal infarction were divided into two groups by the presence or absence of three hours' redistribution in the septal region on exercise thallium-201 myocardial scintigraphy. Two indices of systolic function (ejection fraction and the peak ejection rate) and three indices of diastolic function (1/3 diastolic filling rate, the peak filling rate and time to the peak filling rate) were derived from the right ventricular time-activity curve and its derivative curve. There was no difference in systolic function among normal subjects and patients with or without redistribution. However, diastolic function was impaired only in the patients without redistribution. The RV contractile reserve in the patients without redistribution was less than in those with it. Thus, RV systolic function was maintained in the patients with anteroseptal infarction, but contractile reserve deteriorated only in severe septal ischemia. Similarly, diastolic function was maintained in mild septal ischemia, but impaired in severe septal ischemia. We concluded that RV systolic and diastolic functions are closely related to interventricular septal ischemia.

Diastole↗
PubMed1987

[Evaluation of right ventricular function in severe left ventricular failure: comparison of old myocardial infarction with dilated cardiomyopathy].

To evaluate right ventricular (RV) function in severe left ventricular (LV) failure, we measured RV and LV ejection fractions (EF) in 18 patients with old myocardial infarction (OMI) and in 18 with dilated cardiomyopathy (DCM) using cardiac blood pool scintigraphy. In patients with OMI, RVEF was significantly greater in stage II LV failure than in stage III (functional class of the New York Heart Association, 47 +/- 8% and 28 +/- 12%, respectively: p less than 0.01), and this correlated well with exercise tolerance by bicycle ergometer and mean pulmonary artery pressure (r = 0.83 and r = -0.71, respectively). In patients with DCM, however, there was no correlation between RVEF and these indexes. After the oral administration of denopamine (beta 1 effector), both RVEF and LVEF increased in patients with OMI (35 +/- 13% to 45 +/- 12%, and 27 +/- 9% to 30 +/- 10%: p less than 0.01), but they did not change significantly in patients with DCM. These results indicate that RVEF in patients with OMI correlates well with subjective symptoms, exercise tolerance and RV afterload, but these correlations were not apparent in patients with DCM. We concluded that RV function in cases of severe LV failure has a different meaning between OMI and DCM.

Adult↗
PubMed1986

Regional differences of myocyte hypertrophy and three-dimensional deformation of the heart.

Cross-sectional area was compared between the latitudinally and longitudinally oriented muscle fibers of the hypertrophied left ventricle of the rat heart under aortic banding and isoproterenol infusion. In addition, end-diastolic three-dimensional deformation of the left ventricle as expressed by cavity volume and eccentricity was examined in the early and chronic stages of these treatments. Under aortic banding, myocyte hypertrophy occurred to a greater extent in the latitudinally oriented fibers of the midwall layer than in the longitudinal fibers of the inner and outer layers. Such a regional difference of hypertrophy was not seen under isoproterenol infusion. At the early stage of aortic banding, the left ventricle at end diastole was more dilated and spherical, whereas at the acute stage of isoproterenol infusion, it was more decreased in size and prolate than that of the controls. The deformation of the left ventricle at the early stage of aortic banding is considered to cause, during diastole, axial stretching and increase in tensile stress more on the latitudinal fibers, leading them to the predominant hypertrophy.

Animals↗
PubMed1986

[Left ventricular function during atrial fibrillation assessed by left ventricular function curve using ECG-gated blood pool scintigraphy].

Cardiac function is difficult to assess in patients with atrial fibrillation due to the widely fluctuating cycle lengths resulting in variable ventricular hemodynamics. With respect to ECG-gated blood pool scintigraphy, distortion of the time activity curve occurs due to a summation of irregular cycle lengths. Therefore, performing such a study has been regarded meaningless. To evaluate left ventricular function during atrial fibrillation using scintigraphic technique, a new processing algorithm was devised to make multiple gated images which are discriminated by the preceding R-R interval, and left ventricular filling and function curves were established. The left ventricular filling curve, obtained by plotting end-diastolic volume against the preceding R-R intervals demonstrated an impairment of blood filling in cases of mitral stenosis and constrictive pericarditis, which resolved after mitral commissurotomy in case of mitral stenosis. The left ventricular function curve, established by plotting stroke volume against end-diastolic volume, was analyzed according to indices such as "slope" and "position". Both of these indices were significantly reduced in relation to the severity of heart failure according to the NYHA's functional classification and cardiomegaly on chest radiography. On individual comparisons of underlying diseases, the indices decreased in the following order; lone atrial fibrillation, hyperthyroidism, aging, hypertension, mitral valve disease, ischemic heart disease, dilated cardiomyopathy and aortic regurgitation. The indices correlated closely with ejection fraction. In cases of mitral regurgitation, however, the function curves were situated to the right and above those of lone atrial fibrillation and decreased in slope despite the fairly well-maintained ejection fraction. After treatment with digitalis and/or diuretics, the function curves shifted to the left and upward. In conclusion, left ventricular filling and function curves based on a newly-devised algorithm of ECG-gated blood pool scintigraphy are of considerable clinical value in evaluating cardiac performance in patients with atrial fibrillation. They are widely applicable to the assessment of therapeutic and interventional effects.

Atrial Fibrillation↗
PubMed1986

[Influence of exercise training on left ventricular performance investigated by two-dimensional echocardiography].

The influence of exercise training on left ventricular performance was investigated by exercise two-dimensional echocardiography in 12 top-ranking Japanese volleyball players and 10 untrained subjects. Left ventricular wall thickness and dimension were greater in the athletes than in the nonathletes. The left ventricular wall thickness-internal radius ratio, however, was nearly the same in both groups. At rest, heart rate, the stroke area index, % fractional area and the cardiac index were significantly lower in the athletes than in the nonathletes. During exercise, heart rate was slower in the athletes at every exercise stress stage. The stroke area index, % fractional area and the cardiac index increased linearly in the athletes, although these indices of the nonathletes reached a plateau at the moderate exercise stage. The double product at the last stage was greater in the athletes than in the nonathletes. Both groups did not differ as to segmental fractional area change of left ventricular contraction at rest and during exercise. Serum norepinephrine concentration was significantly lower in the athletes than in the nonathletes at rest. After exercise, however, the difference between the two groups was not apparent. It is suspected that exercise training increased the exercise capacity due to an increase in the left ventricular systolic function reserve, the increment of cardiac VO2 max, and the change of blood flow distribution, and generalized aerobic metabolism in various organs.

Adult↗
PubMed1986

[Cardiac inotropic reserve examined by postextrasystolic potentiation and redistribution of exercise thallium-201 scintigraphy].

Evaluation of regional contractile reserve and the viability of an infarcted segment of the myocardium is very important in determining the indications for aorto-coronary bypass after myocardial infarction and in predicting the prognosis. Regional wall motion of the left ventricle after postextrasystolic potentiation (PESP) was studied in 18 patients with old myocardial infarction, and compared with indices of redistribution of thallium after exercise. Equilibrium radionuclide angiocardiography (RNA) using Tc99m HSA was performed at rest and after PESP produced by a programmable cardiac stimulator via a right ventricular catheter. Regional ejection fractions (REF) were determined, and wall motion was observed visually. The relative thallium activity (RTA) and washout rate (WOR) were obtained from exercise myocardial scintigraphy performed 10 minutes, and 3 hours after thallium-201 injections. Wall motion improved in 12 of 23 infarcted segments after PESP. Regional ejection fraction and relative thallium activity (in three hours, or the difference between the activities of the initial and three hours after exercise) in the improved segments were significantly higher (p less than 0.001) than in the unchanged segments. Washout rate was lower (p less than 0.02) in the improved segments. Significant correlation was observed between the change in regional ejection fraction and relative thallium activity (3 hours after exercise) (r = 0.654, p less than 0.05). Thus, the wall motion of some infarcted regions of the myocardium improved after PESP, and thallium was redistributed during three hours after exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

Exercise Test↗
PubMed1985

Electrophysiological effects of bethanidine sulfate on guinea-pig papillary muscle.

Bethanidine, a chemical analog of bretylium, increased the plateau phase of the action potential of guinea-pig papillary muscle in 2.7 mM K+ Tyrode solution without changing other electrophysiological parameters. In 25 mM K+ Tyrode solution, the amplitude, duration and Vmax of the Ca2+-dependent action potential were increased in a dose-dependent manner by bethanidine. It is speculated that the mechanism of antiarrhythmic effect of bethanidine might be due to the prolongation of action potential by an increase of the slow inward current.

Action Potentials↗
PubMed1985

Effects of S-596, a new beta-adrenoceptor blocking agent on the left ventricular performance of normal subjects during exercise.

The effects of d1-2-(3'-t-butylamino-2'-hydroxypropylthio)-4-(5'-carbamoyl-2'-thi enyl) thiazole hydrochloride (S-596) were evaluated in 9 normal volunteers. Exercise echocardiography was performed in the semi-supine position before and 2, 4 and 24 hours after the oral administration of 15 mg of S-596. Two hours after administration, resting heart rate was unchanged, compared with control, but systolic blood pressure at rest was slightly decreased (114 +/- 6 vs 106 +/- 10 mmHg, p less than 0.05). Left ventricular dimensions were unchanged, but shortening fraction was increased in the resting state (30.3 +/- 4.6 vs 33.1 +/- 4.8%, p less than 0.05). During exercise on oral S-596, heart rate and systolic blood pressure responses were reduced (127 +/- 11 in control vs 108 +/- 6 beats/min on S-596, 198 +/- 25 vs 168 +/- 23 mmHg, p less than 0.001 and 0.05, respectively). Left ventricular end-diastolic dimension was not significantly altered by S-596 compared with the preceding control exercise test; however, end-systolic dimension was significantly larger after beta blockade with S-596 (2.6 +/- 0.4 vs 3.0 +/- 0.4 cm, p less than 0.05). Shortening fraction and cardiac output decreased significantly (43.7 +/- 3.7 vs 40.0 +/- 5.7%, 9.5 +/- 1.4 vs 8.4 +/- 1.3 L/min, p less than 0.05 and 0.01, respectively). These effects of S-596 were maximal at 2 hours after oral administration with reduced response of heart rate to exercise lasting for 24 hours. Compared with the effects of propranolol (30 mg, given orally) in the same subjects, beta-adrenergic blockade during exercise with S-596 was equivalent to or greater than that of propranolol. Thus, S-596 has little, if any, effect on resting left ventricular performance, but demonstrates potent negative chronotropic and inotropic effects during exercise in normal human subjects. Its beta-adrenergic blocking action also has long acting properties, especially its chronotropic effect.

Adrenergic beta-Antagonists↗
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↗
PubMed1985

[Exercise echocardiography to evaluate left ventricular function in mitral and aortic regurgitation].

To assess differences in left ventricular (LV) performance between mitral regurgitation (MR) and aortic regurgitation (AR), exercise echocardiography was performed for 12 patients with MR and 18 patients with AR, and the results were compared with those of 11 normal subjects. These patients with LV volume overloads were all in the NYHA class I or II. There were no differences in age or sex distributions between the two groups. Symptom-limited submaximal exercise was performed on an ergometer in the supine position. The results obtained were as follows: LV dimensions at end-diastole (EDD) and end-systole (ESD) were greater in the diseased groups than in the normal group. Resting EDD and ESD showed no differences between the MR and the AR groups. There were no differences in exercise-induced increases in heart rates or elevations of systolic blood pressures among the three groups. During exercise, EDD increased and ESD decreased in the normal group, and similar results were obtained for the MR group. However, in the AR group, EDD and ESD remained unchanged. Ten of the 18 patients with AR had decreased ESD, and eight had unchanged or increased ESD during exercise. Resting shortening fractions were equally distributed among the three groups. During exercise, the shortening fractions were significantly increased in the normal and the MR groups. In the AR group, shortening fractions remained at resting values, with variable responses in individual cases. Systolic wall thickening of the interventricular septum and the LV posterior wall showed similar responses of shortening fractions. The relation between the peak systolic wall stress index (PSSI) and ESD, or PSSI and the shortening fraction revealed that exercise induced an afterload mismatch of LV performance in some patients with AR. Thus, though resting LV performances did not differ from each other, an afterload mismatch is more easily induced with exercise in patients with AR than in patients with MR. This may be one of the cause of the different clinical courses in these two groups with LV volume overloads.

Adult↗
PubMed1985

[Coronary reserve of the right ventricle evaluated by double dose T1-201 scintigraphy].

Thallium-201 double dose scintigraphy was applied to exercise to estimate the coronary blood flow reserve of the left and right ventricles and this was compared with the degree of coronary artery stenosis. As an index of coronary reserve we measured the rate of change of blood flow distribution (delta F) calculated from the change in myocardial radioactivity following thallium-201 injections, once at rest and once during exercise. With submaximal exercise the increases in delta F of the left ventricle were less in patients with ischemic heart disease than in the control subjects, and were less as the number of diseased coronary vessels increased. The increases of delta F of the right ventricle were less in patients with stenosis of the proximal portion of the right coronary artery than in patients without stenosis and in the control subjects. The more severe the stenosis of the proximal portion of the right coronary artery, the smaller the delta F of the right ventricle. These results indicate that evaluation of the delta F in the left and right ventricles is useful in estimating coronary artery stenosis.

Coronary Circulation↗
PubMed1984

Pulmonary varix.

Pulmonary varix is rare, only 53 cases having been reported. A brief review of the literature is given. Because its radiologic appearance may be indistinguishable from mediastinal or pulmonary lesions, pulmonary angiography is necessary to avoid exploratory thoracotomy, mediastinoscopy, and unnecessary antituberculous therapy.

Aged↗
PubMed1984

Tachyarrhythmia provoked by coughing and other stimuli.

A rare case of cough-induced tachyarrhythmia is described. The effectiveness of atropine sulfate, and worsening of the arrhythmia resulting from administration of digitalis, suggests that vagal reflex might be the mechanism responsible for the tachyarrhythmia.

Cough↗
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↗