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Biomedical subjects

H Toshima

Publications and source records attributed to H Toshima.

At least 145 records · Page 8Linked to original sources
PubMed1984

Prognosis in hypertrophic cardiomyopathy.

One hundred thirty-six patients with hypertrophic cardiomyopathy were followed up for 1 to 17 years. Twenty-one patients had died, 14 of them suddenly, two from heart failure, two from cerebral embolism, and three from noncardiac causes. Life table analysis revealed that sudden death was significantly associated with young age less than 20 years (relative risk [rr] = 8.63, when compared with those greater than 40 years) and with positive Master's single two-step test (rr = 3.55). Heart failure was more frequent in patients with positive Master's single test (rr = 4.27) and with left ventricular end-diastolic pressure greater than 20 mm Hg (rr = 2.58). Atrial fibrillation, observed in 15 patients, was a poor prognostic sign, resulting in five cardiac deaths and seven heart failures. In contrast, prognosis was favorable in patients with apical hypertrophy with giant negative T wave. Thus Japanese patients with hypertrophic cardiomyopathy showed a prognosis consistent with Western patients, except for excellent outcome of apical hypertrophy.

Adult↗
PubMed1984

Changes of left ventricular pressure-diameter-velocity relations by alterations of heart rate in conscious dogs.

Changes of left ventricular (LV) pressure-diameter-velocity relations by alterations in heart rate (HR) were investigated in 6 conscious dogs, instrumented with a pair of ultrasonic crystal probe, a micromanometer in LV and pacing electrodes on the left atrium. By atrial pacing the following four stages of HR were produced: stage (S)-I 112, S-II 134, S-III 158 and S-IV 179 bpm (mean HR). These alterations in HR were repeated before and during acute pressure loadings by methoxamine infusion. LV pressure-diameter and pressure-velocity relations were evaluated by the slope value of LV peak systolic pressure (LVSP)-end-systolic diameter, E (D) max, and by the ratio of changes in mV cf (mean velocity circumferential fiber shortening) and LVSP before and during pressure loading, delta mVcf/delta LVSP, respectively. The average of E(D) max at each stage of HR was 9.45, 12.63, 12.59, 11.22 mmHg/mm, and delta mVcf/delta LVSP was -0.009, -0.006, -0.007, -0.009 circ./sec.mmHg, respectively. E(D) max increased more at S-II and S-III than at S-I, and reversely, E(D) max decreased more at S-IV than at S-II. Similarly, delta mVcf/delta LVSP increased more at S-II than at S-I and decreased more at S-IV than at S-II, while delta LVSP and delta EDD (end-diastolic diameter) were not different between stages. These changes in E(D) max and delta mVcf/delta LVSP presented the mountainous pattern effected by alterations in HR, whose changes were almost similar to that of LV peak positive dp/dt and mVcf before pressure loading. Thus, E(D) max is augmented by an increase in HR, which suggests the Bowditch-effect. Reversely, a decrease in E(D) max at a higher rate indicates a depressed inotropic state. E(D) max is dependent on HR and is a sensitive indicator of the contractility of LV.

Animals↗
PubMed1984

Reconsideration of heart rate-cardiac output relationships and resting cardiac function in patients with brady-arrhythmias.

Different types of heart rate (HR)-cardiac output (COP) relationships were compared with their clinical features and hemodynamic findings in 56 patients with brady-arrhythmias (BA). HR was raised by increments of 10 beats per minute (bpm) at 3 min intervals, from spontaneous rates to 100 or 110 bpm by right ventricular pacing. Cardiac and left ventricular (LV) functions at BA were evaluated by intra-cardiac pressures, COP measured by the thermo-dilution method and echocardiographic data. HR-COP relationships were divided into the following 3 types: 24 patients of flat (F), 18 of peaked (P) and 14 of increased (I) type. There were more patients with complete atrio-ventricular block, particularly His-ventricular block, and cardiomyopathic patients with the "P" type than with the other types. Cardiac index, stroke index, stroke work index and systemic vascular resistance were greater in "I", but these differences were not significant. LV peak systolic pressure (LVSP) and end-diastolic pressure (EDP) in "I" increased more than in "F". EDP, LV end-diastolic and end-systolic dimension (ESD) in "P" increased more than in "F". Systolic excursion and LVSP/ESD ratio in "I" increased more than in the other types. Heart failure prior to implantation of pacemaker (PM) and post-PM occurred more frequently in "P". "F" and "I" patients showed comparatively good clinical courses after PM. Thus, cardiac and LV function during BA are maintained in "F" and are impaired in "P", as reported previously. On the other hand, cardiac functions are maintained in "I" as they are in "F", mainly due to contributions of the Frank-Starling mechanism and partly due to maintenance or slight augmentation of contractility.

Adolescent↗
PubMed1984

[Mechanism of exercise-induced ST segment deviation in myocardial infarction: a 201T1-myocardial scintigraphic study].

Exercise-induced ST segment deviation was investigated using thallium-201 myocardial scintigraphy and correlated with coronary artery lesions in 25 patients with old myocardial infarction. Seven of eight patients without ST deviation showed no reversible perfusion defect by near maximal exercise, and six had no significant stenosis in the coronary arteries perfusing the non-infarcted area. During exercise, ST segment depression was induced in 12 patients and six of them developed a reversible perfusion defect in the non-infarcted area, associated with significant stenosis of the corresponding coronary arteries. Remaining six patients, however, did not show a reversible perfusion defect and four of them had no significant stenosis of the coronary arteries perfusing the non-infarcted area. In nine patients with exercise-induced ST segment elevation in leads with Q waves, a reversible perfusion defect was not detected in seven (78%) and five (71%) of them had no significant coronary artery stenosis as well. Four patients developed both ST segment elevation in leads with Q waves and ST segment depression in other leads. One patient who had significant coronary artery stenosis in the non-infarcted area and showed a reversible perfusion defect developed 1.5 mm ST elevation in II, III, a VF leads and 4 mm ST depression in precordial leads. In the remaining three patients who did not show a reversible perfusion defect and significant coronary artery stenosis in the non-infarcted area, ST depressions were less than 2 mm.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

[Abnormal septal motion following non-surgical closure of the patent ductus arteriosus].

Abnormal ventricular septal motion is usually observed after open heart surgery, but its mechanism is not fully understood. Our previous study suggested that a sudden reduction of left ventricular (LV) volume overload after corrective surgery would be one mechanism, showing that postoperative abnormal septal motion is more frequent in patients who have preoperative LV volume overload. The purpose of this study was to investigate further the direct effect of LV volume alone on the ventricular septal motion in 22 patients who underwent non-surgical closure of a patent ductus arteriosus (PDA) by the Porstmann's method. The non-surgical closure of a PDA reduced LV diastolic diameter (LVDd) from 55.7 +/- 7.3 mm to 48.1 +/- 5.2 mm (P less than 0.001), and LV systolic diameter (LVDs) from 36.3 +/- 7.0 mm to 34.1 +/- 7.0 mm (p less than 0.01). Septal motion decreased in amplitude from 8.5 +/- 2.4 mm to 3.8 +/- 3.4 mm (p less than 0.01) and eight (36%) patients developed abnormal septal motion, while LV posterior wall excursions remained unchanged. When compared these eight patients with 14 without abnormal septal motion, the magnitude of postoperative LVDd reduction (delta LVDd) and its ratio to preoperative volume (delta LVDd/pre op LVDd) were significantly greater in patients with abnormal septal motion. Thus sudden reduction in LV volume overload alone could induce abnormal septal motion without altering other factors such as adhesion of the pericardium.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1984

[Hypertrophic cardiomyopathy with ventricular septal hypertrophy localized to the apical region of the left ventricle (apical ASH)].

Clinical and morphologic features are described in a subgroup of 22 patients with hypertrophic cardiomyopathy, who showed ventricular septal hypertrophy localized to the apical region (apical asymmetric septal hypertrophy: apical ASH). All patients had ventricular septal thickness of 17 mm or less with an average of 13 +/- 3 mm in the M-mode echocardiograms. In contrast, the two-dimensional echocardiograms demonstrated septal hypertrophy localized to the apical region, with an average septal thickness of 20 +/- 3 mm at the mitral valve and papillary muscle levels. On the left ventriculogram, 82% of patients with apical ASH showed inward concavity of the right-inferior wall of the left ventricle, indicating hypertrophy of the ventricular septum. However, no patient showed spade-like appearance of the left ventricle and only two showed giant T wave inversion exceeding 10 mm. Echocardiographic examination performed in eight affected relatives revealed typical asymmetric septal hypertrophy (ASH) in four relatives, one of them showing a resting pressure gradient of 30 mmHg in the left ventricle. The remaining four relatives showed similar apical ASH. When compared with patients of typical ASH, patients with apical ASH demonstrated significantly greater cardiac size, left ventricular end-diastolic pressure, left atrial and left ventricular diameters and significantly lower percent fractional shortening. Atrial fibrillation, B bump of the mitral echogram and heart failure were more frequent in this subgroup of patients. Thus, apical ASH appeared to be a part of the morphologic spectrum of hypertrophic cardiomyopathy with ASH and to be a separate disease entity from apical hypertrophy previously described in Japan. Severely impaired diastolic performances associated with mild to moderately depressed systolic function of the left ventricle were the characteristic clinical features of the subgroup of patients with apical ASH.

Adolescent↗
PubMed1983

Increased left ventricular function as an adaptive response in vibration disease.

Vibration disease results from the long-term use of vibrating tools. Vibration, noise, and cold are stressors that impair the human body, inducing vibration disease. From echocardiographic methods, the left ventricular ejection fraction in vibration disease was 79 +/- 4%, a significantly higher value than that in control subjects (75 +/- 6%) (p less than 0.01). The increase in ejection fraction appeared to be due mainly to an increase in left ventricular end-diastolic dimension. The value of the ejection fraction was proportional to the activity of the autonomic nerves. The stroke volume index in patients with vibration disease was also significantly larger than that in the control subjects (p less than 0.001). Electrocardiograms revealed a significantly lower heart rate at rest and an increase in the ratio of T waves to R waves in precordial lead V6. These data suggest that the cardiovascular system in patients with vibration disease provides an adaptive response to the stressors.

Adaptation, Physiological↗
PubMed1983

Aneurysm of the left aortic sinus causing acute myocardial infarction.

A 30-year-old female had an acute myocardial infarction complicated by congestive heart failure. Angiography demonstrated an aneurysm in the area of the left aortic sinus. The aneurysm compressed and displaced the main trunk of the left coronary artery and the proximal portion of the left anterior descending artery. This aneurysm was considered to be the cause of the infarction. Aortic valve replacement and removal of the aneurysm were performed. Postoperative studies revealed good function of the replaced valve, good antegrade filling of the left coronary artery, and improved left ventricular function.

Adult↗
PubMed1983

Noninvasive assessment of the autonomic nervous tone in angina pectoris: an application of digital plethysmography with auditory stimuli.

To assess the relationship between autonomic nerve activity and the anginal attack, we examined the daily variation of the autonomic tones employing digital plethysmography with auditory stimuli, and also tested the daily variation of exercise capacity. Thirteen of 45 cases (28.9%) of spontaneous angina, excluding Prinzmetal's angina, complained of typical chest discomfort or pain especially in the morning. They manifested an augmented level of the autonomic nerve activity and positive stress testing. The remainder did not demonstrate these abnormal findings in the morning. For the 13 cases, calcium antagonists were given orally immediately after awakening. This resulted in the complete relief from chest discomfort or pain. These findings suggest that an autonomic imbalance plays an important role in the pathogenesis of this type of anginal attack. Thus, the estimation of the daily variation of autonomic nervous tone would be valuable for the diagnosis and treatment of angina pectoris.

Acoustic Stimulation↗
PubMed1983

[Left ventricular performance during exercise in patients with constant heart rate].

In order to evaluate the response of left ventricular (LV) performance in pacemaker implanted patients (PMI pts) with constant heart rate during exercise, supine bicycle ergometer exercise was performed simultaneously in 21 PMI pts and 4 age-matched normal subjects. PMI pts were classified into two groups; Group I consisted of 16 pts with relatively good physical work capacity (maximal load: male; 80 watt or more, female; 60 watt or more), and Group II consisted of 14 pts with depressed physical work capacity (maximal load: male; 60 watt or less, female; 40 watt or less). During dynamic exercise LV end-diastolic dimension (EDD), stroke excursion (SE), percent fractional shortening (%FS) and posterior wall velocity (PWV) showed a significant increase and LV end-systolic dimension (ESD) showed a significant decrease in Group I in contrast with Group II and normal subjects. Systolic blood pressure (sBP) and sBP/ESD ratio significantly increased in Group I and normal subjects than in Group II. Furthermore, resting cardiac parameters were more impaired in Group II than Group I. Thus, it was suggested that Group I adapted to exercise according to Frank-Starling mechanism (increased EDD) and contractility due to probably increasing circulatory catecholamine (increased PWV and decreased ESD). On the other hand, Group II did not adapt sufficiently to exercise because of the limitation of preload-reserve and contractility-reserve on exercise and also at rest.

Cardiac Output↗
PubMed1982

Analysis of organic acids in the hearts of patients with idiopathic cardiomyopathy by gas chromatography-mass spectrometry.

Organic acids in the hearts of patients with idiopathic cardiomyopathy, obtained by biopsy, were studied using gas chromatography--mass spectrometry. The profiling of organic acids was compared among eight cases of hypertrophic cardiomyopathy, three cases of congestive cardiomyopathy, and nine cases of other heart diseases, which were regarded as controls. It was found that almost all organic acids, especially deoxyaldonic acids of 2-deoxytetronic acid, 2,3-dideoxypentonic acid, 3-deoxy-2-C-(hydroxymethyl)tetronic acid, 3-deoxyerythropentonic acid and 3-deoxy-2-C-(hydroxymethyl)erythropentonic acid, were accumulated in large amounts in the heart in congestive cardiomyopathy, while these acids were decreased in hypertrophic cardiomyopathy. It was therefore suggested that deoxyaldonic acid metabolism in the heart in congestive cardiomyopathy is quite different from that in hypertrophic cardiomyopathy.

Carboxylic Acids↗