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Biomedical subjects

H Toshima

Publications and source records attributed to H Toshima.

At least 127 records · Page 7Linked to original sources
PubMed1986

[Left ventricular function in hypertrophic cardiomyopathy: a Tc-99m radionuclide angiographic study during exercise].

Hypertrophic cardiomyopathy (HCM) generally shows increased systolic function of the left ventricle at rest, although patients with HCM often have decreased exercise tolerance and develop dyspnea or chest pain. The present study was to investigate of left ventricular (LV) function during exercise in 26 patients with HCM using Tc-99m equilibrium angiocardiography, and to elucidate the mechanism of impaired functional reserve during exercise. Controls consisted of 11 normal volunteers and 12 patients with chest pain syndrome who had no abnormality on coronary arteriography or left ventriculography. In patients with HCM, LV ejection fraction decreased from 65 +/- 8 (mean +/- SD)% at rest to 59 +/- 18% at peak exercise, in contrast to an increase among controls (from 56 +/- 9% to 64 +/- 9%). As compared with resting values, cardiac output increased to 168 +/- 24% at peak exercise in HCM, but the increase was significantly less than that in controls (215 +/- 47%). Stroke volume decreased gradually to 83 +/- 16% during exercise in HCM, while it increased to 114 +/- 10% at an exercise level of half intensity, and it decreased slightly to 106 +/- 16% at peak exercise. LV end-systolic volume decreased among controls to 78 +/- 27% at peak exercise, but remained unchanged in HCM (118 +/- 58%). An increase in peak ejection rate at peak exercise was less in HCM than in controls (143 +/- 26% vs 170 +/- 42%). No significant differences were observed between the two groups concerning changes in indices of LV diastolic function including LV end-diastolic volume, peak filling rate or 1/3 filling rate during exercise. In the analysis of LV function curves, pulmonary arterial diastolic pressure increased to a greater extent in HCM than in controls (19 +/- 6 mmHg vs 11 +/- 6 mmHg); whereas, an increase in the stroke work index was less in HCM (80 +/- 26 g.m/m2/beat vs 121 +/- 21 g.m/m2/beat) at peak exercise. Thus, the LV function curve shifted downward and to the right in patients with HCM. The above findings indicate that LV functional reserve during exercise is impaired, especially as to systolic function in patients with HCM, while deterioration of diastolic function may be partly compromised by elevated filling pressure.

Cardiomyopathy, Hypertrophic↗
PubMed1986

Lymphocyte subsets in patients with dilated cardiomyopathy and perimyocarditis.

Lymphocyte subsets were analyzed in patients with DCM, arrhythmias following influenza symptoms and acute perimyocarditis, respectively by an automated laser flow cytometry system with the use of monoclonal antibodies. A lower percentage of OKT8+ cells and a high OKT4/OKT8 ratio were found in the DCM and arrhythmias groups. No phenotypic abnormalities in the lymphocyte subsets were found in patients with acute perimyocarditis who were favorably progressing in clinical features. The results suggest that an immunological disturbance thought to play a part of the pathogenesis of DCM or heart failure may cause the abnormality of lymphocyte subsets.

Adult↗
PubMed1986

[Factors related to the pathogenesis and clinicopathological findings in dilated cardiomyopathy].

It has been suggested that various factors related to dilated cardiomyopathy (DCM) may concern its onset and/or progression. This study was performed to clarify whether these factors contribute different clinical and morphological characteristics. Subjects were 39 patients with DCM, consisting of 28 men and 11 women whose average age was 46.5 years. The subjects were divided into five groups; namely, the Familial, Myocarditic, Alcoholic, Hypertensive, and Unknown Groups. Clinical parameters including past history, blood pressure, chest radiographs, electrocardiograms, echocardiograms and left ventricular end-diastolic pressures (LVEDP) were evaluated. Morphology of right ventricular endomyocardial biopsy specimens was evaluated in terms of hypertrophy, disarrangement, fibrosis, degeneration, endocardial thickening, interstitial changes, and types of fibrosis. The results were as follows: The Familial Group was characterized by the onset at younger age, highly elevated LVEDP, a lack of myocardial hypertrophy, and proliferation of small vessels. The Myocarditic Group was characterized by the onset at young age, elevated LVEDP, severe fibrosis showing a plexiform pattern in more than half of the patients, cellular disarrangement, and cellular infiltration. The Alcoholic Group showed possible improvement clinically and fatty infiltration in half of the patients. The Hypertensive Group was characterized by high prevalence of a previous alcohol intake, high diastolic blood pressure on admission, clinical improvement, and myocardial hypertrophy with a mild degree of perivascular fibrosis. From these findings, it is thought that each factor related to DCM offers a somewhat different clinical and histological profiles and that these factors may play an important role in the onset and/or progression of DCM. Furthermore, it is highly suggestive that specific therapy against these factors or the removal of these factors is especially necessary for favorable long-term prognosis of DCM.

Adolescent↗
PubMed1985

Research on cardiomyopathy in Japan.

Many experimental and clinical studies have been performed in Japan, since the Idiopathic Cardiomyopathy Research Committee sponsored by the Ministry of Health and Welfare of Japan was organized in 1974. Much interest has been focused on myocarditis as a possible pathogenesis of dilated cardiomyopathy and extensive experimental studies have been performed as well as histopathologic assessment at autopsy or biopsy. In the clinical field, suspected cases of myocarditis are not uncommon, but determination of etiological viruses is quite difficult in most patients except at the acute stage. Therefore, endomyocardial biopsy has been recently introduced in more than 13 institutes in Japan in an effort to obtain more accurate diagnosis. In 1983, the Idiopathic Cardiomyopathy Research Committee performed a study on the prognosis of cardiomyopathy in 1255 patients (786 hypertrophic and 469 dilated). The prognosis of dilated cardiomyopathy was poor, with a 5-year survival rate of only 54.3%. This figure contrasted with the better prognosis in those with hypertrophic cardiomyopathy (92%).

Adolescent↗
PubMed1985

Termination of ventricular tachycardia by an implantable atrial pacemaker and external pacemaker activator.

An atrial pacemaker was implanted in a patient who had dilated cardiomyopathy, sinus node dysfunction, and drug-resistant ventricular tachycardia (VT). VT episodes were terminated by atrial overdrive pacing using an implanted pacemaker and a newly developed hand-held external programmer/transmitter. Although successful cases of termination of intractable VT by ventricular pacing have recently been reported, the ventricular method might increase the risk of accelerating VT. Atrial overdrive pacing is a safer method since it minimizes the possibility of tachycardia acceleration and, combined with antiarrhythmic drugs, it appeared to be a unique and useful approach for the treatment of drug-resistant VT.

Adult↗
PubMed1985

Medical management of infective endocarditis; limitations and indication for surgery.

Problems and limitations of medical management for infective endocarditis were studied and surgical indications were discussed based on the retrospective analysis of 55 episodes. Since perioperative complications still occur during highly active infection, antibiotic treatment was suggested as the primary management. Intractable or progressing heart failure appeared to be a definite indication for emergency surgery, but medical therapy was recommended for mild to moderate heart failure. For uncontrolled infection of more than one month duration despite the best available antibiotics, surgical debridement of the infected tissue was indicated. Occurrence of peripheral or fatal emboli was difficult to predict from clinical features and echocardiogram and therefore presented a therapeutic dilemma. Since major or fatal emboli frequently occurred during highly active infection, early initiation of effective antibiotic therapy was considered to be of primary importance. Demonstration of vegetation by echocardiography alone did not seem to justify urgent surgery. In addition, disseminated intravascular coagulation appeared to be a serious complication and thus sedimentation rate should be followed carefully. In the healed stage, prophylactic surgery seemed unnecessary for prevention of recurrent infection or embolization, as they were relatively rare.

Adult↗
PubMed1985

Serum N-acetyl-beta-D-glucosaminidase activity in a large population--a useful index of cardiovascular impairment.

Serum N-acetyl-beta-D-glucosaminidase (NAG) levels were measured in 1080 residents in Tanushimaru, Fukuoka, aged 20 to 84 years old, during a periodical epidemiological survey performed in 1982. Thirteen pregnant women were excluded from this study. Serum NAG levels showed an increase with age, but were not different between sexes. We found high serum NAG values in those with high blood pressure, high serum total cholesterol, low serum HDL-cholesterol, or reduced creatinine clearance rate, and women with high serum uric acid, increased skinfold thickness, or high hematocrit. Multiple regression equation was as follows: NAG = 3.53 + 0.07 (age) + 0.14 (hematocrit) + 0.03 (total skinfold thickness) + 0.04 (systolic blood pressure) - 0.03 (HDL-cholesterol) - 0.04 (mean blood pressure) - 0.01 (creatinine clearance). The multiple correlation coefficient was 0.37 (F = 24.4). We suggest that NAG may be a useful index in screening cardiovascular impairment and for cardiovascular risk factors.

Acetylglucosaminidase↗
PubMed1985

Increased cardiovascular response to epinephrine in hypertrophic cardiomyopathy.

To study the role of catecholamines in the pathogenesis of hypertrophic cardiomyopathy (HCM), hemodynamic responses to low and high dose infusions of epinephrine (0.037 and 0.074 micrograms/Kg/min) were compared between 21 patients with nonobstructive HCM and 21 healthy controls, matched for age and sex. During low dose infusion, patients with HCM showed significantly greater responses (p less than 0.05) than controls in echocardiographic left ventricular (LV) end-systolic dimension (-8 +/- 1% vs -4 +/- 1%, mean +/- SEM), fractional shortening (12 +/- 2% vs 7 +/- 1%) and peak systolic velocity of the LV posterior wall (32 +/- 5% vs 15 +/- 4%), but the differences disappeared during high dose infusion. Thus, patients with HCM started to respond to epinephrine earlier than controls and seemed to have an increased sensitivity of beta-adrenergic receptors in the cardiovascular system. As the augmented responses were more evident in younger patients (less than 35 years) who manifested frequent familial occurrences of HCM, the increased sensitivity to catecholamine was postulated to be genetically determined and to be related to the abnormal myocardial hypertrophy of HCM.

Adolescent↗
PubMed1985

An advanced form of familial hypertrophic cardiomyopathy showing massive myocardial fibrosis with intramural small arterial thickening. An autopsy case.

An autopsy case of an advanced form of hypertrophic cardiomyopathy (HCM) showing marked fibrosis with intramural small arterial abnormalities is presented in this report. A 52-year-old woman, who had a positive family history of HCM, was admitted because of palpitations. The chest roentgenogram showed a mildly enlarged cardiac silhouette and the electrocardiogram revealed abnormal Q waves and R wave and T wave abnormalities. The echocardiogram revealed hypokinesis with thinning of the interventricular septum and the anterior wall of the left ventricle. Percutaneous right ventricular endomyocardial biopsies demonstrated moderate interstitial fibrosis with small arterial thickening. At necropsy, the anterior and posterior walls of the left ventricle and the interventricular septum were markedly thinned and showed a massive transmural fibrosis. Moreover, the intramural small arteries, 50-300 microns in diameter, showed marked intimal and medial hypertrophy with proliferation of elastic fibers and smooth muscle cells. From these findings, it is suggested that this was originally a case of HCM which progressed to a decompensated stage because of the abnormal intramural small arteries. The significance of small arterial lesions in HCM is discussed.

Cardiomyopathy, Hypertrophic↗
PubMed1985

[Left ventricular peak filling velocity and its relevant factors in hypertrophic hearts].

To evaluate the relevant factors of left ventricular peak filling velocity, M-mode echocardiograms showing the left ventricular cavity were recorded and digitized for 81 patients with hypertrophic hearts (HTH) due to hypertensive heart disease (HHD, n = 30), hypertrophic cardiomyopathy (HCM, n = 25), aortic valve stenosis (AS, n = 9), and HHD and HCM with congestive heart failure (HHD and HCM with CHF, n = 17). Peak rates of increase or decrease in dimension (Vf and Ve, respectively) and peak values of instantaneous circumferential fiber lengthening and shortening velocities (Vf/D and Ve/D, respectively) were determined by computer analysis of left ventricular internal dimensions. Systolic excursion (SE), percent fractional shortening (%FS), mean circumferential fiber shortening velocity (mVcf), thickness of the interventricular septum and posterior wall at end-diastole and the sum of them (WThivs, WThpw, and WThivs + pw, respectively) were also calculated. Their variables were compared with those of normal subjects (n = 24). The results obtained were as follows: Systolic functions in HTH without CHF were similar to those of the normal subjects, but Vf and Vf/D were significantly decreased. Differences in Vf and Vf/D between various HTH without CHF were not significant. In AS and HTH with CHF, Vf and Vf/D were significantly decreased together with systolic function. Vf correlated significantly with WThivs + pw, SE, Ve, and WThivs, and Vf/D with %FS, SE, Ve/D, and Ve.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

[Dysfunction of Carpentier-Edwards porcine mitral bioprosthesis causing a musical systolic murmur: a report of two cases].

Two patients with disruption of Carpentier-Edwards porcine mitral bioprosthesis presenting with a musical systolic murmur were reported. The two patients noted sudden development of a loud musical murmur 4 (Case 1) and 6.5 (Case 2) years after surgery. Case 1 had associated heart failure. Phonocardiogram disclosed a loud musical systolic murmur with regular vibrations at 230-240 Hz in Case 1, and 250-260 Hz in Case 2. In Case 1, echocardiography demonstrated fine fluttering of the porcine mitral valve at the same frequency as the murmur. Doppler echocardiography revealed characteristic Doppler signals from the porcine valves at a frequency of 250-300 Hz with several harmonics above and below the baseline. In addition, in Case 2, similar Doppler signals were obtained from the aortic walls, ventricular septum and posterior wall of the left ventricle. In both cases, left ventriculograms demonstrated grade 3 mitral regurgitation without paravalvular leakage, and at surgery, the porcine bioprosthesis showed a tear in one of markedly thinned cusps, without evidence of calcification. It was considered that a torn cusp was the source of the murmur, and this, in association with the resonance of the entire heart, produced the loud musical murmur. Thus, a musical systolic murmur is suggested to be one of important signs of dysfunction of porcine bioprosthesis.

Adult↗
PubMed1985

[Apical hypertrophy and its genetic and acquired factors].

Although apical hypertrophy is characterized by a spade-like configuration of the left ventricle and giant negative T waves on electrocardiograms, the identity of apical hypertrophy in the disease spectrum of hypertrophic cardiomyopathy (HCM) is not fully established. The present study compared the demography, familial occurrence, and acquired factors of 43 patients who had apical hypertrophy with those of 104 patients who had asymmetric septal hypertrophy (ASH). Demographically, apical hypertrophy occurred predominantly in middle-aged males (86%). Family surveys showed that 13% of siblings of apical hypertrophy were affected, significantly less than in obstructive (31%) or non-obstructive (29%) HCM with ASH. Thirty-eight percent of siblings of ASH patients less than 35 years of age were affected, with a male/female ratio of 4/5, suggesting an autosomal dominant inheritance. The acquired factors associated with apical hypertrophy were assessed in a case-control study. Relative risk (odds ratio) of the condition was 3.46 (p less than 0.05) in those with histories of hypertension, and increased further to 8.09 (p less than 0.001) in those who were often hypertensive according to their physician's evaluations. Thus a strong association of hypertension with apical hypertrophy was suggested. However, hypertension in this condition was usually mild and labile, the blood pressure reverted to the normal range within several days of hospital admission, implying that transient hypertension during daily activity is associated with apical hypertrophy. Therefore, blood pressure response during exercise stress tests of 25 patients with apical hypertrophy was compared with that of age- and sex-matched controls. Slopes of linear regression between systolic blood pressure and heart rate and oxygen consumption during exercise, were used as indices of blood pressure response. They were significantly greater in apical hypertrophy than in the controls (1.2 +/- 0.4 vs 0.9 +/- 0.3, p less than 0.01 and 4.3 +/- 1.7 vs 2.8 +/- 0.8, p less than 0.001). This trend was observed even in patients without histories of hypertension. These findings suggested that apical hypertrophy has an inheritance pattern different from that of ASH, and has a possible association with acquired factors such as hypertension. Therefore, apical hypertrophy seemed to be a disease entity distinct from HCM with ASH, though it might be included in the disease spectrum of HCM.

Adult↗