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Biomedical subjects

H Takezawa

Publications and source records attributed to H Takezawa.

At least 73 records · Page 4Linked to original sources
PubMed1985

[Quantitative analysis of aortic regurgitation using radionuclide phase analysis].

In this study, the clinical utility of phase analysis using gated blood pool scintigraphy to detect aortic regurgitation (AR) was assessed. The study population included 33 patients with AR documented by cineaortography, and 53 patients without AR diagnosed by clinical features and pulsed Doppler echocardiography or cineaortography. Gated blood pool images were stored in modified left anterior oblique views by the multiple gated method (28 frames per beat) after the in vivo labeling of erythrocytes using 25 mCi 99m-Tc. Amplitude was depressed at the subaortic region toward the apex in patients with AR, and occasionally the phase angle occurred earlier in the same region. This is because diastolic filling began earlier and stroke count was decreased more in the subaortic region than in other regions of the left ventricle in examining the regional time-activity curve. Based on this characteristic finding in the amplitude image, the specificity was 81% and the sensitivity was 79% in the diagnosis of AR. The degree of AR was estimated using the amplitude image as follows: grade 1, depression of amplitude localized to the subaortic region; grade 2, depression of amplitude detected from the subaortic region to the midportion of the left ventricle; grade 3, depression of amplitude detected beyond the midportion of the left ventricle. We compared results with those of the radionuclide (RI's classification) and angiographic methods (Sellers' classification) as to the severity of AR. AR could not be detected using the radionuclide method in all four patients with Sellers' grade 1, and in three of nine patients with Sellers' grade 2.(ABSTRACT TRUNCATED AT 250 WORDS)

Aortic Valve Insufficiency↗
PubMed1985

[Effects of nitroglycerin on left ventricular systolic, diastolic and regional myocardial function in patients with coronary artery disease].

To investigate the actions of nitroglycerin on left ventricular (LV) systolic and diastolic functions in coronary artery disease, high-fidelity LV pressures and LV biplane cineventriculograms were simultaneously made for 16 patients with old myocardial infarction before and 5-10 minutes after the sublingual administration of 0.6 mg of nitroglycerin. Before and after the nitroglycerin administration, heart rates were maintained constant at an average of 73 beats/min by right atrial pacing. LV volume and segmental wall shortening were derived from frame by frame (20 msec) analysis of LV biplane angiograms. The results were as follows: There were significant decreases in LV end-diastolic pressures (-44%) and volumes (-10%), mean arterial pressures (-12%) and LV systolic pressures (-16%), suggesting preload and afterload reductions. Global ejection fraction was significantly increased from 0.41 to 0.45, while cardiac output decreased significantly (-8%) because of a decrease in preload. Augmented ejection fraction was associated with increased shortening of the normal and hypokinetic segments. The dyskinetic segment remained unchanged. Thus, the degree of nitroglycerin-induced potentiation of LV regional contraction seemed related to the degree of regional myocardial ischemia and fibrosis. The time constant (T) of the LV pressure decay was slightly but significantly decreased, which may imply the possibility of improving LV relaxation using nitroglycerin. LV early filling significantly decreased as evidence by a fall in the peak filling rate (PFR) and the normalized PFR. The decrease of the PFR, however, may be related mainly to preload reduction by nitroglycerin. In 11 of 16 patients, there was a displacement of LV diastolic pressure-volume curves downward and to the left. The shift of the curves may be caused by the effects of ventricular interaction and/or the pericardium.

Cardiac Output↗
PubMed1985

[Detection of thrombi by 111In-oxine platelet scintigraphy].

For 52 patients with cardiac disease and 11 patients with vascular disease, In-111-oxine platelet scintigraphy was performed to assess its clinical usefulness for detecting thrombi. Using Hayashida's method, platelets were separated in 43 ml peripheral blood, washed and labeled with 1 mCi In-111-oxine. In addition to planar images in the anterior, 45 degrees left anterior oblique and left lateral views, single photon emission computed tomography (SPECT) was performed in some cases by rotating a dual gamma camera 24 and 72 hours after labeled platelet injection. The functions of platelet and coagulability were examined 36 hours after the injection of labeled platelets. Medical therapy was not changed during this study. Intracardiac thrombi were documented in 16 of 52 cases with cardiac disease and intravascular thrombi in 10 cases with vascular disease by angiography, CT and two-dimensional echocardiography. Positive images were obtained in 10 cases with cardiac disease and in eight cases with vascular disease by scintigraphy. Therefore, sensitivity, specificity, and overall accuracy were 63%, 100% and 88% in intracardiac thrombi; 80%, 100% and 82% in intravascular thrombi; and totally 69%, 100% and 87%, respectively. In the detection of intracardiac thrombi by scintigraphy, the sensitivity seemed to be lower and the specificity higher than those by other graphic studies. In 52 cases with cardiac disease, five out of six cases with false negative images had received antiplatelet and/or anticoagulant drugs, and in these cases, platelet and coagulation functions tended to be decreased compared with those of true positive cases or true negative cases. We conclude that positive images in scintigraphy indicate the existence of growing thrombi, and that In-111-oxine platelet scintigraphy has clinical usefulness, not only for detecting thrombi, but for estimating platelet activity and effect of medical therapy.

Blood Platelets↗
PubMed1985

[Left ventricular wall motion in ischemic heart disease quantitatively assessed by three-dimensional vectors of reference points in multi-directional two-dimensional echocardiography].

Left ventricular wall motion was analyzed in a spatial geometric manner assuming the quantitative vectors formed by the reference points' movement on two-dimensional echocardiogram in 58 normal subjects and 40 patients with ischemic heart disease. Long-axis, RAO-equivalent and short-axis views, termed sagittal, frontal, and horizontal planes, respectively, were visualized and two or three reference points were defined on each plane. The vectors of these points' movement were obtained from video-image tracings on each plane and systolic excursion and distortion angles of each pair of reference points were vectorially assessed. All vectors in myocardial infarction were directed towards the infarcted areas. Clockwise horizontal distortion of the left ventricle apex-to-base axis was observed in normal subjects, but it was slight (3.1 +/- 3.0 degrees: mean +/- SD at the papillary muscle horizontal section). However, larger horizontal distortion was observed in single coronary artery disease, which may lead to the erroneous segmental wall motion analysis using conventional cineangiography because of the overlap of the adjacent segments.

Adult↗
PubMed1985

[Diagnosis and estimation of mitral regurgitation by two-dimensional pulsed Doppler echocardiography].

The sensitivity and specificity of detecting and estimating mitral regurgitation were assessed by two-dimensional pulsed Doppler echocardiography (PDE) for 85 patients, aged 17 to 79 years. Mitral regurgitation was clinically diagnosed in 10 patients, and confirmed by angiography in 60 patients. Using real time two-dimensional images and M-mode displays, the sample volumes were taken at 36 sites, including the mitral ostium, the left atrium, and the left ventricular inflow tract. Doppler signals were analyzed by the FFT method and the diagnosis of mitral regurgitation was based on the systolic turbulence with a wide range of velocities greater than +/- 1 KHz. The results obtained were as follows: In 61 of 70 cases with mitral regurgitation, distinctly abnormal systolic Doppler signals were detected at the mitral ostium or within the left atrium, which were not recorded in the other 15 cases without angiocardiographically documented mitral regurgitation. The signals had either unidirectional or bidirectional wide frequency-band patterns, which were thought to indicate the systolic turbulence caused by mitral regurgitation, because these were occasionally recorded beyond the second heart sound, and increased with the administration of methoxamine and diminished after the inhalation of amyl nitrite. When mitral regurgitation was graded I degree, II degree, III degree and IV degree based on Sellers' classification, a PDE sensitivity for detecting mitral regurgitation was 78.1, 89.5, 100 and 100%, respectively. When approaches were divided by the parasternal long-axis, parasternal short-axis and apical long-axis, a PDE sensitivity was 80.0, 74.2, and 70.0%, respectively. The PDE was highly sensitive in diagnosing mitral regurgitation due to rheumatic valvular disease, mitral valve prolapse or ruptured chordae tendineae (sensitivity 100%), but it was less sensitive in ischemic heart disease, dilated cardiomyopathy or hypertrophic cardiomyopathy. Nine cases in which mitral regurgitation was missed by PDE, mitral regurgitation was mild (seven cases: Sellers I degree, two cases: Sellers II degree). No false positives were found. The overall sensitivity of the PDE was 87.1%, with a specificity of 100%, a diagnostic accuracy of 89.4%, and a predictive value of 100%. By displaying the distribution of systolic turbulence on parasternal or apical long-axis image (flow mapping), the direction and the extent of the regurgitant flow in the left atrium were clearly visualized. The localization of the regurgitant flow at the mitral ostium was visualized in parasternal short-axis images by the flow mapping method.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1983

Effects of diltiazem on cardiovascular responses during exercise in systemic hypertension and comparison with propranolol.

Sixteen patients with uncomplicated systemic hypertension were treated with placebo, diltiazem (180 mg/day) and propranolol (60 mg/day) for 1 month each. Each patient performed multistage symptom-limited treadmill exercise tests during each period of administration. There was no significant difference in maximal exercise duration between placebo, diltiazem and propranolol. Diltiazem significantly decreased both systolic and diastolic blood pressure (BP) and heart rate at rest, during submaximal exercise at the same work load and maximal exercise. Propranolol produced similar changes in systemic BP and heart rate at rest and during exercise. However, the reductions in systolic BP, heart rate and pressure-rate product with diltiazem during exercise were smaller than those with propranolol at small doses, suggesting that diltiazem in its usual therapeutic dose was almost devoid of beta-blocking activity. Thus, diltiazem may be of benefit to hypertensive patients because it reduces systemic BP even during exercise. It is particularly useful when systemic hypertension occurs in association with coronary artery disease because of its effects of coronary artery dilatation and heart rate reduction.

Adult↗
PubMed1983

Natural history and prognosis of ischemic heart disease.

Forty-four cases with myocardial rupture (33 with free wall rupture, 9 with interventricular septal perforation and 2 with papillary muscle rupture), all of which were ascertained by autopsy and/or at surgery, were analyzed. When the following 7 risk factors were actively managed in the acute stage of myocardial infarction, the incidence of myocardial rupture was significantly reduced: a) high blood pressure on admission, b) physical and emotional instability, c) recurrent chest pain, d) aged females, e) no history of angina or myocardial infarction, f) large myocardial infarction on ECG and g) the first 10 days after the attack of myocardial infarction. If cardiogenic shock occurs, surgery should be performed as soon as possible; if not, it should be delayed 3 weeks. The natural history of ischemic heart disease was analyzed in 400 medically-treated patients with significant coronary artery disease. They had been followed up continuously and periodically for more than one year. The prognosis of the patients with 3-vessel disease or left main trunk disease, those with poor left ventricular function (EF less than 30%) and of old age (greater than or equal to 60) and those who had a history of ischemic heart disease was poor. Follow-up study was done in 30 patients with variant angina. They often had life-threatening arrhythmias during attacks (8 ventricular tachycardia or ventricular fibrillation, 8 serious bradyarrhythmia). All patients with variant angina should be treated medically at first, and only patients with organic coronary artery disease and chest pain on effort in spite of the medical treatment should be considered as candidates for AC bypass surgery.

Aged↗
PubMed1983

[Echocardiographic evaluation of cardiac involvement in patients with chronic alcoholism].

Since chronic alcoholics may accompany with asymmetric septal hypertrophy (ASH), the purpose of this study was to find the difference in cardiac function of such cases from the patients with hypertrophic cardiomyopathy. Ninety-seven alcoholic patients (59 non-cirrhotics and 38 cirrhotics) were examined by non-invasive methods including two-dimensional echocardiography and dye dilution method, and these data were compared with those of 16 normal subjects and 26 patients with hypertrophic cardiomyopathy. The results were as follows: Interventricular septal thickness of more than 12 mm was observed in 25.4% of the non-cirrhotics and 28.9% of the cirrhotics. Furthermore, ASH was present in 23.7% of the former and 18.4% of the latter, when ASH was defined as the septal to posterior wall ratio greater than 1.3 with the interventricular septal thickness greater than or equal to 12 mm. In 66.7% of the chronic alcoholics with ASH, hypertrophy was predominantly located in the septum, however 53.8% of the patients with hypertrophic cardiomyopathy had ASH in association with the thickened left ventricular posterior wall. In 21 chronic alcoholics with ASH, ejection indices such as ejection fraction and mean VCF were moderately increased, although scattered widely, as compared with those of the normal subjects. Latent reduced ventricular function compensated by sympathetic overactivity was postulated based on left ventricular performance maintained normally as indicated by a decrease of end-systolic wall stress. Several possible factors including hypertension, catecholamine and metabolic abnormalities were analyzed to explain the genesis of ASH in chronic alcoholics, but the true etiology remained unknown. In conclusion, ASH associated with chronic alcoholism is a type characteristic of alcoholic cardiomyopathy, and seems to belong to a clinical entity different from hypertrophic cardiomyopathy from a standpoint of clinical symptoms, age and the pattern of left ventricular hypertrophy.

Adolescent↗