PubMed Health⌕ Search

Biomedical subjects

M Shukuya

Publications and source records attributed to M Shukuya.

At least 19 recordsLinked to original sources
PubMed1993

[Respiratory changes in the blood flow pattern of the superior vena cava in patients with chronic obstructive pulmonary diseases].

Blood flow patterns in the superior vena cava (SVC) obtained from 20 elderly cases of COPD (aged 60-81) were compared with those from 24 elderly normal subjects (aged 61-80). The peak flow velocity and duration of two major antegrade flows during systole and diastole (S & D wave) were both qualitatively and quantitatively assessed with pulsed Doppler echocardiography. While peak flow velocity and duration of the S and D waves increased during inspiration and decreased during expiration in normal subjects, respiratory variations of these antegrade waves were extremely greater in patients with COPD with augmented and/or fused antegrade waves during inspiration, and there decrease was associated with an upward shift above the zero level during expiration. The duration of the D wave was significantly longer in COPD patients than in normal subjects and also revealed a significantly positive correlation with FEV1.0%. These findings suggest that SVC flow pattern is useful for the assessment of early right ventricular dysfunction in patients with COPD, but further clinical studies are required to confirm this thesis.

Aged↗
PubMed1991

[Hypertrophic cardiomyopathy associated with anomalous origin of the left coronary artery from the right sinus of valsalva].

A 47 year old Japanese male with exertional shortness of breath, cardiac murmur and ECG abnormalities was examined with invasive and non-invasive cardiology techniques that disclosed hypertrophic cardiomyopathy, and the anomalous origin of the left coronary artery from the right sinus of Valsalva. Although both situations have been known to cause sudden death especially under a state of strenuous physical stress, his exercise thallium scintigraphy performed with the symptom limited maximal test did not uncover any significant myocardial ischemia or exercise induced malignant arrhythmias. This is a very rare association of two distinctly identified clinical situations highly indicative of a likelihood of sudden cardiac death. Therefore, careful observation is needed.

Cardiac Catheterization↗
PubMed1991

[Charcot-Marie-Tooth disease associated with dilated cardiomyopathy: an autopsy case report].

This is a clinical report of a rare case of Charcot-Marie-Tooth disease associated with dilated cardiomyopathy. A seventy-seven-year-old Japanese male first visited our outpatient clinic with a ten-year history of muscular weakness in his bilateral lower extremities and gait disturbance characterized by classical features of peroneal muscular atrophy and inverted champagne bottle legs. Biopsy findings of the m. quadriceps femoris and the n. gastrocnemius revealed clustered atrophy of myofibrils and segmental demyelinization mingled with remyelinization. Because of his other problem of dilated cardiomyopathy, he had been treated with salt restriction, digitalis, diuretics and vasodilators, until his third hospitalization, when he developed terminal stage of severe congestive heart failure. Despite our intensive cardiac care, the patient died because of profound pump failure. Autopsy findings disclosed a remarkably dilated left ventricular chamber and an increased total heart weight of 600 grams. Grossly, the cross sectional view of the left ventricle revealed diffuse, but not homogenous fibrosis that was most prominent in the posterior wall. On light microscopic examination, the left ventricular myocardium revealed diffusely scattered muscular degeneration interlaced with fibrosis. Although large epicardial coronary arteries revealed only mild intimal atheromatous thickening, most of the small intramuscular coronary arteries were free from atherosclerosis. Neither diabetic nor amyloid lesions could be detected. It has been well known that cardiomyopathy is often associated with various forms of muscular dystrophy and Friedreich's ataxia.(ABSTRACT TRUNCATED AT 250 WORDS)

Atrophy↗
PubMed1990

Physical training of the patients with coronary heart disease: noninvasive strategies for the evaluation of its effects on the oxygentransport system and myocardial ischemia.

To clarify the central effects of physical training on patients with coronary heart disease, 81 subjects were selected for the present study. Evaluations of the oxygen transport system function were performed according to the definition proposed by Bruce and others in terms of FAI (functional aerobic impairment), LVI (left ventricular impairment) or MRI (myocardial reserve impairment), CRI (chronotropic reserve impairment) and PCI (peripheral circulatory impairment). Remarkable improvement in left ventricular impairment was found in those patients with single vessel disease or those who experienced disappearance of chest pain after the completion of the program. In another series of study on myocardial perfusion performed on 11 patients with coronary heart disease, improvement in ischemia was also demonstrated in 7 of 8 patients who revealed redistribution pattern in 201TL exercise stress images specifying myocardial ischemia. In conclusion, exercise training could induce improvements not only the left ventricular functions characterized by increased maximal pressure rate product and maximal heart rate, but also in myocardial ischemia. Further studies are needed to specify its effects, since natural progression or regression of the disease process itself may influence the results.

Coronary Disease↗
PubMed1989

[Pacemaker catheter induced systolic murmurs in two patients].

Although extracardiac sounds secondary to cardiac pacing have been well known, the murmurs originating in the heart after permanent pacemaker implantation and then disappearance after exchanging a temporary to permanent lead have rarely been reported. In this paper, two patients revealing a musical systolic murmur after placement of a transvenous endocardial pacemaker in the absence of any complications were documented. Case 1: A 43-year-old man with episodes of dizziness and brady-tachycardiac atrial fibrillation. Immediately after the implantation of a temporary transvenous right ventricular pacemaker, a high-pitched systolic musical murmur was heard at the lower left sternal border. No murmur was however gullible after a permanent pacemaker implantation in this case. Case 2 was a 83-year-old female with coronary heart disease associated with sick sinus syndrome to whom a permanent transvenous right ventricular pacemaker was inserted. A musical systolic murmur occurring immediately after the procedure was best audible at the apex. Although numerous papers concerning the mechanisms of these cardiac murmurs have been reported without reaching conclusive explanations, our data based on two cases examined with Doppler echocardiography did not support the idea of tricuspid regurgitation as one of causative factors. In the first case, this murmur appeared only a temporary pacing was performed and disappeared after implantation of a permanent pacemaker lead. On the contrary, however, the 2nd case revealed after the implantation of the permanent pacemaker with a relatively rigid bipolar lead. It is concluded that these murmurs might be produced by vibrations caused by the pacing catheters and physical properties could be related the mechanism of this phenomenon.

Adult↗
PubMed1987

[Dynamic function studies with positron computed tomography: measurements of regional myocardial blood flow in hypertrophic cardiomyopathy].

A major attribute of positron computed tomography (PCT) is its ability to dynamically measure physiologic processes of the heart. However, quantitative data acquisition and analysis are limited by three major problems: bidirectional activity-cross contamination between the myocardium and the blood, the partial volume effect, and the lower temporal resolution of PCT devices. In the present study, we performed serial six-second PCT scans (fast dynamic study) using 13N-ammonia, and evaluated measurements of regional myocardial blood flow. Six patients with hypertrophic cardiomyopathy (HCM) and five normal subjects were observed. 13N ammonia (4.2-13.0 mCi) was intravenously injected as a bolus, and serial six-second PCT scans were initiated at the times of the tracer injections. The results were as follows: 1. Initial passage of the tracer through the right and left sides of the heart were observed with serial six-second images. 2. In patients with HCM, Myocardial 13N activity was determined by assigning a region of interest (ROI) over the myocardium of greater than 25 mm wall thickness as measured by contrast enhanced CT. In these ROIs, corrections for the partial volume effect and spillover of radioactivity from the blood were not necessary. Arterial 13N activity was determined noninvasively by assigning a ROI over the left atrium. 3. The temporal relationships between the arterial input function and myocardial tracer concentrations were demonstrated. Arterial 13N activity was greatest in the second or third frame, and it rapidly declined thereafter. Myocardial 13N activity increased rapidly, reaching a plateau from the sixth to the ninth frame.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

Fast dynamic study in cardiac positron CT using 13N-ammonia in man.

Fast dynamic studies with positron computed tomography (PCT) of the heart have been relatively few because of the technical limitations of prevalently used PCT devices. In the present study, we used a high-sensitivity, whole-body multislice PCT device (POSITOLOGICA-II) and performed serial 6-s PCT scans after the intravenous bolus injection of 13N-ammonia in 15 cardiac patients and 5 normal subjects. On the first image (0-6 s), 13N activity was primarily in the right atrium and ventricle. On the third image (12-18 s), it was primarily in the left atrium and ventricle. These blood-pool images permit evaluation of size and configuration of ventricles and atria in cardiac patients and normal subjects. Clearance of 13N activity in the blood pools and lungs occurred primarily during the 1st min. Thereafter, the myocardial images were delineated. In patients with heart failure, delayed clearance of the tracer from the blood pools and lungs was observed. The results indicate that initial passage of the tracer through the heart can be observed with the use of fast dynamic PCT.

Adult↗
PubMed1985

[Magnetic resonance imaging of cardiovascular diseases: advantages of coronal and sagittal planes].

The usefulness of coronal and sagittal sections of the cardiovascular system by magnetic resonance imaging was evaluated. Coronal, sagittal and transverse spin echo scans using ECG-non-gating and gating during systole and diastole were performed for five normal volunteers, 91 with heart diseases (25 valvular disease, 28 ischemic heart disease, 14 cardiomyopathies, 14 congenital malformations, four pericardial diseases, and six others) and 32 patients with aortic abnormalities (17 aneurysms, 10 dissections and five others) using a 2.5 KGauss unit. Cardiac gating necessitated six to eight min per scan, but it was mandatory to obtain clear images of the details. On the other hand, in most of the aortic abnormalities, diagnostic images were obtained by the ECG-non-gating technique which required only about 2.5 min per scan. Coronal and sagittal sections were useful for estimating the entire shape and size of each cardiac chamber and intracardiac thrombi, the extent of postinfarctional wall thinning and cardiac aneurysms, and hypertrophy or narrowing of both the ventricular outflow tracts and apex. These planes were particularly useful, and more contributory than transverse planes for detecting inferior myocardial damage such as infarction. A few coronal and sagittal scans were sufficient to diagnose extensive lesions of the aorta, such as atherosclerosis, dissections and the aortitis syndrome. Local lesions such as coarctation, supravalvular aortic stenosis, annulo-aortic ectasia and aneurysm, especially those originating in the inferior wall of the aortic arch were easily discovered. Since the main arteries, such as the innominate, left common carotid, left subclavian and renal arteries, were clearly demonstrated by coronal images, coronal scans were considered more useful than transverse ones for observing the relationship between these arteries and dissections or aneurysms of the arch and of the abdominal aorta.

Coronary Disease↗
PubMed1985

[Positron computed tomography for myocardial uptake of N-13 ammonia in patients with hypertrophic cardiomyopathy: a preliminary study].

In the present study, positron computed tomography (PCT) was used to evaluate the myocardial uptake of N-13 ammonia in patients with hypertrophic cardiomyopathy (HCM). Eight subjects including two normal persons, four patients with HCM, and two with old myocardial infarction (OMI) were selected for the study. N-13 ammonia was administered intravenously as a bolus and, commencing with the tracer injection, serial 30-second PCT scans were performed. The results were summarized as follows: The first scan exhibiting cardiac blood pool images revealed a reduced left ventricular cavity in the HCM subjects. After clearance of N-13 from the cardiopulmonary vasculature, the left ventricular myocardium was clearly visualized and an increased myocardial mass with characteristic morphology was demonstrated in the HCM subjects. Detailed analysis of the time-activity curves of the blood pool and myocardium derived from these serial scan images disclosed two uptake phases in the uptake mode of N-13 ammonia. In the initial phase within three minutes, the myocardial uptake of N-13 was rapid in the normal and OMI subjects, whereas its significant delay was observed in the HCM subjects. This may reflect an abnormal initial extraction of N-13 ammonia in the HCM patients compared with the other subjects. Subsequently, in the second phase, which was characterized by a gradual increase of N-13 in the myocardium, the HCM subjects revealed higher uptake ratios than did the others. This may indicate an increased extraction of metabolites of N-13 ammonia during the second phase. These preliminary results underscore the usefulness of dynamic PCT with N-13 ammonia for the assessment of HCM.

Adult↗
PubMed1984

Dynamics of heart failure in ventricular aneurysm studied by a physical model.

Utilizing a model of ventricular aneurysm of varying size and wall thickness produced on a layered thin-walled elastic sac (original ventricle), the static pressure-volume relationships of the ventricle-aneurysm system were determined. Progressive increase in the size of an aneurysm lowered the intracavitary pressure obtained in the system. Decreasing the wall thickness of an aneurysm also decreased the developing pressure in the system. The results indicate that intraventricular pressure to be developed, being common to both ventricle and aneurysm, largely depends on the volume of the remaining intact myocardium of the original ventricle and the mechanical characteristics of the aneurysm, i.e., size, elasticity and wall thickness of the aneurysm. The maximum pressure generated in a thin-walled aneurysm is directly proportional to the wall volume and Young's modulus, and inversely to the unstressed volume (initial radius) of the aneurysmal sac.

Blood Pressure↗
PubMed1984

[Echocardiographic manifestations of postinfarction perforation with extensive dissection of the interventricular septum: report of an autopsied case].

This is a report of the echocardiographic features of postinfarction perforation associated with dissection of the interventricular septum (IVS) in a 61-year-old woman. She had acute myocardial infarction and was admitted to a nearby hospital, and later admitted to our CCU because hemodynamic deterioration. On admission, she was somnolent and hypotensive (90/64 mmHg), with sinus tachycardia, marked cyanosis, and peripheral edema. On auscultation there were a harsh holosystolic murmur over the LLSB and moist rales in both lung fields. An ECG revealed extensive anterior and inferior infarctions. Catheterization data confirmed O2 step-up in the right ventricle. Two-dimensional echocardiograms demonstrated extensive dissection of the IVS characterized by an echo-free lumen extending from the apex to the cardiac base in the long-axis and partly reaching the left ventricular free wall in the short-axis with the concomitant paradoxical movement of the IVS. Autopsy disclosed marked hemorrhagic infarction and extensive dissection of the IVS forming a lumen (5 X 5.5 X 2 cm3) corresponding exactly to the echocardiographic free space. In addition, a shunt between the right and left ventricles was confirmed by the presence of two perforations near the apex on the right and left sides of the IVS, whose diameters were 6 and 10 mm, respectively.

Cardiomyopathies↗
PubMed1983

[Positron computed tomography for the assessment of myocardial infarction].

Positron computed tomography (PCT) was performed on 2 normal subjects and 3 patients with myocardial infarction. The PCT device "Positologica-II" developed at the National Institute of Radiological Science Japan was used in this study (Fig. 1). This is a whole body positron CT consisting of 3 detector rings that provide 5 sliced images simultaneously. The radiopharmaceutical 13N-ammonia (13NH3) synthesized by the cyclotron at the institute was used as an indicator of myocardial blood flow. Immediately after the intravenous administration of 13NH3, five serial 1-min PCT scans were performed with 3 additional scans that provided 15 static images spaced 6 mm apart. Cardiac blood pool images were obtained from the first scan. A patient with extensive anterior myocardial infarction revealed an outward bulging of the blood pool compatible with aneurysmal formation (Fig. 2). Three additional late scans provided high quality cross-sectional images of the distribution of 13N in the left ventricular myocardium. Although 13N distribution in myocardium was uniform in normal subjects (Figs. 3 & 4), the patients with myocardial infarction revealed defects in the accumulation of 13N at the sites corresponding to the infarction (Figs. 5, 6, 7 & 8). The conclusions are as follows: (1) serial PCT scans with 13NH3 provide cardiac blood pool images, and (2) myocardial 13N tissue concentration seems to reflect myocardial blood flow.

Adult↗
PubMed1982

[Amyl nitrite test in the evaluation of left ventricular function: application to ischemic heart disease and Duchenne's progressive muscular dystrophy].

The effect of amyl nitrite (AN) inhalation on the left ventricular function was evaluated by mechanocardiography and echocardiography. The patient's group consisted of 110 cases with ischemic heart disease (IHD) and 25 cases of dystrophia musculorum progressiva (DMP) of Duchenne type. The former was a representative of impairment of blood supply and myocardial involvement, and the latter was of predominant myocardial disease. The control was age-matched 32 normals for IHD group and 17 cases for DMP group. Left ventricular function was mainly evaluated by systolic time intervals (STI) and the echocardiographic correlates. Fifty-five cases of IHD group were tested by coronary angiography and left ventriculography and these data were compared with the noninvasive measures. The results were as follows: I. IHD group: The ratio of ejection time (ET) to pre-ejection period (PEP), ET/PEP, did not change so much as in controls after AN inhalation, and this percent change was much smaller in cases with lesions of the left anterior descending artery (LAD) than in cases with lesions of the right coronary artery (RCA). On the other hand, mean posterior wall velocity (mPWV) and posterior wall excursion (PWE) changed greater in patients with LAD lesion than in those with RCA lesion. In cases with LAD stenosis, percent change in ET/PEP was smaller in cases with asynergy than in cases without it, disclosing more significant impairment of the left ventricle in the former. II. DMP group: In severe cases, ET/PEP was small even at rest, and percent change by AN inhalation was smaller than control in mild cases and smallest in severe cases. This seems to be useful in evaluating the severity of the diseased process. The mPWV and PWE showed impairment of left ventricular motion even at rest, but it was clearly showed in severe cases after AN inhalation. These results indicate that impairment of left ventricular function induces the poor response to AN inhalation and this, in turn, results in the lack of hyperactivity of the heart produced by this drug.

Adolescent↗
PubMed1982

[Estimation of infarct size with 201Tl by multiprojection analysis].

Since mortality resulting from cardiac arrhythmia has been decreased by an introduction of CCU, power failure has become the major cause of death in patients with acute myocardial infarction. The power failure is assumed to be related to an infarct size. Therefore, noninvasive quantification of the infarct size is required for proper assessment of prognosis and treatment. Recently, a scintigraphic technique using radionuclide thallium-201 has developed, which is accumulated not in myocardial necrosis but in the intact myocardium. In this study, we tested two different parameters expressing the infarct size based on 5-projection myocardial scintigrams. One parameter is the ratio of the defect area to the total myocardium (% area), and the other is the ratio of a count decrease by the defect to total counts (% loss counts) in the planar image. Each parameter was obtained from uni- and multi-projection analysis. Six items were selected in the study including % area of 1-projection analysis, % area of 3-projection analysis, % area of 5-projection analysis, % loss counts of 1-projection analysis, % loss counts of 3-projection analysis, and % loss counts of 5-projection analysis. In 56 patients with the first attack of acute myocardial infarction, these parameters showed a clinically acceptable correlation with ejection fractions obtained by contrast ventriculography performed about 4 weeks later, with pulmonary end-diastolic pressure shortly after the onset, and with peak-CPK and sigma CPK obtained by 4 or 6 hourly measurements. Correlation coefficients between two parameters among 6 items showed no difference from each other. Scintigraphy was performed more than twice in 11 patients and the infarct size of these patients was decreased with the clinical course. Validity for estimates of the infarct size obtained with two parameters (% loss counts and % area) in different projection analysis was examined by a phantom model experiment and the clinical implications were discussed. In conclusion, an infarct size estimated by 201Tl scintigraphy provides useful informations about the size of necrosis and cardiac function in patients with acute myocardial infarction.

Adult↗