PubMed Health⌕ Search

Biomedical subjects

H Bunko

Publications and source records attributed to H Bunko.

At least 73 records · Page 4Linked to original sources
PubMed1988

Serial assessment of left ventricular function following coronary bypass surgery by radionuclide angiocardiography.

The serial change in left ventricular function was investigated by radionuclide angiocardiography in 25 patients undergoing coronary artery bypass grafting (CABG). Multiple gated equilibrium blood pool imaging was performed at rest before, and at 1, 2 and 4 weeks after the operation and also during exercise on a supine bicycle ergometer before and 4 weeks after surgery. Global ejection fraction at rest was unchanged after CABG while peak ejection rate increased significantly at 1 and 2 weeks (p less than 0.01 and p less than 0.05 respectively) after the operation. Peak filling rate at rest was generally unchanged after surgery but peak filling rate during the first third of diastole at rest decreased significantly at 1 and 2 weeks (p less than 0.01 and p less than 0.05). After CABG, the increases in ejection fraction and peak ejection rate with exercise were significantly greater than those values measured before surgery. The increases, due to exercise, in peak filling rate and peak filling rate during the first third of diastole were unchanged after the operation. Radionuclide angiocardiography affords a safe, noninvasive, and highly reproducible procedure for serially assessing ventricular function in patients undergoing CABG. Our study revealed early diastolic dysfunction within 2 weeks of surgery and that CABG abolished abnormalities in left ventricular function induced by exercise.

Aged↗
PubMed1986

Clinical studies on diabetic myocardial disease using exercise testing with myocardial scintigraphy and endomyocardial biopsy.

Nine diabetics without significant coronary stenosis participated in an exercise testing protocol with thallium-201 myocardial scintigraphy. Endomyocardial biopsy of right ventricle was also obtained. There were 4 patients with abnormal perfusion (positive group) and 5 patients with normal perfusion (negative group). All cases of the positive group were familial diabetics and there was only one case of dietary treatment, whereas in the negative group, there were only 2 cases of familial diabetics and 3 cases receiving dietary treatment. No statistical differences between the positive and negative groups were observed for the data of exercise performance and hemodynamic parameters in cardiac catheterization at rest. However, the mean ejection fraction in the positive group (62 +/- 13%) was significantly lower than in the negative group (77 +/- 4%). In both groups, the mean diameter of myocardial cells and the mean percent fibrosis of biopsy specimens showed significant increases compared with the control group. The mean percent fibrosis in the positive group (24.1 +/- 8.5%) compared with that in the negative group (16.5 +/- 5.9%) showed a tendency to increase. It is suggested that the abnormal perfusion of thallium-201 in the positive group indicates subclinically a pathological change of microcirculation caused by diabetes mellitus.

Adult↗
PubMed1986

Congenitally corrected transposition of the great arteries associated with the pre-excitation syndrome.

A case with congenitally corrected transposition of the great arteries associated with the pre-excitation syndrome is presented. A gated-blood-pool study and Tl-201 myocardial imaging were performed using SPECT. The tomographic gated-blood-pool images showed the shapes of the right ventricle (RV) and left ventricle (LV), i.e., anatomically LV and RV respectively, to be reversed from that of normal patients. The relationships of the great vessels and ventricles also were easily visualized. RV hypertrophy (anatomical LV) was visualized on the Tl-201 images. Phase analysis showed the earliest excitation was in the anteroseptal region near the base of the LV, which was consistent with the site of the accessory conduction pathway. The gated-blood-pool and Tl-201 tomographic studies were helpful for demonstrating the corrected transposition of the great arteries and the pre-excitation syndrome.

Female↗
PubMed1986

Functional mapping of ventricular contraction and phase using single-photon emission computed tomography (SPECT).

A method for functional mapping of ventricular contraction and phase was developed using gated blood-pool SPECT. Parameters of contraction and phase were calculated using length-based and count-based Fourier analyses. In length-based Fourier analysis (LFA), percentage-shortening and length-based phase were calculated based on the changes of lengths from a ventricular centre to edges. In count-based Fourier analysis (CFA), phase and amplitude were also calculated using serial tomographic phase images. Two-dimensional polar display format was employed to summarize the SPECT data of whole cardiac surface. This program was applied to evaluate coronary artery disease and conduction anomalies. The polar functional map using gated blood-pool SPECT can be an effective method to integrate three-dimensional cardiac information in conjunction with myocardial SPECT studies.

Erythrocytes↗
PubMed1986

[Washout rate in hypertrophic cardiomyopathy assessed by exercise myocardial scintigraphy].

The present study clarified the pathogenesis of disproportional hypertrophy in terms of disturbed coronary microcirculation. Twenty-eight patients with hypertrophic cardiomyopathy (HCM) who had normal coronary angiograms were categorized in four groups according to distributions of disproportional hypertrophy on left ventriculography and biventriculography: (1) Interventricular septal hypertrophy, (2) septal and apico-anterior wall hypertrophy, (3) apico-anterior hypertrophy, and (4) nonspecific hypertrophy of the entire wall. All 28 HCM patients and 10 normal volunteers were tested using exercise myocardial scintigraphy, and the circumferential profiles were processed by computer to relate the washout rate and disproportional hypertrophy. Comparison of the mean curves and mean segmental values of the circumferential profiles of the HCM groups with those of the control group showed that the mean initial uptake values of the HCM groups were to be relatively low in the apical segment and in the lower portion of the anteroseptal segment representing disproportional hypertrophy of these segments. The mean values were significantly elevated in the upper portion of the anteroseptal segment which was projected as the largest amount of the myocardium three-dimensionally. The mean washout rates in the HCM groups were significantly decreased in all segments, especially in those segments which reflected disproportional hypertrophy. This trend was also observed in the segments with increased initial uptakes. On comparing the segmental values of all groups, the segments with initial uptakes and/or washout rates with having the mean value minus 2SD of the control group were observed in the profiles of 12 of the 28 HCM patients. These all had decreased washout rates. In 25 of the total segments of the HCM patients, the initial uptakes and/or washout rates were below the normal limit; 21 of these segments had only decreased washout rates, and 16 of these 21 segments belonged to disproportionally hypertrophic wall. These results indicate that the decreased washout rate in the disproportionally hypertrophic wall is characteristic of HCM. It is suggested that the decreased washout rate with the decreased initial uptake is caused by disturbance of the coronary microcirculation. In addition, the decreased washout rate without a decreased initial uptake is caused not only by disturbance of coronary microcirculation, but by a metabolic disturbance of the myocardial cells as well. Furthermore, both disturbances are closely related to the pathogenesis of disproportional hypertrophy.

Adult↗
PubMed1986

Length-based Fourier analysis in the pre-excitation syndrome.

Length-based Fourier analysis (LFA) was applied to tomographic gated blood-pool study, and phase and percent-shortening diagrams were generated. In 22 patients with pre-excitation syndrome and ten control subjects, the most basal short-axis section was used for tomographic analysis. When the initial abnormal phase was considered as the location of accessory conduction pathway (ACP), correct diagnosis for the localization of ACP was given in 19 of 22 patients. In ten control subjects, no specific segments of initial phase were noted, although six patients had initial phase in the septal or paraseptal segments. The tomographic LFA was more effective for pinpointing the segment of the earliest phase than tomographic count-based phase analysis. The LFA provided objective three-dimensional information for contraction sequence. Because movements of ventricular edges are essential in tomography, the LFA was considered to be a reasonable approach for the analysis of tomographic gated blood-pool study.

Erythrocytes↗
PubMed1986

[Reverse redistribution in dipyridamole-loading thallium-201 images using single photon emission computed tomography].

This study demonstrated the clinical significance of reverse redistribution, i.e., a decrease in the relative Tl activity in the redistribution image compared to that of the stress image after administration of dipyridamole. Dipyridamole was infused intravenously at a rate of 0.142 mg/kg per min for four min, and a stress image was obtained 10 min after the injection of two mCi 201Tl. Each patient returned for redistribution scanning in the identical position three hours after the isotope injection. The myocardial image of Tl was analyzed by single photon emission computed tomography and its washout rate was calculated by the segmental ROI method. Myocardial function and the motion of left ventricular wall were analyzed by 99mTc-RBC-gated cardiac pool imaging. The results were as follows: Reverse redistribution was noted in 27 (21.6%) of 125 consecutive Tl dipyridamole and redistribution myocardial imaging studies. The stress image demonstrated normal perfusion (group 1) and reduced perfusion (group 2) of Tl. Group 1 consisted of 17 patients with diabetes mellitus, supraventricular arrhythmias, hypertension, and others. Group 2 consisted of 10 patients with subendocardial infarction, diabetes mellitus, and hypertension, and others. The percentage prevalence of reverse redistribution among patients with supraventricular arrhythmia was 62.5% (five of eight patients), with subendocardial infarction 60.0% (three of five), with hypertension 42.8% (six of 14), and with diabetes mellitus 40.0% (eight of 20), while in those with transmyocardial infarction and angina pectoris no reverse redistribution percentage was found. The washout rate of Tl in normal perfusion areas was 44.0 +/- 12.8%, the reverse redistribution of group 1 was 47.4 +/- 12.8%, and of group 2 was 51.2 +/- 8.2%. The washout rate of the reverse redistribution of group 2 was significantly greater than that of the normal areas. In gated cardiac pool imaging, patients in group 2 had significantly larger areas showing abnormal contraction of the left ventricular wall and significantly lower ejection fraction than did group 1. In the electrocardiogram ST segment depression was noted more frequently in group 2 than group 1. No Q wave was present in the corresponding reverse redistribution area. These results suggest that reverse redistribution might occur in a region with a combination of scarred and normal myocardium, the metabolically affected myocardium, and an area with relatively increased myocardial blood flow. The patients in group 2 seem to have the more pathological myocardium than do those in group 1.

Adult↗
PubMed1985

Nuclear tomographic phase analysis: localization of accessory conduction pathway in patients with Wolff-Parkinson-White syndrome.

The purpose of this study was to evaluate the usefulness of tomographic phase analysis in detecting the site of the accessory conduction pathway (ACP) in patients with Wolff-Parkinson-White (WPW) syndrome. Gated emission computed tomography and planar gated blood pool scintigraphy were performed in 20 patients with WPW syndrome, 14 with delta waves and six without delta waves (two intermittent types and four concealed types). The abnormal initial contractions in both planar and tomographic phase images were compared with the sites of ACPs confirmed by epicardial mapping and surgery. The atrioventricular ring was divided into eight segments on each side, and the identification of the initial phase in the segment in which the ACP was located, or that adjacent to it, was considered to be the correct diagnosis. In planar phase analysis, the abnormal initial phase was identified correctly in 8 of 14 patients (57%), whereas in tomographic phase analysis, the site of the ACP was detected in 12 of 14 patients (86%). Tomographic phase analysis can be a helpful adjunctive method in patients with WPW syndrome.

Adolescent↗