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Biomedical subjects

K Maeda

Publications and source records attributed to K Maeda.

At least 1,261 records · Page 70Linked to original sources
PubMed1987

[Hypertrophic non-obstructive cardiomyopathy assessed by dipyridamole thallium single photon emission computed tomography: comparisons with hypertrophic cardiomyopathy with a dilated heart].

Thallium-201 (Tl) single photon emission computed tomography (SPECT) after dipyridamole infusion (0.56 mg/kg) was performed in 23 patients with hypertrophic non-obstructive cardiomyopathy (HNCM) and in seven patients with HCM simulating dilated cardiomyopathy (HCM-DCM) to clarify the mechanism and clinical significance of decreased coronary vasodilatory reserve. The coronary vasodilatory reserve in the hypertrophied area assessed by SPECT was compared with the findings of echocardiography, left ventriculography and endomyocardial biopsy. 1. Eleven patients with HNCM had no perfusion defects in the hypertrophied area (group I), but the other 12 patients (52.2%) had such defects (group II). All seven patients with HCM-DCM had perfusion defects in the anterior or septal walls (group III). Redistribution was observed in 11 of the 12 patients in group II and in three of the seven patients in group III. 2. The regional washout rate was relatively low in the upper septum in group II and in the anterior wall and upper septum in group III. Thus, coronary vasodilatory reserve in the hypertrophied area was decreased in groups II and III. 3. Echocardiographically, the degree of hypertrophy did not differ between groups I and II, but the latter had significantly greater left ventricular diastolic dimension (42.3 mm vs 49.5 mm: p less than 0.05) and lower percent fractional shortening (%FS) (43.7% vs 35.6%: p less than 0.05). However, group III showed thinner left ventricular wall, much greater diastolic dimension (60.9 mm vs 49.5 mm: p less than 0.05), and lower %FS (24.0% vs 35.6%: p less than 0.05) than did those of group II. 4. On left ventriculography, those in group II showed larger left ventricular end-diastolic volume index (93.9 ml/m2 vs 79.7 ml/m2: p less than 0.05) than that of group I. Left ventricular ejection fraction showed the same tendency, but this was not statistically significant. 5. On endomyocardial biopsy, the specimens of the patients in group II had significantly higher percent fibrosis than did those of group I (11.4% vs 6.8%: p less than 0.05). These findings suggest that the mechanism of decreased coronary vasodilatory reserve in the hypertrophied area may be related to myocardial fibrosis, and this decrease may induce left ventricular dysfunction and compensatory dilatation.

Adult↗
PubMed1987

[Assessment of regional wall motion and myocardial flow in patients with dilated cardiomyopathy using Tl-201 SPECT during dobutamine infusion].

The present study clarified the relationship between wall motion and myocardial flow in dilated cardiomyopathy (DCM). Two-dimensional echocardiography (2-DE) was performed in 14 patients before and after dobutamine (DOB) drip infusion (8 micrograms/kg/min). Thallium-201 emission computed tomography (ECT) was performed after dobutamine infusion and three hours thereafter. The left ventricle was divided into nine segments. In each segment, the degrees of defects were scored from 0 (normal) to 3 (complete defect), and the severity of wall motion abnormalities was scored from 0 (normal) to 3 (akinesis) by visual inspection. 1. Perfusion defects on ECT images were observed during dobutamine infusion in all patients. Redistribution was observed in nine of 14 (64%) patients. 2. During infusion, 38 (81%) of 47 segments without defects showed normal wall motion, but 44 (86%) of 51 segments with defects showed wall motion abnormalities. 3. Redistribution was observed in 18 (35%) of 51 segments, and these segments showed lower incidence of wall motion abnormalities as compared to the other segments (94% vs 45%, p less than 0.001). 4. After infusion, the segments with redistribution frequently showed improved wall motion as compared to the other segments (56% vs 18%, p less than 0.05). These results indicate that redistribution on the ECT image is observed in some patients with dilated cardiomyopathy after dobutamine administration. This may be due to the capacity of the drug to increase myocardial flow in proportion to the increase of oxygen demand.

Cardiomyopathy, Dilated↗
PubMed1987

Severe fetal supraventricular bradyarrhythmia without fetal hypoxia.

Cardiac anatomy and rhythm were evaluated in a fetus at 39 weeks' gestation in a pregnant woman referred because of severe fetal bradycardia with a persistent fetal heart rate of 50-60 beats per minute. M-mode echocardiograms revealed supraventricular bradyarrhythmia. Umbilical cord blood analysis did not, however, reveal fetal hypoxia. Diagnostic methods of fetal bradyarrhythmia are discussed, and the importance of differentiating bradyarrhythmia from bradycardia due to fetal hypoxia is emphasized.

Adult↗
PubMed1987

A massive dose of vincristine.

An esophageal cancer patient with bilateral lungs and neck lymph nodes metastases received 24 mg of vincristine instead of vinblastine because of the similarity between the two names, and survived multiorgan derangement. Serious states of central and peripheral neuropathy with muscle atrophy, gastrointestinal disorder, bone marrow suppression and mucocutaneous involvement were all encountered. Although hypotension and syndrome of inappropriate secretion of antidiuretic hormone (SIADH) were not observed as vincristine's side actions, toxicity to the myocardium, which has not been documented, was suggested in our case. These toxic impairments, however, subsided clinically within a month, except for paresthesia in the peripheral extremities. The effectiveness of the chemotherapy was remarkable against both the esophageal cancer and the metastatic lesions. No unintentional overdose of a drug, needless to say, should happen, and in order to minimize its possibility, it would be advisable for chemotherapy to be administered only by an experienced physician who is able to check the dose and concentration.

Adult↗