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Biomedical subjects

S Yabe

Publications and source records attributed to S Yabe.

At least 55 records · Page 3Linked to original sources
PubMed1988

Sites of origin of ventricular premature beats in patients with and without cardiovascular disease evaluated by body surface mapping.

The site of origin of ventricular premature beats (VPBs) was estimated by QRS maps and its distribution in two patient groups was studied. VPB origin was determined by comparing the body surface map of VPBs with that during electrical stimuli applied at various sites of the ventricle. Subjects were 100 patients without obvious underlying cardiovascular disease (Group N) and 289 patients with various heart diseases (Group D). Nine sites of origin of VPB were identified. In group N, VPBs of right ventricular origin were noted in 69%, those of left ventricular origin in 6%. There was a relatively high incidence of VPBs with foci estimated to be the divisions of the left bundle branch, and the age of patients with these VPBs was young. In Group D, VPBs of left ventricular origin showed a higher incidence (34.6%) and those of right ventricular origin a lower incidence (41.2%) than those in group N. The data suggest that VPBs originating from the apex and base of the ventricle strongly indicate the presence of basic heart disease and that VPBs originating in or near the divisions of the left bundle branch in younger subjects do not necessarily indicate cardiac disease.

Adolescent↗
PubMed1987

[Eigenvector analysis in body surface potential maps for evaluating right ventricular hypertrophy in primary pulmonary hypertension].

This study related the eigenvectors derived from the QRS complex in body surface isopotential maps of normal subjects to regional myocardial excitation, with special emphasis on the right ventricle. The subjects consisted of 120 normal healthy adults and eight patients with primary pulmonary hypertension and right ventricular hypertrophy (PPH). According to the Karhunen-Loève theory, eigenvectors were derived from the normal group and the eigenvector coefficient of each subject was obtained against time for the first three components. The cumulative proportion of the first three eigenvectors was 90.3% in normals and 80.2% in PPH. The first eigenvector had a peak of eigenvector coefficients early in the QRS and had a bottom late in the QRS. The peak of the second was in the middle of the QRS. The coefficients of the third eigenvector were low compared to the former two eigenvectors, and had no characteristic time pattern. PPH had a similar time pattern of coefficients in the first eigenvector, reduced coefficients in the second, and a definite peak in the mid-QRS in the third. The average eigenvector coefficient of the third eigenvector in PPH was significantly higher than those in normal subjects (p less than 0.01). We conclude that the third eignevector derived from normal subjects strongly reflects right ventricular excitation.

Adult↗
PubMed1985

[Ventricular activation sequence estimated by body surface isochrone map].

This study was performed to evaluate the usefulness of the body surface isochrone map (VAT map) for identifying the ventricular activation sequence, and it was correlated with the isopotential map. Subjects consisted of 42 normal healthy adults, 18 patients with artificial ventricular pacemakers, and 100 patients with ventricular premature beats (VPB). The sites of pacemaker implantations were the right ventricular endocardial apex (nine cases), right ventricular epicardial apex (five cases), right ventricular inflow tract (one case), left ventricular epicardial apex (one case), and posterior base of the left ventricle via the coronary sinus (two cases). An isopotential map was recorded by the mapper HPM-6500 (Chunichi-Denshi Co.) on the basis of an 87 unipolar lead ECG, and a VAT isochrone map was drawn by a minicomputer. The normal VAT map was classified by type according to alignment of isochrone lines, and their frequency was 57.1% for type A, 16.7% for type B, and 26.2% for type C. In the VAT map of ventricular pacing, the body surface area of initial isochrone lines represented well the sites of pacemaker stimuli. In the VAT map of VPB, the sites of origin of VPB agreed well with those as determined by the previous study using an isopotential map. The density of the isochrone lines suggested the mode of conduction via the specialized conduction system or ventricular muscle. The VAT map is a very useful diagnostic method to predict the ventricular activation sequence more directly in a single sheet of the map.

Bundle-Branch Block↗
PubMed1985

[Quantitative evaluation of various cardiac diseases using body surface mapping].

Body surface mapping (map) was used to evaluate various cardiac diseases quantitatively. For 30 cases with old anterior myocardial infarction (AMI), map parameters were compared with infarct size assessed by left ventriculography and 201Tl myocardial scintigraphy (LV% asynergy and 201Tl% defect, respectively). Parameters used in the present study were nSubtraction 40 (sigma Subtr. 40), which were obtained by the summation of voltages less than the lower limit of normal range (mean--2SD) at 40 msec from the QRS onset and nSubtraction 10-60 (sigma Subtr. 10-60), which was obtained by the integral of voltages below the normal range, calculated each 10 msec to 60 msec, as well as the number of lead points with Q waves of 30, 40 msec duration (nQ30, nQ40), and the summation of R voltages over the entire body surface (sigma R). In 19 cases with aortic regurgitation (AR), R and S voltages in each lead were compared with left ventricular diastolic dimension (LVDd) obtained by echocardiography. In 43 healthy persons and two patients with RV pacing, the ventricular activation time was measured in each lead (VAT map). In AMI, nSubtr. 40 correlated best with LV% asynergy (r = 0.70, p less than 0.001). EF and 201Tl% defect were related to nSubtr. 10-60 (r = 0.83, p less than 0.001 and r = 0.85, p less than 0.001, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1984

[Effects of heart rate on body surface potential distribution in patients with atrial pacemaker].

Nine patients of sick sinus syndrome with atrial programmable pacemaker (3 males and 6 females, aged from 53 to 72 years) were studied to assess the effect of heart rate on the body surface potential distribution. Body surface maps (87 lead points) and M-mode echocardiograms were recorded at 20-beat increments of heart rate from 60 to 140 beats/min during atrial pacing. The potential changes of R and S voltages were evaluated quantitatively and were correlated with the changes of echocardiographically measured left ventricular dimension. As the heart rate increased, left ventricular dimension in end-diastole (LVDd) decreased gradually (Table 1), and a significant decrease was observed when the heart rate increased from 80 to 100 beats/min and from 100 to 120 beats/min, respectively, (p less than 0.05). With a decrease in LVDd, the distance between the left ventricular posterior wall and the anterior chest wall decreased and the left ventricular wall increased in its thickness. These changes, however, were not statistically significant. With an increase in the heart rate, R voltages decreased gradually in the left lateral chest and the sum of R voltages (sigma R) of six lead points in the left lateral chest including leads V5-6 decreased significantly when the heart rate increased from 60 to 100 beats/min and from 80 to 120 beats/min, respectively (p less than 0.02) (Table 2). On the other hand, R voltages remained unchanged in the left anterior chest during atrial pacing, then the sum of R voltages of six lead points in the left anterior chest including leads V2-4 and the sum of R voltages of 87 lead points did not show any significant changes (Table 2). An increase in the absolute value of S voltages was observed in the left anterior chest and the sum of S voltages of six lead points in the left anterior chest including leads V2-4 increased when the heart rate increased from 60 to 100 beats/min and from 80 to 120 beats/min, respectively (p less than 0.1) (Table 3) A decrease of R voltages in the left lateral chest was consistent with the reduction in LVDd (p less than 0.005). It is concluded that the changes in body surface QRS amplitudes during atrial pacing are related to those in the left ventricular dimension and that R voltages in the left lateral chest are fairly sensitive to see the changes in LVDd in cases with no abnormal wall motion of the left ventricle.(ABSTRACT TRUNCATED AT 400 WORDS)

Aged↗
PubMed1984

[Clinical application of body surface mapping and its limitations].

The importance of detecting the high fidelity electrical activity of the heart was cited in respect to making diagnosis and providing optimal treatment. Standard 12 lead electrocardiograms (ECG) and vectorcardiograms (VCG) are used in daily practice with well-documented theoretical and experimental bases. However, this system is somewhat inadequate because of its simplicity both in records and basic assumptions. The development of a better lead system is thus mandatory for a high diagnostic sensitivity and specificity and for both qualitative and quantitative assessments of collected data. In recent years, great progress has been promised in "body surface mapping methods" by the medical application of computer technology, providing abundant information including four-dimensional displays; two-dimensional surface spreads of electricity as well as the magnitudes and time references. This method appears to be a powerful diagnostic tool, despite problems inherent in ECG and some unfavorable aspects yet to be settled. The present status, prospects and limitations of this new, powerful strategy are discussed.

Aged↗
PubMed1983

Studies on Japanese encephalitis virus infection of reptiles. I. Experimental infection of snakes and lizards.

Experimental infection of four species of snakes, Rhabdophis tigrinus tigrinus, Elaphe quadrivirgata, Elaphe climacophora and Agkistrodon halys, and five species of lizards, Takydromus tachydromoides, Eumeces latiscutatus, Eumeces barbouri, Eumeces marginatus oshimensis and Gekko japonicus, with Japanese encephalitis virus (JEV) was carried out. Evidence of JEV multiplication in snakes was not obtained at least under the conditions used in the present study. All lizards except G. japonicus were infected with JEV by ip injection of virus suspension. The minimum infectious dose for a lizard was around 10(3) MLD50/0.05 ml, and this dose was considered to be proportional to the virus dose which is injected into a host by a vector mosquito at a single bite. Temperature dependence of JE virus growth in the lizards was demonstrated. JEV multiplied slower at 20 degrees C than at 26 degrees C, though the peak titers of viremia were equivalent in both groups of lizards kept at 20 degrees C and 26 degrees C. E. latiscutatus developed viremia with ip injection of a partially attenuated strain, Nakayama NIH which could not infect adult mice by peripheral inoculation. T. tachydromoides and E. latiscutatus were also infected by oral feeding of JEV infected mosquitoes. E. latiscutatus was infected by oral feeding of only one infected mosquito.

Animals↗
PubMed1983

Studies on Japanese encephalitis virus infection of reptiles. II. Role of lizards on hibernation of Japanese encephalitis virus.

A series of experiments on the role of lizards as overwintering hosts of Japanese encephalitis virus (JEV) was carried out. Two species of lizards, T. tachydromoides and E. latiscutatus, 2 species of mosquitoes, Cx. p. fatigans and Cx. p. pallens, and 2 strains of JEV, JaGAr#01 and JaGAr 19461, were used in this study. Firstly transmission of JEV from infected mosquitoes to uninfected lizards and from infected lizards to normal mice by the bite of mosquitoes was demonstrated successfully. Cx. pipiens group mosquitoes were found to feed readily on lizards as compared to Cx. tritaeniorhynchus, the primary vector of JEV in Japan. Secondly simulated hibernation of JEV in lizards was carried out under indoor and outdoor conditions. In the outdoor hibernation, lizards were injected with JEV on October 14, 1968, entered in hibernation on October 19 and were recovered from hibernation on April 10, 1969. Viremias were demonstrated in the lizards for a few weeks in late April. Thirdly JEV isolation and HI antibody detection were attempted from blood samples of field-caught reptiles, 7 species of snakes and 3 species of lizards and among amphibians, 2 species of frogs. HI antibody against JEV was found at a rate of 14.3% from E. latiscutatus and 4.0% from T. tachydromoides, though JEV was not isolated from all the blood samples of these cold-blooded animals. The roles of lizards as overwintering hosts of JEV were discussed.

Animals↗
PubMed1981

Effect of cadmium on Japanese encephalitis virus infection in mice. 1. Acute and single-dose exposure experiment.

When mice were treated with 0.09 mg cadmium chloride (Cd) per mouse once and inoculated i.p. simultaneously with Japanese encephalitis virus (JEV) they showed a significant difference in the incubation time and mortality between the treated and untreated groups in repeated experiments. Cd treatment shortened the incubation time and the mortality increased greater than twice compared with the untreated control. This effect was not observed in the case of intracerebral inoculation of JEV. Effects of Cd on antibody formation in mice were also determined. Animals given a single s.c. dose of Cd were immunized with JE inactivated vaccine once simultaneously. When mice were treated with Cd, they did not show low neutralizing and hemagglutination inhibition activities compared with the control mice. Pretreatment of Cd did not affect any mortality or antibody formation.

Animals↗