Search PubMed⌕ Search

Biomedical subjects

I Sotobata

Publications and source records attributed to I Sotobata.

At least 109 records · Page 6Linked to original sources
PubMed1982

Correlative studies between Frank vectorcardiograms and thallium-201 myocardial perfusion images in patients with old anterior myocardial infarction.

A correlative study was performed on 70 patients with old anterior myocardial infarction between each of the orthogonal components of instantaneous QRS vectors and the anterior-wall, lateral-wall and septal myocardial uptake ratios (A-MUR, L-MUR, and S-MUR, respectively). These MURs were calculated from the thallium-201 myocardial perfusion images at 5 projections and used as the index of the infarct size of the respective LV wall. The Z components of the 14-msec and 24-msec instantaneous QRS vectors significantly correlated with the S-MUR (r = -0.51) and the A-MUR (r = -0.66) respectively. The X component of the 32-msec instantaneous QRS vector also showed a significant correlation with the L-MUR (r = 0.59). The regression equations obtained in the present study seemed also applicable to patients with complete right bundle branch block. It is concluded that the quantitative analysis of the Frank vectorcardiograms could afford valuable information as to the size as well as the site of myocardial infarctions.

Adult↗
PubMed1982

Influences of the alteration in aortic pressure on regional myocardial function and regional myocardial blood flow in partial coronary artery occlusion.

This study was designed to simultaneously evaluate the effects of alterations in aortic pressure (AoP) on regional myocardial function and regional myocardial blood flow (MBF) in anesthetized dogs with partial coronary occlusion. Regional myocardial function was assessed by both segment-length and tension gauges. The left circumflex coronary artery flow was reduced to 50 to 70% by a constrictor. When systolic aortic pressure (AoPS) fell from 103.6 +/- 7.4 to 72.5 +/- 4.9 mmHg following nitroprusside infusion, systolic shortening (SS) markedly depressed from 0.63 +/- 0.17 to 0.09 +/- 0.20 mm (p less than 0.01), developed tension (DT) decreased by 30% (p less than 0.01), and MBF assessed with tracer microspheres decreased from 0.61 +/- 0.13 to 0.36 +/- 0.11 ml/min/Gm (p less than 0.01) in ischemic regions. In non-ischemic regions SS was enhanced from 0.78 +/- 0.16 to 0.89 +/- 0.15 mm (p less than 0.05), but DT and MBF showed no changes. An elevation of AoPS from 106.4 +/- 5.6 to 143.3 +/- 6.9 mmHg following methoxamine infusion brought about enhanced SS from 0.42 +/- 0.15 to 0.48 +/- 0.09 mm (p less than 0.05), a 50%-increase in DT (p less than 0.01), and was associated with an increase in MBF from 0.66 +/- 0.03 to 1.19 +/- 0.07 ml/min/Gm (p less than 0.01) in ischemic regions. These results indicate that, in partial coronary occlusion, a fall of AoP induces redistribution of blood flow away from ischemic regions and aggravates the function of the ischemic myocardium, while an elevation of AoP may produce beneficial effects upon the ischemic myocardium.

Animals↗
PubMed1981

The quantitative diagnosis of thallium-201 myocardial perfusion images and vectorcardiograms in myocardial infarction and hypertrophic cardiomyopathy.

Correlation studies were carried out between thallium-201 myocardial perfusion images and vectorcardiograms in 77 patients with myocardial infarction (48 anterior and 29 inferior infarctions) and 30 patients with hypertrophic cardiomyopathy. A quantitative method was developed; myocardial 201Tl uptake index (a relative myocardial activity to background, MUI) and myocardial 201Tl uptake ratio (a ratio of regional myocardial counts to maximal myocardial counts, MUR) were utilized to differentiate myocardial infarction from hypertrophic cardiomyopathy, and evaluate them. A fairly good agreement between left ventriculograms and myocardial perfusion images was obtained in myocardial infarction (diagnostic accuracy 95.1% in anterior and 75.6% in inferior infarction). In anterior infarction the linear relationship of r = -0.58 (p < 0.001) was obtained between asynergy index and mean anterior MUR. A highly significant correlation was observed between anterior MUR and the instantaneous 24 msec Z component (r = -0.80, p < 0.001). In inferior infarction, Qy/Ry was correlated to inferior MUR (r = -0.58, p < 0.001). In hypertrophic cardiomyopathy, four types of hypertrophic sites were classified with 201Tl images (septal, apical and anterior, apical and septal, and anterior dominant types). Azimuth angles of instantaneous 10 msec vector were directed right-anteriorly (mean 114.5 degrees) in septal hypertrophy, and left-anteriorly (mean 84.9 degrees) in apical and anterior hypertrophy. Elevation angle of maximal T vector in apical hypertrophy was deviated superiorly (mean 102.6 degrees). There was a good correlation (r = 0.60, p < 0.001) between the magnitude of spatial maximal QRS vector and lateral wall MUR.

Adolescent↗
PubMed1981

Present status of exercise testing in the evaluation of coronary artery disease.

The present status of exercise testing in coronary artery disease (CAD) was discussed in respect to test protocols, ECG criteria and lead systems, and hemodynamic responses. Advantages of modern multistage protocols over single-stage ones such as Master two-step tests are obvious in diagnostic accuracy and patient's safety. Clinical significance of horizontal and downsloping ST depression has already been established. Diagnostic significance of other exercise-induced ECG alterations such as slow upsloping ST depression, ST elevation, U-wave inversion, and R-wave amplitude changes was discussed. The latter parameter is still controversial as to its clinical significance. Use of an inadequate ECG lead system is one of major causes of false negative tests. Necessity of multiple lead systems was emphasized for higher diagnostic accuracy. From the view point of cost-efficacy relation, we will recommend simultaneous recording of CC5 or CM5, V3 and CL or III in routine exercise testing for screening of CAD. Test results such as exercise time, and heart rate and systolic blood pressure responses are also useful parameters for the evaluation of the severity and prognosis of CAD. It was emphasized that in exercise monitoring of ECG and blood pressure is indispensible in multistage exercise testing for improvement of diagnostic accuracy as well as patient's safety.

Angina Pectoris↗
PubMed1980

Non-invasive localization of the pre-excitation site in patients with the Wolff-Parkinson-White syndrome. Vectorcardiographic and echocardiographic correlations.

Vectorcardiographic and echocardiographic correlations were made in 160 patients with no clinical evidence of cardiovascular diseases except for the Wolff-Parkinson-White syndrome. Frank vectorcardiographic classifications of the patients were based on both the morphology of the delta loop and the direction of the mean delta vector in the horizontal plane as follows; group I (93 patients) with a delta loop inscribed nearly straightly anteriorly and either to the left or right and a mean delta vector directed more anteriorly than +20 degrees, group II (31 patients) with a hook-shaped delta loop inscribed initially anteriorly but soon posteriorly and to the left, and group III (36 patients) with a delta loop inscribed nearly linearly to the left and either posteriorly or slightly anteriorly and a mean delta vector directed more posteriorly than +20 degrees. Abnormal echocardiographic patterns of ventricular contractions in the syndrome were seen at the left ventricular posterior wall (LVPW), the interventricular septum (IVS), and the right ventricular anterior wall (RVAW). In group I abnormal LVPW motions were observed in 91 patients (98%), and both abnormal LVPW and IVS motions in 1. The remaining 1 showed no echocardiographic abnormalities either at LVPW or IVS. In contrast, abnormal IVS motions were observed in 29 patients (94%) of group II. No patient of group II showed abnormal LVPW motions. In 17 patients (47%) of group III abnormal LVPW motions alone were observed. Two patients showed both abnormal LVPW and IVS motions. In the remaining 17 patients (47%), no abnormal motions were noted either at LVPW or IVS. Abnormal RVAW motions were invariably observed in 19 patients of group II with satisfactory RVAW echograms, but never seen in groups I and III. Above findings could be explained by the pre-excitation at LVPW in group I, RVAW in group II, and posterior right ventricle in group III. In 19 patients (8 in group I and 11 in group III) frontal QRS loops were very similar to that in left anterior hemiblock. All of these patients except for 1 showed abnormal LVPW motions, so that the site of pre-excitation was presumably located at the posterior paraseptal region or the posterior IVS. Three cases with a combination of a frontal QRS loop of left anterior hemiblock pattern and abnormal IVS motions in addition to abnormal LVPW motions may be explained by the pre-excitation at the right-sided IVS near LVPW. We feel that combinations of vectorcardiographic and echocardiographic approaches are clinically quite useful as an auxiliary non-invasive means of locating the pre-excitation site.

Adolescent↗
PubMed1980

Respiratory changes of the P loop in the Frank vectorcardiogram.

(1) Frank vectorcardiographic P loops of 25 healthy males were recorded at deep inspiration and expiration by using a minicomputer system with an averaging technique. Respiratory changes in 21 P parameters were quantitatively investigated. (2) The maximal left component of the P loop, the magnitude of the horizontal maximal vector and the magnitude of the P polar vector significantly decreased at deep inspiration as compared with those at expiration. The frontal and the spatial maximal vectors were significantly deviated vertically at deep inspiration as compared to those at expiration. (3) It was considered to be better to obtain P loops at a particular phase of respiration or to use those obtained by an averaging technique in order to analyse P loop in detail in various heart diseases, especially in the exercise stress test associated with rapid deep respiration. (4) The mechanism of respiratory P loop changes was discussed.

Adult↗
PubMed1980

Effects of niludipine on regional myocardial blood flow and regional myocardial function in the dog with partial occlusion of the coronary artery.

The effects of bis(2-propoxyethyl)-1,4-dihydro-2,6-dimethyl-4-*3-nitrophenyl)-3,5-pyridine dicarboxylate (niludipine), a newly-synthesized calcium antagonist related in chestical structure to nifedipine, on the ischemic myocardium were studied in eight anesthetized, open-chest dogs, mainly by the simultaneous measurement of regional myocardial blood flow (MBF) and regional myocardial function. The ischemic myocardium was prepared by partial occlusion of the left circumflex coronary artery, and niludipine was given i.v. at a dose of 5 micrograms/kg. MBF was measured by the radioactive microsphere method and regional myocardial function was assessed by measurement of myocardial segment length. Measurements were also taken of aortic pressure, left ventricular pressure, ascending aortic blood flow, and left circumflex coronary blood flow. Niludipine decreased left ventricular contractility, dilated resistance vessels and reduced heart rate. MBF, measured 5 min after the drug was administered, increased in both the ischemic and the non-ischemic myocardium. Improvement in regional myocardial function was observed in the ischemic myocardium 5 min later, when aortic pressure had returned to nearly the pre-administration level. Thus, the results of the study suggest that niludipine improves the balance between myocardial energy supply and demand in the ischemic myocardium when there is little change in aortic pressure, and we concluded that niludipine exerts a beneficial effect on the ischemic myocardium

Animals↗