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Biomedical subjects

C Ibukiyama

Publications and source records attributed to C Ibukiyama.

At least 19 recordsLinked to original sources
PubMed1995

Underestimation of vasodilator effects of nitroglycerin by upper limb blood pressure.

To determine why upper limb blood pressure measurement underestimates the vasodilator effects of nitroglycerin on lowering ascending aortic systolic pressure, we studied 24 patients (58 +/- 11 years, mean +/- SD). Ascending aortic pressure and radial artery pulse calibrated by cuff blood pressure measurement at the brachial artery were recorded simultaneously before and 5 minutes after sublingual administration of 0.3 mg nitroglycerin. Waves were analyzed by a signal processor, and the fourth derivative wave was used to find the early (S1) and late (S2) systolic shoulders (S1 corresponds to the second zero crossing and S2 to the third zero crossing). Before nitroglycerin administration, maximal systolic pressure in the ascending aorta (141 +/- 21 mm Hg) coincided with the late systolic peak in all patients, and in most patients (21 of 24) maximal systolic pressure in the radial artery (140 +/- 19 mm Hg) coincided with the early systolic peak. Maximal systolic pressure decreased more in the ascending aorta than in the radial artery (22 +/- 13 and 11 +/- 11 mm Hg, respectively; P < .001). However, the reduction in the shoulder of late systolic pressure in the radial artery (24 +/- 13 mm Hg) clearly indicated the reduction in maximal systolic pressure (late systolic peak) in the ascending aorta. The augmentation index of the ratio of the height of late systolic pressure to early systolic pressure fell proportionally (r = .74, P < .001) in the radial artery (from 0.88 +/- 0.13 to 0.60 +/- 0.11) and in the ascending aorta (from 1.57 +/- 0.25 to 1.26 +/- 0.24), which indicated the reduction in late systolic pressures.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1995

[Electrocardiographic characteristics of patients with left circumflex-related myocardial infarction in the acute phase without tented T waves or definite ST elevation].

Acute myocardial infarction (AMI) causing ST depression and T wave inversion has been diagnosed as subendocardial or non-Q myocardial infarction. However, some patients eventually develop strictly posterior infarction with a lesion of the left circumflex coronary artery (LCX). This study attempted to determine the electrocardiographic (ECG) characteristics of such myocardial infarction in 32 patients with definite AMI in whom ECG showed no hyperacute T waves or ST elevation and the LCX was an infarct-related coronary artery. ECG on admission (< 6 hours from the onset), at 24 hours, and on the 14th day were analyzed to evaluate QRS, ST, T, and U waves using calipers and magnifying lens. Sixty-six patients with normal circulation served as controls. The characteristic ECG findings on admission were ST depression in chest leads, and prominent positive U waves in leads V2 or V3 with relatively small T waves. Based on these results we proposed new ECG criteria: 1) ST depression > or = 0.1 mV in 2 consecutive chest leads, 2) prominent positive U wave > or = 0.1 mV in leads V2 or V3, 3) T/U ratio in leads V2 or V3 < or = 4. Considering two of the above criteria as positive, the sensitivity was 71.9%, the specificity 97.0%, and the diagnostic accuracy 88.8%. In 85.2% of the patients, ST depression returned to the baseline by 24 hours. As the amplitude of the U waves decrease gradually, the T/U ratio increased. The R/S ratio in leads V1 or V2 became > or = 1 by 24 hours in 46.4% and the amplitude of R wave in lead V1 increased gradually. T waves in the right precordial leads increased with time. These findings were consistent with isolated strictly posterior myocardial infarction. From these results we identified new ECG criteria: 1) R/S ratio in leads V1 or V2 > or = 1, 2) R wave > or = 0.7 mV in lead V1, 3) T wave > or = 0.5 mV in lead V1. Considering any of the above criteria as positive, the sensitivity was 72.0%, the specificity 87.9%, and the diagnostic accuracy 86.7% on the 14th day. These new ECG criteria of strictly posterior myocardial infarction with the LCX as an infarct-related coronary artery apply at less than 6 hours or at 24 hours from the onset of the symptoms.

Aged↗
PubMed1994

A case of creatine kinase isomer anomaly in relation to the diagnosis of acute myocardial infarction.

Creatine kinase (CK) isomers have recently been suggested to be of value in the diagnosis of acute myocardial infarction (AMI). The aim of this report was to determine whether measurement of CK isomers, especially the MM isomer and the cardio-specific marker MB isomer, is practical in the diagnosis of AMI. A 64-year-old female with consistently high values for total CK showed an electrophoretic pattern which suggested AMI. We ruled out all possible causes of increased CK, and its MB isomer, including IgGBB, beta-LP (lipoprotein) and mitochondrial complexes as well as myocarditis, muscular disorders, and myoglobinuria. Regardless of the source of the anomaly, the fact remains that CK macroanomaly cases can be an obstacle in the diagnosis of AMI. CK isomers have proven to be accurate markers in AMI and valuable in doubtful cases, such as non Q-AMI. However, in light of this particular case of CK macroanomaly, isomers are not 100% accurate (specific) in the diagnosis of AMI.

Clinical Enzyme Tests↗
PubMed1994

[Evaluation of myocardial viability and efficacy of reperfusion therapy by dual-SPECT using 99mTc-PYP and 201Tl in acute myocardial infarction].

UNLABELLED: Dual SPECT using 99mTc-PYP and 201Tl was performed in 70 patients with acute myocardial infarction, and the ratio of overlap zone between 201Tl and 99mTc-PYP uptake in the infarcted area was determined (the Y-ratio). The Y-ratio was significantly higher in the group with redistribution in the infarcted area on exercise thallium myocardial scintigraphy in the chronic stage of infarction, as well as in the group with normal left ventricular wall motion. Thus, the Y-ratio value was apparently useful in the evaluation of myocardial viability. Patients from 60% of the Y-ratio upward are suggested that myocardial viability had been survived. When the Y-ratio was determined in 30 patients who underwent early reperfusion therapy (ICT or direct-PTCA), no significant difference was found between the ICT group and the direct-PTCA group. However, the Y-ratio was significantly higher when reperfusion was performed within 6 hours than when it was performed after 6 hours, and a significant positive correlation (r = 0.63, p < 0.01), was found between reperfusion time from cardiac event within 9 hours and the value of (100--the Y-ratio). CONCLUSION: The Y-ratio was grateful appeared to be useful for the quantitative evaluation of myocardial viability in the acute stage of myocardial infarction. In addition, it appears to be important to perform reperfusion as soon as possible to improve myocardial salvage.

Adult↗
PubMed1993

Sudden cardiac death from hypertrophic cardiomyopathy and acute idiopathic (Fiedler's) myocarditis: autopsy report.

A 45-year-old man with a rapidly deteriorating heart condition died suddenly, two hours after admission, after resistance to attempts of cardiac pacing. At autopsy, the heart weighed 600g with asymmetric septal hypertrophy. Histological examination revealed an extensive and diffuse disarray of myocardial fibers in the ventricular septum and in the free wall of both ventricles. Pronounced mononuclear cell infiltrations and interstitial edema were distributed widely in both ventricles. There were few abnormal findings in the other organs. The diagnosis was hypertrophic cardiomyopathy accompanied by Fiedler's myocarditis. Such a case appears to be rare.

Cardiomyopathy, Hypertrophic↗
PubMed1990

[Evaluation of latent cardiac disease in diabetic patients with Tl-201 exercise myocardial scintigram and blood pool scintigram].

To find latent heart disease in diabetic patients, 142 diabetic patients were divided into 4 groups: 1) No hypertension and normal ECG (DM group); 2) Hypertension recognized clinically (HT group); 3) Myocardial damage on ECG (MD group) 4) group associated with the previous 2 (HT + MD group). In all groups Tl-201 exercise myocardial scintigrams and blood pool scintigrams were taken for comparative analysis. Positive rates of SPECT were 27.7% (23/83) in the DM group, 30.0% (9/30) in the HT group, 50.0% (6/12) in MD group, and 70.6% (12/17) in the HT + MD group. The rate in the HT + MD group was significantly higher than in that of the DM and HT groups (p less than 0.001, p less than 0.01). Blood pool scintigrams revealed that in the HT + MD group, as compared with the normal control group, both 1/3 FF and PFR were significantly depressed, in addition to significant TPF prolongation in the former (p less than 0.001, p less than 0.05, p less than 0.05). These findings suggest that in diabetic patients hypertension and myocardial damage would lead to a high incidence of abnormality in SPECT and left ventricular rapid filling dysfunction. This indicate a high incidence of latent cardiac disease which can be recognized in diabetic patients by stress myocardial and blood pool scintigrams.

Adult↗
PubMed1989

Effect of sodium intake on the hypotensive effect of calcium antagonists.

To clarify the influence of Na balance on the hypotensive effect of calcium antagonists, the changes of blood pressure and humoral factors after a single oral administration of 40 mg nicardipine were evaluated in 15 subjects with essential hypertension under high, normal, and low Na regimens (mean 24 hour urinary Na excretion: 320 +/- 24, 147 +/- 7, 27 +/- 6 mEq, respectively). Nicardipine induced a significant reduction of mean blood pressure and increase in heart rate. The change of mean blood pressure after nicardipine was negatively related to the pretreatment mean blood pressure under the three levels of Na intake (p less than 0.01). The slopes of the correlation lines for high, normal, and low Na regimens were -0.61, -0.69, and -0.52, respectively, without statistical significance. Nicardipine brought about significant increases in plasma renin activity and plasma norepinephrine, but no changes in plasma levels of epinephrine, 6-keto-prostaglandin F1 alpha, thromboxane B2 or serum aldosterone concentration. These results suggest that the magnitude of the untreated blood pressure and thereby the peripheral resistance are major determinants of the blood pressure fall caused by calcium antagonists, and that the failure to increase aldosterone and epinephrine in the face of peripheral vasodilation may be responsible in part for the hypotensive effect of this drug.

6-Ketoprostaglandin F1 alpha↗
PubMed1989

[Validity of estimating left ventricular relaxation and filling dynamics by Doppler trans-mitral flow].

To evaluate the validity of estimating left ventricular (LV) diastolic function using the Doppler transmitral flow profile, the relationship of transmitral flow to LV relaxation and LV filling dynamics was observed. A total of 54 subjects, including patients with ischemic heart disease, idiopathic cardiomyopathy, and normal persons were examined. LV filling dynamics were assessed in 20 of them who had no regional wall motion abnormality or irregular LV geometry. Peak velocity of rapid filling (R) and acceleration of rapid filling (AR) at the mitral annular level were measured as indices of transmitral flow during the rapid filling period. LV relaxation was evaluated according to the time constant of LV isovolumic pressure decline (T) using the method of Weiss et al. The correlation coefficient between R and T was -0.27 and that between AR and T was -0.16, indicating lack of correlations. The v-wave of pulmonary wedge pressure (PWPv) was measured as an index for left atrial driving pressure during the rapid LV filling period. Multiple regression analyses of R or AR as dependent variables and T and PWPv as independent variables revealed significant correlations (r = 0.66 and r = 0.59). The peak transit rate (PTR = R/TVI) and atrial transit fraction (ATF = TVIa/TVI) were determined from the time integral of the transmitral flow velocity (TVI = time velocity integral during diastole, TVIa = time velocity integral during the atrial contraction phase). Also, the peak filling rate (PFR) during the rapid filling and atrial filling fraction (AFF) were determined by left ventriculography.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Radionuclide angiography in pulmonary sequestration.

We report a case diagnosed as pulmonary sequestration by radionuclide angiography prior to operation which showed anomalous arteries. Radionuclide angiography clearly revealed the condition of both the pulmonary artery and aorta, and is considered to be extremely useful in the diagnosis of pulmonary sequestration. It will probably be applied to more patients in the future.

Aorta, Thoracic↗
PubMed1983

Exercise parameters for the prediction of post-training increase in exercise tolerance in patient with stable angina pectoris.

Twenty cases with effort angina underwent exercise training for a mean follow-up period of 38 weeks. Various parameters were investigated to clarify whether or not such parameters can be used to predict an increase in exercise tolerance of patients with effort angina. The increase of exercise tolerance after training was found to be related to a reduction of the myocardial oxygen demand at a given external work load. The maximal heart rate (max HR) the maximal systolic blood pressure (max SBP) and the maximal rate-pressure product (max RPP) could not predict the post-training increase in exercise tolerance. Before training, the maximal oxygen intake (VO2max) was found to be lower, and the HR/VO2max and the SBP/VO2max were higher in the group (11 patients) which showed a good response to the exercise program (effective group) than those in the group (9 patients) which did not (unchanged group). Before training, the HR/VO2max and the SBP/VO2max in the effective group were also higher than those of 96 healthy adults. On the other hand, the HR/VO2max and the SBP/VO2max in the unchanged group were not different from those of the healthy adults throughout the training. It is useful to compare the values of the HR/VO2max and the SBP/VO2max of patients with effort angina to those of healthy adults for the prediction of post-training increase in exercise tolerance.

Angina Pectoris↗
PubMed1983

[Evaluation of left ventricular asynergy by two-dimensional echocardiography: comparison between fixed external axis system and floating axis system].

Detection and quantitative estimation of segmental asynergy in the infarcted area has been impeded by the rotation and anterior movement of the heart during systole. In the present communication, we compared the two measurements determined by the floating and fixed external axis systems. The former takes into account of the effect of cardiac movement. Furthermore, we assessed which system is superior by the left ventriculographic and coronary arteriographic analyses. The materials consisted of 24 cases of myocardial infarction. There was no significant difference between the two systems in the estimation of the number of asynergic segments or between echocardiographic and ventriculographic findings. The floating axis system had a tendency to underestimate asynergy, so that the number of hypokinetic segment estimated by the floating system was greater than that by the fixed external axis system. Therefore, the fixed external axis system was superior to the floating axis system in determining the causative coronary artery.

Adult↗
PubMedDate not supplied

A coordinate axis transformation study of spatial QRS loop in hypertrophic cardiomyopathy.

To obtain an overall view of the QRS loop on vectorcardiograms (VCG) of hypertrophic cardiomyopathy (HCM), the coordinate axis was transformed using the resolver method. The morphological features and planarity of the loop were compared with hypertrophic patterns and hypertensive heart disease (HHD). The subjects in the present study included 30 normal individuals, 40 patients with HCM and 30 with HHD. The HHD group was selected from patients showing left ventricular hypertrophy on VCG similar to that of HCM patients. The HCM group showed significantly greater values than the HHD group in the thickness/length ratio, which represents the planarity of the spatial QRS loop. The above finding suggests that the HCM group had greater deformation in the QRS loop than the HHD group. This may provide a useful indicator for the differential diagnosis of the two diseases.

Adult↗
PubMedDate not supplied

Experimental study on enzyme distribution and its relation to myocardial ischemic changes following coronary circulatory disturbances.

Coronary artery ligation of canine heart was performed to investigate the relationship between the lactate dehydrogenase (LDH) pattern in myocardium and the distribution of coronary flow, especially in the early stage of ligation and after reperfusion. In the myocardium of normal dogs, the LDH pattern was similar in the left ventricle, the interventricular septum, and the right ventricle; the average LD5:LD4 ratio was 1.1, 1.2, and 1.2, respectively, and consisted mainly of heart type. In the left and right auricles, however, the ratios were 0.3 and 0.2, respectively, lacking heart type. In the left ventricle, LD5:LD4 ratio in the subendocardium was different from that in the subepicardial layer. Blood flow distribution in canine myocardium was investigated by the fluorescent pattern on the cut surface of heart, in which 10% fluorescein sodium was injected into the cavity. By this method the evolution of the ischemic area from the endocardial layer to the epicardial side following coronary artery ligation and the effect of reperfusion on the ischemic area were clarified. Electron microscopic studies indicated that loss of mitochondrial function may account for the irreversibility of myocardial cell alteration. A new method for studying enzyme localization in tissues was introduced for studying LDH isoenzyme distribution in normal and injured myocardium.

Animals↗