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H Hishida

Publications and source records attributed to H Hishida.

At least 55 records · Page 3Linked to original sources
PubMed1995

[Body surface distribution of the signal-averaged ECG in patients with previous myocardial infarction].

Signal-averaged electrocardiograms (SAEs) were recorded from 28 unipolar leads placed on the upper body in patients with previous myocardial infarction (MI). We measured the filtered QRS duration (fQRSd) for each lead to obtain a new parameter, called a "departure ratio (DR)". The DR was the standardized difference between the fQRSd of a patient and the mean fQRSd obtained in the healthy controls in each of the 28 leads. A DR map was then constructed using the DR. Patients with sustained ventricular tachycardia (VT) demonstrated a small negative area surrounded by dense, positive iso-DR lines and/or a large maximum. These features were located on the left anterior chest through the left back in patients with anterior MI and on the right lateral to the right anterior chest in patients with inferior MI. Both of these characteristic patterns in the area corresponding to the infarct site were present in few patients without VT. These characteristic patterns were highly correlated with the occurrence of sustained VT, suggesting that the characteristics of the DR map represent the body surface manifestation of delayed excitation conduction which can be a sustained VT substrate. Our results indicate that the DR map based on the fQRSd on SAE provides useful information that could not be obtained from vector magnitude analysis.

Body Surface Potential Mapping↗
PubMed1995

[Body surface ST mapping in daily life using multi-lead ambulatory electrocardiograph].

To extend the usefulness of multi-lead ambulatory electrocardiography, we attempted to construct body surface isopotential maps of ST segment using our newly designed multi-lead ambulatory electrocardiograph. Material consisted of 40 patients (pts) with angiographically proven coronary arterial stenosis. By a commercially-available 4-channel recorder and a specially designed adapter, 30-lead ECGs were sequentially recorded together with body position signals for 24 hours. Compensation for ST distortion and interpolation of ST level on time scale techniques were performed before construction of ST maps. The extension of ST depression area in pts with single LAD disease were larger than in pts with single LCX or RCA disease. As time elapsed, after occurrence of ischemia the extension and location of ST depression area were changed. These results were thought to be reasonable. In conclusion, the ambulatory recording of body surface ST maps may become useful for study of myocardial ischemia in daily life.

Aged↗
PubMed1994

Early detection of successful coronary reperfusion based on serum myoglobin concentration: comparison with serum creatine kinase isoenzyme MB activity.

The usefulness of serum myoglobin (Mb) concentration for early detection of successful reperfusion was compared with that of creatine kinase isoenzyme MB (CKMB) activity in 49 patients with acute myocardial infarction. To determine accurately the time of reperfusion, we performed coronary angiography every 5 minutes during reperfusion therapy. Reperfusion was obtained in 32 patients (reperfused group) but not in 17 patients (nonreperfused group) until 60 minutes after the initiation of reperfusion therapy. Blood samples were taken before and 15, 30, and 60 minutes after the angiographic confirmation of reperfusion in the reperfused group. In the nonreperfused group, samples were taken before and 15, 30, and 60 minutes after the initiation of treatment. We calculated the Mb ratio (value after reperfusion or treatment initiation to value before) and CKMB ratio (value after to value before). When values > 2.4 for the Mb ratio or > 2.0 for the CKMB ratio were used as the criteria for reperfusion within 60 minutes after initiation of treatment, the sensitivities were 91% and 56% at 15 minutes after reperfusion, 97% and 84% at 30 minutes, and 100% and 100% at 60 minutes, respectively. For each ratio the specificity of detection was 100% at all times evaluated. Thus the Mb ratio accurately detected the success of reperfusion as early as 15 minutes after reperfusion and may be more useful than the CKMB ratio for detecting the success of reperfusion within 30 minutes.

Adult↗
PubMed1992

Evaluation of cardiac motion and function by cine magnetic resonance imaging.

Cardiac cine magnetic resonance imaging (MRI) was studied to evaluated the cardiac motion and function, and a water-stream phantom study was performed to clarify whether it was possible to quantitatively assess the valvular regurgitation flow by the size of the flow void. In normal subjects, the left ventricular (LV) epicardial apex swung up to the base only a few millimeters, and the mitral annulus ring moved about 14 mm as mean value toward the apex during systole. Those motions of mitral annulus ring may contribute to the left atrial filling. The LV longitudinal shortening and torsions were shown by the tagging method. This tagging method was the best method for estimating cardiac motions. Cardiac cine MRI using software including a modified Simpson's method program and a wall motion analysis program was useful for routine LV volumetry and wall motion analysis because it was a simple and reliable method. Our water-stream phantom studies demonstrated that it might be difficult to perform quantitative evaluation of valvular regurgitation flow by using only the size of the flow void without acquiring information relating to the orifice area.

Adult↗
PubMed1992

Evaluation of the effect of PTCR/PTCA by 99mTc-MIBI myocardial imaging in acute and old myocardial infarction.

This study is to clarify the ability of technetium-99m-Hexakis-2-methoxyisobutyl isonitrile(MIBI) myocardial scintigraphy for assessment of the effect of PTCR/PTCA as compared with conventional thallium-201 myocardial scintigraphy (201Tl). 99mTc-MIBI (740-888MBq) was injected before emergency PTCR/PTCA, and the initial imaging was performed immediately after PTCR/PTCA in 4 patients with acute myocardial infarction (AMI). On the other hand, in 2 patients with old myocardial infarction (OMI), 201Tl and MIBI myocardial imagings were performed before and one week after rescue PTCA. The defect area on the follow-up MIBI imaging was smaller than that on the initial MIBI imaging in 2 patients with successful emergency PTCR/PTCA. But in the other 2 AMI patients with unsuccessful reperfusion, the defect area did not significantly decrease after PTCR/PTCA. Reperfusion was successful in one of the two patients with OMI. In both the two patients with OMI, the MIBI defect area did not significantly decrease after rescue PTCA. MIBI myocardial scintigraphy is a useful noninvasive method for evaluating the effect of emergency PTCR/PTCA for myocardial salvage in patients with AMI, because MIBI is a kit type agent, and it does not redistribute.

Aged↗
PubMed1990

Evaluation of cardiac tissue from two-dimensional echocardiogram: analysis of gray level and its distribution.

Two-dimensional echocardiograms of parasternal long-axis view were recorded and the mean echo intensity and its distribution in the interventricular septum were examined for the purpose of inferring myocardial tissue. Six healthy subjects (N), 29 with left ventricular hypertrophy (LVH), and 12 with old anteroseptal myocardial infarctions (MI) were used in the study. Settings for gain control were adjusted in the constant manner. Data were recorded on a Video tape recorder, with analog data converted to digital signals, subjected to a low-pass filtering, and then analyzed by a Computer tomography image processor. The region of interest was set within the interventricular septum, and a mean relative echo intensity and its histogram (number of pixels showing different echo intensity) was evaluated. The histogram patterns were examined and the parameter for skewness, which shows asymmetrical characteristics, and the parameter for kurtosis, which shows degree of peakedness of distribution, were calculated. Relative echo intensity was found to increase in the order MI greater than LVH greater than N. Histograms showed the majority of pixels were concentrated at the low echo intensity level in the normal group, while pixels were distributed in a relatively gentle slope around the mean value in the LVH group. Many pixels were in the high intensity levels in the MI group, although the rest were dispersed throughout various intensities including low level. The differences are thought to be related to the extent and density of fibrosis. Analysis of two-dimensional echocardiographic echo intensity and distribution may be useful in characterizing myocardial tissues.

Adult↗
PubMed1989

[The pharmacokinetics of cisplatin and its influence on renal function according to different infusion methods (report II)--alleviation of renal impairment by bismuth subnitrate combined with ginseng and tang-koui ten].

In the previous report, we discussed in vivo dynamics and renal impairment resulting from the difference in cisplatin CDDP administration. In the present study, we investigated in vivo dynamics and renal impairment under 1 h of continuous drip infusion of CDDP. The free-type Pt concentration ratio, which is considered to indicate antitumor activity in the overall plasma Pt concentration at the end of the administration, was noted to be approximately 64%. This was significantly higher than other administration methods, making this an effective administration procedure. However, NAG, which is considered to be an index of renal impairment along with the amount of beta 2-microglobulin urine excretion, showed higher values than those by other administration methods. Thus, using the 1-hr continuous CDDP drip infusion, we attempted to alleviate the renal impairment, combining bismuth subnitrate with ginseng and Tang-koui ten. As a result, the amount of beta 2-microglobulin excretion in the urine was diminished as well as NAG, and a reduction of the renal impairment was noted. These alleviational effects of the renal impairment were attributed to the method of consistent oral administration by which alleviation could take place with little load on the patient.

Acetylglucosaminidase↗
PubMed1988

Experimental study on significance of QRS area map--comparison with VAT map.

The QRS area map, which is obtained by time integration of the QRS potential, is assumed to correlate with the ventricular activation time (VAT) map. Using 16 mongrel dogs, the QRS area map and VAT map from cardiac and body surface were compared during sinus rhythm and left and right ventricular endocardial pacing. The cardiac surface QRS area map resembled the cardiac surface VAT map, and it was considered useful to estimate the excitation sequence. The body surface QRS area map localized the stimulus site more easily during pacing than the body surface VAT map. Therefore, it was considered useful to determine the site at which a ventricular extrasystole occurs. The QRS area map proved to be more reproducible than the VAT map.

Animals↗
PubMed1988

[Evaluation of coronary blood flow using digital subtraction technique and cine coronary angiography: a preliminary report].

To evaluate coronary circulation in ischemic heart disease, digital image processing with cine coronary angiography was performed. Using time-density curves obtained from individual pixels, images showing the distribution of contrast density and transit time were obtained. To record angiograms, contrast medium was injected into the coronary artery in a steady manner during right atrial pacing. Frames in the end-diastolic phase immediately before the P wave were selected, and digitized into a 512 x 512 x 8 bit matrix using a system composed of a video camera, an analog-to-digital converter, and a computer. These digitized images were then stored in a disk memory. A mask image was prepared before the injection of contrast medium. Subtraction was performed using the mask image and a series of images following contrast injection. The subtracted images were of sufficient quality to permit clear observation of the individual coronary arterial branches. Time-density curves were then determined from these subtracted images. From these curves, time from the onset of contrast injection to its peak density (Tp), time from the peak density to the half peak density (T 1/2) and the attenuation factor of the curves (tau) were derived. Their distributions were expressed as color images. Examples of a normal control and a case of inferior infarction were demonstrated. Blood flow function images with good spatial resolution were thus obtained. This method is useful for evaluating coronary blood flow.

Angioplasty, Balloon↗
PubMed1988

[Analysis of myocardial texture in two-dimensional echocardiographic images].

To evaluate tissue changes, we studied myocardial texture using two-dimensional echocardiographic images. We investigated 19 normal subjects, 28 patients with left ventricular hypertrophy, and 12 patients with old anteroseptal myocardial infarction of longer than one year duration. Using 2.5, 3.5, and 5.0 MHz transducers, two-dimensional echocardiograms in the parasternal long-axis view were obtained, and the textures of the interventricular septal images were classified in three types; type I, with a nearly uniformly speckled or echolucent appearances; type II, with multiple, discrete, small (2 to 4 mm) highly refractile echoes; type III, with larger highly refractile echoes (greater than 4 mm) appearing as a cluster of broad patches or band-like echoes. Normal subjects belonged to the type I texture, while many with left ventricular hypertrophy belonged to the type II category. Type III was often observed in patients with old anteroseptal infarction. Using a transducer of higher frequency, there tended to be a shift from type II to I or type III to II. In phantom experiments using carbolandam granules instead of the myocardium, the echocardiographic texture became rough when the phantom was farther from the transducer or the transducer was of low frequency. We suggest that the texture in two-dimensional images may reflect myocardial tissue changes, when other factors including the apparatus and technique remain stable.

Adult↗
PubMed1988

[Assessment of interaction between the left and right ventricles using pressure-volume loops in various heart diseases].

To assess the interaction and interdependence of left and right ventricular function, ECG-gated radionuclide angiocardiography was performed immediately after cardiac catheterization during right atrial pacing for 11 patients with old myocardial infarction (MI), two with non-obstructive hypertrophic cardiomyopathy, one with aortic stenosis (AS), two with pulmonary infarction (PI), and one with neurocirculatory asthenia (NCA). Absolute left ventricular (LV) volume curves were obtained by the count-based method with attenuation factor corrections. Biventricular pressure and volume curves were digitized and synchronized to end-diastole, and pressure-volume (P-V) loops were constructed throughout a cardiac cycle. The stroke work index (SWI), the work index per min (WI/M) and the contractility index (CNTI) were calculated from the P-V loops. In a patient with NCA, LV end-diastolic volume decreased during rapid pacing, but no significant change in the LV end-systolic P-V relation was recognized. However, the entire right ventricular (RV) P-V loop was shifted toward the left during rapid pacing. In a patient with AS, the LV P-V loop was markedly enlarged and every parameter of LV function was much greater than that of the right ventricle due to increased LV afterload. The areas of RV P-V loops in two patients with PI were larger than those of other patients, because RV pressure was relatively high, and RV volume was increased. It is suggested that RV pressure and volume overloads prevail in patients with PI. In four MI patients with three vessel disease and having collateral circulation, the LV end-systolic P-V relationship was shifted toward the lower right, and every parameter (SWI, WI/M, CNTI) of LV function decreased by rapid pacing. Myocardial ischemia may be induced by rapid pacing stress, causing decreased LV contractility. It was concluded that the P-V loops obtained by RNA and catheterization are clinically useful for estimating the interaction and interdependence between right and left ventricular hemodynamics.

Adult↗
PubMed1987

[Two-dimensional echocardiographic echo intensity distribution by histographic analysis].

To assess myocardial tissue changes, the distribution of echo intensities of two-dimensional echocardiograms was analyzed using a histogram. The materials were obtained from six normal subjects (N), 29 patients with left ventricular hypertrophy (LVH), and 12 patients one year or more after the onset of anteroseptal myocardial infarction (MI). A transducer with a central frequency of 2.3 MHz was used. Scanner receiver settings, including sensitivity-time control, were kept constant for all subjects. The parasternal long-axis image was digitized and computer-processed. The region of interest was located within the interventricular septum. The mean echo intensity and its distribution were studied. The shape of the histogram was evaluated for skewness and kurtosis. Relative echo intensity: N = 0.23 +/- 0.07 (mean +/- SD) less than LVH = 0.58 +/- 0.18 less than MI = 1.07 +/- 0.25 (p less than 0.01). Skewness: N = 1.58 +/- 0.63 greater than LVH = 0.60 +/- 0.61 greater than MI = -0.14 +/- 0.43 (p less than 0.01). Kurtosis: N = 18.0 +/- 7.3 greater than LVH = 10.5 +/- 3.3 greater than MI = 7.7 +/- 0.9 (p less than 0.01). These differences may closely relate to an increase in collagen fiber content. Consequently, analysis of the myocardial echo intensity distribution, in addition to mean echo intensities, may become a clinically useful approach for identifying myocardial tissue changes.

Adult↗
PubMed1987

[The pharmacokinetics of cisplatin and its influence on renal functions based on different infusion methods].

The pharmacokinetics of cisplatin, together with its renal toxicity in relation to different infusion methods were examined. The subjects were 21 in-patients suffering from pulmonary carcinoma treated by anti-neoplastic agents including cisplatin. The patients included 12 given a 5-division dosage, 5 cases given 24-hour continuous infusion, 6 given 12-hour continuous infusion, and 7 given 6-hour continuous infusion. Cisplatin was determined as the concentrations of Pt in plasma and non-protein-bound Pt. Also, as indices of renal function, NAG in urine together with beta 2-microglobulin were examined. No substantial difference could be found in Pt concentration in plasma upon completion of the respective infusion methods. A dual-phase attenuation curve was obtained after the completion of infusion and the half-life period of the beta-phase was around 200 hours. With respect to non-protein-bound Pt concentrations, the 5-division dosage showed the highest value, which was considered to be a temporary phenomenon, while with continuous infusion, the shorter the infusion period, the higher the value became. With respect to the amount of NAG excreted in urine, 12-and 6-hour continuous infusion showed the higher value in comparison with the others in terms of the maximum value and the total amount. With regard to beta 2-microglobulin, 6-hour continuous infusion showed the highest value. The above results therefore suggest that in continuous infusion, the shorter the infusion period the greater the degree of renal tubule injury, and that particularly, 6-hour continuous infusion will possibly cause dysfunction of the renal tubules.

Acetylglucosaminidase↗
PubMed1987

[Ultrasonic tissue characterization in diagnosing myocardial infarction].

To evaluate myocardial tissue changes using two-dimensional (2D) echocardiography, several approaches were attempted. 1. Quantitative evaluation of the myocardial echo intensity by computerized image processing in patients with old anteroseptal myocardial infarction: 2D echocardiograms of the parasternal long-axis view were converted to digital images to measure the echo intensity of the regions of interest (ROI) placed in the interventricular septum (IVS), the left ventricular posterior wall (LVPW), the left ventricular cavity, and the pericardium. The mean value of the echo intensity was compared with that of the pericardium (maximum echo intensity) and of the left ventricular cavity as the minimum. In 12 normal subjects, the relative echo intensity of the IVS was 0.40 +/- 0.05 (mean +/- SE), whereas it was 0.71 +/- 0.06 in 11 patients with old MI (p less than 0.001). Color display facilitated the visual recognition of the numerical differences in echo intensities. 2. Evaluation of the myocardial echo intensity in acute phase of myocardial infarction: In nine normal elderly persons, the relative echo intensity of IVS was 0.29 +/- 0.14, and there was no significant change in the early stage (three to seven days) of acute infarction (0.31 +/- 0.14). Two weeks later, however, a significant increase was noted (0.61 +/- 0.10) (p less than 0.01), probably due to an increase in collagen fibers. 3. Changes of the myocardial echo intensity in acute myocardial ischemia: Two-dimensional echocardiograms were recorded in nine open-chest dogs using 3 and 5 MHz transducers before and 10 min, 1 hr, 3 hrs, and 6 hrs after coronary artery ligation. With the 5 MHz transducer, the echo intensity of the ischemic myocardium was decreased after 10 min and was remarkable after 1 hr (0.24 +/- 0.08), and restored in six hrs. These changes could not be detected using the 3 MHz transducer. 4. An in vitro study for assessment of ultrasonic attenuation in the canine infarcted myocardium: The frequency dependency of ultrasonic attenuation of the resected canine myocardium in the frequency region of 2 MHz to 7 MHz was estimated one and two weeks after coronary artery ligation. The distributions of attenuation characteristics were nearly consistent with those of collagen contents determined histologically. In conclusion, we demonstrated that acute and chronic ischemia of the myocardium influences the transmission and reflection of ultrasound. By applying this property, ultrasonic tissue characterization may become a useful tool for detecting myocardial ischemia in the near future.

Adult↗