[Small coronary artery disease].
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Coronary Disease↗
Biomedical subjects
K Mitsunami
Publications and source records attributed to K Mitsunami.
Quantitative measurements of cardiac phosphorus metabolites in coronary artery disease by 31P magnetic resonance spectroscopy.
BACKGROUND: 31P metabolite measurements in the human heart by magnetic resonance spectroscopy (MRS) have been reported previously. By use of a method in which metabolite content was quantified with reference to a standard located outside the chest, it has become possible to measure the content of phosphocreatine (PCr) and ATP in vivo in the human heart. In this study, PCr and ATP contents were measured by 31P MRS and compared in human myocardium with reversible ischemia or scar diagnosed by exercise thallium scintigraphy. METHODS AND RESULTS: Forty-one subjects with stenosis of the left anterior descending coronary artery (> 50%) and 11 healthy control subjects (C) composed the present study group. Patients were divided into two groups on the basis of exercise 201Tl scintigraphy: a reversible 201Tl defect group (RD[+], n = 29) who demonstrated redistribution at late image and a fixed 201Tl defect group (RD[-], n = 12). While the subjects lay supine within the magnet, 31P MR spectra were obtained from the anterior and apical regions of the left ventricle by slice-selected one-dimensional chemical shift imaging. For metabolite quantification, a standard was placed at the center of the surface coil. ANOVA revealed significant differences among the three groups with respect to the mean (+/- SD) PCr at rest (C, 12.14 +/- 4.25 > RD[+], 7.64 +/- 3.00 > RD[-], 3.94 +/- 2.21 mumol/g wet heart tissue, P < .05) as well as a significant decrease in ATP in the RD(-) group (C, 7.72 +/- 2.97; RD[+], 6.35 +/- 3.17 > RD[-], 4.35 +/- 1.52 mumol/g wet heart tissue, P < .05). CONCLUSIONS: Compared with healthy control subjects, PCr content decreased significantly in patients with both reversible and fixed 201Tl defects, and ATP content decreased significantly in subjects with fixed thallium defects. These results suggest that the measurement of ATP content in the human heart by 31P MRS is a clinically important method for the evaluation of myocardial viability.
Adenosine Triphosphate↗
[Assessment of 201Tl myocardial SPECT reinjected at 24 hours after stress imaging].
To improve the quality of 24 hours delayed images (24 DL) of stress thallium-201 myocardial SPECT, reinjection was performed at 24 hours later (24 RI), and the results were compared with those of 24 DL. A total of 45 patients were studied, including 18 patients in 24 DL, 27 patients in 24 RI. All of them showed persistent defect or incomplete redistribution on the routine stress and 3 hours delayed SPECT scans. In 24 RI, 37 MBq of thallium-201 was reinjected at 24 hours later. Myocardial count of 24 DL was about 1/4 of stress image, while 24 RI was about 1/2. Quality of 24 RI image was nearly equal to 3 hours delayed image. Of regions without redistribution at 3 hours delayed image, 5 (36%) regions showed new redistribution at 24 RI. Of regions incomplete redistribution, 6 (25%) regions showed further redistribution. Compared with 24 DL, the frequency of redistribution tended to be higher in this protocol than that of the 24 DL (11%, 17% respectively). In conclusion, the reinjection at 24 hours delayed imaging was considered to be useful to evaluate viability of myocardium in patient with CAD.
Aged↗
[Value of stress-rest ECG gated SPECT one day protocol using 99mTc-MIBI].
A total of 110 patients suspected with CAD who had symptoms or ECG abnormalities were enrolled in the stress-rest ECG gated SPECT one day protocol using 99mTc-MIBI. All the patients underwent symptom-limited exercise testing and 250 MBq of MIBI was injected at peak exercise. Exercise perfusion SPECT images were reviewed by two trained doctors to classify into three groups; normal, equivocal and abnormal. Patients with normal stress image (n = 53) did not receive the resting study. On the other hand, those with equivocal (n = 20) and abnormal (n = 37) stress images performed resting study, including gated SPECT. Of 20 equivocal cases, 16 patients showed unchanged resting perfusion. All of these had normal wall motion. The remaining 4 patients showed improved resting perfusion, indicating presence of myocardial ischemia. Of 37 abnormal cases, 12 patients showed improved resting perfusion, whereas 25 patients showed unchanged resting perfusion. Cardiac events were more often observed in abnormal cases, especially those associated with myocardial ischemia, while good prognosis was obtained in normal cases. Values of this protocol are (1) Patients with normal stress images need no resting study. (2) All the procedure can be completed in one day. (3) Both cardiac function and perfusion can be obtained with gated SPECT. These data indicates that this protocol is valuable for screening patients suspected with CAD.
Coronary Circulation↗
Detection of myocardial ischemia by 31P magnetic resonance spectroscopy during handgrip exercise.
BACKGROUND: The metabolic changes of myocardial ischemia in patients with coronary artery disease assessed by 31P magnetic resonance spectroscopy (MRS) have been reported previously. A significant decrease in the ratio of phosphocreatine (PCr) to ATP during handgrip exercise in a group of patients with severe coronary artery disease has been demonstrated. However, there are no reports at present that directly compare cardiac 31P MRS data with exercise 201Tl myocardial scintigraphy, now established as one of the most important clinical methods to assess myocardial ischemia. The purpose of this study was to investigate whether 31P MRS with handgrip exercise testing is able to detect myocardial ischemia, demonstrated by exercise 201Tl scintigraphy. METHODS AND RESULTS: Twenty-seven patients with severe stenosis of the left anterior descending coronary artery (> or = 75%) and 11 normal control subjects composed the present study. Patients were divided into two groups on the basis of exercise 201Tl scintigraphy: a reversible 201Tl defect group (RD[+]) who demonstrated redistribution at the late image and a fixed 201Tl defect group (RD[-]). While lying supine within the magnet, subjects performed handgrip exercise at 30% of maximal force once in every two cardiac cycles. 31P MR spectra were collected before and during handgrip exercise. Data were corrected for the saturation factor. ANOVA revealed significant differences among the three groups with respect to the mean +/- SD PCr/ATP ratio at rest (control, 1.85 +/- 0.28 > RD(+), 1.60 +/- 0.19 > RD(-), 1.24 +/- 0.30; P < .05). The PCr/ATP ratio decreased significantly from 1.60 +/- 0.19 at rest to 0.96 +/- 0.28 during exercise (P < .001) in the RD(+) group (n = 15). However, in the RD(-) group (n = 12), the ratio did not change significantly during handgrip exercise (1.24 +/- 0.30 at rest versus 1.19 +/- 0.28 during exercise). Similarly, the ratio did not change in the control group (n = 11) (1.85 +/- 0.28 at rest versus 1.90 +/- 0.23 during exercise). CONCLUSIONS: Contrary to normal subjects or patients with fixed thallium defects, the PCr/ATP ratio was significantly altered by exercise in patients with reversible thallium defects. These results suggest that 31P MRS with handgrip exercise testing is a sensitive method for detecting myocardial ischemia.
Adenosine Triphosphate↗
[Cardiac 31P nuclear magnetic resonance spectroscopy of ischemic heart disease--an approach for assessing myocardial viability].
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Humans↗
[Assessment of left ventricular count increase with ECG-gated 99mTc-MIBI SPECT using a single-head rotating gamma-camera].
ECG-gated 99mTc-MIBI SPECT was performed in 33 patients, including 17 normal subjects and 16 patients with old myocardial infarction. To compare the findings by echocardiography (UCG), regional wall motion was qualitatively assessed by cine-mode display and quantitatively measured as an increase in regional count from end-diastole to end-systole. The percent count increase and relative count increase was measured to display on the Bull's eye polar map. In the study of normal subjects, the count increase was greater in apical regions and smaller in septal regions. Regional wall motion by this method correlated well with UCG findings (agreement: 97%, complete agreement: 60%). A mild but significant correlation was observed between the count increase by this method and the percent wall thickening by UCG. We conclude that regional wall motion can be accurately evaluated with ECG-gated 99mTc-MIBI SPECT, which thus permits simultaneous assessment of regional wall motion and myocardial perfusion.
Aged↗
Low-dose dobutamine stress test for the evaluation of cardiac function using ultrafast computed tomography.
High dose-dobutamine (DOB) has been previously used as a pharmacological stress test to evaluate wall motion abnormalities. As a result, recent stress echocardiography with low-dose DOB has been reported to be valuable for investigating stunned myocardium after thrombolysis. However, echocardiography requires an operator's skill and experience to evaluate wall motion abnormalities which are subjectively determined by the observer. In contrast, ultrafast computed tomography (UFCT) does not necessarily require extreme technical skill and experience. To evaluate the feasibility of stress UFCT with low-dose DOB, we scanned 10 normal subjects along the short-axis by 8-slice-multicine mode. After scanning at rest for baseline, we scanned during the administration of 4 and 8 micrograms/kg/min of DOB, respectively, for 5 min. Ejection fraction, contraction, and thickening were higher during 8 micrograms/kg/min of DOB than during 4 micrograms/kg/min of DOB and baseline, while the above values were higher during 4 micrograms/kg/min of DOB than during baseline (p < 0.01). It was possible to detect changes of cardiac function and wall motion due to low-dose DOB by UFCT. We therefore conclude that UFCT is a reliable modality for evaluating cardiac function and wall motion for low-dose DOB stress test because of its excellent spatial and contrast resolution.
Adolescent↗
Evaluation of left ventricular mass: comparison of ultrafast computed tomography, magnetic resonance imaging, and contrast left ventriculography.
We measured and compared left ventricular mass in 20 patients by ultrafast computed tomography (UFCT), magnetic resonance imaging (MRI), and contrast left ventriculography (LVG). Left ventricular mass was calculated by UFCT and MRI in two ways: (1) excluding papillary muscles and trabeculae (LV mass), and (2) including papillary muscles and trabeculae (LV mass + PM&T) by Simpson's method. Left ventricular mass excluding papillary muscles and trabeculae (LV mass) in LVG was calculated by Rackley's method by biplane angiocardiography. LV mass was significantly larger in LVG than in MRI and UFCT (p < 0.01). Although LV mass was significantly larger in MRI than in UFCT (p < 0.01), there was no significant difference in LV mass + PM&T between UFCT and MRI. Interobserver and intraobserver variability showed good correlation of coefficient in both UFCT and MRI. We therefore conclude that left ventricular mass is best measured by including papillary muscles and trabeculae by Simpson's method in UFCT or MRI.
Adult↗
[Evaluation of aortic distensibility using cine MR imaging].
Regional aortic distensibility was measured noninvasively using cine MR imaging to determine whether it correlates with aging or risk of coronary artery disease (CAD). Twenty-two patients with CAD confirmed by angiography and 33 without CAD underwent cine MR imaging. Thirty-two sequential images were obtained in one cardiac cycle. The cross sectional area of the descending thoracic aorta was measured on both diastolic (A) and systolic (A') images. Aortic distensibility (A.D.) was calculated from the following equation: A.D. = (A'-A)/A/delta P. (delta P represents pulse pressure). Results of a simple regression analysis showed that decreased regional aortic distensibility was significantly correlated with the age of the patients (r = -0.762, p less than 0.005). In addition, the parameter was lower in patients with CAD than those without CAD (p less than 0.05). In conclusion, regional aortic distensibility derived from cine MR imaging is a useful parameter to evaluate not only aging but also pathological atherosclerosis of the aorta. In addition, this parameter might have some potential to evaluate the prediction of CAD in patients with normal serum cholesterol.
Adolescent↗
In vivo 31P nuclear magnetic resonance spectroscopy in patients with old myocardial infarction.
To assess the usefulness of in vivo 31P nuclear magnetic resonance (NMR) spectroscopy, we investigated spectra from the myocardium in 6 patients with old Q-wave infarction (QMI), 6 with old non-Q-wave infarction (NQMI) and 9 controls by ECG-gated depth-resolved surface-coil spectroscopy. External hexamethylphosphoric triamide (HMPT) was used to quantify the signal intensities. Left ventricular weight in the region of interest (LVW) was estimated from 1H magnetic resonance images. The extent score by 201Tl scintigraphy was determined in 3 QMI and 4 NQMI patients. No significant differences were found among the 3 groups in peak area ratios of 31P NMR spectra to phosphocreatine (PCr) or adenosine triphosphate (ATP). Compared with controls, significant reductions were observed in values for the peak areas of PCr normalized by the standard HMPT (PCr/HMPT) or by both HMPT and LVW (PCr/HMPT/LVW) for QMI patients (p less than 0.05), and in ATP/HMPT and ATP/HMPT/LVW for QMI and NQMI patients (p less than 0.01). There was a significant negative correlation between ATP/HMPT and the 201Tl scintigraphy extent score (p less than 0.05). These findings suggest that in vivo 31P NMR spectroscopy can detect high-energy phosphate reduction in the infarcted myocardium and may be useful in evaluating myocardial viability.
Adenosine Triphosphate↗
[Cardiac sarcoidosis with multinucleated giant cells detected in endomyocardial biopsy specimens: report of 3 cases].
This is a report of 3 cases of cardiac sarcoidosis. None of the 3 patients had other overt systemic involvement. Multinucleated giant cells and non-caseating epithelial cell granulomas with small lymphocytic infiltrations were detected in the endomyocardial biopsy specimen. Some focal left ventricular wall motion abnormalities were detected by echocardiography and angiography in all 3 patients. Paroxysmal ventricular tachycardia and multifocal ventricular premature complexes were observed by Holter 24-hour electrocardiography in all 3 patients. Two of the 3 patients did not receive corticosteroids, but remaining patient is on a regimen of corticosteroid.
Adult↗
[Evaluation of hepatic venous flow patterns using a pulsed Doppler technique].
Evaluation of hepatic venous flow patterns was attempted by pulsed Doppler echocardiography. Subjects were 80 patients including those with dilated cardiomyopathy, old myocardial infarction, angina pectoris, pulmonary hypertension, constrictive pericarditis, tricuspid regurgitation (TR), lone atrial fibrillation, and post-cardiac surgery. Eleven normal subjects served as controls. The mean age was 53.0 +/- 12.4 years. Most of the TR patients had atrial fibrillation. Patients with aortic regurgitation and significant mitral regurgitation were excluded. Afterload stress by angiotensin II infusion was performed in 51 subjects, mainly for those with ischemic heart disease, cardiomyopathy and the normal controls. Hepatic venous flow patterns included double-peaked flow signals toward the right atrium, and the relationship between systolic (S) and diastolic flow velocities (D) was expressed as the velocity ratio [S/(S+D)]. A reversed flow during atrial systole was expressed as an "A wave" and that between the S and D waves, as an "O wave". Systolic flow velocity was less than diastolic flow velocity in cases with atrial fibrillation and the post-surgical cases. The velocity ratio was greater than 0.5 in nearly all patients with normal sinus rhythm, and less than 0.5 in cases with atrial fibrillation and the post-surgical cases. In the former, systolic flow velocity was less than diastolic flow velocity after defibrillation, in spite of restoration of normal sinus rhythm. These findings indicate that systolic flow velocity was influenced by atrial relaxation; diastolic flow velocity, by ventricular diastolic function. The A wave was increased in cases with pulmonary hypertension and A wave velocity in the hepatic vein correlated with systolic pulmonary artery pressure. In cases with tricuspid regurgitation, reversed flows were detected during ventricular systole both in normal sinus rhythm and in atrial fibrillation. After infusions of angiotensin II the velocity ratio increased in cases with dilated cardiomyopathy and in normal controls (p less than 0.01). The hepatic venous flow pattern after infusion in the former was characterized by dominant systolic and diminished diastolic flow velocities with a consequent increase in the velocity ratio toward 1.0, while a change in the ratio was less marked in normal controls. In conclusion, analysis of the hepatic venous flow pattern by pulsed Doppler echocardiography is very useful for evaluating cardiac function. A marked increase in the velocity ratio after angiotensin II infusion suggests decreased cardiac function.
Adult↗
Comparison of antianginal activity of nicorandil, propranolol and diltiazem with reference to the antianginal mechanism.
Nicorandil was compared with placebo, propranolol and low and high doses of diltiazem therapy in 12 patients with chronic stable angina pectoris to elucidate its antianginal mechanism. A computer-assisted treadmill exercise test was performed after administration of either placebo, 30 mg of nicorandil, 40 mg of propranolol, or low-dose 60 and high-dose 120 mg of diltiazem. Exercise duration and time to the onset of ischemia were significantly increased after each drug administration and there was no significant difference in the percent increase in exercise duration between nicorandil (44 +/- 7%), propranolol (47 +/- 11%) and high-dose diltiazem (39 +/- 5%) compared with placebo. Nicorandil increased exercise duration in patients with 1-vessel disease more effectively (7.5 +/- 0.7 minutes, p less than 0.05) than either propranolol or low-dose diltiazem (6.7 +/- 0.7, 6.1 +/- 0.9 minutes, respectively). The decrease in blood pressure obtained with nicorandil was approximately the same as that with diltiazem. Nicorandil increased exercise duration associated with higher peak double product compared with low-dose diltiazem. In contrast, high-dose diltiazem increased exercise duration at the same double product as low-dose diltiazem. Propranolol increased exercise duration at a lower level of peak double product. Because our previous study demonstrated that low-dose diltiazem yielded a plasma concentration high enough to reduce coronary tone, it appears unlikely that nicorandil will reduce coronary tone further and subsequently increased coronary reserve. Therefore, left ventricular preload reduction may be the mechanism responsible for higher values of double product obtained with nicorandil.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Clinical significance of Aqrs, At and ventricular gradient in single vessel coronary artery diseases.
Deflection area vectors of QRS (Aqrs) and T (At) and ventricular gradient (G) calculated from vectorcardiographic leads were compared in single vessel coronary artery diseases divided into subgroups of normokinetic, hypokinetic and akinetic by left ventriculography. In the LAD group, Aqrs shifted posteriorly, At were smaller and shifted to the right and G were smaller and shifted posteriorly or to the right. In the RCA group, Aqrs were smaller and shifted upwards, At shifted upwards and G were smaller and shifted upwards. In the LCx group, Aqrs shifted upwards, At shifted anteriorly and upwards and G were smaller and shifted upwards. Decreased magnitude and directional change of G reflect the severity and location of myocardial damage.
Adult↗
[A case of cardiac sarcoidosis diagnosed by endomyocardial biopsy].
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Biopsy↗
Clinicopharmacological studies of a newly synthesized cardiotonic agent (TA-064) in patients with congestive heart failure.
In animal experiments, a new inotropic agent, (-)-(R)-1-(p-hydroxyphenyl)-2-[(3,4-dimethoxyphenetyl)amino] ethanol, designated TA-064 was found to possess a more positive inotropic than chronotropic action. Its effectiveness and lack of significant toxicity make it beneficial for clinical use as a cardiotonic in human heart failure. The effects of TA-064 were investigated in patients with various types of heart disease (n = 29). Cardiac output increased, left ventricular end-systolic dimension decreased, and left ventricular fractional shortening increased for 15 minutes after a single intravenous dose (1 mg). The plasma level of TA-064 at the cessation of infusion was 61.1 +/- 49.6 ng/ml and thereafter declined biexponentially. After a single oral dose (10 mg), TA-064 appeared in the plasma at 30 minutes and reached its peak levels of 13.7 +/- 5.6 ng/ml at 60 minutes. Seven hours later, the plasma level was 5.9 +/- 3.1 ng/ml which was considered to be within the effective range according to the results after intravenous administration. In conclusion, minimal effective plasma levels of TA-064 are obtained by oral administration of 10 mg three times a day.
Administration, Oral↗
Changes of Ca2+-ATPase and cytochrome oxidase activity of myocardial cell under early and late ischemia:--comparison with ultrastructural changes.
Using the histo- and cytochemical technique we assessed the Ca2+-transporting function of mitochondria (Mit) and sarcoplasmic reticulum (SR), and the ATP producing function of Mit in the ischemic myocardial cell of a dog's heart. In comparing ultrastructural ischemic changes, cytochrome oxidase (CO) and Ca2+-ATPase were cytochemically and histochemically measured when the myocardium was subjected to the ischemia of left anterior descending coronary artery occlusion for 15 min, and 60 min. After 15 min of occlusion the ischemic alterations consisted of a wide I band, decreased glycogen (G) and Mit swelling with a slight reduction of matrix density. Although CO activity was not reduced, Ca2+-ATPase had decreased mainly in Mit. Sixty min of ischemia resulted in loss of G, intermyofibrillar edema, marked Mit swelling with loss of matrix density and partial disruption of cristae, and dilatation of SR. Ca2+-ATPase activity was significantly reduced in Mit, SR and myofibrils. Although there was Mit swelling with partial disruption of cristae after 60 min of ischemia, CO activity was found to still exist in the remaining cristae. These findings suggest that intracellular organelle dysfunction progresses in the ischemic myocardial cell at different rates, and that disruption of intracellular Ca2+-homeostasis may occur early in the ischemic state.
Animals↗