[Atrial volumes after Fontan operation].
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Adolescent↗
Biomedical subjects
A Takao
Publications and source records attributed to A Takao.
[Azygos and hemiazygos connections imaged by two-dimensional, and pulsed and color Doppler echocardiography].
Identification of the azygos or hemiazygos connection is important in the diagnosis of congenital heart disease, especially in cases of the polysplenia syndrome. Although two-dimensional echocardiographic observation of this anomaly has been reported, the direct visualization of drainage sites is still rather difficult. A method for visualizing the azygos or hemiazygos connection by a combined use of two-dimensional and pulsed and color Doppler echocardiography was reported here. Subjects consisted of 10 patients with the polysplenia syndrome, each of whom had been confirmed as having the azygos or hemiazygos connection; five each of the azygos and hemiazygos types. The transducer was placed over the second intercostal space on the right side for the azygos, and on the left side for hemiazygos connection. The two-dimensional echocardiographic plane was adjusted to visualize the long-axis view of the superior vena cava; the right superior vena cava for the azygos and the left superior vena cava for the hemiazygos connection. The mode of the equipment was changed to color Doppler, and an orange-colored blood flow toward the transducer, draining into the superior vena cava was carefully sought. Finally the pulsed Doppler mode was selected and the sampling volume was set in the orange-colored area. The wave form of the pulsed Doppler echocardiogram of the azygos or hemiazygos vein potentially had two peaks per cardiac cycle, and was modified by respiration. We found azygos or hemiazygos veins coursing from the posterior aspect of the right pulmonary artery in seven of 10 cases by two-dimensional echocardiography alone, while we observed all veins by the additional use of color and pulsed Doppler echocardiography.
Adolescent↗
[Our technique of sagittal splitting of the mandibular ramus].
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Asian People↗
Enhancement of 5-fluorouracil delivery to sarcoma 180 tissue under angiotensin II-induced hypertension chemotherapy.
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Angiotensin II↗
An infant with dilated cardiomyopathy confirmed as myocarditis by endomyocardial biopsy.
A case of an 11-month-old infant who was incidentally diagnosed as having myocarditis by right and left ventricular endomyocardial biopsy is reported. This patient was admitted because of heart failure. Chest X-ray showed cardiomegaly and an electrocardiogram revealed decreased voltage with right atrial and right ventricular overloading. A dilated left ventricle with poor ejection fraction was shown in an echocardiogram. Dilated cardiomyopathy was the initial diagnosis since there was no episode of preceding viral infection or evidence of an inflammatory process in routine laboratory investigations. However, the biopsy findings, including massive infiltration of inflammatory cells and myocyte degeneration, indicated myocarditis. To our knowledge, this is the youngest patient in whom myocarditis has been confirmed by endomyocardial biopsy.
Biopsy↗
Effect of isoproterenol on myocardial mechanical function and cyclic AMP content in the fetal rabbit.
The effect of isoproterenol on mechanical function was studied in the isolated arterially perfused heart of the fetal (21st and 28th day of gestation) and newborn rabbits. The inotropic effect of isoproterenol in the fetus was less than in the newborn. In contrast, myocardial cyclic AMP levels after isoproterenol infusion in the fetus were greater than in the newborn. The inotropic effects of dibutyryl cyclic AMP and of calcium in the fetus were less than in the newborn. These data suggest that the process from beta-receptor to cyclic AMP in the fetus was equally or even more responsive to isoproterenol than in the newborn. The diminished inotropic effect of isoproterenol in the fetus may be due, at least in part, to the decreased inotropic effect of calcium.
Animals↗
Thrombocytopenia in patients with aortopulmonary transposition and an intact ventricular septum.
Relations between platelet counts and mean pulmonary arterial pressures, capillary oxygen tension, and haematocrit were studied in 37 patients, aged 2 to 16 months, with simple aortopulmonary transposition (an intact ventricular septum and no ductus arteriosus). There was a statistically significant inverse relation between pulmonary arterial pressures and platelet counts. Six out of the eight patients (4-16 months old) with raised mean pulmonary arterial pressure had thrombocytopenia (less than 100,000/mm3) and none of the 25 patients with a normal mean pulmonary pressure (less than or equal to 20 mm Hg) showed thrombocytopenia. Pulmonary arterial pressures were not measured in four patients: the platelet count was 7000/mm3 in the patient with a left ventricular systolic pressure of 90 mm Hg but it was greater than 100,000/mm3 in the three in whom left ventricular systolic pressure was less than 50 mm Hg. Platelet counts were positively correlated with capillary oxygen tension and inversely correlated with haematocrit in all 37 patients. Despite the persistence of pulmonary hypertension, thrombocytopenia improved after corrective surgery in five patients, even in those who had thrombocytopenia before operation. These data suggest that the presence of thrombocytopenia is not solely related to the development of pulmonary vascular disease. Pulmonary vascular disease, however, does contribute to the early development of thrombocytopenia in patients with simple aortopulmonary transposition.
Blood Pressure↗
Obstruction of the central pulmonary artery after shunt operations in patients with pulmonary atresia.
The central pulmonary artery was studied angiographically 1-10 years after a palliative operation in 56 patients (mean age 6 years, range 1-20) with congenital heart disease and pulmonary atresia. All of them had originally had a central pulmonary artery that was common to both the right and left pulmonary arteries. Juxtaductal obstruction of the left pulmonary artery had developed in 70% of the patients; in 40% the obstruction was atretic unilaterally. Atresia developed at the right junction to the ductus where there was a shunt to the right pulmonary artery and at the left junction where there was a shunt to the left pulmonary artery. Stenosis causing a reduction of more than 50% of the inner diameter developed at the anastomotic site in 10% of 30 patients with a functioning Blalock shunt. In contrast, there was occlusion of the pulmonary artery or its upper branch in 73% of 11 patients with a non-functioning anastomosis.
Adolescent↗
Influence of acidosis on inotropic effect of catecholamines in newborn rabbit hearts.
The influence of acidosis on the inotropic effect of isoproterenol was studied in the isolated arterially perfused heart of the newborn rabbits. Baseline mechanical function during acidosis (pH 6.8) was not different from control (pH 7.4). However, the inotropic effect of isoproterenol was significantly suppressed in the acidotic muscles. The increment of myocardial adenosine 3',5'-cyclic monophosphate (cAMP) content during isoproterenol infusion was also reduced in acidosis. Inotropic effects of Ca and dibutyryl cAMP in the acidotic muscles were not significantly different from those in the control muscles. beta-Receptor number and affinity in the respiratory acidotic muscle was similar to those in the control muscle. Effects of pH on myocardial beta-receptor and adenylate cyclase activity were further determined in the membrane fraction by changing the pH of the reaction medium from 7.4 (control) to 6.8 or 6.0. beta-Receptor numbers were significantly decreased at pH 6.0 but not at pH 6.8. Adenylate cyclase activity was depressed at pH 6.8 and 6.0. These data suggest that the inotropic effect of isoproterenol is diminished in the acidotic muscle. This may be due to the decreased activation of cAMP production, which in turn most likely results from depressed adenylate cyclase activity.
Acidosis↗
Flow dynamics in the main pulmonary artery after the Fontan procedure in patients with tricuspid atresia or single ventricle.
We analyzed the flow velocity pattern in the main pulmonary artery after Fontan operation in patients with tricuspid atresia (n = 10) or with single ventricle (n = 10) by means of a catheter-mounted velocity probe. The area underneath the velocity signal of the forward flow was integrated, and ratios of the portions during atrial systole and during the diastolic phase to the total area (Fa and Fd) were calculated. The Fa was 0.54 +/- 0.09 in patients with tricuspid atresia and 0.45 +/- 0.05 in those with single ventricle (p less than .01). Cardiac output, obtained by the thermodilution method, was 2.45 +/- 0.48 liters/min/m2 in patients with tricuspid atresia and 2.75 +/- 0.72 liters/min/m2 in those with single ventricle. The forward flow during atrial contraction, calculated by multiplying Fa by cardiac output, was 1.32 +/- 0.35 liters/min/m2 in patients with tricuspid atresia and 1.23 +/- 0.33 liters/min/m2 in those with single ventricle. The diastolic forward flow, calculated from Fd and cardiac output, was 0.99 +/- 0.25 liter/min/m2 in patients with tricuspid atresia and 1.52 +/- 0.45 liters/min/m2 in those with single ventricle (p less than 0.005). The sum of cross-sectional areas of the right and left pulmonary arteries normalized by body surface area (PA index) was 282 +/- 85 cm2/m2 in patients with tricuspid atresia and 462 +/- 65 cm2/m2 in those with single ventricle (p less than .005). The Fa was inversely correlated with the PA index in the whole group (r = -.69) and also in the tricuspid atresia group alone (r = -.87).(ABSTRACT TRUNCATED AT 250 WORDS)
Blood Flow Velocity↗
Development of myocardial contractile system in the fetal rabbit.
Developmental changes in the myocardial contractile system were evaluated in the fetus at 18, 21, and 28 days of gestation (full term 31 days) and in 3- to 5-day-old newborn rabbits. Mechanical function was studied using the isolated arterially perfused heart. Perfusion with ryanodine (10(-5) M), an inhibitor of Ca release from the sarcoplasmic reticulum, decreased contractile force and increased the time to peak tension in the 28-day fetus and newborn but these changes were minimal in the 18- and 21-day fetus. Postextrasystolic potentiation, which is thought to be caused by Ca release from the sarcoplasmic reticulum, was observed in the 28-day fetus and the newborn, but was not significant in the 18- and 21-day fetus. An ultrastructural study showed poorly developed sarcoplasmic reticulum and myofibrils in the 18- and 21-day fetus. Although the maximum developed tension observed at high extracellular calcium increased with development, the relative value of developed tension at various extracellular calcium was similar in the three fetal groups and only in the newborn the extracellular calcium-developed tension curve shifted to the right. Myofibrillar yield increased with development but sensitivity of myofibrillar ATPase activity to Ca was similar in the fetus and newborn. These data suggest that 1) the sarcoplasmic reticulum does not function significantly in the 18- and 21-day fetus, 2) although sarcoplasmic reticulum starts to function at late gestation, it does not cause significant changes in intracellular calcium in the fetal period, 3) myocardial contractility remains similar in the fetus from the 18th to 28th day of gestation and major changes in contractility occur after birth.
Animals↗
Effect of milrinone on myocardial mechanical function and cyclic AMP content in the fetal rabbit.
The effect of milrinone on mechanical function was studied in the isolated arterially perfused heart of the fetal (28th day of gestation) and newborn rabbits. The inotropic effect of milrinone in the fetus was significantly less than in the newborn. After milrinone infusion, myocardial cyclic AMP levels increased significantly in the two age groups and the fetal values before and after milrinone infusion were not significantly different from the newborn values. In our previous study the inotropic effects of dibutyryl cyclic AMP and high extracellular calcium in the fetus were significantly less than in the newborn. These data suggest that the diminished inotropic effect of milrinone in the fetus may be due, at least in part, to the decreased inotropism of cyclic AMP and calcium.
1-Methyl-3-isobutylxanthine↗
In vivo constriction of the ductus arteriosus by nonsteroidal antiinflammatory drugs in near-term and preterm fetal rats.
Herein we report age differences of in vivo constriction of the fetal ductus arteriosus by nonsteroidal antiinflammatory drugs in near-term and preterm rats. Two potent nonsteroidal antiinflammatory drugs, indomethacin and flurbiprofen, were studied in preterm (19th and 20th day) and near-term (21st day) rats, whose gestational period was 21.5 days. The time course of fetal ductus constriction was studied on the 20th (preterm fetus) and the 21st (near-term fetus) days of gestation with indomethacin (1 mg/kg, 10 mg/kg) and flurbiprofen (10 mg/kg). In addition, 5 mg/kg of indomethacin was used on the 21st day. Maximal ductal constriction was noticed 8 h after administration. Constriction of the ductus was significantly weaker on the 20th day than on the 21st day in all three studies including indomethacin 1 mg/kg, 10 mg/kg, and flurbiprofen, 10 mg/kg. Dose-response curves were studied at 4 h following administration of indomethacin on the 19th, 20th, and 21st days, and flurbiprofen on the 20th and 21st days. With both drugs, the ductus constricted more vigorously on the 21st day than on the 20th or 19th day. These studies showed a weaker constrictive response of the ductus to nonsteroidal antiinflammatory drugs in the preterm fetus than in the near-term fetus. Twenty-four h after administration of indomethacin on the 20th day, the fetal ductus was dilated, although its plasma indomethacin concentration was high and comparable with that obtained 4 h after administration. These results show that the response of the fetal ductus to indomethacin decreased further at 24 h after administration to preterm rats.
Animals↗
In situ morphology of the heart and great vessels in fetal and newborn rats.
Morphology of the cardiac chambers and great vessels of fetal and neonatal rats was studied using the whole body freezing technique and by sectioning through the short axis of the heart with a freezing microtome. Compared to the fetal heart, the neonatal heart showed rapid change 2 to 8 days after birth. The ventricular sinus septum was straight in the fetus and became concave to the left ventricle after birth. The right ventricular wall was as thick as the left in the fetus and became thinner rapidly after birth. At the same time, the right ventricular cavity dilated. The right and left pulmonary arteries and pulmonary veins were small in the fetus and enlarged soon after birth. At the same time, the foramen ovale was closed and the diameters of the inferior vena cava and descending aorta were diminished. One-half-mm thick sections were cut serially and then photographed. Ventricular volumes and masses were calculated from summation of the areas of each chambers. Left ventricular mass per body weight increased rapidly after birth, whereas right ventricular mass per body weight remained constant from 0 to 8 days after birth.
Animals↗
Acute hemodynamic effects of dopamine, dobutamine, and isoproterenol in congested infants or young children with large ventricular septal defect.
We studied the acute hemodynamic effects of dopamine, dobutamine, and isoproterenol in infants and young children with large ventricular septal defect (VSD). Dopamine (5 micrograms/kg/min) had no significant hemodynamic effects. Dobutamine (5 micrograms/kg/min) administration resulted in modest increases in heart rate and systemic arterial pressure and a decrease in left atrial pressure. This drug decreased the pulmonary blood flow, and the pulmonary-to-systemic blood flow (Qp/Qs) ratio, although these changes were not statistically significant. Isoproterenol, infused at doses of 0.03 and 0.06 micrograms/kg/min, increased the heart rate and lowered left atrial pressure. Only the high dose of isoproterenol lowered systemic and pulmonary arterial pressure. The low dose infusion of this drug increased the pulmonary blood flow as well as the systemic flow, whereas the high dose infusion resulted in a decrease of the Qp/Qs ratio without an increase in the pulmonary blood flow. Right atrial pressure was lowered by dobutamine and the high dose of isoproterenol, but the mean change was only 1 to 2 mmHg. The difference of the effects among these catecholamines is due to their relative strength of action on the vascular bed and the myocardium. Although the doses and durations of the drug infusions were limited, these acute hemodynamic effects should be taken into account when they are to be given to congested infants and young children with large VSD.
Dobutamine↗
[Effects of ketamine on hippocampal synaptic transmission and cell excitation].
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Action Potentials↗
Mitral regurgitation in Kawasaki disease.
The clinical characteristics and prognosis of 16 cases of mitral regurgitation (MR) secondary to Kawasaki disease (KD) were studied, and its pathogenesis was discussed. The observation period ranged from 3 years and 17 months to 15 years. Six of the 16 patients died, and 10 are alive. MR has disappeared spontaneously in 2 of these survivors. Thirteen of the 16 patients were male and 3 were female, there being a predominance in male, which is a striking contrast to rheumatic mitral regurgitation which is predominant in females. The age at the time of diagnosis ranged from 3 months to 7 years. The appearance time of MR showed two different patterns, one with early onset within a few weeks to one month after affliction with KD and the other with MR developing months or years later during the course of the follow-up. The cardiothoracic ratio was greater in those who had a progressively downhill course, and whose sigma RV1-6 decreased with time course. This was considered to be due to the decrease of the remaining functioning myocardial mass. The outcome of the patients with a severe degree of coronary arterial stenosis and occlusion observed on the coronary angiogram was poor. The prognosis of the patients with severe left coronary arterial stenosis was especially poor. MR due to KD is regarded as a new clinical entity, and its pathogenesis is thought to be due to ischemia, papillary muscle dysfunction, coronary angitis, myocardial failure and valvulitis. Incidence of MR will increase when examined by Doppler echocardiography especially in the acute stage. Our experience as well as that of others indicates the presence of valvulitis, myocarditis or left ventricular dilatation leading to MR in the acute stage.
Child↗
[Diagnosis of tricuspid stenosis by two-dimensional and pulsed Doppler echocardiography].
This study verified the usefulness of two-dimensional (2-D) and pulsed Doppler echocardiography (PDE) in the diagnosis of tricuspid stenosis (TS), and estimated the diastolic pressure gradient (PG) across the tricuspid valve (TV). Fifty-two patients with rheumatic mitral stenosis showing a decreased EF slope of the TV less than 40 mm/sec were studied. All patients underwent cardiac catheterization, and the mean diastolic pressure gradients (PG) across the TV were calculated with simultaneous recordings of right atrial and ventricular pressures. Based on surgical findings, all patients were categorized as the TS group consisting of 10 patients with TS (mean PG less than or equal to 5.0 mmHg; seven patients, greater than 5.0 mmHg; three patients), and the non-TS group consisting of 42 patients without TS. In three patients with PG exceeding 5 mmHg, the TV disclosed typical commissural fusions between the leaflets. 1. 2-D echocardiography The diagnosis of TS was made by recording diastolic doming and thickening of the TV in the parasternal long-axis and apical 4-chamber views. Among the 52 patients, 2-DE detected stenosis in all 10 patients with TS, for a sensitivity of 100%, while excluding TS in 40 of 42 patients without TS for a specificity of 95%. 2. Pulsed Doppler echocardiography The transtricuspid flow velocity in diastole was recorded from the apical window.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗