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Heart 2004;90:77-81 Objective: To evaluate immediate and midterm results after balloon valvoplasty in a paediatric population with congenital aortic stenosis, giving special consideration to aortic regurgitation. Design: Retrospective study. Setting: [...]

The volume of submarine landslides is a key controlling factor for their damage potential. Particularly large landslides are found in active sedimentary regions. However, the mechanism controlling their volume, and in particular their thickness, remains unclear. Here we present a mechanism that explains how rapid sedimentation can lead to localized slope failure at a preferential depth and set the conditions for the emergence of large‐scale slope‐parallel landslides. We account for the contractive shearing behavior of the sediments, which locally accelerates the development of overpressures in the pore fluid, even on very mild slopes. When applied to the Santa Barbara basin, the mechanism offers an explanation for the regional variation in landslide thickness and their sedimentation‐controlled recurrence. Although earthquakes are the most likely trigger for these mass movements, our results suggest that the sedimentation process controls the geometry of their source region. The mechanism introduced here is generally applicable and can provide initial conditions for subsequent landslide triggering, runout, and tsunami‐source analyses in sedimentary regions. Rapid sedimentation on slopes can set the conditions for the emergence of large, slope parallel submarine mass movementsContractive, nonlinear shearing behavior of sediments locally accelerates overpressure development in slopesAnalysis of landslides in the Santa Barbara basin offers explanation for their observed thickness and sedimentation controlled recurrence

The Tetralogy of Fallot refers to the most common cyanotic congenital heart defect. Anatomically, this is essentially a perimembranous subaortic ventricular septal defect, together with a right ventricular outflow obstruction, resulting from an infundibular and often valvular pulmonary stenosis. The pathophysiology is a right to left shunt at ventricular level. Clinical signs include cyanosis, which is often progressive with age, squatting, and often hypoxic spells. The natural history is characterized by progressive cyanosis, erythrocytosis, and complications such as cerebrovascular accidents and brain abscesses. Death occurs in the second decade as a mean. Surgical correction is therefore mandatory and lifesaving. The operation includes closure of the ventricular septal defect with a patch, and relief of pulmonary infundibular and valvular stenosis. This may often require patch enlargement of the right ventricular outflow tract, including the pulmonary valve annulus, leaving the pulmonary orifice partially unguarded. As a consequence, pulmonary valve regurgitation is very often observed. If it is important, it may compromise right ventricular function in the long term. Rhythm disturbances are another common complication in the late follow-up of operated tetralogy of Fallot. For these reasons, medical follow-up is indicated. Despite these possible complications, it is obvious that longevity and quality of life have been considerably improved by surgical repair.

Arrhythmias and sudden death are well-recognized complications that occur late after correction of tetralogy of Fallot. This study, based on the literature and personal work, reviews the numerous investigations prompted by these complications and provides recommendations regarding follow-up. Conduction disturbances and ventricular arrhythmias are both common; although mostly asymptomatic, they are the likely cause of syncopy and sudden death. Supraventricular arrhythmias are less common but cause symptoms more frequently. Detecting patients at risk for life-threatening arrhythmias is an important task. The simple surface electrocardiogram (ECG) gives a host of information regarding patients at risk. Holter recordings, signal-averaged ECG, and invasive electrophysiological studies may all be helpful; the indications to perform these investigations are discussed and propositions are made for the follow-up of the postoperative patient. There is hope that a systematic approach along these lines, together with surgery done at an earlier age, will decrease the incidence of severe arrhythmias and sudden death in the future.

Cardiac chamber size and function indices were studied repeatedly over the first months of life in two groups of babies, born either spontaneously or by caesarian section under peridural anaesthesia.

Transient systolic murmurs in neonates and premature infants due to mild left (LPA) and right (RPA) pulmonary branch stenosis is recognized but follow up studies are lacking. We studied echocardiographically 21 neonates with murmur and 10 controls. Diameters of the main pulmonary artery (MPA), LPA and RPA were smaller in patients with murmur. Colour-coded Doppler showed turbulent flow in LPA and RPA in 20/21 (95%) patients and flow velocities of both pulmonary branches were significantly higher than in controls. The follow up study at 3 months in 14/21 (67%) patients showed absent or decreased murmur in 9 (64%). Echographically, absolute and relative diameters of LPA and RPA increased whereas the ratio of MPA/aorta did not change suggesting accelerated growth or dilatation of the pulmonary branches. Flow velocities decreased significantly in the branches. Thus, transient systolic murmurs in neonates are associated with temporary relative hypoplasia of the pulmonary branches which showed increased growth leading to disappearance of the murmur in most cases within 3 months of life.

The clinical manifestations and pathological features of an extremely rare cardiac tumour, a mature (benign) teratoma, in a 6 year-old girl are described. These are compared with those reported in the literature.

To assess the respective roles of chonotropism, inotropism, and afterload reduction in increasing cardiac index early after corrective operations for tetralogy of Fallot, we measured vascular pressures and cardiac output and evaluated left ventricular dimension changes before and after a 35% rise in heart rate over baseline. This rise was induced by atrial pacing with intact atrioventricular conduction, isoproterenol, or atrial pacing together with dobutamine. With atrial pacing, left ventricular end-diastolic diameter decreased (38.7 ± 4.3 to 34.2 ± 5.6 mm, p < 0.05), the shortening fraction (ratio of the difference between left ventricular end-diastolic and end-systolic diameters to left ventricular end-diastolic diameter) remained constant, and stroke volume index was reduced (28.8 ± 4.5 to 19.7 ± 4.6 ml/m2, p < 0.05). As a result, cardiac index was left unchanged. When dobutamine was added as supplemental inotropic support, left ventricular end-diastolic diameter remained constant, shortening fraction increased (30% ± 5.4% to 36% ± 3.3%, p < 0.05), and cardiac index rose significantly (3.04 ± 0.61 to 4.18 ± 0.85 L/min/m2, p < 0.05). Heart rate acceleration with isoproterenol, combining chronotropism, positive inotropic support, and afterload reduction, slightly increased left ventricular end-diastolic diameter, significantly raised shortening fraction, and markedly enhanced cardiac index (3.03 ± 0.55 to 4.9 ± 1.09 L/min/m2). Atrial pacing with intact atrioventricular conduction, as an isolated chronotropic stimulus, is not suited to increase cardiac index early after operations for tetralogy of Fallot unless additional inotropic support is simultaneously provided.

The purpose of the study was to investigate the effect of low doses of dopamine in children. Fourteen cases were studied after open heart surgery. Cardiac output and renal parameters were determined under baseline conditions and under continuous infusion of dopamine 2.5 and 5 Alt0181gkgmin. During the control period cardiac index was 2.62 ± 0.19 Lminm2, renal plasma flow was decreased at 269 ± 41 mLmin1.73 m2, GFR was 86.6 ± 9.2 mLmin 1.73 m2, and filtration fraction was elevated at 37.1 ± 1.9. Plasma concentration of aldosterone correlated with the filtration fraction. At 5 Alt0181gkgmin dopamine increased significantly cardiac output, renal plasma flow, and to a lesser extent GFR, thus decreasing the filtration fraction. At 2.5 Alt0181gkgmin dopamine, increased renal plasma flow only in patients older than 5 y and had no effect on the other parameters. The increase of cardiac output in response to dopamine was abolished by propanolol pretreatment. By contrast, the hemodynamic renal response to dopamine was not altered by ß-blockade. These results indicate that 5 Alt0181gkgmin of dopamine could prevent renal failure after open heart surgery in children by increasing renal blood flow and attenuating renal compensatory mechanisms.

In order to compare the effect of isoprenaline and dobutamine immediately after correction of tetralogy of Fallot, 12 randomly selected patients were studied postoperatively. Left ventricular end-diastolic volume, measured preoperatively by means of left ventricular angiograms in eight patients, was decreased to a mean value of 58.6 ± 5.5 ml/m2(mean ± standard error of the mean). Postoperatively, cardiac output was measured by thermodilution before, during, and after infusion of increasing doses of isoprenaline (0.05, 0.1, and 0.2 üg/kg/min) and dobutamine (2.5, 5, and 10 üg/kg/min) successively given in each patient. Simultaneously, central venous, left atrial, pulmonary arterial, and systemic arterial pressures were recorded. Cardiac index increased significantly in response to all three doses of isoprenaline. Dobutamine produced only a small increase which was not statistically significant. Stroke volume index did not vary significantly with either drug. Consequently, cardiac index was directly related to heart rate. Preload of the left ventricle as well as afterload was significantly reduced (p < 0.01 and p < 0.05, respectively) by isoprenaline but not by dobutamine. An increase in left ventricular work index per minute was found with both drugs; however, only with isoprenaline was the increased work accompanied by a significant increase in cardiac index. We conclude that patients with tetralogy of Fallot usually have a small left ventricle which, immediately after correction, reacts to catecholamines by only an insignificant increase in stroke volume index. Consequently, isoprenaline is more effective than dobutamine in raising cardiac index due to the increase in heart rate. Moreover, it decreases systemic vascular resistances and obviates the need for administration of a vasodilator.

Résumé L'échocardiographie foetale (bidimensionnelle en temps réel et en M-mode) se pratique chez nous depuis 3 ans dans le cadre d'une consultation spécialisée. L'indication pour une évaluation cardiaque a été posée à cause d'un facteur de risque familial chez 78 cas, pour des raisons foetales chez 78 grossesses, pour un problème maternel 9 fois. Dans 25 cas, aucune indication spécifique n'a existé. L'examen échocardiographique a été pratiqué entre la 18ème et la 39ème semaine de la grossesse (moyenne: 28ème semaine). Parmi 190 grossesses, dont 169 à haut risque, nous avons mis en évidence 33 cas de malformation cardiaque (17,4%) dont 14 cardiopathies complexes graves et 3 arythmies isolées (1,6%) mais nécessitant un traitement pendant la grossesse. Les porteurs de telles malformations ont bénéficié d'une surveillance appropriée et de soins immédiats lors de leur naissance. Dans 154 grossesses, les futurs parents ont pu être rassurés.

We report the results and long-term follow up in 273 children (aged 2 to 16 years) who underwent prosthetic valve replacement. Mechanical valves (mostly Starr-Edwards) were used in almost all, and in 62 children more than one valve was replaced. Operative mortality was 4.7%. Actuarial survival curves (including hospital mortality) indicate a 86% survival rate at 5 years and 75% at 10 years. For isolated mitral valve prostheses (the largest subgroup), the figures are 87% at 5 years and 82% at 10 and 15 years. The main complication was thromboembolism, which occurred at a linearized rate of 2.7 per 100 patient-years. Actuarial curves indicate that 88 % of patients are embolus free at 5 years, and 77 % at 10 years. No patient with aortic valve replacement only had an embolism. Five of eight tricuspid prostheses thrombosed. Patients given aspirin and dipyridamole only did not have a higher rate of thromboembolic events than those given warfarin. There were five cases of endocarditis (two fatal) and four of dehiscence. No patient so far has needed replacement of a prosthesis because of somatic growth. Thus valve replacement can be performed with low mortality in children, and with satisfactory long-term survival. Thromboembolism remains a significant problem, although it appears to be less common than in adults. In this study, treatment with antiplatelet drugs only did not carry a higher rate of thromboembolic events than did treatment with warfarin.

Dopexamine hydrochloride, a synthetic dopamine analog with predominantly beta and delta agonist properties, has been shown to improve cardiac performance and renal function in adults with heart failure. This study was designed to investigate the haemodynamic and renal effects of dopexamine in children after cardiac surgery. Seven children were selected in whom a need for postoperative vasodilation after cardiac surgery was anticipated. Haemodynamics and renal function were determined under baseline conditions and during a continuous infusion of dopexamine at 2 and 6 μg.kg-1.min-1for 90 minutes, the sequence being randomized for the initial dose. Cardiac output was measured by thermodilution and glomerular filtration rate (GFR) and renal plasma flow (RPF) by the clearances of inulin and para-aminohippurate respectively. Dopexamine induced a dose-related increase in cardiac index (CI) expressed as mean (SD) from 3.5 (0.7) to 3.9 (0.76) and 4.5 (0.8) l.min.-1m-2(both P<0.05), and in heart rate (HR) from 107 (17) to 122 (17) and 136 (17) beats.min-1(P<0.05). Stroke volume index (SVI) and mean systemic pressure were unchanged, but pulmonary wedge pressure decreased from 14 (3) to 11 (4) and 12 (3) mmHg (both P<0.05). Systemic vascular resistances (SVR) decreased from 24 (7) to 20 (5) mmHg.l-1.min-1.m-2(P<0.05), with dopexamine 6 μg.kg-1.min-1. Renal blood flow (RBF) increased from 319 (113) to 441 (230) and 410 (138) ml.min-1.m-2(both P<0.05), GFR from 115 (32) to 142 (34) and 146 (29) ml.min-1.1.73m-2(both P<0.05), urine output and fractional excretion of sodium respectively from 3.12 (2) to 7.16 (8) and 7.21 (6) ml.kg-1(both P<0.05) and from 2.24 (1) to 4.25 (3.4) (P<0.05) and 3.15 (3.1)% (n.s.). The fraction of CI delivered to the kidneys, the fraction of RBF filtered in the kidneys, plasma renin activity and aldosterone levels remained unchanged. In children after cardiac surgery, dopexamine increases CI at the expense of a concomitant increase in heart rate and demonstrates few selective vascular systemic or intrinsic renal actions.

Abstract: Congenital cardiac malformations (CCM) are the commonest congenital anomalies. Using ultrasonography (US), the incidence of CCM in a selected group of fetuses and the impact of CCM on perinatal and postnatal care was evaluated. The indication for fetal echocardiography (F-ECHO) in 152 pregnancies was a positive family history in 61, fetal arrhythmias seen by routine obstetrical controls in 53, suspected CCM during obstetrical US in 9, growth retardation in 3 and contracted maternal factors in 6. Twenty pregnancies had no special indication. F-ECHO was performed between the 18th and the 39th gestational week. Twentyseven cardiac malformations were found (18%), 10 of which were important; 3 succumbed at birth, 2 after surgical intervention, 1 was aborted and 4 needed intensive care at birth. Of 53 cases with arrhythmias, 3 needed special care during pregnancy: Digitalis in a case of atrial flutter, sick leave and bedrest in 2 with supraventricular tachycardia, premature delivery in 1 case with complete AV block due to an intraventricular tumor. The extremely high incidence of CCM in this group proves the need for careful fetal evaluation to detect malformations. Nowadays F-ECHO can and should be performed as early as in the 18th gestational week, allowing either to interrupt a pregnancy or to plan delivery in a well-equiped center which provides the necessary measures for these newborns.

Abstract: The hemodynamic effects of amrinone were assessed in seven children following cardiac surgery. Amrinone was administered as a bolus of 1 mg kg−1 body wt., followed by continuous infusion at 10μg kg−1 min−1 for 1h and two stepwise increases to 20 and 40μg kg−1 min−1 for 30 min each. Hemodynamic data were obtained and plasma concentrations of amrinone measured 1 h after the bolus dose and immediately before each increment of the infusion rate. Amrinone levels ranged from 0.7 to 2.3 mgl−1. Administration of amrinone lowered systemic vascular resistance from 20.04.3 to 16.54.6 mmHgl−1 min−1 m−2 (p<0.05) and reduced mean arterial pressure from 71.79.5 to 62.613.5 mmHg (p<0.05) at the highest infusion rate, confirming the known vasodilative effect of the drug. However, these effects did not result in a statistically significant increase in stroke volume (35.07.5 to 35.57.0ml m−2, NS) or cardiac index (3.100.50 to 3.200.40 l min−1 m−2). One additional patient, in whom a higher loading dose was tried in order to achieve a higher plasma concentration, developed systemic hypotension. A correlation was established between the plasma concentrations of amrinone and the percentage decrease in systemic resistance (r=0.70,p<0.05). These results suggest that in children after open heart surgery, amrinone acts primarily as a systemic vasodilator, with questionable inotropic effect. Accordingly, its use should be restricted to children with severe cardiac failure and documented highly elevated afterload.

Summary: To determine the most reliable echocardiographic criteria of the pulmonary valve echo in predicting pulmonary artery (PA) pressures or PA resistance, 48 children, aged 6 months to 16 years with congenital (CHD) or rheumatic heart disease (RHD), were studied During routine heart catheterization, simultaneously recorded PA pressures and one-dimensional PA valve echograms were obtained. Echocardiographic measurements of the e–f and b–c slopes, the “a” dip, right ventricular (RV) and left ventricular (LV) systolic time intervals (STI; PEP = pre-ejection period; ET = ejection time), and their ratios were compared with PA systolic, diastolic, and mean pressures as well as with pulmonary arteriolar resistance (PAR) and the ratio PAR to systemic resistance (SR). The e–f slope and b–c slope correlated poorly with PA pressures and PAR. RVPEP/RVET ratio gave a good second-degree polynomial correlation with PA diastolic pressure, PAR and PAR/SR in CHD (r=.78, .79, .87). The correlation was better for children with CHD than for those with RHD. This correlation was also more significant than RVPEP/LVPEP, and RVET/LVET. The “a” dip correlated well with the diastolic PA pressure in CHD and RHD (r=.73). A multivariant analysis of the “a” dip and RVSTI ratios slightly improves the correlation coefficient and the prediction rate for PA diastolic pressures, PAR, and resistance ratios in CHD and CHD + RHD.

Two cases of very difficult weaning from cardiopulmonary bypass after cardiac surgery in children with pulmonary hypertension and ventricular dysfunction are reported. Children fail to respond to conventional therapy combining nitrovasodilators and inotropic support and react successfully to combined inhaled nitric oxide (NO) and epinephrine or left atrial infused norepinephrine. Postoperative NO inhalation must be prolonged and no toxicity appears. Pulmonary endothelial function recovers only after several days.

We analyzed the T cell receptor (TCR) rearrangements of 100 TCR-alpha/beta CD4-CD8- (double negative [DN]) T cell clones from normal individuals. We found that in four out of six donors this subset contains expanded clones that often account for 0.5% and, in one individual, even 7% of all peripheral blood lymphocytes. By combining limiting dilution analysis and N region oligotyping of polymerase chain reaction amplified TCR cDNA, we could measure the clonal size and show that two of these expanded clones remain stable in size for up to 4 yr in peripheral blood. The expanded clones analyzed ex vivo are not cycling and CD45 RAhi ROlo, but express high levels of alpha 4/beta 1 integrins, suggesting that they may have reverted to resting cells after activation. One of these expanded DN clones proliferates in vitro in response to Escherichia coli presented by monocytes cultured in GM-CSF plus IL-4 and kills CD1a+ Molt-4 cells. In contrast to what was found in the alpha/beta DN subset, alpha/beta CD4+ T cell clones specific for a tetanus toxin epitope showed a very small clonal size (< 1 in 10(7)) and could not be reisolated after 2 yr. Taken together, these results indicate that large clonal size and persistence are distinctive features of alpha/beta DN cells specific for bacterial antigens. These cells may use antigen-presenting cells, restriction molecules, and selection routes different from those used by antigen-specific CD4+ T cells.

Seventeen rabbits of various weights underwent osteotomy of the right femoral neck; the right hip was relieved of weight-bearing. Histological studies at various times revealed focal changes in the region of the proximal metaphysis and in the acetabulum; the epiphysis revealed no changes. As a result of the disturbed blood supply, the hematopoietic cells and fat cells disappeared. The intercellular marrow spaces correspondingly enlarged. Thereafter, the interstices became filled with reticulocytes and dilated capillaries; the latter often were malformed and defective. Further changes depended upon the degree of ischemia. Later, bone cysts formed and in the medullary regions near the articular surfaces hernia-like invaginations of joint capsule developed. From the experiments the following may be stated: 1) Cysts and herniations of articular capsule are late consequences of a disturbed circulation to the osteoarticular tissues. 2) The vascular supply to the femoral head and neck is segmental and very variable.

We report a case of pleuropulmonary actinomycosis in a child followed by a most unusual complication: the appearance of a systemic-to-pulmonary artery fistula in the area where the abscess was drained. Fifteen months after successful treatment with penicillin and surgical drainage, a continuous murmur was heard over the scar. Aortic angiography showed multiple connections between the intercostal arteries and the left pulmonary artery through an angiomatous lesion in the left lower lobe. This resulted in a considerable left-to-right shunt. Possible pathogenic mechanisms are discussed.

A 16-month-old girl developed severe pulmonary hyptertension after closure of a large ventricular septal defect. All conventional therapeutic measures failed; an attempt to add nitric oxide at a continous low dose to the inspired gas allowed resolution of pulmonary hypertension and low cardiac output. This report documents that continuous inhalation of low dose nitric oxide is capable of selective resolution of pulmonary hypertension following cardiac surgery for a large septal defect in a child. This suggests that a transient dysfunction in the release of nitric oxide by the pulmonary endothelial cell is responsible for the vasoconstriction.

Despite the high prevalence of sickle cell disease and trait in the black population and its serious potential for microinfarction, there are only a few reports on acute myocardial damage during vasoocclusive crisis. We report a unique case of transient second degree atrioventricular (A-V) block of Mobitz I and II type during a severe sickle cell crisis. Localized high ventricular septum hypoperfusion demonstrated by a 99mTc-MIBI radionuclide study and reversible echocardiographic wall motion abnormalities in the same area were strong indicators for a local ischemic event in the A-V node and His bundle area, explaining the observed transient conduction abnormalities. The present report draws attention to a potentially lethal complication of sickle cell crisis.

We have previously demonstrated the presence of lymphocyte function associated antigen-1 (LFA-1) on human platelets. The genes encoding the CD18 (LFA-1 β chain) and CD11a (LFA-1 α chain) are located on chromosomes 21 and 16 respectively. Down syndrome patients are known to have a substantial overexpression of LFA-1 on lymphoid cells, probably due to the extra copy of CD18 gene in Trisomy 21 (T21). However, on some cells (monocytic and granulocytic), the effect of T21 was not clear. In this study, we looked for a possible difference in LFA-1 expression between T21 and normal donor platelets, using comparative flow cytometry analysis and Western blot. Using this approach, we show that the expression of the common β subunit LFA-1 was constitutively increased on platelets from 5 to 7 T21 patients. The expression of the α chain on resting and thrombin-activated platelets from children or adults with T21 compared to age-matched controls, showed a similarly increased expression to that of the β chain. These data indicate that a trisomy-dependent constitutive effect on the expression of CD18 on platelets occurs in Down's syndrome, and that this also increases CD11a expression, which therefore leads to the overexpression of LFA-1. This alteration may be related to the higher incidence of cardiovascular disease in such patients.