Objectives: To investigate the indications for, and outcome of, cardiac catheterisation in infants weighing less than 2500 g at a single institution over an 8-year period. Patients and Methods: We assessed all infants who were less than 2500 g at the time of cardiac catheterisation at Texas Children's Hospital from January 1993 to January 2001. Comparisons of morbidity and mortality were drawn with an equivalent number of infants of similar age weighing greater than 2500 g seen over the same period of time. Results: We performed interventional procedures in 22, and diagnostic catheterisations in 12 infants weighing less than 2500 g. Interventions included pulmonary valvoplasty in six patients, balloon angioplasty of critical coarctation in one, aortic valvoplasty in two, septostomy in ten, and coil occlusion of an arteriovenous malformation, redirection of a subclavian venous line, and coil occlusion of a patent arterial duct in one patient each. The median age at catheterisation was 5 days for children less than 2500 g, and 10 days for those above 2500 g. The median weights were 2.3 kg and 3.3 kg, and the median gestational ages were 35 weeks and 38 weeks, for the two respective groups. Of those weighing less than 2500 g, two died (6%), with no deaths occurring in those weighing more than 2500 g. In 3 patients weighing less than 2500 g (9%), there was vascular compromise, one child with bilateral femoral venous obstruction requiring fasciotomy compared, to one in the group weighing greater than 2500 g (2%). Conclusion: There is a significantly increased risk of mortality and vascular compromise in infants weighing less than 2500 g. Interventional catheterisation in these infants may be lifesaving, but given the aforementioned risks, diagnostic catheterisation should be deferred if possible in favor of noninvasive modalities.

In patients who have undergone a superior cavopulmonary anastomosis, the superior caval venous flow provides the only, or the most important, pulmonary blood supply, while the inferior caval venous blood is not oxygenated, being mixed with the pulmonary venous blood before entering the systemic circulation. In healthy children, the contribution of superior caval venous flow to total cardiac output has been shown to decrease during growth. Patients who have undergone a superior cavopulmonary anastomosis, however, often have a higher oxygen saturation than predicted by the age-matched ratio of superior to inferior caval venous flows. This study was designed, therefore, to assess the ratio of flows in the superior and inferior caval veins subsequent to a superior cavopulmonary anastomosis. We carried out 18 magnetic resonance imaging studies with velocity-mapping and heart catheterisations so as to assess the contribution of superior caval venous flow to total cardiac output. Patients were divided into 3 groups according to their age. There were five aged from 8 to 24 months, eight aged from 24 to 48 months, and five older than 48 months. No significant difference could be found in the ratios of superior-to-inferior caval venous flow, nor of superior caval venous-to-systemic flow, between the 3 groups. The ratio of venous flows was 0.89 ± 0.34 in those aged from 8 to 24 months, 1.09 ± 0.42 in those from 24 to 48 months, and 1.25 ± 0.27 in the older patients (F analysis of variance 1.06, p 0.37). The ratio of superior caval venous-to-systemic flow was 0.46 ± 0.08 in the youngest patients, 0.50 ± 0.09 in those aged from 24 to 48 months, and 0.55 ± 0.05 in the older patients (F analysis of variance 0.76, p 0.49). These findings suggest that the hemodynamics of a cavopulmonary anastomosis may affect the normal decrease of superior caval venous flow with age. This could be related to a redistribution of flow, with a proportionally higher flow to the head and upper body after construction of a superior cavopulmonary anastomosis. Since increasing cyanosis and progressive exercise intolerance are the main indications for creation of a total cavopulmonary connection, these findings should be taken into account when determining the timing for completion of the Fontan circulation.

Objectives: Our aim was to review the clinical records from children with large pericardial effusions of inflammatory origin presenting to a tertiary referral centre over the last 21 years, with emphasis on their clinical presentation, management and outcome. Background: The common identifiable causes of pericardial effusion in children include prior cardiac surgery, bacterial pericarditis, malignancy, and connective tissue disorders. In a significant number of children, however, despite extensive investigation, it is not possible to identify a clear aetiology. A viral cause is often considered, though rarely confirmed. The clinical course of such large idiopathic pericardial effusions in children has not been extensively reported. Methods and results: We reviewed retrospectively the records of all patients seen between 1981 and 2001 with large pericardial effusions of inflammatory origin requiring drainage, excluding the effusions related to cardiac surgery or malignancy. We found 31 patients fulfilling our criterions for study. They could be divided into three groups, with 15 patients having no specific identifiable aetiology despite extensive investigation, 12 patients having evidence of bacterial pericarditis, and four with a probable immunologic disorder. Fever was present in only eight patients (53%) in the idiopathic group. All patients in the other groups had fever. Except for fever and the resultant tachycardia, it was not possible to distinguish on clinical grounds, nor on the presence or otherwise of cardiac tamponade, between those with idiopathic aetiology and those with bacterial infection. Of the patients with presumed bacterial pericarditis, five (42%) had both positive blood and pericardial fluid cultures, three (25%) had positive blood cultures, while a further three patients (25%) had only positive pericardial fluid cultures. All patients required drainage of the pericardial effusion, either under echocardiographic guidance or surgically. None of the patients died. The hospital stay was significantly shorter for those with idiopathic as opposed to bacterial pericarditis. Of those with an idiopathic aetiology, six required readmission due to recurrence of the pericardial effusion, with four patients requiring further surgical drainage. No patients required readmission with a bacterial or immunologic aetiology. No patient developed constrictive pericarditis after a median follow-up of 22 months. Conclusion: Patients with large idiopathic pericardial effusion had relatively few constitutional symptoms as compared with their gross echocardiographic findings. Those with bacterial pericarditis had more urgent need for treatment. Patients with pericardial effusion of inflammatory origin, when treated appropriately, had an excellent outcome with no mortality or development of constrictive pericarditis.

Aims: To determine the accuracy of data relating to pulmonary vascular resistance data in patients with a bidirectional Glenn anastomosis as calculated using predicted versus measured uptake of oxygen. Methods: We studied retrospectively the data from 33 patients with a bidirectional Glenn anastomosis who underwent cardiac catheterisation prior to surgery to complete the Fontan circulation. Their weight ranged from 5.4 to 51.7 kg, and they were aged up to 12 years. Uptake of oxygen was measured using the Deltatrac II metabolic monitor. From the calculated indexed pulmonary vascular resistance, cases were stratified according to the risk of failure of the subsequent Fontan circulation. The six patients with a resistance of greater than 4 Um2 were deemed at high risk, the six with a resistance from 3 to 4 Um2 at moderate risk, and the 21 patients with a resistance less than 3 Um2 at low risk. Uptake of oxygen was also estimated from the predictive formulas of Lindahl, Lundell et al. and LaFarge and Miettinen. The indexed resistance was similarly calculated using these formulas and a comparable stratification of risk made from this data. Results: The predicted values for uptake of oxygen were consistently higher than those measured, leading to an underestimation of indexed resistance, with mean difference between −0.62 and −1.57 Um2. This difference resulted in misclassification of between five and nine of the 12 patients considered at moderate or high risk as being at low-risk. No other haemodynamic data could reliably separate the subjects deemed at low-risk from those considered to be at high-risk. A transpulmonary gradient of greater than 7 mm of mercury was found to be 100 percent specific for elevated indexed resistance, but only 60 percent sensitive. Conclusions: In patients with bidirectional Glenn anastomoses, all formulas based on predictive uptake of oxygen lead to underestimation of the true indexed pulmonary vascular resistance, to an extent that could significantly influence clinical decision-making. The transpulmonary gradient is not a reliable surrogate for indexed pulmonary vascular resistance.

To date, no reference values have been provided for right and left atrial filling in normal children. The aim of our study, therefore, was to characterize measurements of superior caval, hepatic, and pulmonary venous flow using Doppler echocardiography in a large group of normal children to reflect the effects of age, body mass index, sex, heart rate and respiration.

Doppler echocardiographic examinations of the superior caval, hepatic and pulmonary veins were performed during inspiration and expiration in 72 healthy children with a mean age of 6.73 ± 5.10 years. The subjects were segregated into four age groups, namely infants <2 years, preschool children between the ages of 2 and 7 years, children of school age between 7 and 11 years, and adolescents older than 11 years.

Age has significant effect on the systolic and reverse atrial flows within the superior caval vein (p < 0.05). No change in the Doppler velocities was observed related to body mass index or sex. All peak systolic velocities decreased significantly during expiration (p < 0.05). This decrease was most prominent in the hepatic vein (26%), but less remarkable in the superior caval vein (5.7%) and the pulmonary veins (3.9%). During expiration, the peak diastolic flow in the superior caval and the hepatic veins decreased, while the reverse atrial flow in the hepatic vein increased (p < 0.05). Pulmonary venous velocities were similar in all age groups (p > 0.05). Except for the systolic pulmonary venous velocities, these parameters were not influenced by respiration (p > 0.05). The diastolic time, the interval between reverse atrial flow and ventricular systole reflected by the R wave on the electrocardiogram, and the interval between ventricular systole and diastolic flow, were negatively correlated with heart rate (p < 0.05; r = −0.35, −0.85, and −0.8 respectively), and positively correlated with age (p < 0.05; r = 0.3, 0.8, and 0.7 respectively). They were not influenced by respiration.

Our study provides data of the patterns and the normal ranges of velocities of superior caval, hepatic, and pulmonary venous flow in a series of normal children. The results can now be used for comparison with the patterns found in the setting of disease.

The morphogenesis of most types of human congenital cardiac malformations is still obscure. The reasons for this are, first, the paucity of data from human embryos and fetuses and, second, the paucity of appropriate animal models. During the past few years, we have tested several chemicals for their teratogenic potential, hoping to find, particularly in the chick, substances that could be used for the development of models for specific cardiac malformations. We have now discovered that suramin, an antitrypanosomal drug, can induce a special type of congenital cardiac defect in which the two atrial appendages are positioned to the left of the great arteries. This situation resembles the situation found in humans and classified as left juxtaposition of the atrial appendages. In the present study, we have analysed the pathomorphological features of a series of our chicken hearts to assess precisely how accurately these cardiac malformations in the chick correspond to the situation seen in the human. We found that the cases observed in the chick did, indeed, have many features in common with the human cases described in the literature. This suggests that we have developed an animal model for human left juxtaposition. Our model could be used for two kinds of embryological studies: first, documentation of the morphogenesis of left juxtaposition; and second, studies on the mechanisms driving the normal positional changes between the atriums and outflow tract of the embryonic heart during the late phase of cardiac looping. The fact that left juxtaposition of the atrial appendages can be induced by suramin might help to elucidate the molecular mechanisms underlying this type of congenital cardiac malformation. Furthermore, the fact that suramin is used for the chemotherapy of frequent tropical diseases, such as African trypanosomiasis and onchocerciasis, poses the question as to whether this drug might play a role in the aetiology of left juxtaposition in some human populations.

Cardiopulmonary bypass induces a generalized inflammatory response, with fever and leukocytes, which is difficult to differentiate from an infection. Recently, procalcitonin has been proposed as an early and specific marker of bacterial infection. The influence of cardiopulmonary bypass on production of procalcitonin, therefore, must be assessed before considering this molecule as a valuable marker of infection after cardiac surgery in children. With this in mind, we measured levels of procalcitonin, interleukin 6, and C-reactive protein before and 6 h, 1, 3 and 5 days after cardiopulmonary bypass, in 25 children undergoing cardiac surgery. Cardiopulmonary-bypass induced a transient increase in procalcitonin, with a peak at 24 h, with a median of 1.13 μg/l, a 25th and 75th interquartile of 0.68–2.25, and a p value of less than 0.001. The value had returned to normal in the majority of the children by the third day after surgery. Peak values correlated with the duration of cardiopulmonary-bypass, with a r-value of 0.58 and a p value of 0.003; cross-clamp time, with a r-value of 0.62 and a p value of 0.001; days of mechanical ventilation, with a r-value of 0.62 and a p value of 0.001; and days of stay in intensive care, with a r-value of 0.68, and a p value of 0.0003. The value returned to normal after 3 days in 83% of the patients. Levels of interleukin 6 and C-reactive protein also increased significantly after surgery, and remained elevated for up to 5 days.

Thus, in contrast to other markers, levels of procalcitonin in the serum are only slightly and transiently influenced by cardiopulmonary bypass, and may prove to be useful in the early recognition of an infection subsequent to cardiopulmonary bypass.

Background: In recent years, the diagnosis of infective endocarditis has been enhanced by the use of echocardiography. We sought, therefore, to review its effect on the management of endocarditis in children. Methods: We reviewed all the patients presenting to our institution for evaluation for infective endocarditis from May 1994 to January 2002. The patients were stratified according to whether or not they had congenitally malformed hearts. Results: Of the 90 referred patients identified, 46 (51%) had positive ultrasonic findings. Of these, we excluded 26 patients because of the presence of indwelling lines. The remaining 20 patients with features of endocarditis had a median age of 6.5 years, and a range from 0.14 to 8.5 years. There were 4 patients with normal hearts, and 16 with congenital cardiac malformations. We identified rupture of a sinus of Valsalva in four patients, with rupture into the left ventricle in two, and into the right ventricle and right atrium in one each. The mitral valve was involved in six patients, the aortic valve in another six, including all four with rupture of the sinus of Valsalva, both mitral and aortic valves in three, the pulmonary trunk in three patients, and the tricuspid valve and a Blalock-Taussig shunt in one patient each. Organisms isolated included Streptococcus mitis in 4 patients, Streptococcus pneumoniae in 2 patients, Streptococcus sanguis in 1, Staphylococcus aureus in 3, Staphylococcus epidermidis in 1, and Enteroccocus in 2. Cultures proved negative in 7 patients. Surgical intervention was needed in 12 patients, and one died (5%). Only the left-sided chambers were involved in those with normal hearts. Both patients infected with Streptococcus pneumoniae had rupture of a sinus of Valsalva. Conclusion: Involvement of the left-sided chambers is more likely in structurally normal hearts, and in cases with rupture of a sinus of Valsalva, in which case infection with Streptococcus pneumonia should be suspected.

In my Mannheimer lecture, designed to meet the needs of a mainly clinical audience, I present aspects of cardiac development that link basic science to clinically relevant problems. During development of the cardiac tube, and its subsequent changes as a dextrally looped structure, which is still connected to the dorsal body wall by a venous and an arterial pole, there are basic requirements. These consist of the development of myocardium, endocardium and the interposed cardiac jelly from the cardiogenic plates. In this primitive heart tube, septation and valvar formation then take place to convert it into a four-chambered heart. I demonstrate that the refining of the above events cannot take place without the addition of extracardiac populations of cells. These are presented as the “quintessence of heart development”, and consist of cells derived from the neural crest, along with epicardially derived cells. Without these contributions, the embryos uniformly die of cardiac insufficiency. Important contributions are made by the cells derived from the neural crest to septation and the formation of the arterial valves, and possibly in differentiation of the central conduction system. The epicardially derived cells are essential for formation of the interstitial fibroblasts and the myocardium, as well as the coronary vascular system. I conclude by discussing specific malformations of the heart that might be linked to these extracardiac contributions.

An 11-month-old infant had undergone a primary arterial switch operation, including the Lecompte maneuver, for correction of discordant ventriculo-arterial connections and closure of an accompanying ventricular septal defect.

At discharge, there were no signs of aortic valvar incompetence. Regurgitation across the aortic valve was detected first at the age of 2 years, and then increased progressively, as documented by serial echocardiographic studies. There had been no history of bacterial endocarditis. At the age of 10 years, echocardiography revealed severe aortic valvar incompetence. At operation, the aortic valve had three leaflets, all of which were short, with very restricted movement. Absence of sufficient leaflet tissue precluded a durable valvar reconstruction, so the aortic valve was replaced with a 21 mm mechanical prosthesis. Histological examination of the removed leaflets revealed nodular swelling due to mucous changes of the matrix, as well as fibrous alteration and formation of scar tissue, including areas of fibroblastic and capillary proliferation. There were no signs of calcification or acute inflammatory changes. Improvement of left ventricular function was observed both early postoperatively and later on. Our observation shows that aortic valvar incompetence after an arterial switch operation can be caused by degenerative changes of the neo-aortic leaflets, which prevent plastic reconstruction of the valve, necessitating valvar replacement.

In a fetus at 20 weeks gestation, we found a large fistula from the left coronary artery to the left atrium in association with tetralogy of Fallot. Postnatally, the therapeutic issues were complex because of prematurity, low birth weight, decreased flow of blood to the lungs, and volume overload of the left ventricle because of the huge fistula. At three months, the baby underwent repair of tetralogy of Fallot, with surgical ligation of the fistula, but the baby died postoperatively.

We treated a neonate with pulmonary atresia and a ventricular septal defect complicated by straddling of the atrioventricular valves by constructing a central aorto-pulmonary shunt. The postoperative course was complicated by obstruction of the shunt, which was treated by implantation of a coronary stent. Six months after the stenting, a Glenn anastomosis was created and the stented shunt removed. Analysis showed that the shunt was completely covered by a vascularized neointima. The stent had not produced injury to the shunt, with struts of the stent covered nicely by neoendothelium, with sparse inflammation surrounding the artificial implants.

We report a novel technique using an Amplatzer atrial septal occluder to close a defect located in the inferior-posterior portion of the interatrial septum that extended into the mouth of the inferior caval vein. Because of the close relation of the defect to the inferior caval vein, the right atrial disc was opened into the inferior caval vein and pushed toward the right atrium by use of the delivery cable. There was no residual shunting immediately and 3 months after the intervention. We conclude that even defects located infero-posteriorly within the oval fossa may be successfully closed by transcatheter techniques using the Amplatzer device.

A 53-year-old man with tetralogy of Fallot had been palliated with two classic Blalock-Taussig shunts. Cardiac catheterization in our center revealed acquired atresia of the pulmonary valve. We perforated and dilated the valve as a palliative procedure with a new system using radiofrequency energy.

The postpericardiotomy syndrome occurs in up to one-third of children undergoing cardiac surgery. Its treatment includes anti-inflammatory agents, diuresis, and drainage of effusions. Administration of steroids can have a dramatic effect, but is limited by adverse effects. Usually the syndrome lasts weeks only, and persistence beyond six months is exceptional. We describe a rare case of chronic postpericardiotomy syndrome, with recurrent pericardial effusions and steroid dependency, that was treated successfully with a low weekly dose of methotrexate.

Ischemia of the leg in a peripartum female is an uncommon condition. Paradoxical arterial embolisation, and arterial dissection, are rarely encountered but recognized causes of this clinical condition. Peripartum cardiomyopathy is a rare life-threatening cardiac condition that can foster intracardiac thrombosis and produce peripheral vascular complications through embolization. We present here the case of a young, healthy, postpartum female who developed acute ischemia of the left leg, and asymptomatic arterial insufficiency of the right lower leg, as the presenting symptoms of peripartum cardiomyopathy, highlighting the fact that ischemia threatening the loss of a limb can be the initial manifestation of peripartum cardiomyopathy.