Evaluation of the diagnostic work-up in children with myocarditis and idiopathic dilated cardiomyopathy.

The underlying etiology of dilated cardiomyopathy (DCM) in children varies, 14-22% is secondary to myocarditis, and the majority remains idiopathic. Etiology has prognostic value; however, 'a clinical diagnosis of myocarditis' has been frequently used because the gold standard [endomyocardial biopsy (EMB)] is often not performed. Therefore, a consistent diagnostic approach and interpretation is needed. In this multicenter study, we evaluated the diagnostic approach and interpretation of the viral results in children with myocarditis and idiopathic DCM. We included 150 children with DCM, of whom 103 were assigned the diagnosis myocarditis (n = 21) or idiopathic DCM (n = 82) by the attending physician. Viral tests were performed in 97/103 patients, in only 34% (n = 35) some of the tests were positive. Of those patients, we evaluated the probability of the assigned diagnosis using the viral test results. We classified viral test results as reflecting definite or probable myocarditis in 14 children and possible or unlikely myocarditis in 21 children. Based on this classification, 23% of patients were misclassified. We found that in children with DCM, the diagnostic approach varied and the interpretation was mainly based on viral results. Since a 'clinical diagnosis of myocarditis' has been frequently used in daily practice because of the lack of EMB results, a uniform protocol is needed. We propose to use viral test results in several steps (blood PCR, serology, PCR and/or cultures of the gastro-intestinal and respiratory tract, and EMB results) to estimate the probability of myocarditis.

Immediate and intermediate results of stent therapy for aortic coarctation.

OBJECTIVES: The aim of the study was to assess the immediate and intermediate outcomes of stent therapy for coarctation or recoarctation of the aorta. SETTING: Tertiary referral centres. METHODS: A case review of all patients who have undergone stent implantation for coarctation of aorta in the Netherlands and Belgium. RESULTS: Stents were implanted in 33 patients (mean age 21±16 years) and successful outcome occurred acutely in 32 of these 33 patients. Peak systolic blood pressure decreased from 149±37 to 124±24 mmHg. The pressure gradient decreased from 37±16 to 7±7 mmHg. The diameter of the coarctation segment increased from 7.3±3.8 to 13.3±3.9 mm. Three patients had major complications and three had minor complications. During a mean follow-up of 21±17 months recoarctation was found in ten patients, seven of whom have undergone further procedures. There were no deaths at follow-up. CONCLUSIONS: Stent implantation is a good alternative to balloon dilation in selected patients with coarctation of the aorta. However, follow-up evaluation reveals a varying incidence of recoarctation and the long-term outcomes need to be determined.

The influence of ductal left-to-right shunting during extracorporeal membrane oxygenation.

BACKGROUND/PURPOSE: The aim of this study was to analyze whether a ductal left-to-right (L-R) shunt will prolong extracorporeal membrane oxygenation (ECMO) in neonates with severe pulmonary hypertension. This report discusses the onset and termination of a ductal L-R shunt and its potential influences on ECMO when pulmonary hypertension decreases during venoarterial bypass. METHODS: Twenty-nine neonates were monitored during veno-arterial ECMO, using bedside echocardiography with 12-hour interval observations. RESULTS: Up to 43% of the patients showed this type of shunt already after 12 hours on bypass. In total, this type of ductal shunt was found between 12 and 72 hours on ECMO in 62% of the patients. After 72 hours, the ductal L-R shunt no longer was detected. In 38% of the patients, no ductal L-R shunt was found during ECMO. Comparisons between these 2 patient groups showed a significantly longer ECMO duration in patients with ductal L-R shunt (P <.007). The mean prolongation time was 46 hours. Also, a significant decrease of left atrium to aorta ratio (P <.01) was observed during ECMO in the ductus group after closure of the duct, illustrating the decrease in volume load for the left heart and lungs. CONCLUSIONS: Ductal L-R shunting is related with a substantial prolongation of the ECMO course (mean prolongation of almost 2 days). The authors suggest that on one side, the ductal L-R shunt will lead to pulmonary hypercirculation and on the other side, postductal stealing from the descending aortic circulation will lead to prerenal failure. Possibly because of interactions with pulmonary and renal function, a ductal L-R shunt will, among other factors, interfere with weaning from ECMO, resulting in a prolonged bypass time.

The use of transesophageal echocardiography monitoring of transcatheter closure of a persistent ductus arteriosus.

We performed transesophageal echocardiography (TEE) with pediatric biplane probes throughout the procedure of transcatheter closure of the ductus arteriosus in 42 out of 46 patients who were scheduled for this intervention. Patient ages ranged from 15 months to 14 years and body weight from 9-53 kg. Both Rashkind double umbrella devices and coils were used. The described approach resulted in fewer contrast injections and was helpful in monitoring the procedure and in deciding when to release the device. To the best of our knowledge this is the first report describing a large series where continuous monitoring of transcatheter ductus closure was combined with x-ray fluoroscopy and TEE.

Neonatal pulmonary hypertension during extracorporeal membrane oxygenation.

OBJECTIVES: This prospective study was designed to monitor severe pulmonary hypertension during extra corporeal membrane oxygenation using echo Doppler variables. BACKGROUND: All neonates treated with extracorporeal membrane oxygenation also have severe pulmonary hypertension. A study which monitors the reaction of the pre-existing pulmonary hypertension during extracorporeal oxygenation by frequent sampling of those variables related to pulmonary pressure is still lacking. Such a study is necessary to analyze the complex haemodynamic changes in patients undergoing extracorporeal membrane oxygenation. METHOD: In 29 neonates, we estimated pulmonary arterial pressure using peakflow velocity of regurgitation across the tricuspid- and pulmonary valve, peakflow velocity of shunting across persistent arterial ductus, and systolic time intervals of the right ventricle. Correlation between the several estimations of pulmonary arterial pressure were analysed with the Spearman correlation coefficient. RESULTS: Systolic pulmonary arterial pressure measured by the velocity of tricuspid regurgitation illustrated severe pulmonary hypertension prior to extra corporeal membrane oxygenation (mean 63 mmHg, sd 20). Similar levels for the systolic pulmonary arterial pressure could be derived (mean 73 mmHg, sd 17) from ductal shunting. A fair correlation of 0.76 (p< 0.002) could be demonstrated. Pulmonary hypertension responded well and quickly to treatment by extra corporeal membrane oxygenation, with reductions within 24 hours to mean systolic levels of 35 mmHg, sd 23. This very early reaction has not previously been demonstrated and could be of importance in defining parameters for weaning from cardiopulmonary bypass. Diastolic pulmonary arterial pressure was investigated because of its relation to vascular resistance. It proved more difficult to measure because of the low incidence of pulmonary regurgitation. Derived diastolic pressures did not show any good correlations. CONCLUSION: Pulmonary hypertension is well documented prior to extra corporeal membrane oxygenation and response very quickly to the institution of treatment. Ultra sound techniques are indicated at the bedside, and prove useful in monitoring pulmonary blood pressure during the procedure.

Difficulties generated by the small, persistently patent, arterial duct.

Over recent years, echo-Doppler cardiography has shown that a small, sometimes silent, arterial duct exists in more patients than previously recognized. To know the incidence of an arterial duct subsequent to therapy, we studied retrospectively our patients undergoing open-heart surgery and surgical or catheter closure. Three groups of patients were studied: those with patency of the duct subsequent to open heart surgery without any sign of patency before or during surgery, those with persistent duct after surgical ligation and those with persistent patency after attempted catheter occlusion with the Rashkind device. In the first group (of 431 children) four (0.9%) had persistence of this duct, of which three were silent. In the second group, patency persisted in four of 100 patients (4%), three being silent. In the last group there were five persisting shunts, three producing no murmur, in 30 patients (17%). We compared our results with those reported in the literature and conclude that echo-Doppler cardiography is needed to detect persistent shunting across a duct after therapy, since most of the residual ducts in this study were silent. This means that clinical findings alone cannot be relied upon, and careful echo-Doppler cardiography is essential. Also, the process of closure of a persistent duct by surgical ligation or transcatheter intervention is no guarantee of success. The risk of infective endocarditis is important in such persistent ducts and, at present, it is unknown either for a small, silent duct or in a persistent duct that remains open after attempted transcatheter closure, but now is in association with a foreign body.

Pulmonary perfusion after endovascular stenting of pulmonary artery stenosis.

UNLABELLED: Pulmonary artery stenosis is a well-known condition after surgical correction of tetralogy of Fallot. Endovascular stenting of the stenosis is a new technique for correction without surgical intervention. Objective evaluation of the procedure, however, is often hampered by moderate or severe pulmonary valve insufficiency. This disadvantage does not apply to 99mTc-macroaggregates of albumin (MAA) scintigraphy of the lungs. Moreover, quantification can be performed relatively easy. METHODS: Seven patients with surgically corrected tetralogy of Fallot (4 men, 3 women, mean age 15.7 yr, range 5-24 yr) were studied. The mean diameter decrement of a pulmonary artery was 69% +/- 8.7%. Before and after stenting, relative uptake in the left and right lung was assessed after injection of 37-55 MBq 99mTc-MAA. Three patients were studied twice after stenting. RESULTS: In all patients, perfusion of the affected lung increased significantly: before 22.7% +/- 10.8%, after 38.6% +/- 12.3% (p < 0.0001). All patients claimed clinical improvement of their condition after stenting. The perfusion gain did not correlate with the prestenting diameter decrement or with the pressure gradient over the stenosis. Lung uptake in the patients studied twice after stenting was similar between the initial and poststenting study (< or = 2% difference). CONCLUSION: Quantitative 99mTc-MAA lung imaging is a noninvasive technique without patient discomfort that objectively measures the effect of stenting pulmonary artery stenosis. The final outcome of stenting with regard to increment of pulmonary blood flow is not predicted by the severity of the stenosis or the pressure gradient over the stenosis.

[Endovascular stent in the treatment of residual pulmonary stenosis in patients operated on for congenital heart defects; initial results]. / Endovasculaire stent ter behandeling van resterende pulmonalistakstenose bij patiënten geopereerd wegens aangeboren hartafwijking; eerste ervaringen.

OBJECTIVE: Evaluation of the preliminary results of stent implantation as a new technique of intervention cardiology to treat (residual) stenosis of pulmonary arteries in congenital heart disease. DESIGN: Descriptive. SETTING: Children's Heart Centre, University Hospital Nijmegen, the Netherlands. METHODS: Data about physical condition, heart catheterization/angiography and lung perfusion scan were collected. Special attention was paid to the lung perfusion scan as a potential parameter of evaluation. RESULTS: The physical condition was not a useful parameter to judge the result of the pulmonary intravascular stenting, due to a simultaneously present important pulmonary valve insufficiency in most cases. Angiography showed a good result immediately after the procedure in all cases, except in one with kinking of the stent. The increase of lung perfusion could be confirmed by lung scintigraphy in most cases. The relative perfusion of the affected lung increased from 22.7% (SD: 10.8) to 38.6% (12.3) (p < or = 0.001). CONCLUSION: Percutaneous implantation of endovascular stents in pulmonary artery branch stenosis is a welcome alternative to (reconstructive) cardiac surgery. Objective quantification of this stenting by lung perfusion scintigraphy, a technique without patient discomfort, is possible.

Urokinase therapy in neonates with catheter related central venous thrombosis.

The results of fibrinolytic therapy with urokinase were evaluated in 26 neonates with catheter related central venous thrombosis. Complete thrombolysis could be achieved in 13 patients (50%), partial thrombolysis in 3 patients (12%). No effect was seen in 10 patients (38%). Therapy success was influenced by age, size and location of the thrombus. Coincidence of infection occurred in 16 patients (62%). Mild hemorrhagic complications were seen in 2 patients (8%), no other significant side effects were observed. Nine patients with residual thrombosis were treated with oral anticoagulants following urokinase resulting in resolution of the thrombus in 6 patients within 3 months (67%). The incidence of asymptomatic recurrent thrombosis was high (28%). Urokinase might be an effective and safe treatment for central venous thrombosis in neonates. Prophylactic antibiotic therapy during the infusion of urokinase and long-term treatment with oral anticoagulants after thrombosis are advisable. Early detection of thrombosis might enhance the success rate of fibrinolytic therapy. Therefore, we strongly recommend routine echocardiographic screening of central venous catheters.

Mid-term results of the modified Senning operation for cavopulmonary connection with autologous tissue.

UNLABELLED: The aim of this study was to determine the results and mid-term outcome of a modified Senning technique using autologous tissue for total cavopulmonary connection. The study involved 31 children, 8 with tricuspid atresia and 23 with complex congenital heart disease. In this operation, a flap of autologous atrial free wall tissue was used to tunnel inferior vena caval blood to the pulmonary arteries. An additional Damus-Kay-Stansel operation was required in 9 patients with subaortic obstruction. RESULTS: the early mortality rate was 16% (5 out of 31 patients) and there were four late deaths. COMPLICATIONS: Pleural effusions were encountered in 17 patients, of whom 4 had a concomitant pericardial effusion. Diaphragmatic paralysis was diagnosed in five patients, one of whom underwent surgical plication. Median hospital stay was 26 days. The 1- to 5-year actuarial survival was 68.6%. Follow-up ranged from 10 months to 7.1 years, mean 3.2 years. A serious atrial arrhythmia was diagnosed in one patient and another one died, possibly from rhythm disorders. Exercise tolerance and quality of life has improved in all but one of the survivors. Although follow-up is short, we have thus far witnessed a low incidence of hemodynamic and rhythm disturbances with this modification of the cavopulmonary connection.

The modified Senning operation for cavopulmonary connection with autologous tissue.

UNLABELLED: A modified Senning technique was used for intraatrial channeling of the systemic venous blood into the pulmonary arteries to create a Fontan circulation in 26 children, six with tricuspid atresia and 20 with complex congenital heart disease. In this technique a flap of atrial free wall tissue is used to create an atrial tunnel without artificial material. Eight patients had subaortic stenosis and required a Damus-Kay-Stansel procedure, in addition. Early mortality was two of 26 and late mortality one of 26. Pleural effusion was encountered in 17 of 26 patients, of whom four had a pericardial effusion, in addition. One patient required pacemaker implantation for complete atrioventricular block. Follow-up ranged from 2 months to 5 years. In this period the ability level index rose by one level. No thrombi were encountered in the right atrium/cavopulmonary tunnel. One patient required antiarrhythmic medication. Protein-losing enteropathy was diagnosed in one patient. CONCLUSION: This modified Senning technique has the advantage of avoiding the use of prosthetic material in the creation of a Fontan circulation and the potential for fewer long-term complications.

Thrombus detection on central venous catheters in the neonatal intensive care unit.

Between September, 1989, and September, 1992, 193 infants were investigated prospectively for development of central-venous-catheter-induced thrombosis. In 25 infants intracardiac or central-venous-catheter-induced thrombosis was demonstrated (13%). A slightly higher incidence of thrombosis was found in infants with umbilical catheters in comparison with infants with subclavian catheters, although no significant difference was demonstrated. The results make clear that central venous catheters in neonatal intensive care have considerable risk in developing central venous or intracardiac thrombosis, and echocardiography is an excellent technique for diagnosing these thromboses.

[Congenital complete atrioventricular block in neonatal lupus erythematosus]. / Congenitaal compleet atrioventriculair block bij neonatale lupus erythematosus.

Fetal bradycardia of 60 beats per minute was diagnosed in the 22nd week of a normal pregnancy. Echocardiography showed a complete fetal atrioventricular heart block. The fetal heart was without structural abnormalities. Auto-antibodies (Ro/SS-A and antinuclear antibodies) could be demonstrated in both mother and child. The mother, however, showed no signs or symptoms of a connective tissue disease. We describe neonatal lupus erythematosus as an important cause of congenital heart block.

[Purulent pericarditis in children. A continuously life-threatening disease]. / Purulente pericarditis bij kinderen. Een nog altijd levensbedreigend ziektebeeld.

Acute purulent pericarditis in children is usually fatal, if not recognized and adequately treated. The history of three children with acute purulent pericarditis is presented. In every septic child who presents with signs of right heart decompensation, acute purulent pericarditis should be seriously considered. Echocardiography is essential for the diagnosis. If possible, diagnostic pericardiocenthesis should be performed. Experience of the last years suggests that excellent results can be obtained when adequate surgical drainage and antibiotic therapy are combined.

Multichannel transmission of proprioceptive input to motoneurons.

A model has been developed to simulate the parallel channels of muscle spindles and their monosynaptic connections to a homonymous motoneuron in the turtle. Input to the model is muscle length and beta stimulation, output is motoneuronal membrane potential. Quality of transmission is greatly dependent upon dispersive properties of the system. The contributions of different dispersive features are compared and also cumulative effects are considered. Reference is made to conditions which are found in actual movements.

The effects of beta motor stimulation on the interpretation of signals from muscle spindles.

A previously proposed method for the interpretation of the signals in sensory nerve fibres is extended to incorporate beta activation of muscle spindles. simulations, based on previous experimental observations, of muscles spindles subjected to ramp and hold stretches are used as input to an "interpreter", where the simulated trains of action potentials are reconverted to a length change interpretation. The interpreted signals are compared with the original length change inputs to observe the effects of beta-stimulation and stochastic variability.

A method for the interpretation of signals in afferent nerves from muscle spindles.

A method is proposed for the interpretation of the signals in sensory nerve fibres. It is applicable to systems in which the transfer function between the input to a sense organ and the action potential firing frequency is known. In the present case, the chelonian muscle spindle is considered since its output to ramp-hold-release and sinusoidal stretches can be rather accurately simulated.