Efficacy and safety of carvedilol in infants with dilated cardiomyopathy: a preliminary report.

BACKGROUND: Carvedilol has proven to be beneficial in a majority of adult patients with congestive heart failure. Although the experience from adult patients may be extrapolated to older children, symptomatic infants remain a subset for whom dosage, safety and efficacy need to be established. The purpose of this study was to assess whether treatment with carvedilol is efficacious and safe for infants with dilated cardiomyopathy who do not show satisfactory clinical improvement despite treatment with conventional medications. METHODS AND RESULTS: Eight infants with dilated cardiomyopathy (ejection fraction <30%) who were symptomatic despite tailored treatment with decongestive medications, were enrolled in the study. Echocardiographic findings and heart failure symptom scores were analyzed before and after starting carvedilol. Patients were hospitalized and monitored for side-effects during up-titration of carvedilol. At a follow-up of 4.5+/-2.2 months, patients receiving carvedilol showed a significant improvement in the left ventricular ejection fraction (38.5+/-11% v. 24.4+/-5%), and heart failure symptom score (p<0.05). No adverse events related to carvedilol administration occurred. There were no deaths. CONCLUSIONS: Carvedilol is well tolerated in infants with dilated cardiomyopathy and there is significant improvement in their functional status. Optimal timing of starting therapy, dosage and long-term effects need to be investigated with multi-institutional trials.

Diagnosis and management of primary pulmonary hypertension.

Pulmonary arterial hypertension in children can occur secondary to shunt lesion like ventricular septal defect, patent ductus arteriosus or it may be idiopathic, the so-called primary pulmonary hypertension (PPH). The progression of PPH is usually rapid in children as compared to adults and the mean survival is 2-3 years after the diagnosis is made. Histological changes in the form of medical muscular hypertrophy, intinal hyperplasia and later angiornatous, plexiform lesions occur in pulmonary vasculature. The pulmonary vasculature normally is a high flow, low resistance circuit and allows large blood flow without marked increase in pulmonary arterial pressure. However, with prolonged increased flow or any other vasoconstrictor stimulus, histological changes start occurring in the pulmonary bed resulting in increasing pressure in pulmonary artery. Right ventricular hypertension follows resulting in right ventricular hypertrophy and later dysfunction. Life threatening arrhythmias may result in sudden death in some of these patients. Clinical presentation is in the form of exertional dyspnoea with syncope at times. Over 50% of children with PPH are helped by vasodilators. They may be treated with calcium channel blockers (e.g. nifedipine, dose titrated to blood pressure) orally. Those not responding to oral vasodilators can be put on chronic inhaled nitric oxide or continuous intravenous prostacyclin infusion. Chronic anticoagulation therapy may also increase survival. In symptomatic cases, blade/balloon atrial septostomy may increase survival in patients of PPH with intact atrial sptum. For children not responding to medical therapy, lung transplantation may be the answer in near future.

Diagnosis and management of primary pulmonary hypertension.

Pulmonary arterial hypertension in children can occur secondary to shunt lesion like ventricular septal defect, patent ductus arteriosus or it may be idiopathic, the so called primary pulmonary hypertension (PPH). The progression of PPH is usually rapid in children as compared to adults and the mean survival is 2-3 years after the diagnosis is made. Histological changes in the form of medical muscular hypertrophy, intinal hyperplasia and later angiomatous, plexiform lesions occur in pulmonary vasculature. The pulmonary vasculature normally is a high flow, low resistance circuit and allows large blood flow without marked increase in pulmonary arterial pressure. However, with prolonged increased flow or any other vasoconstrictor stimulus, histological changes start occurring in the pulmonary bed resulting in increasing pressure in pulmonary artery. Right ventricular hypertension follows resulting in right ventricular hyypertrophy and later dysfunction. Life threatening arrhythmias may result in sudden death in some of these patients. Clinical presentation is in the form of exertional dyspnoea with syncope at times. Over 50% of children with PPH are helped by vasodilators. They may be treated with calcium channel blockers (e.g. nifedipine, dose titrated to blood pressure) orally. Those not responding to oral vasodilators can be put on chronic inhaled nitric oxide or continuous intravenous prostacyclin infusion. Chronic anticoagulation therapy may also increase survival. In symptomatic cases, blade/balloon atrial septostomy may increase survival in patients of PPH with intact atrial sptum. For children not responding to medical therapy, lung transplantation may be the answer in near future.

Diagnosis of the sinus venosus defect by echocardiography and angiocardiography.

A retrospective analysis of forty five cases of sinus venosus defect was done to compare the ability of transthoracic echocardiography, transesophageal echocardiography and cineangiography in diagnosing this lesion. Left atrial and superior vena cava angiography delineated sinus venosus defect accurately in all the 45 cases (100%). Transthoracic cross-sectional echocardiography combined with colour flow mapping could visualize this defect in 28 out of 45 cases (62.2%) and proved inferior to transesophgeal technique which diagnosed the defect in all the 8 cases (100%) studied. An anomalous venous connection associated with sinus venosus defect was best diagnosed at cardiac catheterization although transesophgeal technique seems promising.

High affinity uptake of L-glutamate and γ-aminobutyric acid in Drosophila melanogaster.

Preparations having properties resembling those of synaptosomes have been isolated from whole fly homogenates of Drosophila melanogaster using ficoll gradient floatation technique. These have been characterized by marker enzymes and electron microscopy and binding of muscarinic antagenist 3H Quinuclidinyl benzilate. An uptake system for neurotransmitter, ã-Aminobutyric acid has been demonstrated in these preparations. A high affinity uptake system for L-glutamate has also been studied in these subcellular fractions. This uptake of glutamate is transport into an osmotically sensitive compartment and not due to binding of glutamate to membrane components. The transport of glutamate has an obligatory requirements for either sodium or potassium ions. Kinetic experiments show that two transport systems, with Km values 0·33×10–6Μ and 2·0×10–6Μ, respectively, function in the accumulation of glutamate. ATP stimulates lower affinity transport of glutamate. Inhibition of glutamate uptake by L-aspartate but not by phenylalanine and tyrosine indicates that a common carrier mediates the transport of both glutamate and aspartate. β-N-oxalyl-L-β β-diamino propionic acid and kainic acid, both inhibitors of glutamate transport in mammalian brain preparations, strongly inhibited transport of glutamate in Drosophila preparations Comparison with uptake of ã-aminobutyric acid and glutamate in isolated larval brain is presented to show that the synaptosome-like preparations we have isolated are rich in central nervous system derived structures, and presynaptic endings from neuromuscular junctions.