Beta-blocker treatment of dilated cardiomyopathy with congestive heart failure in children: a multi-institutional experience

Cardiomyopathy as cause of death in Duchenne muscular dystrophy: a longitudinal observational study

Background

Cardiomyopathy has become an important life-limiting factor since survival in Duchenne muscular dystrophy (DMD) has greatly increased with long-term ventilation and cough assistance. The aim of this study was to investigate the association between impaired left ventricular ejection fraction (LVEF) and survival.

Methods

In a >20-year observational study in patients with DMD (age ≥16 years) with at least three echocardiograms, the association between LVEF and survival and time to cardiac or non-cardiac death was investigated using Kaplan-Meier survival analysis and Cox regression (for LVEF).

Results

In 67 DMD patients (430 echocardiograms), the decrease in LVEF over a mean±sd follow-up period of 9.1±5.1 years was -10.0±13.9% absolute, but LVEF progression varied widely. 84% were receiving an angiotensin-converting enzyme inhibitor and 54% a β-blocker at last follow-up with an LVEF of 37.5±12.4% at that time-point. Median (interquartile range) survival was 33 (25-40) years. 28 out of 67 (42%) of the cohort had died and LVEF was a significant negative predictor of survival (hazard ratio 0.95 (95% CI 0.91-0.99); p<0.007). Those who died of cardiac death (53% of known causes of death) had significantly lower LVEF at the time of death (LVEF -11.0% (95% CI -21.1- -0.9%); p=0.035) compared with non-cardiac death and tended to die at a younger age.

Conclusions

Cardiomyopathy with systolic heart failure is the leading cause of death and lower LVEF is an independent predictor of mortality at younger ages in patients with DMD. Patients with DMD appear to be undertreated with respect to heart failure drug therapy.

Drug Treatment of Heart Failure in Children: Gaps and Opportunities

Medical therapy for pediatric heart failure is based on a detailed mechanistic understanding of the underlying causes, which are diverse and unlike those encountered in most adult patients. Diuresis and improved perfusion are the immediate goals of care in the child with acute decompensated heart failure. Conversion to maintenance oral therapy for heart failure is based on the results of landmark studies in adults, as well as recent pediatric clinical trials and heart failure guidelines. There will continue to be an important role for newer drugs, some of which are in active trials in adults, and some of which are already approved for use in children. The need to plan for clinical trials in children during drug development for heart failure is emphasized.

Beta-blockers for congestive heart failure in children

BACKGROUND

Beta-blockers are an essential part of standard therapy in adult congestive heart failure and therefore, are expected to be beneficial in children. However, congestive heart failure in children differs from that in adults in terms of characteristics, aetiology, and drug clearance. Therefore, paediatric needs must be specifically investigated. This is an update of a Cochrane review previously published in 2009.

OBJECTIVES

To assess the effect of beta-adrenoceptor-blockers (beta-blockers) in children with congestive heart failure.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, and LILACS up to November 2015. Bibliographies of identified studies were checked. No language restrictions were applied.

SELECTION CRITERIA

Randomised, controlled, clinical trials investigating the effect of beta-blocker therapy on paediatric congestive heart failure.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted and assessed data from the included trials.

MAIN RESULTS

We identified four new studies for the review update; the review now includes seven studies with 420 participants. Four small studies with 20 to 30 children each, and two larger studies of 80 children each, showed an improvement of congestive heart failure with beta-blocker therapy. A larger study with 161 participants showed no evidence of benefit over placebo in a composite measure of heart failure outcomes. The included studies showed no significant difference in mortality or heart transplantation rates between the beta-blocker and control groups. No significant adverse events were reported with beta-blockers, apart from one episode of complete heart block. A meta-analysis of left ventricular ejection fraction (LVEF) and fractional shortening (LVFS) data showed a very small improvement with beta-blockers. However, there were vast differences in the age, age range, and health of the participants (aetiology and severity of heart failure; heterogeneity of diagnoses and co-morbidities); there was a range of treatments across studies (choice of beta-blocker, dosing, duration of treatment); and a lack of standardised methods and outcome measures. Therefore, the primary outcomes could not be pooled in meta-analyses.

AUTHORS' CONCLUSIONS

There is not enough evidence to support or discourage the use of beta-blockers in children with congestive heart failure, or to propose a paediatric dosing scheme. However, the sparse data available suggested that children with congestive heart failure might benefit from beta-blocker treatment. Further investigations in clearly defined populations with standardised methodology are required to establish guidelines for therapy. Pharmacokinetic investigations of beta-blockers in children are also required to provide effective dosing in future trials.

Imaging the heart to detect cardiomyopathy in Duchenne muscular dystrophy: A review

Duchenne Muscular Dystrophy is the most common paediatric neuromuscular disorder. Mutations in the DMD gene on the X-chromosome result in progressive skeletal muscle weakness as the main clinical manifestation. However, cardiac muscle is also affected, with cardiomyopathy becoming an increasingly recognised cause of morbidity, and now the leading cause of mortality in this group. The diagnosis of cardiomyopathy has often been made late due to technical limitations in transthoracic echocardiograms and delayed symptomatology in less mobile patients. Increasingly, evidence supports earlier pharmacological intervention in cardiomyopathy to improve outcomes. However, the optimal timing of initiation remains uncertain, and the benefits of prophylactic therapy are unproven. Current treatment guidelines suggest initiation of therapy once cardiac dysfunction is detected. This review focuses on new and evolving techniques for earlier detection of Duchenne muscular dystrophy-associated cardiomyopathy. Transthoracic echocardiography or cardiac magnetic resonance imaging performed under physiological stress (dobutamine or exercise), can unmask early cardiac dysfunction. Cardiac magnetic resonance imaging can define cardiac function with greater accuracy and reliability than an echocardiogram, and is not limited by body habitus. Improved imaging techniques, used in a timely fashion, offer the potential for early detection of cardiomyopathy and improved long-term outcomes.

Reproducibility of Left Ventricular Dimension Versus Area Versus Volume Measurements in Pediatric Patients With Dilated Cardiomyopathy

BACKGROUND

Multiple echocardiographic methods are used to measure left ventricular size and function. Clinical management is based on individual evaluations and longitudinal trends. The Pediatric Heart Network VVV study (Ventricular Volume Variability) in pediatric patients with dilated cardiomyopathy has reported reproducibility of several of these measures, and how disease state and number of beats impact their reproducibility. In this study, we investigated the impact of observer and sonographer variation on reproducibility of dimension, area, and volume methods to determine the best method for both individual and sequential evaluations.

METHODS AND RESULTS

In 8 centers, echocardiograms were obtained on 169 patients prospectively. During the same visit, 2 different sonographers acquired the same imaging protocol on each patient. Each acquisition was analyzed by 2 different observers; first observer analyzed the first acquisition twice. Intraobserver, interobserver, interacquisition, and interobserver-acquisition (different observers and different acquisition) reproducibility were assessed on measurements of left ventricular end-diastolic dimension, area, and volume. Left ventricular shortening fraction, ejection fraction, mass, and fractional area change were calculated. Percent difference was calculated as (interobservation difference/mean)×100. Interobserver reproducibility for both acquisitions was better for both volume and dimension measurements (P≤0.002) compared with area measurements, whereas intraobserver, interacquisition (for both observers), and interobserver-acquisition reproducibilities (for both observer-acquisition sets) were best for volume measurements (P≤0.01). Overall, interobserver-acquisition percent differences were significantly higher than interobserver and interacquisition percent differences (P<0.001).

CONCLUSIONS

In pediatric patients with dilated cardiomyopathy, compared with dimension and area methods, left ventricular measurements by volume method have the best reproducibility in settings where assessment is not performed by the same personnel.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov. Unique identifier: NCT00123071.

Pediatric Cardiac Intensive Care Society 2014 Consensus Statement: Pharmacotherapies in Cardiac Critical Care Chronic Heart Failure

OBJECTIVE

Heart failure is a serious complication that can occur in patients with a variety of congenital and acquired disorders including congenital heart disease, cardiomyopathy, and myocarditis. Furthermore, heart failure patients comprise an increasing number of ICU admissions. Thus, it is important for those caring for patients with critical cardiovascular disease to have a thorough understanding of the medications used for the treatment of heart failure. The aim of this review is to provide an overview, rationale, indications, and adverse effects of medications used in the treatment of chronic heart failure.

DATA SOURCES

PubMed, Medline, Cochrane Database of Systemic Reviews.

STUDY SELECTION

Studies were selected on their relevance for pediatric heart failure. When limited data on pediatric heart failure were available, studies in adult patients were selected.

DATA EXTRACTION

Relevant findings from studies were selected by the authors.

DATA SYNTHESIS

The rationale for the efficacy of most heart failure medications used in pediatric patients is extrapolated from studies in adult heart failure. Commonly used medications for chronic heart failure include β-receptor antagonists (e.g., carvedilol and metoprolol), and medications aimed at blocking the renin-angiotensin-aldosterone system (e.g., angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, aldosterone receptor antagonists). In addition, diuretics are useful for symptoms of fluid overload. For patients with impaired perfusion, inotropic agents are useful acutely, but may be associated with worse outcomes when used chronically. Newer medications that have been recently approved in adults (e.g., serelaxin, ivabradine, and neprilysin inhibitor [angiotensin receptor blocker]) may prove to be important in pediatric heart failure.

CONCLUSIONS

Heart failure patients are in an important population of critically ill children. The pharmacologic approach to these patients is aimed at treating symptoms of congestion and/or poor perfusion and improving long-term outcomes.

Beta-blockers for congestive heart failure in children

BACKGROUND

Beta-blockers are an essential part of standard therapy in adult congestive heart failure and therefore, are expected to be beneficial in children. However, congestive heart failure in children differs from that in adults in terms of characteristics, aetiology, and drug clearance. Therefore, paediatric needs must be specifically investigated. This is an update of a Cochrane review previously published in 2009.

OBJECTIVES

To assess the effect of beta-adrenoceptor-blockers (beta-blockers) in children with congestive heart failure.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, and LILACS up to November 2015. Bibliographies of identified studies were checked. No language restrictions were applied.

SELECTION CRITERIA

Randomised, controlled, clinical trials investigating the effect of beta-blocker therapy on paediatric congestive heart failure.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted and assessed data from the included trials.

MAIN RESULTS

We identified four new studies for the review update; the review now includes seven studies with 420 participants. Four small studies with 20 to 30 children each, and two larger studies of 80 children each, showed an improvement of congestive heart failure with beta-blocker therapy. A larger study with 161 participants showed no evidence of benefit over placebo in a composite measure of heart failure outcomes. The included studies showed no significant difference in mortality or heart transplantation rates between the beta-blocker and control groups. No significant adverse events were reported with beta-blockers, apart from one episode of complete heart block. A meta-analysis of left ventricular ejection fraction (LVEF) and fractional shortening (LVFS) data showed a very small improvement with beta-blockers.However, there were vast differences in the age, age range, and health of the participants (aetiology and severity of heart failure; heterogeneity of diagnoses and co-morbidities); there was a range of treatments across studies (choice of beta-blocker, dosing, duration of treatment); and a lack of standardised methods and outcome measures. Therefore, the primary outcomes could not be pooled in meta-analyses.

AUTHORS' CONCLUSIONS

There is not enough evidence to support or discourage the use of beta-blockers in children with congestive heart failure, or to propose a paediatric dosing scheme. However, the sparse data available suggested that children with congestive heart failure might benefit from beta-blocker treatment. Further investigations in clearly defined populations with standardised methodology are required to establish guidelines for therapy. Pharmacokinetic investigations of beta-blockers in children are also required to provide effective dosing in future trials.

Clinical Characteristics and Treatment of Cardiomyopathies in Children

Cardiomyopathies are diseases of the heart muscle, a term introduced in 1957 to identify a group of myocardial diseases not attributable to coronary artery disease. The definition has since been modified to refer to structural and or functional abnormalities of the myocardium where other known causes of myocardial dysfunction, such as systemic hypertension, valvular disease and ischemic heart disease, have been excluded. In this review, we discuss the pathophysiology, clinical assessment and therapeutic strategies for hypertrophic, dilated and hypertrophic cardiomyopathies, with a particular focus on aspects unique to children.

Anthracycline-related cardiotoxicity in childhood cancer survivors

PURPOSE OF REVIEW

Anthracyclines have markedly improved the survival rates of children with cancer. However, anthracycline-related cardiotoxicity is also well recognized and can compromise the long-term outcome in some patients. The challenge remains of how to balance the chemotherapeutic effects of anthracycline treatment with its potentially serious cardiovascular complications. Here, we review the pathophysiology, risk factors, clinical manifestations, prevention, and treatment of anthracycline-related cardiotoxicity.

RECENT FINDINGS

Some risk factors and biomarkers associated with an increased probability of anthracycline-related cardiotoxicity have been identified. Modifying the structural forms and dosages of anthracyclines and coadministering cardioprotective agents may prevent some of these cardiotoxic effects. Cardiovascular complications have also been treated with angiotensin-converting enzyme inhibitors, β-blockers, and growth hormone replacement therapy. Cardiac transplantation remains the treatment of last resort.

SUMMARY

Despite major advances in cancer treatment, anthracycline-related cardiotoxicity remains a major cause of morbidity and mortality in survivors of childhood cancer. Promising areas of research include: use of biomarkers for early recognition of cardiac injury in children receiving chemotherapy, development and application of cardioprotective agents for prevention of cardiotoxicity, and advancements in therapies for cardiac dysfunction in children after anthracycline treatment.

Variability of M-mode versus two-dimensional echocardiography measurements in children with dilated cardiomyopathy

M-mode and 2-dimensional (2D) echocardiographic imaging are routinely used to quantify left-ventricular (LV) size and function in pediatric patients with dilated cardiomyopathy (DCM). The reproducibility of and correlation between these techniques are unknown. This analysis sought to compare interreader, intrareader, and interacquisition reproducibility of M-mode versus 2D measurements in pediatric DCM patients. The Ventricular Volume Variability study of the Pediatric Heart Network is a multicenter, prospective, observational study assessing the course of chronic DCM in children. Two sonographers performed baseline image acquisitions locally, and two readers performed measurements at the echocardiographic core laboratory. One reader repeated measurements 1 month later. These data were used to assess reproducibility and agreement between M-mode and 2D measurements. One hundred sixty-nine subjects were enrolled. M-mode had similar or greater reproducibility in both intrareader and interreader settings for LV dimensions, shortening fraction (SF), and most wall thicknesses. In contrast, 2D reproducibility was similar or better for nearly all variables in the interacquisition setting but not for SF. Interacquisition variability was approximately twice the intrareader variability. LV dimensions by either modality consistently had high reproducibility and had the highest agreement between modalities. In pediatric DCM patients, variability of linear echocardiographic assessment could be minimized by relying on a single reader and using a consistent method (M-mode or 2D) for serial measurements, preferably M-mode when SF is the primary variable of interest. Except for LV dimensions, M-mode and 2D values should not be used interchangeably due to poor agreement.

Carvedilol: use in chronic heart failure

Carvedilol is a beta-adrenergic antagonist with vasodilatory properties (alpha1-antagonism), which has been extensively evaluated in the treatment of patients with heart failure. In patients with chronic heart failure carvedilol improves left-ventricular (LV) ejection fraction over 6 to 12 months of treatment, and attenuates LV remodelling. Large-scale randomised, placebo controlled trials involving more than 4000 patients with chronic heart failure have demonstrated that carvedilol improves survival and reduces hospitalizations. Comparative studies with metoprolol in patients with heart failure have suggested that carvedilol may be associated with greater survival benefit although differences in the preparation of metoprolol have left uncertainty in this area. Carvedilol has a high safety profile and the clinical benefits appear maintained across a wide range of patients with comorbidities such as diabetes and renal failure. Carvedilol has also been shown to attenuate LV remodeling and improve clinical outcomes in patients with LV dysfunction and/or heart failure following acute myocardial infarction. As a result of these data, carvedilol is recommended for treatment of patients with heart failure in heart-failure guidelines. This evidence-based treatment should be widely implemented to ensure that patients with heart failure receive appropriate medical therapy.

Long-Term Outcomes of Dilated Cardiomyopathy Diagnosed During Childhood

Background—

Existing studies of childhood dilated cardiomyopathy deal mainly with early survival. This population-based study examines long-term outcomes for children with dilated cardiomyopathy.

Methods and Results—

The diagnosis of dilated cardiomyopathy was based on clinical, echocardiographic, and pathological findings. The primary study end point included time to the combined outcome of death or cardiac transplantation. There were 175 patients 0 to <10 years of age at the time of diagnosis. Survival free from death or transplantation was 74% (95% confidence interval, 67–80) 1 year after diagnosis, 62% (95% confidence interval, 55–69) at 10 years, and 56% (95% confidence interval, 46–65) at 20 years. In multivariable analysis, age at diagnosis <4 weeks or >5 years, familial cardiomyopathy, and lower baseline left ventricular fractional shortening Z score were associated with increased risk of death or transplantation, as was lower left ventricular fractional shortening Z score during follow-up. At 15 years after diagnosis, echocardiographic normalization had occurred in 69% of surviving study subjects. Normalization was related to higher baseline left ventricular fractional shortening Z score, higher left ventricular fractional shortening Z score during follow-up, and greater improvement in left ventricular fractional shortening Z score. Children with lymphocytic myocarditis had better survival and a higher rate of echocardiographic normalization. At the latest follow-up, 100 of 104 of survivors (96%) were free of cardiac symptoms, and 83 (80%) were no longer receiving pharmacotherapy.

Conclusions—

Death or transplantation occurred in 26% of patients with childhood dilated cardiomyopathy within 1 year of diagnosis and ~1% per year thereafter. Risk factors for death or transplantation include age at diagnosis, familial cardiomyopathy, and severity of left ventricular dysfunction. The majority of surviving subjects are well and free of cardiac medication.

β-Adrenergic receptor antagonism in mice: a model for pediatric heart disease

Children with heart failure are treated with similar medical therapy as adults with heart failure. In contrast to adults with heart failure, these treatment regiments are not associated with improved outcomes in children. Recent studies have demonstrated age-related pathophysiological differences in the molecular mechanisms of heart failure between children and adults. There are no animal models of pediatric cardiomyopathy to allow mechanistic studies. The purpose of the current experiments was to develop a mouse model of pediatric heart disease and test whether the influence of β-adrenergic receptor (β-AR) antagonism could be modeled in this system. We hypothesized that isoproterenol treatment of young mice would provide a model system of cardiac pathology, and that nonselective β-AR blockade would provide benefit in adult, but not young, mice, similar to clinical trial data. We found that isoproterenol treatment (through osmotic minipump implantation) of young and adult mice produced similar degrees of cardiac hypertrophy and recapitulated several age-related molecular abnormalities in human heart failure, including phospholamban phosphorylation and β-AR expression. We also found that nonselective β-AR blockade effectively prevented pathological cardiac growth and collagen expression in the adult but not young mice, and that selective β1-AR blockade was effective in both young and adult isoproterenol-treated mice. In conclusion, we have developed the first model system for β-AR-mediated pediatric heart disease. Furthermore, we have generated novel data suggesting beneficial effects of selective β1-AR blockade in the pediatric heart.

Clinical and echocardiographic outcome in patients receiving carvedilol for treatment of dilated cardiomyopathy

OBJECTIVE

To determine outcome of children receiving carvedilol in addition to other standard drug therapy for treatment of dilated cardiomyopathy.

METHODS

Children receiving carvedilol for treatment of dilated cardiomyopathy with moderate to severe ventricular dysfunction were included into the study. Data on history, clinical examination and investigations were obtained and detailed echocardiography findings were recorded for the initial and all subsequent visits.

RESULTS

Thirty-three children, mean age 26 ± 30 mo (range 7 mo to 138 mo) were enrolled. Carvedilol was initiated at a mean dose of 0.14 ± 0.03 mg/kg/d and the maintenance dose was 0.46 ± 0.14 mg/kg/d. At a follow up of 6-90 mo (mean of 28 ± 23 mo), functional class using Ross classification for pediatric heart failure improved from 2.7 to 1.3. The left ventricular ejection fraction rose from a basal value of 22 % ± 7 % (10-40 %) to 42 % ± 15 % (15-65 %) (p < 0.0001). Similarly, left ventricular fractional shortening increased significantly from 16 ± 6 % (8-34 %) to 21 ± 7 % (10-44 %) (p < 0.0001). One patient deteriorated and died of refractory heart failure. Carvedilol was discontinued in two more patients temporarily due to bronchospasm during respiratory infection.

CONCLUSIONS

The present study suggests that improvement in ventricular function and clinical symptoms is seen on oral carvedilol added to standard drug therapy in pediatric patients with dilated cardiomyopathy and moderate to severe ventricular dysfunction. The drug is well tolerated with minimal side effects but close monitoring is required as it may worsen heart failure and bronchospasm.

An expert opinion on pharmacologic approaches to reducing the cardiotoxicity of childhood acute lymphoblastic leukemia therapies

INTRODUCTION

Acute lymphoblastic leukemia (ALL) is the most common hematologic malignancy in children. Treatment-related cardiac damage is progressive and often difficult to reverse. Strategies to minimize cardiotoxicity during treatment are crucial to prevent severe lasting effects on health and quality of life.

AREAS COVERED

This comprehensive review covers the pathophysiology and various presentations, both clinical and subclinical, of treatment-induced cardiotoxicity and characteristics associated with increased risk of cardiac dysfunction in childhood ALL survivors. Additionally, contemporary prevention strategies such as limiting cumulative anthracycline dose, altering drug administration schedule, the use of anthracycline structural analogs, liposomal encapsulated anthracyclines, cardioprotective agents and nutritional supplements are critically analyzed. Finally, this review covers the management options of chemotherapy-induced damage and other treatment-related cardiotoxicity.

EXPERT OPINION

Higher lifetime cumulative doses of anthracyclines, younger age at diagnosis, longer follow-up, female sex, higher dose rates and cranial irradiation are associated with more severe cardiotoxic effects. Long-term adverse effects of both anthracycline and non-anthracycline chemotherapeutic agents are becoming an increasing focus during treatment of childhood malignancies. There must be a careful balance between achieving remission of childhood ALL while avoiding the development of another often-fatal illness, heart failure.

Management of hypertension in the young: role of antihypertensive medications

Traditionally, antihypertensive medications were used in few children or adolescents, usually just those with underlying renal or other organ system disease. However, with recent data suggesting that the incidence of primary hypertension may be increasing in the young, it is possible that more children and adolescents will be prescribed antihypertensive agents. This article will review currently available pediatric data on the use of calcium channel blockers, agents affecting the renin-angiotensin-aldosterone system and other classes of antihypertensive medications in children, highlighting appropriate indications and safety considerations. Guidelines for use of antihypertensive medications, including choice of initial agent and how to prescribe appropriately, will be presented.

Effects of steroids and angiotensin converting enzyme inhibition on circumferential strain in boys with Duchenne muscular dystrophy: a cross-sectional and longitudinal study utilizing cardiovascular magnetic resonance

BACKGROUND

Steroid use has prolonged ambulation in Duchenne muscular dystrophy (DMD) and combined with advances in respiratory care overall management has improved such that cardiac manifestations have become the major cause of death. Unfortunately, there is no consensus for DMD-associated cardiac disease management. Our purpose was to assess effects of steroid use alone or in combination with angiotensin converting enzyme inhibitors (ACEI) or angiotension receptor blocker (ARB) on cardiovascular magnetic resonance (CMR) derived circumferential strain (εcc).

METHODS

We used CMR to assess effects of corticosteroids alone (Group A) or in combination with ACEI or ARB (Group B) on heart rate (HR), left ventricular ejection fraction (LVEF), mass (LVM), end diastolic volume (LVEDV) and circumferential strain (εcc) in a cohort of 171 DMD patients >5 years of age. Treatment decisions were made independently by physicians at both our institution and referral centers and not based on CMR results.

RESULTS

Patients in Group A (114 studies) were younger than those in Group B (92 studies)(10 ± 2.4 vs. 12.4 ± 3.2 years, p < 0.0001), but HR, LVEF, LVEDV and LVM were not different. Although εcc magnitude was lower in Group B than Group A (-13.8 ± 1.9 vs. -12.8 ± 2.0, p = 0.0004), age correction using covariance analysis eliminated this effect. In a subset of patients who underwent serial CMR exams with an inter-study time of ~15 months, εcc worsened regardless of treatment group.

CONCLUSIONS

These results support the need for prospective clinical trials to identify more effective treatment regimens for DMD associated cardiac disease.

Current management of pediatric dilated cardiomyopathy

PURPOSE OF REVIEW

American and European guidelines for treatment of adult heart failure have been recently revised. This review will reconcile those guidelines to recent studies and experience in the treatment of pediatric dilated cardiomyopathy.

RECENT FINDINGS

Therapy for pediatric dilated cardiomyopathy includes establishing a diagnosis for diagnostic-specific therapies as well as preventive strategies for anthracycline toxicity and muscular dystrophy. Pediatric studies demonstrate safety and efficacy for use of angiotensin-converting enzyme inhibition and beta-blockers in dilated cardiomyopathy. Cardiac resynchronization and mitral annuloplasty represent potential nonpharmacologic therapies. Implantable defibrillator therapy may be of less import in children as compared with adults. Ventricular assist devices (VADs) are now available for all ages, which can improve survival and potentially can lead to recovery.

SUMMARY

The robust development of new therapies for adult heart failure has been successfully applied to children with dilated cardiomyopathy. Therapies for severe, intractable heart failure have been more widely utilized than therapies for mild-to-moderate heart failure.

Outpatient management of pediatric heart failure

The management of heart failure in children is becoming a specialized discipline within pediatric cardiology. Unlike the treatment of heart failure in adults, for which an extensive body of literature supports current treatment regimens, management of heart failure in children is largely guided by extrapolation from adult studies and expert opinion. This review focuses on the current state-of-the-art with respect to the outpatient management of heart failure in children.

Diagnosis and management of Duchenne muscular dystrophy, part 2: implementation of multidisciplinary care

Optimum management of Duchenne muscular dystrophy (DMD) requires a multidisciplinary approach that focuses on anticipatory and preventive measures as well as active interventions to address the primary and secondary aspects of the disorder. Implementing comprehensive management strategies can favourably alter the natural history of the disease and improve function, quality of life, and longevity. Standardised care can also facilitate planning for multicentre trials and help with the identification of areas in which care can be improved. Here, we present a comprehensive set of DMD care recommendations for management of rehabilitation, orthopaedic, respiratory, cardiovascular, gastroenterology/nutrition, and pain issues, as well as general surgical and emergency-room precautions. Together with part 1 of this Review, which focuses on diagnosis, pharmacological treatment, and psychosocial care, these recommendations allow diagnosis and management to occur in a coordinated multidisciplinary fashion.

Role of β-blocker therapy in pediatric heart failure

Heart failure is becoming an increasingly common and significant problem in the field of pediatric cardiology. The numerous types of cardiomyopathies, and more recently, long-term survival of patients with congenital heart disease, have added to a growing patient population. Over the last several decades, our knowledge base regarding mechanisms of disease and therapeutic intervention in adult patients with heart failure has drastically changed. The most recent and important breakthrough in the pharmacologic treatment of heart failure has been the particular role of β-blocker therapy. This medication has led to significant improvements in survival and symptoms in adults, with less convincing findings in limited studies in pediatrics. The ability to study the benefits of this therapy in patients has been challenging owing to the heterogeneity of the patient population and lack of large sample sizes. However, as we investigate the mechanisms behind the disease process, the differences that exist between disease conditions and ages, and the significant alterations that may exist at the molecular and genetic level, our understanding of β-blocker therapy in pediatric heart failure will improve, and ultimately may lead to patient-specific therapy.

Molecular pathogenetic mechanisms and new therapeutic perspectives in anthracycline-induced cardiomyopathy

Anthracyclines are among the most powerful drugs for the treatment of oncologic diseases both in childhood and in adulthood. Nevertheless, their major antineoplastic efficacy can be seriously impaired by collateral toxic cardiac effects causing cardiomyopathy with chronic heart failure that is refractory to conventional medical therapy.

This article reports possible subcellular molecular alterations of anthracycline-induced cardiomyopathy (reactive oxygen species formation, apoptosis, inflammatory signalling, altered expression of cardiomyocytes specific genes, etc) and indicates some new therapeutic perspectives resulting from a better understanding of the molecular pathogenetic mechanisms.

Beta-blockers for congestive heart failure in children

BACKGROUND

Beta-blockers are an essential part of standard therapy in adult congestive heart failure and are therefore also expected to be beneficial in children. However, congestive heart failure in children differs strongly from that in adults in terms of characteristics and aetiology; also, an increased drug clearance has been reported. Paediatric needs have therefore to be specifically investigated.

OBJECTIVES

To assess the effect of beta-adrenoceptor-blockers in children with congestive heart failure.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) on The Cochrane Library (Issue 4 2007), MEDLINE (1966 to January 2008), EMBASE (1980 to January 2008), and LILACS (1980 to January 2008). Bibliographies of identified studies were checked. No language restrictions were applied.

SELECTION CRITERIA

Randomised, controlled clinical trials investigating the effect of beta-blocker therapy on paediatric congestive heart failure.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted and assessed data from the included trials.

MAIN RESULTS

Three studies with an overall number of 203 participants were identified. Two small studies, with 20 and 22 children respectively, showed an improvement of congestive heart failure, while a larger study with 161 participants showed no evidence of benefit over placebo in the composite measure of heart failure outcomes which was the main outcome measure of the trial (56% improvement in both the placebo and the treatment group, p=0.74). However, study populations showed vast differences with regard to treatment (choice of beta-blocker, dosing, duration of treatment), age and age range of the participants and in particular with regard to condition (aetiology and severity of heart failure; homogeneity of condition in the study population). In addition methods and outcome measures differed strongly and were not standardised. The results can therefore not be compared against each other.

AUTHORS' CONCLUSIONS

There are not enough data to recommend or discourage the use of beta-blockers in children with congestive heart failure. Further investigations in clearly defined populations with standardised methodology are required to establish guidelines for therapy. Pharmacokinetic investigations of beta-blockers in children are required to provide effective dosing in future trials.

Pediatric heart failure therapy with beta-adrenoceptor antagonists

Management of chronic heart failure in pediatrics has been altered by the adult literature showing improvements in mortality and hospitalization rates with the use of beta-adrenoceptor antagonists (beta-blockers) for routine therapy of all classes of ischemic and non-ischemic heart failure. Many pediatric heart failure specialists have incorporated these agents into their routine management of pediatric heart failure related to dilated cardiomyopathy or ventricular dysfunction in association with congenital heart disease. Retrospective and small prospective case series have shown encouraging improvements in cardiac function and symptoms, but interpretation has been complicated by the high rate of spontaneous recovery in pediatric patients. A recently completed pediatric double-blind, randomized, placebo-controlled clinical trial showed no difference between placebo and two doses of carvedilol over a 6-month period of follow-up, with significant improvement of all three groups over the course of evaluation. Experience with adults has suggested that only certain beta-blockers, including carvedilol, bisoprolol, nebivolol, and metoprolol succinate, should be used in the treatment of heart failure and that patients with high-grade heart failure may derive the most benefit. Other studies surmise that early or prophylactic use of these medications may alter the risk of disease progression in some high-risk subsets, such as patients receiving anthracyclines or those with muscular dystrophy. This article reviews these topics using experience as well as data from all the recent pediatric studies on the use of beta-blockers to treat congestive heart failure, especially when related to systolic ventricular dysfunction.

Contemporary management of pediatric heart failure

The spectrum of causes of pediatric heart failure is broad and differs significantly from that seen in most adult patients. Left-to-right shunts and outflow obstruction lesions are responsible for a large number of pediatric cases of heart failure. Most of these are now treated successfully with surgery or catheter intervention. Medical therapy is the mainstay of care for myocardial disorders with diuretics, angiotensin-converting enzyme inhibitors, beta-blockade and cardiac glycosides. There are few prospective trials of these agents in a pediatric population, but extrapolated data support their use in children. In addition to medical therapy, interventions such as automatic implantable cardioverter defibrillators and resynchronization therapy have become increasingly common in pediatric heart disease, as well as in adult patients with congenital heart disease.

Safety and efficacy of carvedilol therapy for patients with dilated cardiomyopathy secondary to muscular dystrophy

BACKGROUND

By the age of 20 years, almost all patients with Duchenne's or Becker's muscular dystrophy have experienced dilated cardiomyopathy (DCM), a condition that contributes significantly to their morbidity and mortality. Although studies have shown carvedilol to be an effective therapy for patients with other forms of DCM, few data exist concerning its safety and efficacy for patients with muscular dystrophy. This study aimed to evaluate the safety and efficacy of carvedilol for patients with DCM.

METHODS

A clinical trial at an outpatient clinic investigated 22 muscular dystrophy patients, ages 14 to 46 years, with DCM and left ventricular ejection fraction (LVEF) less than 50%. Carvedilol up-titrated over 8 weeks then was administered at the maximum or highest tolerated dose for 6 months. Baseline and posttreatment cardiac magnetic resonance imaging (CMR), echocardiography, and Holter monitoring were recorded.

RESULTS

Carvedilol therapy was associated with a modest but statistically significant improvement in CMR-derived ejection fraction (41% +/- 8.3% to 43% +/- 8%; p < 0.02). Carvedilol also was associated with significant improvements in both the mean rate of pressure rise (dP/dt) during isovolumetric contraction (804 +/- 216 to 951 +/- 282 mmHg/s; p < 0.05) and the myocardial performance index (0.55 +/- 0.18 to 0.42 +/- 0.15; p < 0.01). A trend toward improved shortening fraction, E/E' ratio, and isovolumetric relaxation time also was observed. Two patients had runs of nonsustained ventricular tachycardia exceeding 140 beats per minute (bpm) before carvedilol administration. Ventricular tachycardia exceeding 140 bpm was not observed after carvedilol therapy. Carvedilol was well tolerated, and no serious adverse events were identified.

CONCLUSIONS

Carvedilol therapy appears to be safe for patients with DCM secondary to muscular dystrophy and produces a modest improvement in systolic and diastolic function.

Beta-blocker therapy for cardiac dysfunction in patients with muscular dystrophy

BACKGROUND

In muscular dystrophy, cardiac function deteriorates with time and heart failure is one of the major causes of death. Although the combination of angiotensin-converting enzyme inhibitors (ACEI) and beta-blockers improves cardiac function in adults, little is known about the efficacy of those drugs in patients with muscular dystrophy.

METHODS AND RESULTS

The effect of the beta-blocker, carvedilol, and/or ACEI on ventricular function in patients with muscular dystrophy was studied. Carvedilol and an ACEI were given to 13 patients (ACEI group; mean age 18 years, range 7-27 years), and an ACEI only to 15 patients (carvedilol group; mean age 15 years, range 8-29 years). Diagnoses included Duchenne muscular dystrophy (n=25), Fukuyama muscular dystrophy (n=2), and Emery-Dreifuss muscular dystrophy (n=1). Echocardiographic parameters of the left ventricle were measured during the 2-3 years of follow-up. In the carvedilol group, combination therapy of carvedilol and an ACEI for 2 years resulted in a significant increase in left ventricular fractional shortening (LVFS). In the ACEI group, there was no significant change in LVFS. Left ventricular end-diastolic dimension increased in the ACEI group, but not in the carvedilol group.

CONCLUSION

Carvedilol plus an ACEI improves left ventricular systolic function in patients with muscular dystrophy.

Future pharmacologic agents for treatment of heart failure in children

The addition of new agents to the armamentarium of treatment options for heart failure in pediatric patients is exciting and challenging. Administration of these therapies to pediatric patients will require careful scrutiny of the data and skilled application. Developmental changes in drug metabolism, excretion, and distribution are concerning in pediatric patients, and inappropriate evaluation of these parameters can have disastrous results. Manipulation of the neurohormonal pathways in heart failure has been the target of most recently developed pharmacologic agents. Angiotensin receptor blockers (ARBs), aldosterone antagonists, beta-blockers, and natriuretic peptides are seeing increased use in pediatrics. In particular, calcium sensitizing agents represent a new frontier in the treatment of acute decompensated heart failure and may replace traditional inotropic therapies. Endothelin receptor antagonists have shown benefit in the treatment of pulmonary hypertension, but their use in heart failure is still debatable. Vasopressin antagonists, tumor necrosis factor inhibitors, and neutral endopeptidase inhibitors are also targeting aspects of the neurohormonal cascade that are currently not completely understood. The future of pharmacologic therapies will include pharmacogenomic studies on new and preexisting therapies for pediatric heart failure. The education and skill of the practitioner when applying these agents in pediatric heart failure is of utmost importance.

Heart failure therapy in children

The most common reason for heart failure in children is volume overload secondary to a left-to-right shunt. Therefore, an accurate diagnosis with identification of possible surgical or interventional reactions should be the first priority. Medical therapy is mainly based on diuretics, angiotensin-converting enzyme inhibitors, cardiac glycosides and beta-blockers. There are few prospective trials in pediatric cardiology, but the available data reach a similar conclusion to that of adults with heart failure. Diuretics are an important tool in patients with fluid retention, and angiotensin-converting enzyme inhibitors are helpful in patients with volume overload of the ventricles. Cardiac glycosides are still in use, but there is a trend toward primary use of diuretics. Angiotensin-converting enzyme inhibitors and beta-blockers have been used successfully in the treatment of heart failure in children, but there are limited data on its efficacy.

Effectiveness of carvedilol for congestive heart failure that developed long after modified Fontan operation

We report a case of a patient with severe heart failure after Fontan procedure in whom carvedilol was very effective. A 27-year-old man had intractable congestive heart failure due to severe ventricular dysfunction after Fontan operation. Central venous pressure was elevated to 29 mmHg. A right-to-left shunt was noted across a large collateral vessel between the innominate vein and the pulmonary vein. He was administered carvedilol (initial dose, 2 mg/day; maximum dose, 30 mg/day). Cardiac catheterization performed 1 year after carvedilol administration revealed a decrease in atrial pressure and improvement of ventricular function. He underwent a conversion operation to total cavopulmonary connection (TCPC) and ligation of a collateral vein communicating with the innominate and pulmonary veins. Carvedilol may be a legitimate treatment before TCPC conversion or heart transplantation for the high-risk group of patients with a failed Fontan circulation.

Prospective single-arm protocol of carvedilol in children with ventricular dysfunction

The objective of this study was to evaluate the safety and efficacy of carvedilol in pediatric patients with stable moderate heart failure. We performed a single-arm prospective drug trial at three academic medical centers and the results were compared to historical controls. Patients were 3 months to 17 years old with an ejection fraction <40% in the systemic ventricle for at least 3 months on maximal medical therapy including ACE inhibitors. Treated patients were started on 0.1 mg/kg/day and uptitrated to 0.8 mg/kg/day or the maximal tolerated dose. Echocardiographic parameters of function were prospectively measured at entry and at 6 months. Two composite endpoints were recorded: severe decline in status and significant clinical change. Adverse events were reviewed by a safety committee. Data were also collected from untreated controls with dilated cardiomyopathy meeting entry criteria, assessed over a similar time frame. Twenty patients [12 dilated cardiomyopathy (DCM) and 8 congenital] with a median age of 8.4 years (range, 8 months to 17.8 years) were treated with carvedilol. Three patients discontinued the drug during the study. At entry, there was no statistical difference in age, weight, or ejection fraction between the treated group and controls. The ejection fraction of the treated DCM group improved significantly from entry to 6 months (median, 31 to 40%, p = 0.04), with no significant change in ejection fraction in the control group [median, 29 to 27%, p = not significant (NS)]. The median increase in ejection fraction was larger for the treated DCM group than for the untreated DCM controls (7 vs 0%, p = 0.05). By Kaplan-Meier analysis, time to death or transplant tended to be longer in treated patients (p = 0.07). The difference in the proportion of patients with severe decline in status or significant clinical change in the treated group was not significant compared to the controls (5 vs 12%, p = NS). We conclude that in this prospective protocol of pediatric patients, the use of adjunct carvedilol in the DCM group improved ejection fraction compared to untreated controls and trended toward delaying time to transplant or death.

Protecting against anthracycline-induced myocardial damage: a review of the most promising strategies

Over the last 40 years, great progress has been made in treating childhood and adult cancers. However, this progress has come at an unforeseen cost, in the form of emerging long-term effects of anthracycline treatment. A major complication of anthracycline therapy is its adverse cardiovascular effects. If these cardiac complications could be reduced or prevented, higher doses of anthracyclines could potentially be used, thereby further increasing cancer cure rates. Moreover, as the incidence of cardiac toxicity resulting in congestive heart failure or even heart transplantation dropped, the quality and extent of life for cancer survivors would improve. We review the proposed mechanisms of action of anthracyclines and the consequences associated with anthracycline treatment in children and adults. We summarise the most promising current strategies to limit or prevent anthracycline-induced cardiotoxicity, as well as possible strategies to prevent existing cardiomyopathy from worsening.

Cardiovascular health supervision for individuals affected by Duchenne or Becker muscular dystrophy

Duchenne muscular dystrophy is the most common and severe form of the childhood muscular dystrophies. The disease is typically diagnosed between 3 and 7 years of age and follows a predictable clinical course marked by progressive skeletal muscle weakness with loss of ambulation by 12 years of age. Death occurs in early adulthood secondary to respiratory or cardiac failure. Becker muscular dystrophy is less common and has a milder clinical course but also results in respiratory and cardiac failure. The natural history of the cardiomyopathy in these diseases has not been well established. As a result, patients traditionally present for cardiac evaluation only after clinical symptoms become evident. The purpose of this policy statement is to provide recommendations for optimal cardiovascular evaluation to health care specialists caring for individuals in whom the diagnosis of Duchenne or Becker muscular dystrophy has been confirmed.

Cardiovascular complications in pediatric end-stage renal disease

Mortality from end-stage renal disease (ESRD) is often due to cardiac causes. Although cardiovascular complications of ESRD have long been recognized, only recently has the presence of traditional cardiovascular risk factors been associated with late cardiovascular complications. This review presents a history of cardiac involvement in ESRD, the pathophysiology of accelerated atherosclerosis and left ventricular hypertrophy, and a summary of the literature on cardiovascular risk assessment in children. Techniques for non-invasive assessment of cardiac end-organ injury are also discussed. Recommendations for monitoring of risk factors and treatment in the pediatric ESRD population are presented.

Characteristics of the increase in plasma brain natriuretic peptide level in left ventricular systolic dysfunction, associated with muscular dystrophy in comparison with idiopathic dilated cardiomyopathy

To determine whether the plasma brain natriuretic peptide level increases differentially in muscular dystrophy and idiopathic dilated cardiomyopathy, we investigated the plasma brain natriuretic peptide level and echocardiographic parameters in patients with similarly low left ventricular ejection fraction. The plasma brain natriuretic peptide level was lower, and the left ventricular end-diastolic diameter was shorter in the patients with muscular dystrophy than in those with idiopathic dilated cardiomyopathy. The correlation between the plasma brain natriuretic peptide and left ventricular ejection fraction was shifted downward in the patients with muscular dystrophy compared with those with idiopathic dilated cardiomyopathy. Those between the brain natriuretic peptide and left ventricular end-diastolic diameter were superimposable, although the data from the muscular dystrophy patients were located at the shorter left ventricular end-diastolic diameter side. The plasma brain natriuretic peptide level may differentially increase in the two diseases with similar left ventricular systolic dysfunction. Differences in the left ventricular distension and in the physical activity might explain at least partially the different plasma brain natriuretic peptide levels.

Evidence of early impairments in both right and left ventricular inotropic reserves in children with Duchenne's muscular dystrophy

In Duchenne's muscular dystrophy (DMD), cardiac function deteriorates with time and heart failure is one of the major causes of death. The aim of the study was to determine if a decrease in the ventricular inotropic reserves could be an early sign of cardiac dysfunction in these children. Nineteen children with DMD (aged 9 to 18 years, mean age 13.6 +/- 2.4) underwent equilibrium radionuclide angiography at rest and during an inotropic stimulation with low-dose dobutamine perfusion (7.5 to 15 microg. kg(-1). min(-1)). In all patients, this investigation was short (<30 minutes), successful, and uncomplicated. At rest, left ventricular (LV) ejection fraction (EF) was normal (>0.50) in 79% of patients, and right ventricular (RV) EF was normal (>0.45) in 95%. There was a trend toward a decrease with age for rest LVEF (p = 0.051) but not for rest RVEF (p = 0.8). By contrast, marked declines with age could be documented for the increases (Delta) in LVEF and RVEF during dobutamine perfusion (p = 0.002 for DeltaLVEF and p = 0.015 for DeltaRVEF). Thus, by multivariate analysis, the sole best indicator of decline in cardiac function with age was LVEF determined with dobutamine. In children with DMD, low-dose dobutamine radionuclide angiography gives evidence of an early decline with age of the inotropic reserves of both ventricles.

Should beta-blockers be used for the treatment of pediatric patients with chronic heart failure?

In multiple clinical trials, beta-blockers have been shown to significantly improve morbidity and mortality in adults with chronic congestive heart failure, but there is little reported experience with their use in children. Heart failure involves activation of the adrenergic nervous system and other neurohumoral systems in order to maintain cardiovascular homeostasis. These compensatory mechanisms have been shown to cause myocardial damage with chronic activation, which has been hypothesized to be a major contributing factor to the clinical deterioration of adults with heart failure. Studies have demonstrated inhibition of this neurohumoral response and concomitant clinical benefits with beta-blockers. Consequently, beta-blockers have evolved to become an important part of comprehensive medical therapy for congestive heart failure in adults. Pediatric heart failure represents an entirely different spectrum of disease, caused more commonly by congenital heart disease than cardiomyopathy. Surgical palliation and correction are important components of pediatric heart failure therapy, and residual, postsurgical cardiac lesions can lead to chronic heart failure. Although neurohumoral activation in children is similar to that in adults with heart failure, there are important differences from adults in physiology and developmental changes that are especially observed in infants. Current published clinical experience with beta-blocker use in children with heart failure is limited to case series with relatively small numbers of patients. Nevertheless, these series show consistent symptomatic improvement, and improvement in ventricular systolic function in patients with cardiomyopathies and congenital heart disease, similar to findings in adults. Adverse effects were common and many patients in these studies had adverse outcomes (death and/or need for transplantation). One study has noted differences in pharmacokinetics in children compared with adults. However, a multicenter, randomized controlled trial to evaluate carvedilol in pediatric heart failure from systolic ventricular dysfunction is currently ongoing and should help to clarify the efficacy and tolerability of carvedilol in children.

Cardiomyocyte injury to transplant: pediatric management

Cardiomyocyte injury in pediatric patients has a vast number of causes, which are often distinct from the causes of adult heart failure. However, the management of pediatric heart failure and heart transplantation has generally been inferred from adult studies. New therapies show great promise for the neurohormonal regulation of heart failure and the ability to control immunosuppression after heart transplantation. Large, randomized, multicenter, controlled clinical trials are needed to determine the efficacy of these therapies in this population. This article reviews the current recommendations and evidence-based medicine, where available, for the medical management of myopathic dysfunction and transplantation in pediatric patients.

Delisting of infants and children from the heart transplantation waiting list after carvedilol treatment

OBJECTIVES

We performed a prospective, randomized, double-blind, placebo-controlled study of carvedilol effects in children with severe, chronic heart failure (HF), despite the use of conventional therapy.

BACKGROUND

Little is known about the effects of carvedilol in youngsters with chronic HF and severe left ventricular (LV) dysfunction.

METHODS

We conducted a double-blind, placebo-controlled study of 22 consecutive children with severe LV dysfunction. The children had chronic HF and left ventricular ejection fraction (LVEF) <30%. Patients were randomly assigned to receive either placebo (8 patients) or the beta-blocker carvedilol (14 patients) at 0.01 mg/kg/day titrated up to 0.2 mg/kg/day, followed-up for six months.

RESULTS

During the follow-up and the up-titration period in the carvedilol group, four patients died and one underwent heart transplantation. In patients receiving carvedilol evaluated after six months, a significant increase occurred in LVEF, from 17.8% (95% confidence interval [CI], 14.1 to 21.4%) to 34.6% (95% CI, 25.2 to 44.0%); p = 0.001. Modified New York Heart Association (NYHA) functional class improved in nine patients taken off the transplant waiting list. All nine patients were alive at follow-up. In the placebo group, during the six-month follow-up, two patients died, and two underwent heart transplantation. Four patients persisted with HF symptoms (NYHA functional class IV). No significant change occurred in LVEF or fractional shortening.

CONCLUSIONS

Carvedilol added to standard therapy may reduce HF progression and improve cardiac function, allowing some youngsters to be removed from the heart transplantation waiting list.

The Pediatric Randomized Carvedilol Trial in Children with Heart Failure: rationale and design

BACKGROUND

Carvedilol is a medication with both beta-receptor and alpha-receptor blocking properties that has been approved for the treatment of heart failure in adults. Little is known about its safety, efficacy, pharmacokinetics, and dosing profile in children.

METHODS

The primary objective of this study is to evaluate the efficacy of carvedilol administered twice daily for 8 months in terms of its effect compared with placebo on a composite measure of clinical outcomes in children with symptomatic systemic ventricular systolic dysfunction and heart failure. The secondary objectives are to determine the effect of carvedilol on individual components of a composite of clinical outcomes (hospitalizations for worsening heart failure, all-cause mortality and cardiovascular hospitalizations, all cause mortality, heart failure symptoms, and patient and physician global assessment); determine the effect of carvedilol on echocardiographic indices of ventricular function and remodeling; characterize the pharmacokinetics of carvedilol in pediatric patients with heart failure; characterize the effects carvedilol on neurohormonal systems; and provide data for the selection of an optimal titration schedule and daily dose of carvedilol in children with heart failure. This study will enroll 150 children between birth and 17 years of age with chronic symptomatic heart failure caused by systemic ventricular systolic dysfunction.

CONCLUSION

This study will determine whether carvedilol improves symptoms in children with heart failure as a result of systemic ventricular systolic dysfunction. The study also will provide information on echocardiographic changes of ventricular performance and neurohormonal levels in children with heart failure before and after treatment with carvedilol, in addition to pharmacokinetics of carvedilol in children.

Intermediate effects of treatment with metoprolol or carvedilol in children with left ventricular systolic dysfunction

The use of beta-blocking agents in adults with congestive heart failure has been shown to improve symptoms and outcome; however, experience in pediatric patients with left ventricular systolic dysfunction is limited. We identified 12 pediatric patients treated with beta-blocking agents for left ventricular systolic dysfunction and reviewed echocardiographic indices of left ventricular systolic performance prior to initiation of beta-blocker therapy and at intermediate follow-up. Left ventricular fractional shortening and ejection fraction increased significantly from baseline to intermediate follow-up (13 +/- 4% to 21 +/- 8% [p = 0.01] and 26 +/- 8% to 41 +/- 17% [p = 0.04], respectively). When added to conventional therapy, beta-blocker therapy resulted in an increase in ejection-phase indices of left ventricular systolic performance at intermediate follow-up in pediatric patients with systolic dysfunction.