Treatment Strategies for Cardiomyopathy in Children: A Scientific Statement From the American Heart Association

Cardiovascular Toxicity in Patients Treated for Childhood Cancer: A Scientific Statement From the American Heart Association

The field of cardio-oncology has expanded over the past 2 decades to address the ever-increasing issues related to cardiovascular disease in patients with cancer and survivors. There is increasing recognition that nearly all cancer treatments pose some short- or long-term risk for development of cardiovascular disease and that pediatric patients with cancer may be especially vulnerable to cardiovascular disease because of young age at treatment and expected long life span afterward. Anthracycline chemotherapy and chest-directed radiotherapy are the most well-studied cardiotoxic therapies, and dose reduction, use of cardioprotection for anthracyclines, and modern radiotherapy approaches have contributed to improved cardiovascular outcomes for survivors. Newer treatments such as small-molecule inhibitors, antibody-based cytotoxic therapy, and immunotherapy have expanded options for previously difficult-to-treat cancers but have also revealed new cardiotoxic profiles. Application of effective surveillance strategies in patients with cancer and survivors has been a focus of practitioners and researchers, whereas the prevention and treatment of extant cardiovascular disease is still developing. Incorporation of new strategies in an equitable manner and appropriate transition from pediatric to adult care will greatly influence long-term health-related outcomes in the growing population of childhood cancer survivors at risk for cardiovascular disease.

Serial Exercise Testing in Children With Known or Suspected Congenital and Acquired Heart Disease: A Narrative Review and Survey of Current Practice

BACKGROUND

Exercise parameters can be altered in children with congenital heart disease or acquired heart disease compared with children with normal hearts. Exercise testing has proven a useful tool to predict patient outcomes and even the need for reintervention in several cardiovascular disease processes. There are established guidelines for serial exercise stress testing in adults with congenital heart disease, but corollary guidelines do not exist for the pediatric population.

METHODS AND RESULTS

A narrative literature review was completed. Evidence was ranked by a 4-point scale as outlined by the American College of Sports Medicine evidence categories. A survey was sent to experts in pediatric exercise physiology across the country regarding their current testing practices for 26 unique congenital heart disease or known or suspected acquired heart disease lesions. Survey questions were related to the frequency of testing, the age at which exercise testing is started, and if the frequency of testing is altered by a patient presenting with symptoms. Our literature search yielded 122 relevant studies pertaining to exercise stress testing in pediatric heart disease. We received 59 responses to our survey from 33 unique institutions in the United States and Canada.

CONCLUSIONS

Twenty-one summaries were provided regarding exercise stress testing in pediatric patients with heart disease. Multicentered or national stress testing registries may allow for adequate sample sizes of rare pediatric diseases to allow for development of improved guidelines regarding the type and timing of stress testing.

A predictive model for left ventricular reverse remodeling after pharmacological therapy in children with recent-onset dilated cardiomyopathy

BACKGROUND

Pharmacological advances have improved pediatric dilated cardiomyopathy (DCM) prognosis, which manifests as left ventricular reverse remodeling (LVRR). However, significant inter-individual variability exists in therapeutic response. Identifying predictors is critical for individualizing management to inform device and transplant timing.

AIM

To develop a nomogram for predicting LVRR in pediatric DCM.

METHODS

A retrospective analysis of 146 children hospitalized for DCM from January 2012 to June 2023. 55 exhibited LVRR. A nomogram predicting pediatric DCM-LVRR was developed using univariate analysis and logistic regression to select predictors. The nomogram was validated via bootstrapping and receiver operating characteristic curves for discrimination. Calibration was assessed with the Hosmer-Lemeshow test. Decision curve analysis evaluated performance and utility.

RESULTS

Age, left ventricular end-diastolic dimension Z-score, and QRS interval were associated with the occurrence of LVRR. Discrimination was high (C-index 0.903) and internally validated on bootstrapping with 1000 repetitions (Adjusted C-index 0.895). The Hosmer-Lemeshow test revealed no significant deviation between nomogram predictions and outcomes (χ2 =  10.883; P =  0.207). DCA revealed that the model was clinically useful at threshold probabilities > 4%.

CONCLUSIONS

We developed and internally validated a nomogram predicting LVRR for pediatric DCM patients, exhibiting high sensitivity, specificity and clinical utility.

Clinical characteristics and mortality risk factors in pediatric hypertrophic, restrictive, and rapidly progressive hypertrophic cardiomyopathy: a retrospective cohort study with follow-up

Background

Pediatric cardiomyopathies are rare but life-threatening conditions with high mortality. Limited data exists on their clinical features and risk factors, especially in Asian populations, highlighting the need for further research in this area.

Methods

This retrospective cohort study analyzed data from 212 pediatric patients diagnosed with hypertrophic cardiomyopathy (HCM), restrictive cardiomyopathy (RCM), or restrictive phenotype hypertrophic cardiomyopathy (RP-HCM) at a single center in China from October 2012 to October 2023, with follow-up until October 31, 2024. Demographic, clinical, and diagnostic data, as well as follow-up outcomes, were reviewed. Logistic and Cox regression models identified risk factors for in-hospital and long-term mortality.

Results

Among the 212 patients, 79.72% (169/212) had HCM, 16.98% (36/212) had RCM, and 3.30% (7/212) had RP-HCM. Infection (75.47%, 160/212) and heart failure (51.42%, 109/212) were common comorbidities. In-hospital mortality was 5.19% (11/212), with follow-up mortality of 20.28% (43/212). The independent risk factors for mortality included left ventricular ejection fraction (LVEF), pulmonary hypertension, and low-density lipoprotein (LDL) levels (P < 0.05). Patients with RP-HCM showed the poorest outcomes, with a follow-up mortality rate of 42.86%. Only 10.4% (22/212) of patients underwent genetic testing, yet the positive detection rate was 63.7% (14/22).

Conclusions

This study underscores the importance of early diagnosis, genetic testing, and integrated management in pediatric cardiomyopathies. LVEF, pulmonary hypertension, and LDL levels are critical prognostic factors, offering insights for risk assessment and management in affected children.

A Multidimensional Approach to Understanding Genetic Diversity, Risk Stratification, and Personalized Interventions in Pediatric Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy (HCM) in children presents unique challenges distinct from adult manifestations, with potentially devastating consequences, including sudden cardiac death. This comprehensive review synthesizes current evidence on the pathophysiology, clinical presentation, and management of pediatric HCM, highlighting critical differences from adult populations. While affecting approximately 1 in 500 individuals, pediatric HCM demonstrates more significant etiological heterogeneity, with up to 35% of cases stemming from non-sarcomeric causes, including RASopathies, metabolic disorders, and syndromic conditions. This etiological diversity contributes to variable disease trajectories and treatment responses, creating a significant research gap in pediatric-specific management protocols. Current pharmacological approaches primarily employ beta-blockers as first-line therapy, with calcium channel blockers serving as alternatives for intolerant patients. However, these conventional medications manage symptoms without addressing underlying pathophysiology or preventing disease progression. Emerging investigational therapies, including angiotensin receptor blockers and myosin inhibitors like mavacamten, show promise in preliminary studies but lack robust pediatric-specific evidence. Surgical interventions, including septal myectomy and the modified Konno procedure, demonstrate efficacy in medication-refractory cases but carry higher complication risks in younger patients. The critical research gap lies in developing targeted therapeutic approaches for pediatric-specific HCM subtypes, particularly those associated with syndromic and metabolic disorders. Additionally, risk stratification models for sudden cardiac death prevention remain inadequately validated in pediatric populations. This review identifies the urgent need for pediatric-focused clinical trials investigating both conventional and novel therapies alongside the development of age-appropriate risk assessment tools to guide personalized management strategies for this vulnerable population.

Cardiomyopathies and a brief insight into DOX-induced cardiomyopathy

BACKGROUND

Cardiomyopathy is a heterogeneous group of myocardial disorders characterized by structural and functional abnormalities of the heart muscle. It is classified into primary (genetic, mixed, or acquired) and secondary categories, resulting in various phenotypes including dilated, hypertrophic, and restrictive patterns. Hypertrophic cardiomyopathy, the most common primary form, can cause exertional dyspnea, presyncope, and sudden cardiac death. Dilated cardiomyopathy typically presents with heart failure symptoms, while restrictive cardiomyopathy is rarer and often associated with systemic diseases. Diagnosis involves a comprehensive evaluation including history, physical examination, electrocardiography, and echocardiography. Treatment options range from pharmacotherapy and lifestyle modifications to implantable cardioverter-defibrillators and heart transplantation in refractory cases.

MAIN BODY

Anthracyclines, particularly doxorubicin, have emerged as crucial components in cancer treatment, demonstrating significant antitumor activity across various malignancies. These drugs have become standard in numerous chemotherapy regimens, improving patient outcomes. However, their use is associated with severe cardiotoxicity, including cardiomyopathy and heart failure. The mechanisms of anthracycline action and toxicity are complex, involving DNA damage, iron-mediated free radical production, and disruption of cardiovascular homeostasis. Doxorubicin-induced cardiomyopathy (DIC) is a severe complication of cancer treatment with a poor prognosis and limited effective treatments. The pathophysiology of DIC involves multiple mechanisms, including oxidative stress, inflammation, mitochondrial damage, and calcium homeostasis disorder. Despite extensive research, no effective treatment for established DIC is currently available. Dexrazoxane is the only FDA-approved protective agent, but it has limitations. Recent studies have explored various potential therapeutic approaches, including natural drugs, endogenous substances, new dosage forms, and herbal medicines. However, the lack of experimental models incorporating pre-existing cancer limits the understanding of DIC pathophysiology and treatment efficacy.

CONCLUSION

Cardiomyopathy, whether primary or secondary, poses a significant clinical challenge due to its varying etiologies and poor prognosis in advanced stages. Anthracycline-induced cardiomyopathy is a severe complication of chemotherapy, with doxorubicin being a notable contributor. Despite advancements in cancer therapies, the cardiotoxic effects of anthracyclines necessitate further investigation into effective preventive strategies and therapeutic interventions to improve patient outcomes.

NT-proBNP for Predicting All-Cause Death and Heart Transplant in Children and Adults with Heart Failure

Plasma N-terminal prohormone B-type natriuretic peptide (NT-proBNP) concentration is a heart failure (HF) biomarker in adults and children. Its prognostic value for HF-related events has been established only in adults. Therefore, we aimed to test the hypothesis that plasma NT-proBNP concentrations predicted the risk of heart transplantation or death in children with HF. We studied the medical records of 109 children with HF enrolled in the IBM Watson Explorys database and from 150 children enrolled in the Pediatric Cardiomyopathy Registry (PCMR). Nonlinear regression was used to assess the relationship between plasma NT-proBNP concentrations and the risk of events in the two cohorts. All children in the PCMR cohort had dilated cardiomyopathy. The Explorys cohort also included children with congenital cardiovascular malformations. Median plasma NT-proBNP concentrations were 1250 pg/mL and 184 pg/mL in the Explorys and PCMR cohorts, respectively. The percentage of deaths/heart transplantations was 7%/22%, over 2 years in the Explorys cohort and 3%/16% over 5 years in the PCMR cohort. Mean estimates of plasma NT-proBNP concentration indicative of half-maximum relative risk for events (EC50 values) at 2 and 5 years were 3730 pg/mL and 4199 pg/mL, respectively, values both close to the mean of 3880 pg/mL established for adults with HF. The plasma NT-proBNP concentration is suitable for estimating relative risk of mortality and heart transplantation in children with HF, independent of etiology and shows similar relations to clinical outcomes as in adults, indicating its likely value as a surrogate marker both for adult and pediatric HF.ClinicalTrials.gov Identifiers: NCT00005391 (May 26, 2000), NCT01873976 (June 10, 2013).

Age-Based Classification and Outcomes in Pediatric Heart Failure: Findings From a Retrospective Multicenter Cohort Study

BACKGROUND

Although heart failure is a well-known major global public health concern, the general understanding of the clinical status of pediatric heart failure (PHF) is inadequate. Therefore, this study aims to enhance the general understanding of clinical characteristics across different PHF age groups and provide references for improving PHF treatment strategies.

METHODS

This multicenter retrospective cohort study involved patients from 20 Chinese provinces, primarily including hospitalized patients (aged ≤18 years) diagnosed with heart failure between January 2013 and December 2022. The study subjects were categorized into 4 groups: neonatal, infant and toddler, young children, and adolescent.

RESULTS

Herein, 2903 hospitalized patients with PHF were included. Significant differences were observed across age groups in clinical characteristics, auxiliary examination results, comorbid diagnoses, and hospitalization outcomes. After adjusting for covariates, the odds of in-hospital death were significantly lower in the infant and toddler (odds ratio [OR], 0.46 [95% CI, 0.25-0.85]), young children (OR, 0.39 [95% CI, 0.18-0.85]), and adolescent (OR, 0.34 [95% CI, 0.13-0.87]) groups compared with the neonatal group. Furthermore, the odds of cardiovascular adverse events were significantly higher in the young children (OR, 1.91 [95% CI, 1.62-2.88]) and adolescent (OR, 2.16 [95% CI, 1.15-4.06]) groups compared with the neonatal group. Additionally, regarding the odds of a bad Ross class, the adolescent group had 1.85 times higher odds (95% CI, 1.11-3.09) compared with the neonatal group, 2.36 times (95% CI, 1.67-3.35) higher odds compared with the infant and toddler group, and 1.45 times (95% CI, 1.05-2.02) higher odds compared with the young children group (P<0.05).

CONCLUSIONS

This study emphasizes the importance of age-specific stratification in PHF management, revealing distinct clinical and prognostic differences across various developmental stages.

REGISTRATION

URL: https://www.chictr.org.cn. Unique identifier: ChiCTR2300078262.

Targeting senescence and GATA4 in age-related cardiovascular disease: a comprehensive approach

The growing prevalence of age-related cardiovascular diseases (CVDs) poses significant health challenges, necessitating the formulation of novel treatment approaches. GATA4, a vital transcription factor identified for modulating cardiovascular biology and cellular senescence, is recognized for its critical involvement in CVD pathogenesis. This review collected relevant studies from PubMed, Google Scholar, and Science Direct using search terms like 'GATA4,' 'cellular senescence,' 'coronary artery diseases,' 'hypertension,' 'heart failure,' 'arrhythmias,' 'congenital heart diseases,' 'cardiomyopathy,' and 'cardiovascular disease.' Additionally, studies investigating the molecular mechanisms underlying GATA4-mediated regulation of GATA4 and senescence in CVDs were analyzed to provide comprehensive insights into this critical aspect of potential treatment targeting. Dysregulation of GATA4 is involved in a variety of CVDs, as demonstrated by both experimental and clinical research, comprising CAD, hypertension, congenital heart diseases, cardiomyopathy, arrhythmias, and cardiac insufficiency. Furthermore, cellular senescence enhances the advancement of age-related CVDs. These observations suggested that therapies targeting GATA4, senescence pathways, or both as necessary may be an effective intervention in CVD progression and prognosis. Addressing age-related CVDs by targeting GATA4 and senescence is a broad mechanism approach. It implies further investigation of the molecular nature of these processes and elaboration of an effective therapeutic strategy. This review highlights the importance of GATA4 and senescence in CVD pathogenesis, emphasizing their potential as therapeutic targets for age-related CVDs.

Metrnl and Cardiomyopathies: From Molecular Mechanisms to Therapeutic Insights

Cardiomyopathies, a diverse group of diseases affecting the heart muscle, continue to pose significant clinical challenges due to their complex aetiologies and limited treatment options targeting underlying genetic and molecular dysregulations. Emerging evidence indicates that Metrnl, a myokine, adipokine and cardiokine, plays a significant role in the pathogenesis of various cardiomyopathies. Therefore, the objective of this review is to examine the role and mechanism of Metrnl in various cardiomyopathies, with the expectation of providing new insights for the treatment of these diseases.

Next-generation pediatric care: nanotechnology-based and AI-driven solutions for cardiovascular, respiratory, and gastrointestinal disorders

BACKGROUND

Global pediatric healthcare reveals significant morbidity and mortality rates linked to respiratory, cardiac, and gastrointestinal disorders in children and newborns, mostly due to the complexity of therapeutic management in pediatrics and neonatology, owing to the lack of suitable dosage forms for these patients, often rendering them "therapeutic orphans". The development and application of pediatric drug formulations encounter numerous challenges, including physiological heterogeneity within age groups, limited profitability for the pharmaceutical industry, and ethical and clinical constraints. Many drugs are used unlicensed or off-label, posing a high risk of toxicity and reduced efficacy. Despite these circumstances, some regulatory changes are being performed, thus thrusting research innovation in this field.

DATA SOURCES

Up-to-date peer-reviewed journal articles, books, government and institutional reports, data repositories and databases were used as main data sources.

RESULTS

Among the main strategies proposed to address the current pediatric care situation, nanotechnology is specially promising for pediatric respiratory diseases since they offer a non-invasive, versatile, tunable, site-specific drug release. Tissue engineering is in the spotlight as strategy to address pediatric cardiac diseases, together with theragnostic systems. The integration of nanotechnology and theragnostic stands poised to refine and propel nanomedicine approaches, ushering in an era of innovative and personalized drug delivery for pediatric patients. Finally, the intersection of drug repurposing and artificial intelligence tools in pediatric healthcare holds great potential. This promises not only to enhance efficiency in drug development in general, but also in the pediatric field, hopefully boosting clinical trials for this population.

CONCLUSIONS

Despite the long road ahead, the deepening of nanotechnology, the evolution of tissue engineering, and the combination of traditional techniques with artificial intelligence are the most recently reported strategies in the specific field of pediatric therapeutics.

Management of Pediatric Heart Failure

Heart failure (HF) in children is a complex syndrome with multiple diverse etiologies and both acute and chronic presentations. Chronic presentations can persist throughout childhood and adolescence, and require diligent management with ongoing reassessment to maximize survival and quality of life. Stages of HF are key to recognize as they guide both management and inform prognosis. In more severe cases, children can present with signs of low cardiac output and circulatory collapse with potential to transition either to a chronic HF stage or progress to a need for advanced HF therapies. Morbidity and mortality are high. Managing HF requires a multi-disciplinary approach that can adapt to the needs of the different phases of childhood and adolescence. Treatment can include medications, nutritional support, activity modifications, and potentially surgical intervention, pacemaker, respiratory or mechanical support, or even heart transplantation. Limited evidence exists for almost all medical therapies used in the management of HF in children and approaches are predominantly extrapolated from extensive adult experience. There are multiple maladaptive pathways in the failing heart; medications that modify these maladaptive pathways promote "reverse remodelling" of the myocardium and are key to the management, forming the basis for "guideline directed medical therapy". The purpose of this review is to summarize the current state of the art management of systolic HF in children.

Hemodynamic instability in the transitional period after birth

It is not uncommon for a patient to experience hemodynamic instability following birth. This is due to the fact that the transitional period requires dramatic cardiorespiratory changes. When it goes well, improved lung compliance and successful transition to the postnatal circulation is seen. However, it is highly beneficial that clinicians have a solid understanding of all of the required changes, the unique aspects of the neonatal myocardium, and the influence of cardiovascular disease on normal adaptive mechanisms. In this manuscript, we will review the physiology of the normal postnatal circulatory adaptation, the unique characteristics of the neonatal myocardium and how it behaves in states of altered loading conditions, and the impact of hemodynamic disease states on health and wellbeing during the immediate postnatal time-period.

Clinical profile of dilated cardiomyopathy in children enrolled in chronic cardiac care: a decade review in a sub-Saharan African tertiary center

BACKGROUND

Dilated cardiomyopathy (DCM) is a myocardial disease characterized by a dilated left ventricle (LV) and reduced LV systolic function. The clinical profile of DCM is not well studied in Africa with no reports from Ethiopia. This study aimed to describe the clinical profile of DCM and the factors associated with its clinical outcome in a tertiary center.

RESULTS

This study included 75 DCM patients, males 52%. The median age at DCM diagnosis was 18 months (Interquartile range/IQR: 7-46). The major DCM clinical presentations were cough, 84%, fast breathing, 64% and shortness of breath, 56%. The median left ventricular systolic ejection fraction (LVEF) and left ventricular fractional shortening (LVFS) at diagnosis were 30% (IQR: 24-36) and 14% (IQR: 11-18), respectively. The majority don't have a cause labeled or documented, 81.3% while HIV and anthracycline-related DCM accounted for 6.7% each. Concerning outcomes, the majority didn't show any clinical status change or were static, 62.7% while one-third, 32%, showed improvement. The case fatality rate in this series was 5.3% [4] (95% CI: 1.47-13.1). The presence of severe acute malnutrition (wasting) at presentation, p 0.017; the latest LV systolic function (LVEF, p 0.000 and LVFS, p 0.000) and the use of enalapril, p 0.017, were associated with DCM clinical outcome.

CONCLUSION

Boys in their second birth year were most affected by DCM. The major DCM presentations were a mix of respiratory and cardiac symptoms with severely depressed LV systolic function. Nutritional status at presentation, recent LV systolic function and enalapril use were associated with DCM clinical outcome. Timely nutritional assessment, treatment and support, and enhanced HF medical treatment are recommended to improve DCM clinical outcomes.

Cardiomyopathy: pathogenesis and therapeutic interventions

Cardiomyopathy is a group of disease characterized by structural and functional damage to the myocardium. The etiologies of cardiomyopathies are diverse, spanning from genetic mutations impacting fundamental myocardial functions to systemic disorders that result in widespread cardiac damage. Many specific gene mutations cause primary cardiomyopathy. Environmental factors and metabolic disorders may also lead to the occurrence of cardiomyopathy. This review provides an in-depth analysis of the current understanding of the pathogenesis of various cardiomyopathies, highlighting the molecular and cellular mechanisms that contribute to their development and progression. The current therapeutic interventions for cardiomyopathies range from pharmacological interventions to mechanical support and heart transplantation. Gene therapy and cell therapy, propelled by ongoing advancements in overarching strategies and methodologies, has also emerged as a pivotal clinical intervention for a variety of diseases. The increasing number of causal gene of cardiomyopathies have been identified in recent studies. Therefore, gene therapy targeting causal genes holds promise in offering therapeutic advantages to individuals diagnosed with cardiomyopathies. Acting as a more precise approach to gene therapy, they are gradually emerging as a substitute for traditional gene therapy. This article reviews pathogenesis and therapeutic interventions for different cardiomyopathies.

Storytelling of Hypertrophic Cardiomyopathy Discovery

The discovery of hypertrophic cardiomyopathy (HCM) dates back to 1958, when the pathologist Donald Teare of the St. George's Hospital in London performed autopsies in eight cases with asymmetric hypertrophy of the ventricular septum and bizarre disorganization (disarray) at histology, first interpreted as hamartoma. Seven had died suddenly. The cardiac specimens were cut along the long axis, similar to the 2D echo. In the same year, at the National Institute of Health U.S.A., Eugene Braunwald, a hemodynamist, and Andrew Glenn Morrow, a cardiac surgeon, clinically faced a patient with an apparently similar morbid entity, with a systolic murmur and subaortic valve gradient. "Discrete" subaortic stenosis was postulated. However, at surgery, Dr. Morrow observed only hypertrophy and performed myectomy to relieve the obstruction. This first Braunwald-Morrow patient underwent a successful cardiac transplant later at the disease end stage. The same Dr. Morrow was found to be affected by the familial HCM and died suddenly in 1992. The term "functional subaortic stenosis" was used in 1959 and "idiopathic hypertrophic subaortic stenosis" in 1960. Years before, in 1957, Lord Brock, a cardiac surgeon at the Guy's Hospital in London, during alleged aortic valve surgery in extracorporeal circulation, did not find any valvular or discrete subaortic stenoses. In 1980, John F. Goodwin of the Westminster Hospital in London, the head of an international WHO committee, put forward the first classification of heart muscle diseases, introducing the term cardiomyopathy (dilated, hypertrophic, and endomyocardial restrictive). In 1995, the WHO classification was revisited, with the addition of two new entities, namely arrhythmogenic and purely myocardial restrictive, the latter a paradox of a small heart accounting for severe congestive heart failure by ventricular diastolic impairment. A familial occurrence was noticed earlier in HCM and published by Teare and Goodwin in 1960. In 1989-1990, the same family underwent molecular genetics investigation by the Seidman team in Boston, and a missense mutation of the β-cardiac myosin heavy chain in chromosome 14 was found. Thus, 21 years elapsed from HCM gross discovery to molecular discoveries. The same original family was the source of both the gross and genetic explanations of HCM, which is now named sarcomere disease. Restrictive cardiomyopathy, characterized grossly without hypertrophy and histologically by myocardial disarray, was found to also have a sarcomeric genetic mutation, labeled "HCM without hypertrophy". Sarcomere missense mutations have also been reported in dilated cardiomyopathy (DCM) and non-compaction cardiomyopathy. Moreover, sarcomeric gene defects have been detected in some DNA non-coding regions of HCM patients. The same mutation in the family may express different phenotypes (HCM, DCM, and RCM). Large ischemic scars have been reported by pathologists and are nowadays easily detectable in vivo by cardiac magnetic resonance with gadolinium. The ischemic arrhythmic substrate enhances the risk of sudden death.

A case report of a rare genetic mutation (LMNA-C.185G>C, p.Arg62Pro) associated with dilated cardiomyopathy in a Han Chinese child

Dilated cardiomyopathy (DCM) remains an enigmatic myocardial disorder characterized either by enlargement of either the left or right ventricle or both and reduced contractility, posing a significant burden on pediatric populations as a leading cause of cardiac-related mortality and morbidity. This paper presents a compelling case of DCM in a Han Chinese child whose genomic analysis unveiled a novel LMNA-C.185G>C (p.Arg62Pro) variant. Over a meticulous 3-year clinical follow-up, spanning ten outpatient consultations and hospital admissions since the initial diagnosis, the patient exhibited a progressive emergence of various cardiac conduction anomalies closely mirroring LMNA-associated phenotypes. Delving into a comprehensive review of the patient's 14-year medical journey and familial history, antecedent signs of muscular dystrophy (MD) predated DCM onset. Familial scrutiny revealed a lineage marred by muscular atrophy, with the patient's maternal grandmother having a history of muscular dystrophy and an episode of DCM, necessitating cardiac transplantation in the patient's uncle at age 37. This scenario illuminates the intricate interplay between LMNA-associated diseases and genetic predisposition. Timely identification of etiological triggers stands paramount in DCM management. Beyond conventional genetic scrutiny, leveraging novel serum biomarkers such as anti-heart muscle antibodies (AHA) remarkably enhanced diagnostic precision. Notably, personalized therapeutic interventions comprising prednisolone regimens and intravenous immunoglobulin infusions precipitated marked amelioration in heart failure symptoms and serum biomarker profiles. It is noteworthy to identify this novel genetic locus within the Han Chinese populace, underscoring the imperative of expanding the LMNA mutation repository within this demographic cohort. Early recognition of clinical manifestations and etiological cues in pediatric DCM heralds a paradigm shift in risk prognostication and individualized therapeutic interventions, underscoring the profound significance of precision medicine in combating rare familial cardiomyopathies.

Pediatric dilated cardiomyopathy: a review of current clinical approaches and pathogenesis

Pediatric dilated cardiomyopathy (DCM) is a rare, yet life-threatening cardiovascular condition characterized by systolic dysfunction with biventricular dilatation and reduced myocardial contractility. Therapeutic options are limited with nearly 40% of children undergoing heart transplant or death within 2 years of diagnosis. Pediatric patients are currently diagnosed based on correlating the clinical picture with echocardiographic findings. Patient age, etiology of disease, and parameters of cardiac function significantly impact prognosis. Treatments for pediatric DCM aim to ameliorate symptoms, reduce progression of disease, and prevent life-threatening arrhythmias. Many therapeutic agents with known efficacy in adults lack the same evidence in children. Unlike adult DCM, the pathogenesis of pediatric DCM is not well understood as approximately two thirds of cases are classified as idiopathic disease. Children experience unique gene expression changes and molecular pathway activation in response to DCM. Studies have pointed to a significant genetic component in pediatric DCM, with variants in genes related to sarcomere and cytoskeleton structure implicated. In this regard, pediatric DCM can be considered pediatric manifestations of inherited cardiomyopathy syndromes. Yet exciting recent studies in infantile DCM suggest that this subset has a distinct etiology involving defective postnatal cardiac maturation, such as the failure of programmed centrosome breakdown in cardiomyocytes. Improved knowledge of pathogenesis is central to developing child-specific treatment approaches. This review aims to discuss the established biological pathogenesis of pediatric DCM, current clinical guidelines, and promising therapeutic avenues, highlighting differences from adult disease. The overarching goal is to unravel the complexities surrounding this condition to facilitate the advancement of novel therapeutic interventions and improve prognosis and overall quality of life for pediatric patients affected by DCM.

Unique Aspects of Hypertrophic Cardiomyopathy in Children

Hypertrophic cardiomyopathy (HCM) is a primary heart muscle disease characterized by left ventricular hypertrophy that can be asymptomatic or with presentations that vary from left ventricular outflow tract obstruction, heart failure from diastolic dysfunction, arrhythmias, and/or sudden cardiac death. Children younger than 1 year of age tend to have worse outcomes and often have HCM secondary to inborn errors of metabolism or syndromes such as RASopathies. For children who survive or are diagnosed after 1 year of age, HCM outcomes are often favourable and similar to those seen in adults. This is because of sudden cardiac death risk stratification and medical and surgical innovations. Genetic testing and timely cardiac screening are paving the way for disease-modifying treatment as gene-specific therapies are being developed.

Natural history and outcomes in paediatric RASopathy-associated hypertrophic cardiomyopathy

AIMS

This study aimed to describe the natural history and predictors of all-cause mortality and sudden cardiac death (SCD)/equivalent events in children with a RASopathy syndrome and hypertrophic cardiomyopathy (HCM).

METHODS AND RESULTS

This is a retrospective cohort study from 14 paediatric cardiology centres in the United Kingdom and Ireland. We included children <18 years with HCM and a clinical and/or genetic diagnosis of a RASopathy syndrome [Noonan syndrome (NS), NS with multiple lentigines (NSML), Costello syndrome (CS), cardiofaciocutaneous syndrome (CFCS), and NS with loose anagen hair (NS-LAH)]. One hundred forty-nine patients were recruited [111 (74.5%) NS, 12 (8.05%) NSML, 6 (4.03%) CS, 6 (4.03%) CFCS, 11 (7.4%) Noonan-like syndrome, and 3 (2%) NS-LAH]. NSML patients had higher left ventricular outflow tract (LVOT) gradient values [60 (36-80) mmHg, P = 0.004]. Over a median follow-up of 197.5 [inter-quartile range (IQR) 93.58-370] months, 23 patients (15.43%) died at a median age of 24.1 (IQR 5.6-175.9) months. Survival was 96.45% [95% confidence interval (CI) 91.69-98.51], 90.42% (95% CI 84.04-94.33), and 84.12% (95% CI 75.42-89.94) at 1, 5, and 10 years, respectively, but this varied by RASopathy syndrome. RASopathy syndrome, symptoms at baseline, congestive cardiac failure (CCF), non-sustained ventricular tachycardia (NSVT), and maximal left ventricular wall thickness were identified as predictors of all-cause mortality on univariate analysis, and CCF, NSVT, and LVOT gradient were predictors for SCD or equivalent event.

CONCLUSIONS

These findings highlight a distinct category of patients with Noonan-like syndrome with a milder HCM phenotype but significantly worse survival and identify potential predictors of adverse outcome in patients with RASopathy-related HCM.

The clinical profile, genetic basis and survival of childhood cardiomyopathy: a single-center retrospective study

Cardiomyopathy (CM) is a heterogeneous group of myocardial diseases in children. This study aimed to identify demographic features, clinical presentation and prognosis of children with CM. Clinical characteristics and prognostic factors associated with mortality were evaluated by Cox proportional hazards regression analyses. Genetic testing was also conducted on a portion of patients. Among the 317 patients, 40.1%, 25.2%, 24.6% and 10.1% were diagnosed with dilated cardiomyopathy (DCM), hypertrophic cardiomyopathy (HCM), left ventricular noncompaction cardiomyopathy (LVNC) and restrictive cardiomyopathy (RCM), respectively. The most common symptom observed was dyspnea (84.2%). Except for HCM, the majority of patients were classified as NYHA/Ross class III or IV. The five-year survival rates were 75.5%, 67.3%, 74.1% and 51.1% in DCM, HCM, LVNC and RCM, respectively. The ten-year survival rates were 60.1%, 56.1%, 57.2% and 41.3% in DCM, HCM, LVNC and RCM, respectively. Survival was inversely related to NYHA/Ross class III or IV in patients with DCM, HCM and RCM. Out of 42 patients, 32 were reported to carry gene mutations.

CONCLUSIONS

This study demonstrates that CM, especially RCM, is related to a high incidence of death. NYHA/Ross class III or IV is a predictor of mortality in the patients and gene mutations may be a common cause.

TRIAL REGISTRATION

MR-50-23-011798.

WHAT IS KNOWN

• Cardiomyopathy (CM) is a heterogeneous group of myocardial diseases and one of the leading causes of heart failure in children due to the lack of effective treatments. • There remains scarce data on Asian pediatric populations though emerging studies have assessed the clinical characteristics and outcomes of CM.

WHAT IS NEW

• A retrospective study was conducted and the follow-up records were established to investigate the clinical characteristics, the profile of gene mutations and prognostic outcomes of children with CM in Western China. • CM, especially RCM, is related to a high incidence of death. NYHA/Ross class III or IV is a predictor of mortality in the patients and gene mutations may be a common cause.

Inherited Arrhythmias in the Pediatric Population: An Updated Overview

Pediatric cardiomyopathies (CMs) and electrical diseases constitute a heterogeneous spectrum of disorders distinguished by structural and electrical abnormalities in the heart muscle, attributed to a genetic variant. They rank among the main causes of morbidity and mortality in the pediatric population, with an annual incidence of 1.1-1.5 per 100,000 in children under the age of 18. The most common conditions are dilated cardiomyopathy (DCM) and hypertrophic cardiomyopathy (HCM). Despite great enthusiasm for research in this field, studies in this population are still limited, and the management and treatment often follow adult recommendations, which have significantly more data on treatment benefits. Although adult and pediatric cardiac diseases share similar morphological and clinical manifestations, their outcomes significantly differ. This review summarizes the latest evidence on genetics, clinical characteristics, management, and updated outcomes of primary pediatric CMs and electrical diseases, including DCM, HCM, arrhythmogenic right ventricular cardiomyopathy (ARVC), Brugada syndrome (BrS), catecholaminergic polymorphic ventricular tachycardia (CPVT), long QT syndrome (LQTS), and short QT syndrome (SQTS).

Focus on Paediatric Restrictive Cardiomyopathy: Frequently Asked Questions

Restrictive cardiomyopathy (RCM) is characterized by restrictive ventricular pathophysiology determined by increased myocardial stiffness. While suspicion of RCM is initially raised by clinical evaluation and supported by electrocardiographic and echocardiographic findings, invasive hemodynamic evaluation is often required for diagnosis and management of patients during follow-up. RCM is commonly associated with a poor prognosis and a high incidence of heart failure, and PH is reported in paediatric patients with RCM. Currently, only a few therapies are available for specific RCM aetiologies. Early referral to centres for advanced heart failure treatment is often necessary. The aim of this review is to address questions frequently asked when facing paediatric patients with RCM, including issues related to aetiologies, clinical presentation, diagnostic process and prognosis.