Cardiomyopathy in Children: Classification and Diagnosis: A Scientific Statement From the American Heart Association

Effect of beta-blockers and exercise restriction on the prevention of sudden cardiac death in pediatric hypertrophic cardiomyopathy

BACKGROUND

Risk assessment tools and effective prevention strategies for sudden cardiac death (SCD) in pediatric patients with hypertrophic cardiomyopathy (HCM) have not been established. This study aimed to evaluate the efficacy of beta-blockers and exercise restriction for SCD prevention in this population.

METHODS

We retrospectively reviewed the medical records of patients aged <18 years who were diagnosed with HCM at our center between January 1996 and December 2021. SCD and aborted SCD were defined as SCD equivalents. We divided patients based on whether they were prescribed beta-blockers or exercise restriction and compared the outcomes among the groups. The primary outcome was the overall survival (OS), and the secondary outcome was the cumulative SCD equivalent rate. Outcomes were analyzed using Kaplan-Meier curves and Cox proportional hazard analysis. We also compared patients according to the occurrence of SCD equivalents to identify SCD risk predictors.

RESULTS

Among the 43 included patients [mean age, 7.7 (1.6-12.1) years; 23 male individuals], SCD equivalents occurred in 13 patients over 11.2 (4.5-15.6) years of follow-up, among whom 12 were resuscitated and 1 died. The OS rate was significantly higher in the beta-blocker and exercise restriction groups than in the non-beta-blocker and non-exercise restriction groups (81.3 % vs. 19.1 %, p < 0.01 and 57.4 % vs. 12.7 %, p < 0.01, respectively). Among the 13 patients with SCD equivalents, 5 had 9 recurrent SCD equivalents. A significant difference was observed between the SCD equivalent and non-SCD equivalent groups in the history of suspected arrhythmogenic syncope (p < 0.01) in the univariable but not in the multivariable analysis.

CONCLUSIONS

Beta-blockers and exercise restriction may decrease the risk of SCD in pediatric patients with HCM and should be considered for SCD prevention in this population, particularly because predicting SCD in these patients remains challenging.

Cardiomyopathy in children: a single-centre, retrospective study of genetic and clinical characteristics

OBJECTIVES

This study aimed to describe the genetic and clinical characteristics of paediatric cardiomyopathy in a cohort of Chinese patients.

METHODS

We retrospectively reviewed the clinical history and mutation spectrum of 75 unrelated Chinese paediatric patients who were diagnosed with cardiomyopathy and referred to our hospital between January 2016 and December 2022.

RESULTS

Seventy-five children with cardiomyopathy were enrolled, including 32 (42.7%) boys and 43 (57.3%) girls. Dilated cardiomyopathy was the most prevalent cardiomyopathy (61.3%) in the patients, followed by hypertrophic cardiomyopathy (17.3%), ventricular non-compaction (14.7%), restrictive cardiomyopathy (5.3%) and arrhythmogenic right ventricular cardiomyopathy (1.3%). Whole-exome sequencing and targeted next-generation sequencing identified 34 pathogenic/likely pathogenic variants and 1 copy number variant in 14 genes related to cardiomyopathy in 30 children, accounting for 40% of all patients. TNNC1 p.Asp65Asn and MYH7 p.Glu500Lys have not been reported previously. The follow-up time ranged from 2 months to 6 years. Twenty-two children died (mortality rate 29%).

CONCLUSIONS

Comprehensive genetic testing was associated with a 40% yield of causal genetic mutations in Chinese cardiomyopathy cases. We found diversity in the mutation profile in different patients, which suggests that the mutational background of cardiomyopathy in China is heterogeneous, and the findings may be helpful to those counselling patients and families.

Paediatric Restrictive Cardiomyopathy - Diagnosis and Challenges: A report of two cases

Restrictive cardiomyopathy is one of the rarest forms of cardiomyopathies in paediatric patients characterised by impaired myocardial relaxation or compliance with restricted ventricular filling, leading to a reduced diastolic volume with a preserved systolic function. We report 2 cases-a 5-year-old boy who presented with abdominal distension and palpitation with family history of similar complaints but no definite genetic diagnosis as yet and a 5-year-old girl who presented with chronic cough and shortness of breath. Both cases were diagnosed in a tertiary care hospital in Muscat, Oman, in 2019 and are managed supportively with regular outpatient follow-up. This is the first series of reported cases of paediatric restrictive cardiomyopathy from Oman.

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.

Modeling the Relationship Between Diastolic Phenotype and Outcomes in Pediatric Hypertrophic Cardiomyopathy

BACKGROUND

Pediatric hypertrophic cardiomyopathy (HCM) is associated with adverse events. The contribution of diastolic dysfunction to adverse events is poorly understood. The aim of this study was to explore the association between diastolic phenotype and outcomes in pediatric patients with HCM.

METHODS

Children <18 years of age with diagnosed with HCM were included. Diastolic function parameters were measured from the first echocardiogram at the time of diagnosis, including Doppler flow velocities, tissue Doppler velocities, and left atrial volume and function. Using principal-component analysis, key features in echocardiographic parameters were identified. The principal components were regressed to freedom from major adverse cardiac events (MACE), defined as implantable cardioverter-defibrillator insertion, myectomy, aborted sudden cardiac death, transplantation, need for mechanical circulatory support, and death.

RESULTS

Variables that estimate left ventricular filling pressures were highly collinear and associated with MACE (hazard ratio, 0.86; 95% CI, 0.75-1.00), though this was no longer significant after controlling for left ventricular thickness and genetic variation. Left atrial size parameters adjusted for body surface area were independently associated with outcomes in the covariate-adjusted model (hazard ratio, 0.69; 95% CI, 0.5-0.94). The covariate-adjusted model had an Akaike information criterion of 213, an adjusted R2 value of 0.78, and a concordance index of 0.82 for association with MACE.

CONCLUSION

Echocardiographic parameters of diastolic dysfunction were associated with MACE in this population study, in combination with the severity of left ventricular hypertrophy and genetic variation. Left atrial size parameters adjusted for body surface area were independently associated with adverse events. Additional study of diastolic function parameters adjusted for patient size could facilitate the prediction of adverse events in pediatric patients with HCM.

Design and Analysis of a Polymeric Left Ventricular Simulator via Computational Modelling

Preclinical testing of medical devices is an essential step in the product life cycle, whereas testing of cardiovascular implants requires specialised testbeds or numerical simulations using computer software Ansys 2016. Existing test setups used to evaluate physiological scenarios and test cardiac implants such as mock circulatory systems or isolated beating heart platforms are driven by sophisticated hardware which comes at a high cost or raises ethical concerns. On the other hand, computational methods used to simulate blood flow in the cardiovascular system may be simplified or computationally expensive. Therefore, there is a need for low-cost, relatively simple and efficient test beds that can provide realistic conditions to simulate physiological scenarios and evaluate cardiovascular devices. In this study, the concept design of a novel left ventricular simulator made of latex rubber and actuated by pneumatic artificial muscles is presented. The designed left ventricular simulator is geometrically similar to a native left ventricle, whereas the basal diameter and long axis length are within an anatomical range. Finite element simulations evaluating left ventricular twisting and shortening predicted that the designed left ventricular simulator rotates approximately 17 degrees at the apex and the long axis shortens around 11 mm. Experimental results showed that the twist angle is 18 degrees and the left ventricular simulator shortens 5 mm. Twist angles and long axis shortening as in a native left ventricle show it is capable of functioning like a native left ventricle and simulating a variety of scenarios, and therefore has the potential to be used as a test platform.

Clinical Genetic and Genomic Testing in Congenital Heart Disease and Cardiomyopathy

Congenital heart disease (CHD) and cardiomyopathies are the leading cause of morbidity and mortality worldwide. These conditions are often caused by genetic factors, and recent research has shown that genetic and genomic testing can provide valuable information for patient care. By identifying genetic causes, healthcare providers can screen for other related health conditions, offer early interventions, estimate prognosis, select appropriate treatments, and assess the risk for family members. Genetic and genomic testing is now the standard of care in patients with CHD and cardiomyopathy. However, rapid advances in technology and greater availability of testing options have led to changes in recommendations for the most appropriate testing method. Several recent studies have investigated the utility of genetic testing in this changing landscape. This review summarizes the literature surrounding the clinical utility of genetic evaluation in patients with CHD and cardiomyopathy.

HOIL-1L deficiency induces cell cycle alteration which causes immaturity of skeletal muscle and cardiomyocytes

HOIL-1L deficiency was recently reported to be one of the causes of myopathy and dilated cardiomyopathy (DCM). However, the mechanisms by which myopathy and DCM develop have not been clearly elucidated. Here, we sought to elucidate these mechanisms using the murine myoblast cell line C2C12 and disease-specific human induced pluripotent stem cells (hiPSCs). Myotubes differentiated from HOIL-1L-KO C2C12 cells exhibited deteriorated differentiation and mitotic cell accumulation. CMs differentiated from patient-derived hiPSCs had an abnormal morphology with a larger size and were excessively multinucleated compared with CMs differentiated from control hiPSCs. Further analysis of hiPSC-derived CMs showed that HOIL-1L deficiency caused cell cycle alteration and mitotic cell accumulation. These results demonstrate that abnormal cell maturation possibly contribute to the development of myopathy and DCM. In conclusion, HOIL-1L is an important intrinsic regulator of cell cycle-related myotube and CM maturation and cell proliferation.

Combined Pharmacological Modulation of Translational and Transcriptional Activity Signaling Pathways as a Promising Therapeutic Approach in Children with Myocardial Changes

Myocardial hypertrophy is the most common condition that accompanies heart development in children. Transcriptional gene expression regulating pathways play a critical role both in cardiac embryogenesis and in the pathogenesis of congenital hypertrophic cardiomyopathy, neonatal posthypoxic myocardial hypertrophy, and congenital heart diseases. This paper describes the state of cardiac gene expression and potential pharmacological modulators at different transcriptional levels. An experimental model of perinatal cardiac hypoxia showed the downregulated expression of genes responsible for cardiac muscle integrity and overexpressed genes associated with energy metabolism and apoptosis, which may provide a basis for a therapeutic approach. Current evidence suggests that RNA drugs, theaflavin, neuraminidase, proton pumps, and histone deacetylase inhibitors are promising pharmacological agents in progressive cardiac hypertrophy. The different points of application of the above drugs make combined use possible, potentiating the effects of inhibition in specific signaling pathways. The special role of N-acetyl cysteine in both the inhibition of several signaling pathways and the reduction of oxidative stress was emphasized.

Familial dilated cardiomyopathy in a child: a case report

BACKGROUND

Dilated cardiomyopathy (DCM) commonly leads to heart failure (HF) and represents the most common indication for cardiac transplantation in the pediatric population. Clinical manifestations of DCM are mainly the symptoms of heart failure; it is diagnosed by EKG, chest x-ray and echocardiography. For the idiopathic and familial diseases cases of DCM, there are no definite guidelines for treatment in children as they are treated for prognostic improvement.

CASE PRESENTATION

We report the case of a 2-year-old girl diagnosed with dilated cardiomyopathy associated with homozygous mutation in the Myosin Light Chain 3 gene admitted for edema in lower extremities, muscle weakness, lethargy and vomiting, and she was found to be in cardiogenic shock. Chest x-ray showed cardiomegaly and EKG showed first degree atrioventricular block. Echocardiogram showed severe biventricular systolic and diastolic dysfunction. After 70 days of hospitalization, the patient went into cardiac arrest with cessation of electrical and mechanical activity of the heart, despite cardiopulmonary resuscitative efforts.

CONCLUSION

Although rare, pediatric DCM carries a high risk of morbidity and mortality and a lack of curative therapy.

The multifaceted role of neuropsychology in pediatric solid organ transplant: preliminary guidelines and strategies for clinical practice

The incidence of pediatric solid organ transplantation (SOT) has increased in recent decades due to medical and surgical advances as well as improvements in organ procurement. Survival rates for pediatric kidney, liver, and heart transplantation are above 85% but patients continue to experience complex healthcare needs over their lifetime. Long-term developmental and neuropsychological sequelae are becoming increasingly recognized in this population, although preliminary work is limited and deserves further attention. Neuropsychological weaknesses are often present prior to transplantation and may be related to underlying congenital conditions as well as downstream impact of the indicating organ dysfunction on the central nervous system. Neuropsychological difficulties pose risk for functional complications, including disruption to adaptive skill development, social-emotional functioning, quality of life, and transition to adulthood. The impact of cognitive dysfunction on health management activities (e.g., medication adherence, medical decision-making) is also an important consideration given these patients' lifelong medical needs. The primary aim of this paper is to provide preliminary guidelines and clinical strategies for assessment of neuropsychological outcomes across SOT populations for pediatric neuropsychologists and the multidisciplinary medical team, including detailing unique and shared etiologies and risk factors for impairment across organ types, and functional implications. Recommendations for clinical neuropsychological monitoring as well as multidisciplinary collaboration within pediatric SOT teams are also provided.

Pediatric Chest Pain: A Review of Diagnostic Tools in the Pediatric Emergency Department

Pediatric chest pain is a common chief complaint in the emergency department. Not surprisingly, children with chest pain are usually brought to the emergency department by their parents out of fear of heart disease. However, chest pain in the pediatric population is generally a benign disease. In this review, we have identified musculoskeletal pain as the most prevalent etiology of chest pain in the pediatric population, accounting for 38.7-86.3% of cases, followed by pulmonary (1.8-12.8%), gastrointestinal (0.3-9.3%), psychogenic (5.1-83.6%), and cardiac chest pain (0.3-8.0%). Various diagnostic procedures are commonly used in the emergency department for cardiac chest pain, including electrocardiogram (ECG), chest radiography, cardiac troponin examination, and echocardiography. However, these examinations demonstrate limited sensitivity in identifying cardiac etiologies, with sensitivities ranging from 0 to 17.8% for ECG and 11.0 to 17.2% for chest radiography. To avoid the overuse of these diagnostic tools, a well-designed standardized algorithm for pediatric chest pain could decrease unnecessary examination without missing severe diseases.

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.

A MYH7 variant in a five-generation-family with hypertrophic cardiomyopathy

Background: Hypertrophic cardiomyopathy (HCM) is a genetic condition with a prevalence of 1:500-1:3 000. Variants in genes encoding sarcomeric proteins are mainly responsible for the disease. MYH7 gene encoding a myosin heavy chain beta, together with MYPBC3 gene are the two most commonly affected genes. The clinical presentation of this disease varies widely between individuals. This study aims to report a variant of MYH7 responsible for HCM in a five-generation family with a history of cardiac problems. Methods: The diagnosis was established according to the European Society of Cardiology HCM criteria based on two-dimensional Doppler echocardiography or cardiovascular magnetic resonance. Genetic analysis was performed using next-generation-sequencing and Sanger method. Results: The medical history of the presented family began with a prenatal diagnosis of HCM in the first child of a family with previously healthy parents. Five generations of the family had a long history of sudden cardiac death and cardiac problems. A NM_000257.4:c.2342T>A (p.Leu781Gln) variant was detected in the MYH7 gene. It was heterozygous in the proband and in all affected individuals in a large family. The variant was present in 10 affected members of the family, and was absent in 7 members. The clinical course of the disease was severe in several members of the family: three family members died of sudden cardiac death, one patient required heart transplantation, three underwent septal myectomy, and three required implantable cardioverter defibrillator (ICD) implantation. Conclusion: Herein, we report a MYH7 variant responsible for HCM. Familial HCM is inherited primarily in autosomal dominant mode, which is in accordance with our study. However, the presented family showed a broad clinical spectrum of HCM. Out of 10 family members with positive genetic testing 8 had severe presentation of the disease and 2 had a mild phenotype. This suggests that the severity of the disease may depend on other factors, most likely genetic.

Dilated Cardiomyopathy Due to Alimentary Iron Deficiency

Dilated cardiomyopathy (DCM) is a severe condition, characterised by left ventricular dilation and systolic dysfunction, necessitating heart transplantation when all other treatment options fail. This case report describes a 2-year-old girl initially presenting with oedema, listlessness, and severe iron deficiency anaemia. She was diagnosed with DCM. Extensive diagnostic workup ruled out other causes, leading to the suspicion of DCM due to alimentary iron deficiency. This was confirmed by the parents' report that the girl was fed almost exclusively with low-fat cow's milk. Prompt treatment, including packed red cell transfusion, iron supplementation, and heart failure medications (diuretics, ACE inhibitors, beta blockers, and aldosterone antagonists), resulted in significant improvement in cardiac function within days. This report demonstrates the potential risks of alimentary iron deficiency, the most common cause of microcytic hypochromic anaemia in young children, which might even result in the development of life-threatening cardiac dysfunction in extreme cases.

The impact of fragmented QRS on clinical findings and outcomes in children with dilated cardiomyopathy with or without left ventricular non-compaction

OBJECTIVE

The aim of this study is to investigate the frequency of fragmented QRS and its associations with clinical findings and prognosis in children diagnosed with dilated cardiomyopathy with or without left ventricular non-compaction.

METHODS

This retrospective study was conducted between 2010 and 2020. Patients with dilated cardiomyopathy were classified into two groups according to the presence of left ventricular non-compaction: Dilated cardiomyopathy with left ventricular non-compaction and dilated cardiomyopathy without left ventricular non-compaction. Patients were also divided into two groups according to the presence of fragmented QRS (fragmented QRS group and non-fragmented QRS group).

RESULTS

Twenty-three of 44 patients (52.3%) were male. Among left ventricular non-compaction patients, the fragmented QRS group had more complex ventricular arrhythmias (p = 0.003). Patients with fragmented QRS had a significantly higher rate of major adverse cardiac events and/or cardiac death in both cardiomyopathy groups (p = 0.003 and p = 0.005). However, the rate of major adverse cardiac events and/or cardiac death was similar between dilated cardiomyopathy patients with and without left ventricular non-compaction. Multivariate logistic regression analysis showed that the presence of fragmented QRS strongly predicts major adverse cardiac events and/or cardiac death (odds ratio, 31.186; 95% confidence interval, 2.347-414.307). Although the survival rates between cardiomyopathy groups were similar, patients with fragmented QRS had a markedly lower survival rate during the follow-up period, as mean of 15 months (p = 0.001).

CONCLUSION

Our study showed that the presence of fragmented QRS may be an important ECG sign predicting an major adverse cardiac event and/or cardiac death in patients with dilated cardiomyopathy. We believe that recognising fragmented QRS could be valuable in forecasting patient prognosis and identifying high-risk patients who require additional support.

Trends in prevalence of major etiologies leading to heart failure in young patients: An integrative review

The prevalence of Heart failure (HF) is increasing with the aging of the population but it is estimated that 10% of HF patients are younger than 50 years-old. HF development in this population is characterized with a fast-growing prevalence, and important disparities according to underlying etiologies or gender. These observations highlight the need to identify specific and preventable factors in these patients, a topic that is under-studied. Here we provide an overview of trends in prevalence of major etiologies leading to HF in young subjects, including genetic factors associated with cardiomyopathies, premature vascular dysfunction and related ischemia, metabolic stress, cardio-toxic responses to different agents, and myocarditis. We also highlight the increasing influence of major risk factors that are driving HF in younger patients, such as obesity, diabetes or arterial hypertension.

Introduction of transcatheter edge-to-edge repair in patients with congenital heart disease at a children's hospital

BACKGROUND

Atrioventricular valve regurgitation (AVVR) is a devastating complication in children and young adults with congenital heart disease (CHD), particularly in patients with single ventricle physiology. Transcatheter edge-to-edge repair (TEER) is a rapidly expanding, minimally invasive option for the treatment of AVVR in adults that avoids the morbidity and mortality associated with open heart surgery. However, application of TEER in in CHD and in children is quite novel. We describe the development of a peri-procedural protocol including image-derived pre-intervention simulation, with successful application to four patients.

AIMS

To describe the initial experience using the MitraClip system for TEER of dysfunctional systemic atrioventricular valves in patients with congential heart disease within a pediatric hospital.

METHODS

A standardized screening and planning process was developed using cardiac magnetic resonance imaging, three dimensional echocardiography and both virtual and physical simulation. Procedures were performed using the MitraClip G4 system and patients were clinically followed post-intervention.

RESULTS

A series of four CHD patients with at least severe AVVR were screened for suitability for TEER with the MitraClip system: three patients had single ventricle physiology and Fontan palliation, and one had repair of a common atrioventricular canal defect. Each patient had at least severe systemic AVVR and was considered at prohibitively high risk for surgical repair. Each patient underwent a standardized preprocedural screening protocol and image-derived modeling followed by the TEER procedure with successful clip placement at the intended location in all cases.

CONCLUSIONS

The early results of our protocolized efforts to introduce TEER repair of severe AV valve regurgitation with MitraClip into the CHD population within our institution are encouraging. Further investigations of the use of TEER in this challenging population are warranted.

Diagnostic Yield of Exome Sequencing in Pediatric Cardiomyopathy

OBJECTIVE

To assess the diagnostic yield of exome sequencing (ES) in pediatric cardiomyopathy.

STUDY DESIGN

A single-institution, retrospective chart review of 91 patients with pediatric cardiomyopathy was performed. While pediatric cardiomyopathy is often genetic in nature, no genetic test is recommended as standard of care. All our patients were diagnosed with cardiomyopathy and evaluated by a medical geneticist between January 2010 through September 2022. Demographic information and clinical data were abstracted.

RESULTS

Of 91 patients with pediatric cardiomyopathy, 36 (39.6%) received a diagnosis by ES. Twenty-two (61.1%) of these diagnoses would have been missed on cardiac multigene panel testing. The diagnostic yield for cardiomyopathy presenting under 1 year of age was 38.3%, while the yield for patients over 1 year of age was 41.9%.

CONCLUSIONS

ES has a high diagnostic yield in pediatric cardiomyopathy compared with a gene panel. Over 60% of patients with diagnosis by ES would not have received their molecular genetic diagnosis if only multigene panel testing was sent. Diagnostic yield did not vary significantly between the subtypes of cardiomyopathy and patient age groups, highlighting the likely clinical utility of ES for all pediatric cardiomyopathy patients.

Arrhythmogenic Right Ventricular Cardiomyopathy in Children: A Systematic Review

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited disease characterized by the progressive replacement of the normal myocardium by fibroadipocytic tissue. The importance of an early diagnosis is supported by a higher risk of sudden cardiac death in the pediatric population. We reviewed the literature on diagnosis, risk stratification, and prognosis in the pediatric population with ARVC. In case reports which analyzed children with ARVC, the most common sign was ventricular tachycardia, frequently presenting as dizziness, syncope, or even cardiac arrest. Currently, there is no gold standard for diagnosing ARVC in children. Nevertheless, genetic analysis may provide a proper diagnosis tool for asymptomatic cases. Although risk stratification is recommended in patients with ARVC, a validated prediction model for risk stratification in children is still lacking; thus, it is a matter of further research. In consequence, even though ARVC is a relatively rare condition in children, it negatively impacts the survival and clinical outcomes of the patients. Therefore, appropriate and validated diagnostic and risk stratification tools are crucial for the early detection of children with ARVC, ensuring a prompt therapeutic intervention.

Contemporary review on pediatric hypertrophic cardiomyopathy: insights into detection and management

Hypertrophic cardiomyopathy is the most common genetic cardiac disorder and is defined by the presence of left ventricular (LV) hypertrophy in the absence of a condition capable of producing such a magnitude of hypertrophy. Over the past decade, guidelines on the screening, diagnostic, and management protocols of pediatric primary (i.e., sarcomeric) HCM have undergone significant revisions. Important revisions include changes to the appropriate screening age, the role of cardiac MRI (CMR) in HCM diagnosis, and the introduction of individualized pediatric SCD risk assessment models like HCM Risk-kids and PRIMaCY. This review explores open uncertainties in pediatric HCM that merit further attention, such as the divergent American and European recommendations on CMR use in HCM screening and diagnosis, the need for incorporating key genetic and imaging parameters into HCM-Risk Kids and PRIMaCY, the best method of quantifying myocardial fibrosis and its prognostic utility in SCD prediction for pediatric HCM, devising appropriate genotype- and phenotype-based exercise recommendations, and use of heart failure medications that can reverse cardiac remodeling in pediatric HCM.

Adolescent Onset of Acute Heart Failure

Heart failure in adolescents can manifest due to a multitude of causes. Presentation is often quite variable ranging from asymptomatic to decompensated heart failure or sudden cardiac death. Because of the diverse nature of this disease, a thoughtful and extensive evaluation is critical to establishing the diagnosis and treatment plan. Identifying and addressing reversible pathologies often leads to functional cardiac recovery. Some disease states are irreversible and progressive, requiring chronic heart failure management and potentially advanced therapies such as transplantation.

Cardiac Involvement in Classical Organic Acidurias: Clinical Profile and Outcome in a Pediatric Cohort

BACKGROUND

Cardiac involvement is reported in a significant proportion of patients with classical organic acidurias (OAs), contributing to disability and premature death. Different cardiac phenotypes have been described, among which dilated cardiomyopathy (DCM) is predominant. Despite recent progress in diagnosis and treatment, the natural history of patients with OAs remains unresolved, specifically with regard to the impact of cardiac complications. We therefore performed a retrospective study to address this issue at our Referral Center for Pediatric Inherited Errors of Metabolism.

METHODS

Sixty patients with OAs (propionic (PA), methylmalonic (MMA) and isovaleric acidemias and maple syrup urine disease) diagnosed from 2000 to 2022 were systematically assessed at baseline and at follow-up.

RESULTS

Cardiac anomalies were found in 23/60 OA patients, all with PA or MMA, represented by DCM (17/23 patients) and/or acquired long QT syndrome (3/23 patients). The presence of DCM was associated with the worst prognosis. The rate of occurrence of major adverse cardiac events (MACEs) at 5 years was 55% in PA with cardiomyopathy; 35% in MMA with cardiomyopathy; and 23% in MMA without cardiomyopathy. Liver transplantation was performed in seven patients (12%), all with PA or MMA, due to worsening cardiac impairment, and led to the stabilization of metabolic status and cardiac function.

CONCLUSIONS

Cardiac involvement was documented in about one third of children diagnosed with classical OAs, confined to PA and MMA, and was often associated with poor outcome in over 50%. Etiological diagnosis of OAs is essential in guiding management and risk stratification.

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.

Age and Sex Differences in the Genetics of Cardiomyopathy

Cardiomyopathy has variable penetrance. We analyzed age and sex-related genetic differences in 1,397 cardiomyopathy patients (Ontario, UK) with whole genome sequencing. Pediatric cases (n = 471) harbored more deleterious protein-coding variants in Tier 1 cardiomyopathy genes compared to adults (n = 926) (34.6% vs 25.9% respectively, p = 0.0015), with variant enrichment in constrained coding regions. Pediatric patients had a higher burden of sarcomere and lower burden of channelopathy gene variants compared to adults. Specifically, pediatric patients had more MYH7 and MYL3 variants in hypertrophic cardiomyopathy, and fewer TTN truncating variants in dilated cardiomyopathy. MYH7 variants clustered in the myosin head and neck domains in children. OBSCN was a top mutated gene in adults, enriched for protein-truncating variants. In dilated cardiomyopathy, female patients had a higher burden of z-disc gene variants compared to males. Genetic differences may explain age and sex-related variability in cardiomyopathy penetrance. Genotype-guided predictions of age of onset can inform pre-test genetic counseling. Pediatric cardiomyopathy patients were more likely to be genotype-positive than adults with a higher burden of variants in MYH7, MYL3, TNNT2, VCL. Adults had a higher burden of OBSCN and TTN variants. Females with dilated cardiomyopathy (DCM) had a higher burden of z-disc gene variants compared to males.

Administrative Databases: Friend or Foe in Paediatric Cardiomyopathy

Background

Cardiomyopathy (CM) is a rare childhood disease associated with morbidity and mortality. Limited data exist on paediatric CM in Canada. Given the rare nature, single-centre studies are not sufficiently powered to address important questions. Therefore, administrative health data may serve as a resource for the study of childhood CM. The goal of this study was to validate the accuracy of International Classification of Diseases (ICD)-based algorithms to identify paediatric CM in health databases using a clinical registry as the gold standard.

Methods

The clinical registry was compiled from outpatient and inpatient records at the Stollery Children's Hospital (January 1, 2013, to December 31, 2021). Patients were categorized as having CM or screened without CM. Data were linked to administrative health databases using the patient's Unique Lifetime Identifier. Algorithms based on the presence of ICD, 10th Revision, codes for CM were then evaluated, and cross-tabulations against the clinical registry were generated. Accuracy, positive predictive value, negative predictive value, sensitivity, and specificity were calculated.

Results

The clinical registry had 90 patients with CM and 249 screened without CM. The algorithms ruled out CM (high negative predictive value) but had variability in the ability to diagnose CM positive predictive value. The algorithm that performed the best was based on a diagnosis of CM in a hospitalization or 2 ambulatory visits.

Conclusions

A combination of inpatient and outpatient databases can be used, with acceptable accuracy, to identify paediatric patients with CM. This finding allows for the use of the identified algorithm for the comprehensive study of paediatric CM in Canada.

Cardiovascular involvement in later-onset malonyl-CoA decarboxylase deficiency: Case studies and literature review

BACKGROUND

Malonyl-CoA decarboxylase deficiency (MLYCDD) is an ultra-rare inherited metabolic disorder, characterized by multi-organ involvement manifesting during the first few months of life. Our aim was to describe the clinical, biochemical, and genetic characteristics of patients with later-onset MLYCDD.

METHODS

Clinical and biochemical characteristics of two patients aged 48 and 29 years with a confirmed molecular diagnosis of MLYCDD were examined. A systematic review of published studies describing the characteristics of cardiovascular involvement of patients with MLYCDD was performed.

RESULTS

Two patients diagnosed with MLYCDD during adulthood were identified. The first presented with hypertrophic cardiomyopathy and ventricular pre-excitation and the second with dilated cardiomyopathy (DCM) and mild-to-moderate left ventricular (LV) systolic dysfunction. No other clinical manifestation typical of MLYCDD was observed. Both patients showed slight increase in malonylcarnitine in their plasma acylcarnitine profile, and a reduction in malonyl-CoA decarboxylase activity. During follow-up, no deterioration of LV systolic function was observed. The systematic review identified 33 individuals with a genetic diagnosis of MLYCDD (median age 6 months [IQR 1-12], 22 males [67%]). Cardiovascular involvement was observed in 64% of cases, with DCM the most common phenotype. A modified diet combined with levocarnitine supplementation resulted in the improvement of LV systolic function in most cases. After a median follow-up of 8 months, 3 patients died (two heart failure-related and one arrhythmic death).

CONCLUSIONS

For the first time this study describes a later-onset phenotype of MLYCDD patients, characterized by single-organ involvement, mildly reduced enzyme activity, and a benign clinical course.

Heart Failure with Recovered Ejection Fraction in Patients with Vinculin Loss-of-function Variants

Predictors of myocardial recovery in heart failure (HF) are poorly understood. We explored if vinculin (VCL) variants are associated with myocardial recovery in dilated cardiomyopathy (DCM). Six infants with DCM with a VCL loss-of-function (LOF) variant were identified. Median age at diagnosis was 2 months, median LV ejection fraction was 24%, and median LV end-diastolic diameter z-score was 10.8. All patients received HF medications. Five patients (83%) showed normalization of LV function at a median age of 2.7 years. One patient progressed to end-stage HF requiring heart transplant. This case series identified a unique phenotype of HF with reduced ejection fraction at presentation that evolved to HF with recovered EF in over 80% of infant DCM cases with LOF VCL variants. These findings have prognostic implications for counseling and management of VCL-associated DCM and highlight a possible genetic basis for HF with recovered ejection fraction.

Clinical features of pediatric Danon disease and the importance of early diagnosis

Successful therapy in a cohort with early onset Danon disease (DD) highlights the potential importance of earlier disease recognition. We present experience from the largest National Pediatric Center in Russia for cardiomyopathy patients. This report focuses on identification of early clinical features of DD in the pediatric population by detailed pedigree analysis and review of medical records. RESULTS: Nine patients (3 females) were identified with DD at the Russian National Medical Research Center of Children's Health ("National Pediatric Center") aged birth to 16 years. At presentation/evaluation: all patients had left ventricular hypertrophy (LVH), ECG features of Wolff-Parkinson-White (WPW), and an increase in hepatic enzymes (particularly lactate dehydrogenase (LDH)); three had marked increase in NT-proBNP; two had HCM with impaired LV function; one had LVH with LV noncompaction; five had arrhythmia with paroxysmal supraventricular and/or ventricular tachycardia. Two teenagers died at ages 16-17 from refractory heart failure and two underwent heart transplantation. All patients were found to have a pathogenic/likely pathogenic variant in the LAMP2 gene, six patients had no family history and a de novo evolvement was documented in 4/6 of those available for genetic tested. Retrospective review related to family background and earlier clinical evaluations revealed a definitive or highly suspicious family history of DD in 3, early clinical presentation with cardiac abnormalities (ECG, echo) in 3, and cerebral, hepatic and/or neuromuscular symptoms in 5. Abnormalities were detected 9,5 months to 5,8 years, median 3,5 years prior to referral to the National Pediatric Center. CONCLUSION: The earliest clinical manifestations of Danon disease occur in the first 12 years of life with symptoms of skeletal muscle and cerebral disease, raised hepatic enzymes, and evidence of cardiac disease on ECG/echo.

Cardiac arrest and cardiopulmonary resuscitation in pediatric patients with cardiac disease: a narrative review

Children with cardiac disease are at a higher risk of cardiac arrest as compared to healthy children. Delivering adequate cardiopulmonary resuscitation (CPR) can be challenging due to anatomic characteristics, risk profiles, and physiologies. We aimed to review the physiological aspects of resuscitation in different cardiac physiologies, summarize the current recommendations, provide un update of current literature, and highlight knowledge gaps to guide research efforts. We specifically reviewed current knowledge on resuscitation strategies for high-risk categories of patients including patients with single-ventricle physiology, right-sided lesions, right ventricle restrictive physiology, left-sided lesions, myocarditis, cardiomyopathy, pulmonary arterial hypertension, and arrhythmias. Cardiac arrest occurs in about 1% of hospitalized children with cardiac disease, and in 5% of those admitted to an intensive care unit. Mortality after cardiac arrest in this population remains high, ranging from 30 to 65%. The neurologic outcome varies widely among studies, with a favorable neurologic outcome at discharge observed in 64%-95% of the survivors. Risk factors for cardiac arrest and associated mortality include younger age, lower weight, prematurity, genetic syndrome, single-ventricle physiology, arrhythmias, pulmonary arterial hypertension, comorbidities, mechanical ventilation preceding cardiac arrest, surgical complexity, higher vasoactive-inotropic score, and factors related to resources and institutional characteristics. Recent data suggest that Extracorporeal membrane oxygenation CPR (ECPR) may be a valid strategy in centers with expertise. Overall, knowledge on resuscitation strategies based on physiology remains limited, with a crucial need for further research in this field. Collaborative and interprofessional studies are highly needed to improve care and outcomes for this high-risk population. What is Known: • Children with cardiac disease are at high risk of cardiac arrest, and cardiopulmonary resuscitation may be challenging due to unique characteristics and different physiologies. • Mortality after cardiac arrest remains high and neurologic outcomes suboptimal. What is New: • We reviewed the unique resuscitation challenges, current knowledge, and recommendations for different cardiac physiologies. • We highlighted knowledge gaps to guide research efforts aimed to improve care and outcomes in this high-risk population.

Analysis of the disease burden of cardiomyopathy in children aged 0-14 years in China from 1990 to 2019

Objectives

To assess the disease burden and changing trend of cardiomyopathy in children aged 0-14 years in China from 1990 to 2019.

Methods

This study was based on the Global Burden of Disease Study 2019; the age-specific prevalence rate, mortality rate and disability-adjusted life year (DALY) rate were used for analysis. Estimated annual percentage change (EAPC) in burden rate and its 95% confidence interval were calculated. The data of China were compared with the global average level.

Results

In 2019, the numbers of prevalence, deaths, and DALYs of cardiomyopathy in children aged 0-14 years in China were 4,493 [95% uncertainty interval (UI): 2687 ~ 6,838], 434 (95%UI: 337 ~ 565) and 37,522 (95%UI: 29,321 ~ 48,891), with declining amplitudes of 16.32, 70.56, and 70.74%, compared with 1990, respectively. In 2019, the prevalence rate of cardiomyopathy in Chinese children aged 0-14 years was 2.00/100,000 (95%UI: 1.2/100,000 ~ 3.04/100,000), higher than 1990 [1.66/100,000 (95%UI:1.00/100,000 ~ 2.53/100,000)]; mortality rate was 0.19/100,000 (95%UI: 0.15/100,000 ~ 0.25/100,000), significantly lower than 1990 [0.46/100,000 (95%UI: 0.25/100,000 ~ 0.95/100,000)]; DALY rate was 16.69/100,000 (95%UI: 13.04/100,000 ~ 21.75/100,000), also significantly lower than 1990 [39.71/100,000 (95%UI: 22.06/100,000 ~ 82.8/100,000)]. All burden rates of cardiomyopathy in Chinese children aged 0-14 years old were all lower than the global averages of 2019; the burden rates of male children were higher than female children. In all calendar years from 1990 to 2019, the mortality and DALY rates of children younger than 1-year-old were significantly higher than in the other age groups of 0-14 years old. From 1990 to 2019, the prevalence rate of cardiomyopathy aged 0-14 years old gradually increased, with EAPC of 0.82 (95%CI: 0.71-0.93); mortality rate and DALY rate decreased [EAPC = -2.32 (95%CI: -2.59 to -2.05)].

Conclusion

From 1990 to 2019, the disease burden of cardiomyopathy in children of China aged 0-14 years was heterogeneous; the burden of male children was higher than females; and the burden of cardiomyopathy in children younger than 1 year old needs more attention.

Pediatric heart failure with preserved ejection fraction, a review

Diastolic dysfunction refers to a structural or functional abnormality of the left ventricle, resulting in impaired filling of the heart. Severe diastolic dysfunction can lead to congestive heart failure even when the left ventricle systolic function is normal. Heart failure with preserved ejection fraction (HFpEF) accounts for nearly half of the hospitalizations for acute heart failure in the adult population but the clinical recognition and understanding of HFpEF in children is poor. The condition is certainly much less frequent than in the adult population but the confirmatory diagnosis of diastolic dysfunction in children is also challenging. The underlying causes of HFpEF in children are diverse and differ from the main cause in adults. This review addresses the underlying causes and prognostic factors of HFpEF in children. We describe the pulmonary hypertension profiles associated with this cardiac condition. We discuss diagnosis difficulties in clinical practice, and we provide a simplified diagnostic algorithm for HFpEF in children.

Targeted Therapies in Pediatric and Adult Patients With Hypertrophic Heart Disease: From Molecular Pathophysiology to Personalized Medicine

Hypertrophic cardiomyopathy is a myocardial disease defined by an increased left ventricular wall thickness not solely explained by abnormal loading conditions. It is often genetically determined, with sarcomeric gene mutations accounting for around 50% of cases. Several conditions, including syndromic, metabolic, infiltrative, and neuromuscular diseases, may present with left ventricular hypertrophy, mimicking the hypertrophic cardiomyopathy phenotype but showing a different pathophysiology, clinical course, and outcome. Despite being rare, they are collectively responsible for a large proportion of patients presenting with hypertrophic heart disease, and their timely diagnosis can significantly impact patients' management. The understanding of disease pathophysiology has advanced over the last few years, and several therapeutic targets have been identified, leading to a new era of tailored treatments applying to different etiologies associated with left ventricular hypertrophy. This review aims to provide an overview of the existing and emerging therapies for the principal causes of hypertrophic heart disease, discussing the potential impact on patients' management and clinical outcome.

PRDM16 Deletion Is Associated With Sex-dependent Cardiomyopathy and Cardiac Mortality: A Translational, Multi-Institutional Cohort Study

BACKGROUND

1p36 deletion syndrome can predispose to pediatric-onset cardiomyopathy. Deletion breakpoints are variable and may delete the transcription factor PRDM16. Early studies suggest that deletion of PRDM16 may underlie cardiomyopathy in patients with 1p36 deletion; however, the prognostic impact of PRDM16 loss is unknown.

METHODS

This retrospective cohort included subjects with 1p36 deletion syndrome from 4 hospitals. Prevalence of cardiomyopathy and freedom from death, cardiac transplantation, or ventricular assist device were analyzed. A systematic review cohort was derived for further analysis. A cardiac-specific Prdm16 knockout mouse (Prdm16 conditional knockout) was generated. Echocardiography was performed at 4 and 6 to 7 months. Histology staining and qPCR were performed at 7 months to assess fibrosis.

RESULTS

The retrospective cohort included 71 patients. Among individuals with PRDM16 deleted, 34.5% developed cardiomyopathy versus 7.7% of individuals with PRDM16 not deleted (P=0.1). In the combined retrospective and systematic review cohort (n=134), PRDM16 deletion-associated cardiomyopathy risk was recapitulated and significant (29.1% versus 10.8%, P=0.03). PRDM16 deletion was associated with increased risk of death, cardiac transplant, or ventricular assist device (P=0.04). Among those PRDM16 deleted, 34.5% of females developed cardiomyopathy versus 16.7% of their male counterparts (P=0.2). We find sex-specific differences in the incidence and the severity of contractile dysfunction and fibrosis in female Prdm16 conditional knockout mice. Further, female Prdm16 conditional knockout mice demonstrate significantly elevated risk of mortality (P=0.0003).

CONCLUSIONS

PRDM16 deletion is associated with a significantly increased risk of cardiomyopathy and cardiac mortality. Prdm16 conditional knockout mice develop cardiomyopathy in a sex-biased way. Patients with PRDM16 deletion should be assessed for cardiac disease.

A multi-site survey of providers on the management of heart failure with dilated cardiomyopathy in children

We conducted a scientific survey of paediatric practitioners who manage heart failure with dilated cardiomyopathy in children. The survey covered management from diagnosis to treatment to monitoring, totalling 63 questions. There were 54 respondents from 40 institutions and 3 countries. There were diverse selections of management options by the respondents in general, but also unanimity in some management options. Variation in practice is likely due to the relative paucity of scientific data in this field and lack of strong evidence-based recommendations from guidelines, which presents an opportunity for future research and quality improvement efforts as the evidence base continues to grow.

The Role of Multimodality Imaging in Pediatric Cardiomyopathies

Cardiomyopathies are a heterogeneous group of myocardial diseases representing the first cause of heart transplantation in children. Diagnosing and classifying the different phenotypes can be challenging, particularly in this age group, where cardiomyopathies are often overlooked until the onset of severe symptoms. Cardiovascular imaging is crucial in the diagnostic pathway, from screening to classification and follow-up assessment. Several imaging modalities have been proven to be helpful in this field, with echocardiography undoubtedly representing the first imaging approach due to its low cost, lack of radiation, and wide availability. However, particularly in this clinical context, echocardiography may not be able to differentiate from cardiomyopathies with similar phenotypes and is often complemented with cardiovascular magnetic resonance. The latter allows a radiation-free differentiation between different phenotypes with unique myocardial tissue characterization, thus identifying the presence and extent of myocardial fibrosis. Nuclear imaging and computed tomography have a complementary role, although they are less used in daily clinical practice due to the concern related to the use of radiation in pediatric patients. However, these modalities may have some advantages in evaluating children with cardiomyopathies. This paper aims to review the strengths and limitations of each imaging modality in evaluating pediatric patients with suspected or known cardiomyopathies.

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

This scientific statement from the American Heart Association focuses on treatment strategies and modalities for cardiomyopathy (heart muscle disease) in children and serves as a companion scientific statement for the recent statement on the classification and diagnosis of cardiomyopathy in children. We propose that the foundation of treatment of pediatric cardiomyopathies is based on these principles applied as personalized therapy for children with cardiomyopathy: (1) identification of the specific cardiac pathophysiology; (2) determination of the root cause of the cardiomyopathy so that, if applicable, cause-specific treatment can occur (precision medicine); and (3) application of therapies based on the associated clinical milieu of the patient. These clinical milieus include patients at risk for developing cardiomyopathy (cardiomyopathy phenotype negative), asymptomatic patients with cardiomyopathy (phenotype positive), patients with symptomatic cardiomyopathy, and patients with end-stage cardiomyopathy. This scientific statement focuses primarily on the most frequent phenotypes, dilated and hypertrophic, that occur in children. Other less frequent cardiomyopathies, including left ventricular noncompaction, restrictive cardiomyopathy, and arrhythmogenic cardiomyopathy, are discussed in less detail. Suggestions are based on previous clinical and investigational experience, extrapolating therapies for cardiomyopathies in adults to children and noting the problems and challenges that have arisen in this experience. These likely underscore the increasingly apparent differences in pathogenesis and even pathophysiology in childhood cardiomyopathies compared with adult disease. These differences will likely affect the utility of some adult therapy strategies. Therefore, special emphasis has been placed on cause-specific therapies in children for prevention and attenuation of their cardiomyopathy in addition to symptomatic treatments. Current investigational strategies and treatments not in wide clinical practice, including future direction for investigational management strategies, trial designs, and collaborative networks, are also discussed because they have the potential to further refine and improve the health and outcomes of children with cardiomyopathy in the future.

Cardiomyopathies in children: An overview

Paediatric cardiomyopathies form a heterogeneous group of disorders characterized by structural and electrical abnormalities of the heart muscle, commonly due to a gene variant of the myocardial cell structure. Mostly inherited as a dominant or occasionally recessive trait, they might be part of a syndromic disorder of underlying metabolic or neuromuscular defects or combine early developing extracardiac abnormalities (i.e., Naxos disease). The annual incidence of 1 per 100,000 children appears higher during the first two years of life. Dilated and hypertrophic cardiomyopathy phenotypes share an incidence of 60% and 25%, respectively. Arrhythmogenic right ventricular cardiomyopathy (ARVC), restrictive cardiomyopathy, and left ventricular noncompaction are less commonly diagnosed. Adverse events such as severe heart failure, heart transplantation, or death usually appear early after the initial presentation. In ARVC patients, high-intensity aerobic exercise has been associated with worse clinical outcomes and increased penetrance in at-risk genotype-positive relatives. Acute myocarditis in children has an incidence of 1.4-2.1 cases/per 100,000 children per year, with a 6-14% mortality rate during the acute phase. A genetic defect is considered responsible for the progression to dilated cardiomyopathy phenotype. Similarly, a dilated or arrhythmogenic cardiomyopathy phenotype might emerge with an episode of acute myocarditis in childhood or adolescence. This review provides an overview of childhood cardiomyopathies focusing on clinical presentation, outcome, and pathology.

Cardiotoxicity in children with cancer treated with anthracyclines: A position statement on dexrazoxane

Cardiovascular disease is the leading cause of non-malignant morbidity and mortality in childhood cancer survivors (CCSs). Anthracyclines are included in many treatment regimens for paediatric cancer, but unfortunately, these compounds are cardiotoxic. One in 10 CCSs who has received an anthracycline will develop a symptomatic cardiac event over time. Given the crucial need to mitigate anthracycline-related cardiotoxicity (ARC), the authors critically examined published data to identify effective cardioprotective strategies. Based on their expert analysis of contemporary literature data, it was concluded that consideration should be given for routine use of dexrazoxane in children with cancer who are at risk of ARC.

Feasibility of the Omaha system for the care of children with dilated cardiomyopathy

Aim

To explore the feasibility of Omaha system theory in the care of children with dilated cardiomyopathy (DCM), which may provide a practical basis for the continuous nursing of DCM children.

Methods

A total of 1,392 records describing symptoms, signs, and nursing interventions were extracted from the medical records of 76 children suffered from DCM. Content analysis method was used to find out existent nursing problems, make precise nursing plans, and take corresponding nursing measurements according to the medical records of DCM children. Cross-mapping method was utilized to compare the conceptual consistency of the medical records and Omaha system (problem classification and intervention subsystems).

Results

Of the total 1,392 records, 1,094 (78.59%) were complete consistency, while 245 (17.60%) were partial consistency, and 53 (3.81%) were inconsistency with the Omaha system concepts. The concept matching degree of medical records and Omaha system was approximately 96.19%.

Conclusions

The Omaha system may be an effective nursing language for Chinese DCM children, which may be useful to guide nurses in the care of DCM. Further well-design studies need to fully evaluate the feasibility and effectiveness of the Omaha system in nursing children with DCM.

Whole-Exome Sequencing Identifies Homozygote Nonsense Variants in LMOD2 Gene Causing Infantile Dilated Cardiomyopathy

As an essential component of the sarcomere, actin thin filament stems from the Z-disk extend toward the middle of the sarcomere and overlaps with myosin thick filaments. Elongation of the cardiac thin filament is essential for normal sarcomere maturation and heart function. This process is regulated by the actin-binding proteins Leiomodins (LMODs), among which LMOD2 has recently been identified as a key regulator of thin filament elongation to reach a mature length. Few reports have implicated homozygous loss of function variants of LMOD2 in neonatal dilated cardiomyopathy (DCM) associated with thin filament shortening. We present the fifth case of DCM due to biallelic variants in the LMOD2 gene and the second case with the c.1193G>A (p.W398*) nonsense variant identified by whole-exome sequencing. The proband is a 4-month male infant of Hispanic descent with advanced heart failure. Consistent with previous reports, a myocardial biopsy exhibited remarkably short thin filaments. However, compared to other cases of identical or similar biallelic variants, the patient presented here has an unusually late onset of cardiomyopathy during infancy. Herein, we present the phenotypic and histological features of this variant, confirm the pathogenic impact on protein expression and sarcomere structure, and discuss the current knowledge of LMOD2-related cardiomyopathy.

Global burden of myocarditis and cardiomyopathy in children and prediction for 2035 based on the global burden of disease study 2019

BACKGROUND

Myocarditis and cardiomyopathy are commonly occurring cardiovascular diseases that seriously threaten children's health. It was urgent to update the global incidence and mortality of childhood myocarditis and cardiomyopathy, and to predict the incidence rate of 2035 by the Global Burden of Disease database.

METHODS

The Global Burden of Disease study data from 1990 to 2019 in 204 countries and territories were used to determine: global incidence and mortality rates of childhood myocarditis and cardiomyopathy from 0 to 19 by five age groups; relationship between sociodemographic index (SDI) and incidence and mortality rates by age group; and, based on an age-period-cohort model, the projected incidence of childhood myocarditis and cardiomyopathy for 2035.

RESULTS

From 1990 to 2019, global age-standardized incidence rate decreased by 0.1% (95% UI 0.0-0.1) to 7.7% (95% UI 5.1-11.1). Boys had higher age-standardized incidence of childhood myocarditis and cardiomyopathy than girls [9.12, (95% UI 6.05-13.07) vs. 6.18, (95% UI 4.06-8.92)]. Childhood myocarditis and cardiomyopathy affected 121,259 (95% UI 80,467-173,790) boys and 77,216 (95% UI 50,684-111,535) girls in 2019. At the regional level, SDI changes in most areas showed no meaningful difference. In East Asia and high-income Asia Pacific, increased SDI was associated with decreased and increased incidence rate, respectively. In 2019, 11,755 (95% UI 9,611-14,509) children died from myocarditis and cardiomyopathy worldwide. Age-standardized mortality rate decreased significantly by 0.4% (95% UI 0.2-0.6)-0.5% (95% UI 0.4-0.6). Number of deaths from childhood myocarditis and cardiomyopathy in 2019 was highest in the <5-year-old group [7,442 (95% UI 5,834-9,699)]. Myocarditis and cardiomyopathy incidence in 10-14- and 15-19-year-olds is projected to increase by 2035.

CONCLUSION

Global data on childhood myocarditis and cardiomyopathy from 1990 to 2019 showed a decreasing trend in incidence and mortality, and an increasing trend in older children, especially in high SDI regions.

Challenges of anaesthetising a child with Bow Hunter's syndrome and dilated cardiomyopathy for occipitocervical fusion

Paediatric Bow Hunter's syndrome (BHS), or rotational vertebral artery syndrome, is a rare cause of posterior circulation insufficiency in children. It results from mechanical obstruction of the vertebral artery by the transverse process of cervical vertebrae resulting in vertebrobasilar insufficiency during the neck rotation to the sides. Paediatric dilated cardiomyopathy (DCM) is a rare myocardial disease that presents with ventricular dilatation and cardiac dysfunction. This case report describes the successful anaesthetic management of an boy with BHS due to atlantoaxial dislocation and DCM. The child was anaesthetised by keeping the following anaesthetic goals in mind such as maintenance of the heart rate, rhythm, preload, afterload and contractility close to the baseline for both DCM and BHS. Haemodynamic management with optimal fluids, inotrope and a vasopressor and titrating its volume and doses using multimodal haemodynamic monitoring while keeping both cardio and neuroprotective strategies, and the multimodal analgesia techniques helped the child for faster recovery.

A case report of isolated right ventricular noncompaction with mutation of ACVRL1: a new cause of noncompaction of ventricular myocardium?

BACKGROUND

Noncompaction of ventricular myocardium(NVM) is a rare kind of cardiomyopathy associated with genetic mutations and nongenetic factors, among which the isolated right ventricular noncompaction (iRVNC) is the most rare type. ACVRL1 is the pathogenic gene of type 2 hereditary hemorrhagic telangiectasia (HHT2), and there's no NVM reported to be associated with ACVRL1 mutation.

CASE PRESENTATION

This is a rare case diagnosed as iRVNC and pulmonary hypertention with ACVRL1 mutation detected.

CONCLUSION

iRVNC in this case may be due to ACVRL1 mutation, secondary to pulmonary hypertention and right ventricular failure caused by ACVRL1 mutation, or they happened in the same case coincidently.

Genetic Screening Reveals Heterogeneous Clinical Phenotypes in Patients with Dilated Cardiomyopathy and Troponin T2 Variants

Background: Cardiomyopathies (CMs) are a heterogeneous and severe group of diseases that shows a highly variable cardiac phenotype and an incidence of app. 1/100.000. Genetic screening of family members is not yet performed routinely. Patients and methods: Three families with dilated cardiomyopathy (DCM) and pathogenic variants in the troponin T2, Cardiac Type (TNNT2) gene were included. Pedigrees and clinical data of the patients were collected. The reported variants in the TNNT2 gene showed a high penetrance and a poor outcome, with 8 of 16 patients dying or receiving heart transplantation. The age of onset varied from the neonatal period to the age of 52. Acute heart failure and severe decompensation developed within a short period in some patients. Conclusion: Family screening of patients with DCM improves risk assessment, especially for individuals who are currently asymptomatic. Screening contributes to improved treatment by enabling practitioners to set appropriate control intervals and quickly begin interventional measures, such as heart failure medication or, in selected cases, pulmonary artery banding.

Sudden Cardiac Death Among Adolescents in the United Kingdom

BACKGROUND

Causes and precipitating factors of sudden cardiac death (SCD) in adolescents are poorly understood.

OBJECTIVES

The authors sought to investigate the etiologies of SCD and their association with physical activity in a large cohort of adolescents.

METHODS

Between 1994 and June 2022, 7,675 cases of SCD were consecutively referred to our national cardiac pathology center; 756 (10%) were adolescents. All cases underwent detailed autopsy evaluation by expert cardiac pathologists. Clinical information was obtained from referring coroners.

RESULTS

A structurally normal heart, indicative of sudden arrhythmic death syndrome was the most common autopsy finding (n = 474; 63%). Myocardial diseases were detected in 163 cases (22%), including arrhythmogenic cardiomyopathy (n = 36; 5%), hypertrophic cardiomyopathy (n = 31; 4%), idiopathic left ventricular hypertrophy (n = 31; 4%), and myocarditis (n = 30; 4%). Coronary artery anomalies were identified in 17 cases (2%). Decedents were competitive athletes in 128 cases (17%), and 159 decedents (21%) died during exercise. Arrhythmogenic cardiomyopathy was diagnosed in 8% of athletes compared with 4% of nonathletes (P = 0.05); coronary artery anomalies were significantly more common in athletes (9% vs 1%; P < 0.001), as well as commotio cordis (5% compared with 1% in nonathletes; P = 0.001). The 3 main comorbidities were asthma (n = 58; 8%), epilepsy (n = 44; 6%), and obesity (n = 40; 5%).

CONCLUSIONS

Sudden arrhythmic death syndrome and myocardial diseases are the most common conditions diagnosed at autopsy in adolescent victims of SCD. Among causes of SCD, arrhythmogenic cardiomyopathy, coronary artery anomalies, and commotio cordis are more common in young athletes than in similar age sedentary individuals.

Sudden cardiac death in childhood hypertrophic cardiomyopathy

The most prevalent cause of mortality in children with hypertrophic cardiomyopathy (HCM) is sudden cardiac death (SCD), which happens more frequently than in adult patients. Risk stratification tactics have generally been drawn from adult practice, however emerging data has revealed significant disparities between children and adult cohorts, implying the need for pediatric-specific risk stratification methodologies. We conducted an all-language literature search on Medline, Cochrane, Embase, and Google Scholar until October 2021. The following search strings and Medical Subject Heading (MeSH) terms were used: "HCM," "SCD," "Sudden Cardiac Death," and "Childhood Onset HCM." We explored the literature on the risk of SCD in HCM for its epidemiology, pathophysiology, the role of various genes and their influence, associated complications leading to SCD and preventive and treatment modalities. Childhood-onset HCM is linked to significant life-long morbidity and mortality, including a higher SCD rate in children than in adults. The present focus is on symptom relief and avoiding illness-related consequences, but the prospect of future disease-modifying medicines offers an intriguing opportunity to alter disease expression and outcomes in these young individuals. Current preventive recommendations promote implantable cardioverter defibrillator placement based on cumulative risk factor thresholds, although they have been demonstrated to have weak discriminating capacity. This article addresses questions and discusses the etiology, risk factors, and method to risk stratification for SCD in children with HCM.