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

Understanding inherited cardiomyopathies: clinical aspects and genetic determinants

Cardiomyopathies (CMs) are a clinically heterogeneous group of cardiovascular diseases characterized by structural and functional abnormalities of the heart muscle in the absence of coronary artery disease, hypertension, valve disease, or congenital heart disease as a leading cause. The phenotypic spectrum of CMs ranges from silent heart failure to symptomatic heart failure and sudden cardiac death, and CMs are one of the leading causes of cardiovascular morbidity worldwide. CMs are highly heritable, although a clear distinction between inherited and acquired forms remains challenging, particularly due to observed incomplete penetrance and variable expressivity of inherited CMs. Based on their specific morphological phenotypes and functional characteristics, CMs can be divided into at least 5 different subgroups: hypertrophic cardiomyopathy (HCM), dilated cardiomyopathy (DCM), arrhythmogenic cardiomyopathy (ACM), restrictive cardiomyopathy (RCM), and (left ventricular) non-compaction cardiomyopathy (LVNC), which show both clinical as well as genetic overlap. Since the identification of pathogenic variants in MYH7 as a genetic cause of HCM in 1990, enormous progress has been made in understanding genetic factors contributing to cardiomyopathies. Currently, over 100 genes have been associated with at least one of the CM subtypes, providing a deeper understanding of the cellular basis of genetic heart failure syndromes, unveiling new insights into the molecular biology of heart function in both health and disease, and, thereby, facilitating the development of novel therapeutic strategies and personalized treatment approaches.

Precision phenomapping of pediatric dilated cardiomyopathy using clustering models based on electronic hospital records

BACKGROUND

Pediatric dilated cardiomyopathy (PDCM) is a heterogeneous disease, and its clinical management is still considered challenging. This study aimed to establish clinically relevant PDCM subtypes to evaluate prognosis and guide its treatments.

METHODS

Multidimensional data of study participants were derived from electronic hospital records based on a multicenter retrospective cohort in China. Six clustering models for heterogeneous data were adopted to identify PDCM subtypes, and multiple indices were used to select the best model. Multivariable Cox models were adopted to evaluate the association between PDCM subtypes and the risk of adverse clinical events. Finally, a clinical classifier was constructed for clinical application.

RESULTS

A total of 279 idiopathic PDCM cases were included in this study, and two phenotypes developed by the Kamila model were recognized as optimal. Group I was mainly infants and toddlers (median age: 6.32 months) with larger dimensions but mild systolic dysfunction of the left ventricle (LV) while group II was older children (median age: 111.77 months) with severe LV systolic dysfunction, reduced LV wall thickness, and higher prevalence of abnormal valvular regurgitation and arrhythmia. Moreover, group II had a significantly lower event-free survival probability than group I after adjusting for all covariates (HR = 8.096, P = 0.002). The conditional interference tree model with five parameters could accurately distinguish PDCM subtypes.

CONCLUSIONS

PDCM subtypes in our study showed distinct clinical profiles and risks of worse prognosis, and probably have different responses to current standard therapies, which would provide novel directions for precision management and pathological studies of PDCM.

Dilated cardiomyopathy evaluation with Imagenomics: combining multimodal cardiovascular imaging and genetics

Dilated cardiomyopathy (DCM) is a clinical diagnosis characterized by the presence of left ventricular dilatation and systolic dysfunction unexplained by abnormal loading conditions or coronary artery disease. However, a broad range of phenotypic manifestations, encompassing isolated scar, DCM with preserved ejection fraction, and overt DCM, should be regarded as a diagnostic classification representing a broad spectrum of underlying aetiologies, including both inherited and acquired heart muscle disorders. A multimodal non-invasive imaging approach is essential for accurate morpho-functional assessment of cardiac chambers and is key to establish the cardiac phenotype and to rule out an underlying ischaemic aetiology. Furthermore, advanced imaging techniques enable deep cardiovascular phenotyping and non-invasive tissue characterization. The aim of this review is to propose a systematic approach to the diagnosis of DCM, emphasizing the importance of genetics and clinical findings for a precise and practical clinical approach. Also, we strive to qualify the role of cardiac imaging in the diagnosis of DCM, particularly on the relevance of novel techniques and clinical utility of actionable parameters to improve current diagnostic schemes and risk stratification algorithms. We further elaborate on the role of cardiac imaging to deliver optimal guidance to aetiology-based therapeutic approaches, verification of treatment response and disease progression monitoring.

The Cardiovascular Care of the Pediatric Athlete

Sports cardiology broadly encompasses the cardiovascular care of individuals who place a high premium on habitual exercise, sports performance, and/or sports competition. Some of the essential aspects within sports cardiology include the preparticipation cardiac evaluation and the management of cardiac diseases in athletes. Although most sports cardiology practitioners are trained in adult cardiology, a significant number of individuals who participate in sports are pediatric-aged, <18 years old. Up to two-thirds of children in middle and high school participate in organized sports or are involved in nonorganized recreational sports. The cardiovascular care of pediatric-aged athletes can be challenging because many of the classic tenets and principles in adult sports cardiology do not fully generalize to pediatrics, and there is a lack of the evidence base that may be present for adult athletes. The epidemiology, presentation, and progression of cardiovascular diseases can be significantly different between pediatric and adult athletes. The evaluation of potential diseases and management considerations may also differ between pediatric and adult athletes. Similar to adults, there are "gray zones" where it is difficult to differentiate between normal exercise-induced cardiac remodeling and true cardiac pathology, but the additional lack of normative standards further complicates assessments in pediatric athletes. Management decisions for pediatric athletes are generally based on limited data but carry substantial short- and long-term implications. Thus, shared decision-making as part of the determination of clinical management strategies and for sports participation is critical and requires the participation of the parents or guardian(s). In this state-of-the-art review, key differences between pediatric and adult-aged athletes are highlighted. Specifically, how to define the "pediatric athlete," consider cardiovascular adaptations observed among pediatric athletes, determine preparticipation screening options and optimal symptom-driven evaluations in children, and consider best practices for pediatric athletes with several key cardiac conditions are detailed. The purpose of this document is to represent the first primary reference available to providers who care for pediatric athletes with cardiovascular concerns.

An Extended Phenotype of PPP1R13L Cardiocutaneous Syndrome

Dilated cardiomyopathy (DCM) is a rare disease in children and a leading cause of heart failure. There are numerous causes of DCM including genetic causes leading to isolated or syndromic presentations, with a wide variety of implicated genes. Among them, PPP1R13L is associated with a recessive syndrome leading to cardiac anomalies with skin, teeth, and hair abnormalities. Fifteen patients have been described so far. We report a patient born to unrelated parents with early-onset and progressive DCM, skin appendage anomalies, and an anorectal anomaly. Her late brother shared the same phenotype. Exome sequencing revealed biallelic loss-of-function (LoF) variants of PPP1R13L in the proband, also present in her affected brother. To our knowledge, anorectal anomalies had never been previously described in PPP1R13L mutated individuals. As exome sequencing did not identify any other candidate variant to explain this malformation, this feature may expand the phenotype of PPP1R13L LoF disorder.

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.

Missed or Delayed Diagnosis of Heart Disease by the General Pediatrician

Missed or delayed heart disease diagnoses pose a major challenge in pediatric primary care. Many cardiac conditions present with subtle or nonspecific symptoms that resemble benign childhood illnesses, making their prompt recognition difficult. This review describes congenital and acquired heart diseases prone to diagnostic delays, including critical congenital heart disease, coarctation of the aorta, atrial and ventricular septal defects, myocarditis, Kawasaki disease, heart failure, and pulmonary arterial hypertension. The atypical presentations of these disorders and the associated diagnostic pitfalls are emphasized. Furthermore, the importance of alarming symptoms and signs, such as chest pain, palpitations, syncope, and abnormal heart murmurs, is underscored. A structured approach to these red flags is presented to assist primary care pediatricians in identifying children at risk, initiating appropriate management, and referring them for specialized evaluation. The importance of preparticipation screening for athletes is also discussed, highlighting how it can be applied to all children during routine health visits to identify those with heart disease. Appropriate training is essential to increase pediatricians' ability to recognize and manage cardiac patients.

A de novo TNNI3K variant aggravates the pathogenicity of DMD-associated early-onset cardiomyopathy: a case report

Background

Dystrophin is a DMD coding protein that serves as a connector maintaining the structural formation and functional hemostasis of myofilaments, which regulate the contraction of cardiomyocytes. However, early-onset heart failure or cardiomyopathy is closely associated with adverse clinical outcomes in Duchenne muscular dystrophy (DMD)-affected patients. Pathogenicity screening and identification of the potential combined variants are thus critical for the management of such patients. Herein, we report a rare case of a patient with early-onset DMD attributed to a compound genetic variant in the DMD and TNNI3K genes.

Case presentation

The proband, a 15-month-old male patient, presented with severe heart failure, enlarged ventricles, and diffuse fibrosis. Whole-exome sequencing was used to identify a compound missense variant as c.1540G>T (p.V514L) of the DMD gene and c.1633G>T of the TNNI3K gene, resulting in disease. The protein structures of the mutant dystrophin and TNNI3K were built using AlphaFold3. The amino acid residues around site 514 had changed in DMD p.V514L, and the altered surrounding structures resulted in protein dysfunction. Furthermore, the amino acid residues around site 545 had changed in TNNI3K p.G545C, causing significant alterations to the hydrogen bonding. As both of these mutations contribute to regulating the myofilaments, potential interactions are suspected. Then, the binding structure was established using AlphaFold3, and the structural changes were identified based on the compound variants.

Conclusion

We present a rare case of a compound genetic variant that induces severe and very-early-onset heart failure in DMD patients. The compound variant attenuates the interactions between DMD and TNNI3K, leading to functional collapse of the myofilaments. This finding emphasizes the importance of comprehensive genetic analysis in DMD patients. Identification of additional variants can significantly aggravate the pathological process and disease prognosis, and such patients always require swift and careful clinical management to obtain desirable outcomes.

Predicting Cardiac Magnetic Resonance-Derived Ejection Fraction from Echocardiogram Via Deep Learning Approach in Tetralogy of Fallot

Systolic function assessment is essential in children with congenital heart disease. Traditional methods of echocardiographic left ventricular ejection fraction (LVEF) estimation might overestimate systolic function compared to the gold standard of cardiac magnetic resonance imaging (CMR), especially in Tetralogy of Fallot (TOF). Deep learning technologies such as EchoNet-Dynamic offer more consistent cardiac evaluations and can potentially accurately predict LVEF using echocardiographic videos. The EchoNet-Dynamic/EchoNet-Peds models predict LVEF using echocardiograms with expert-measured LVEF as the ground truth. Using a transfer learning approach, we fine-tuned this model to predict LVEF with CMR-derived LVEF as ground truth and TOF echocardiograms as input images. For echocardiograms in the PSAX view, the model predicted CMR LVEF with an R2 of 0.79 and an MAE of 4.41. For the A4C view, the model predicted CMR LVEF with an R2 of 0.53 and an MAE of 6.4. Plotted ROC curves indicate that both tuned models differentiated well between normal and reduced LVEF. This study shows the potential of Convolutional Neural Network (CNN) models in transforming the field of cardiac imaging interpretation via a hybrid approach using the CMR labels and echocardiogram videos offering advancements over conventional methods.

2025 Heart Disease and Stroke Statistics: A Report of US and Global Data From the American Heart Association

BACKGROUND

The American Heart Association (AHA), in conjunction with the National Institutes of Health, annually reports the most up-to-date statistics related to heart disease, stroke, and cardiovascular risk factors, including core health behaviors (smoking, physical activity, nutrition, sleep, and obesity) and health factors (cholesterol, blood pressure, glucose control, and metabolic syndrome) that contribute to cardiovascular health. The AHA Heart Disease and Stroke Statistical Update presents the latest data on a range of major clinical heart and circulatory disease conditions (including stroke, brain health, complications of pregnancy, kidney disease, congenital heart disease, rhythm disorders, sudden cardiac arrest, subclinical atherosclerosis, coronary heart disease, cardiomyopathy, heart failure, valvular disease, venous thromboembolism, and peripheral artery disease) and the associated outcomes (including quality of care, procedures, and economic costs).

METHODS

The AHA, through its Epidemiology and Prevention Statistics Committee, continuously monitors and evaluates sources of data on heart disease and stroke in the United States and globally to provide the most current information available in the annual Statistical Update with review of published literature through the year before writing. The 2025 AHA Statistical Update is the product of a full year's worth of effort in 2024 by dedicated volunteer clinicians and scientists, committed government professionals, and AHA staff members. This year's edition includes a continued focus on health equity across several key domains and enhanced global data that reflect improved methods and incorporation of ≈3000 new data sources since last year's Statistical Update.

RESULTS

Each of the chapters in the Statistical Update focuses on a different topic related to heart disease and stroke statistics.

CONCLUSIONS

The Statistical Update represents a critical resource for the lay public, policymakers, media professionals, clinicians, health care administrators, researchers, health advocates, and others seeking the best available data on these factors and conditions.

The Relationship Between Vitamin D Levels and Cardiac Remodelling in a Pediatric Dilated Cardiomyopathy Population: A Case-Control Study

Dilated cardiomyopathy (DCM) is a significant contributor to heart failure (HF) in the pediatric population despite its lower incidence compared to adults.

METHOD

We present a case-control study that investigates serum levels of Vitamin D, measured as 25-hydroxyvitamin D (25-OHD), in children diagnosed with DCM and explores the relationship between Vitamin D levels and left ventricular (LV) dimensions and systolic function.

RESULTS

Thirty patients (mean age: 10.61 ± 6.54 years) with DCM were included, with a control group of thirty-one matched healthy children. We found a high prevalence of 25-OHD deficiency (67%) in the DCM group, which was statistically significant compared to the control group (p < 0.05). Notably, a significant negative correlation was observed between 25-OHD levels and both LV end-diastolic diameter (LVEDD; r = -0.43, p < 0.01) and end-systolic diameter (LVESD; r = -0.46, p < 0.01). However, no significant correlation was found between Vitamin D levels and LV ejection fraction or shortening fraction.

CONCLUSION

These findings emphasise the importance of assessing Vitamin D status in pediatric DCM patients and may suggest that Vitamin D supplementation can be beneficial in managing this condition through its potential effects on cardiac remodelling and function. Further research is warranted to clarify the underlying mechanisms and therapeutic implications.

Genotype-phenotype insights of pediatric dilated cardiomyopathy

Dilated cardiomyopathy (DCM) in children is a severe myocardial disease characterized by enlargement of the left ventricle or both ventricles with impaired contractile function. DCM can cause adverse consequences such as heart failure, sudden death, thromboembolism, and arrhythmias. This article reviews the latest advances in genotype and phenotype research in pediatric DCM. With the development of gene sequencing technologies, considerable progress has been made in genetic research on DCM. Research has shown that DCM exhibits notable genetic heterogeneity, with over 100 DCM-related genes identified to date, primarily involving functions such as calcium handling, the cytoskeleton, and ion channels. As human genomic variations are linked to phenotypes, DCM phenotypes are influenced by numerous genetic variations across the entire genome. Children with DCM display high genetic heterogeneity and are characterized by early onset, rapid disease progression, and poor prognosis. The genetic architecture of pediatric DCM markedly differs from that of adult DCM, necessitating analyses through clinical phenotyping, familial cosegregation studies, and functional validation. Clarifying the genotype-phenotype relationship can improve diagnostic accuracy, enhance prognosis, and guide follow-up treatment for genotype-positive and phenotype-negative patients identified through genetic testing, providing new insights for precision medicine. Future research should further explore novel pathogenic genes and mutations and strengthen genotype-phenotype correlation analyses to facilitate precise diagnosis and treatment of DCM in children.

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.

Clinical impact of genetic testing in a large cohort of pediatric cardiomyopathies

BACKGROUND

There are limited data that can explain the earlier penetrance and the different expressivity of pediatric cardiomyopathy (pCM) compared to adult-onset cardiomyopathy (aCM). In addition, the relationship between genotype and pCM results is poorly described.

OBJECTIVE

We compared the genotypes between a cohort of aCM and a cohort of pCM to propose hypotheses on the earlier penetrance and expressivity of pCM. Finally, we report how genetic testing was used to guide genetic counseling in pCM.

METHODS

253 pCM (<18 years old) and 1466 aCM patients were sequenced on a panel of 67 cardiomyopathy genes. Risk factors for death and heart transplantation were analyzed.

RESULTS

In pCM, the variant of interest (VOI) yield was 53.7 % including 24.2 % carrying two VOI. De novo variants represented 11 % of VOI in pCM and 50 % in restrictive pCM. An age at diagnosis younger than 1 year (HR = 2.07, p = 0.029), restrictive phenotype (HR = 2.87, p = 0.03) and the presence of two VOI (HR = 2.97, p = 0.001) were independent risk factors for death or heart transplantation. In comparison with aCM, pCM patients harbored more frequently two VOI (p = 0.02), or de novo variants (p = 4.10-13). In addition, the distribution of VOI was different in aCM and pCM. Genotyping of pCM improved genetic counseling in families and led to ten prenatal-diagnosis.

CONCLUSIONS

Genetic testing provides clues for earlier penetrance of pCM. The presence of two VOI in children with CM is a risk factor for severe and early cardiac events.

Clinical Management and Transplant Considerations in Pediatric Pulmonary Hypertension Due to Left Heart Disease: A Scientific Statement From the American Heart Association

Children with left heart disease are at risk for developing pulmonary hypertension, initially secondary to pulmonary venous hypertension that can progress to include elevated pulmonary vascular resistance, known as combined pre- and postcapillary pulmonary hypertension. Elevated pulmonary vascular resistance may pose a risk to the right ventricle of a newly transplanted heart because of increased afterload and is an important consideration for heart transplant eligibility. However, the epidemiology, pathophysiology, optimal diagnostic and treatment approaches, and thresholds for pulmonary vascular resistance in pulmonary hypertension associated with left heart disease remain unclear because of lack of evidence, particularly in pediatrics. The result is heterogeneity with respect to hemodynamic assessment, use of pulmonary vasodilator therapies, and heart transplant listing. This scientific statement aims to synthesize the available data and highlight areas of general consensus as well as important knowledge gaps.

Myocardial Work for Dynamic Monitoring of Myocardial Injury in Neonatal Asphyxia

To assess the value of parameters of myocardial work for dynamic monitoring of myocardial injury after neonatal asphyxia. Fifty-three neonates with asphyxia admitted within 24 h after delivery were divided into a mild asphyxia group (n = 40) and severe asphyxia group (n = 13). Echocardiography was performed within 24 h post-birth, within 72 h post-birth (48 h after first echo), and during recovery. The left ventricular ejection fraction on M-mode echocardiography and by Simpson's biplane method (LVEF and Bi-EF, respectively), stroke volume (SV), cardiac output (CO), cardiac index (CI), global longitudinal strain (GLS), global work index (GWI), global constructive work (GCW), and other parameters were measured. Echocardiographic indicators were compared between groups and over time. GWI was significantly increased at 72 h in the mild asphyxia group (P < 0.05) but showed no significant change over time in the severe asphyxia group (P > 0.05). While GCW increased significantly over time in both groups (P < 0.05), it increased earlier in the mild asphyxia group. Time and grouping factors had independent effects on GWI and GCW (P > 0.05). The characteristics of differences in GWI and GCW between the two groups were different from those for LVEF, Bi-EF, SV, CO, CI, and GLS and their change characteristics with improvement from treatment. GWI and GCW changed significantly during recovery from neonatal asphyxia, and their change characteristics differed between mild and severe asphyxia cases. Myocardial work parameters can be used as valuable supplements to traditional indicators of left ventricular function to dynamically monitor the recovery from myocardial injury after neonatal asphyxia.

Genetic variations in PTPN11 lead to a recurrent left ventricular outflow tract obstruction phenotype in childhood hypertrophic cardiomyopathy

OBJECTIVE

Left ventricular septal myotomy provides a favorable prognosis for children with hypertrophic obstructive cardiomyopathy (HOCM). However, some children still suffer from recurrent left ventricular outflow tract obstruction (LVOTO) after surgery. Poor prognosis exists for HOCM caused by PTPN11 mutation. Therefore, the aim of this study was to determine the clinical features of recurrent obstruction in children with HOCM caused by pathogenic mutations in the PTPN11 gene.

METHODS

Fifty-six children who were diagnosed with HOCM underwent septal myectomies. Whole-exome sequencing of 49 pediatric cardiomyopathy-associated genes (including PTPN11) was performed. We performed hematoxylin-eosin, Masson, and wheat germ agglutinin staining of those tissues positive and negative for PTPN11.

RESULTS

Whole-exome sequencing results showed 11 children with the PTPN11 mutation (19.6%). In long-term follow-up (median 37 months, maximum 9 years), children with the PTPN11 mutation had 6 (54.5%) recurrent LVOTOs compared with other groups (P = .015) but similar survival rates (P = .514). The mean postoperative time to recurrent obstruction was 22 ± 7 months. Children with PTPN11 mutation were 9-fold more likely to experience the risk associated with recurrent obstruction (95% confidence interval, 1.77-45.81, P < .001). Hematoxylin-eosin, Masson, and wheat germ agglutinin staining also revealed more cardiomyocyte hypertrophy in tissues with the PTPN11 mutation.

CONCLUSIONS

Children with PTPN11 mutation-associated hypertrophic cardiomyopathy have a greater risk of recurrent LVOTO.

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.

Catastrophic antiphospholipid antibody syndrome associated with ischaemic cardiomyopathy

We report the case of a 16-year-old female with previously diagnosed bilateral sub-segmental pulmonary emboli who presented in cardiogenic shock from depressed biventricular function with cardiac MRI demonstrating concern for microvascular coronary injury. She was ultimately diagnosed with catastrophic antiphospholipid antibody syndrome-induced ischaemic cardiomyopathy, potentially associated with an underlying autoimmune connective tissue disease.

Pattern and Frequency of Congenital Heart Defects Among Infants of Diabetic Mothers

Background Maternal diabetes mellitus (DM) is a known risk factor for congenital heart diseases (CHDs), which are of significant concern to infants born to diabetic mothers. Compared to newborns born to non-diabetic mothers, infants born to diabetic mothers had a higher overall risk of developing congenital malformations. This association has a complex pathophysiology that includes genetic predispositions, metabolic abnormalities, and environmental factors during key stages of fetal development. By developing screening strategies for neonates born to diabetic mothers, it will be imperative to reduce preventable neonatal mortality by healthcare providers. Purpose The primary objective of this study was to explore the spectrum of congenital heart defects (infants of diabetic mothers, IDMs). Methods This exploratory study was conducted at the maternity and children's hospital in AlAhsa, Saudi Arabia, from 2022 to 2023. The study included 401 neonates delivered at our institution. Within the first seven days of life, an expert pediatric cardiologist from the same institute performed echocardiography on all patients. Results A total of 401 infants born to diabetic mothers were selected, with 293 meeting the inclusion criteria. In total, 144 (49.1%) were boys and 149 (50.9%) were girls. Nearly more than half of mothers (189, 64.5%) had gestational diabetes, while 104 (35.5%) had pre-gestational diabetes. Out of 293 infants born to diabetic mothers, 200 (68.3%) had various CHDs, while the remaining 93 (31.7%) were found to be normal after echocardiography. The most commonly reported CHD is patent ductus arteriosus (PDA) (71.5%), followed by hypertrophic cardiomyopathy (36.5%) and ventricular septal defect (VSD) (11%), and only one patient has a complex congenital heart disease. Conclusion More than half of the infants born to diabetic mothers had congenital heart defects, according to the current study, which examined the various types of congenital heart diseases in neonates of diabetic mothers. It thus emphasizes the necessity of a thorough evaluation and the strong recommendation for an early diagnosis of CHD in this high-risk group. In our population, prenatal CHD screening programs need to be developed.

Special considerations for the stabilization and resuscitation of patients with cardiac disease in the Neonatal Intensive Care Unit

Effective resuscitation of neonates with congenital heart disease (CHD) depends on comprehensive planning, thorough understanding of physiology, vigilant monitoring, and interdisciplinary collaboration to achieve the best outcomes. Neonatal heart disease can affect cardiac structure, rhythm, or ventricular function, and may be either congenital or acquired. Critical congenital heart disease (CCHD) can result in inadequate pulmonary blood flow, impaired intracardiac mixing, airway obstruction, or insufficient cardiac output. Tailored resuscitation strategies are important as early as the delivery room, where some CHD lesions may cause immediate cardiovascular instability during the transition from fetal to postnatal circulation. Premature infants with CHD are at higher risk due to their small size and the complications associated with prematurity, affecting both CHD management and overall clinical stability. Addressing both cardiac and non-cardiac causes of decompensation requires a precise understanding of each patient's unique physiology and trajectory from delivery through postintervention intensive care.

A case report of reversible dilated cardiomyopathy due to left main coronary artery ostial stenosis: optimal imaging is key

Background

Congenital coronary artery anomalies are a rare but reversible cause of dilated cardiomyopathy in infants and children. Optimal imaging strategies to efficiently identify and confirm the diagnosis in the setting of extracorporeal membrane oxygenation (ECMO) are crucial to timely surgery.

Case summary

A 2-month-old boy presented with dilated cardiomyopathy and severe left ventricular dysfunction requiring ECMO support. During an unsuccessful ECMO wean, turbulent flow was noted at the origin of the left coronary artery on echocardiography with subsequent computed tomography (CT) angiogram and cardiac angiogram via catheter confirming the very rare diagnosis of left main coronary artery ostial stenosis. He underwent emergency left coronary artery augmentation with excellent outcome.

Discussion

A high index of suspicion for coronary artery anomalies is required for infants presenting with suspected dilated cardiomyopathy. While CT is a potential diagnostic tool for investigating coronary abnormalities in children, image optimization on ECMO is challenging, with further imaging often required. The superior spatial and temporal resolution of cardiac angiography via catheterization allows definitive diagnosis of coronary artery abnormalities in this situation and facilitates timely surgical intervention.

Maternal hemoglobin A1c and left ventricular hypertrophy in infants of mothers with pre-gestational diabetes

OBJECTIVE

Maternal hemoglobin A1c (HbA1c) has been suggested to be a predictor of left ventricular hypertrophy (LVH) in the offspring of mothers with pre-gestational diabetes mellitus, although there is little data supporting this contention. We aimed to assess the relationship between maternal HbA1c and postnatal LVH.

METHODS

We performed a retrospective cohort study of infants born to mothers with pre-gestational diabetes mellitus from 2015 to 2021 at our institution. The primary predictor was maternal HbA1c; neonatal left ventricular mass (LVM) z-score was the primary outcome; LVM z-score was considered as both a continuous variable and a binary variable by dichotomizing at 4 to define LVH. Additionally, we used linear regression to determine the relationship between maternal HbA1c and LVM z-score.

RESULTS

There were 116 infants who met inclusion (50% female). Mean maternal HbA1c was generally higher in infants with LVH compared to those without LVH (8.2% with LVH vs. 7.2% without LVH [p = 0.009] in the second trimester, and 7.8% vs. 7.0% [p = 0.025] in the third trimester; no significant difference for first trimester). A greater percentage of infants with LVH were intubated (36% vs. 6%, p < 0.001) and had longer average days of hospitalization (9 vs. 5, p = 0.044). Second and third trimester HbA1c was weakly associated with LVM z-score (R2 = 0.063, p < 0.001 and R2 = 0.068, p < 0.001, respectively); first trimester HbA1c was not significantly predictive of LVM z-score.

CONCLUSION

Second and third trimester HbA1c is modestly predictive of LVH in infants born to mothers with pre-gestational diabetes mellitus.

Tachycardia-Induced Cardiomyopathy: A Case Series and a Literature Review

Tachycardia-induced cardiomyopathy (TIC), also known as arrhythmia-induced cardiomyopathy or tachycardiomyopathy, is a reversible form of heart failure characterized by persistent tachyarrhythmias and associated ventricular dysfunction. TIC is characterized by the reversal of myocardial damage with resolution of the arrhythmia. Early diagnosis of TIC is imperative, as the treatment course is distinct from cardiomyopathy of other or unknown causes. However, distinguishing TIC from tachycardia secondary to increased catecholamines due to congestive heart failure can be very challenging. There are relatively few paediatric reports, and herein we present a case series of 48 paediatric patients with TIC from literature (2014-2024). We also present 4 illustrative cases with TIC seen at our site (BC Children's Hospital, Vancouver, Canada). The mean age in this case series was 6.98 ± 4.9 years. The majority of patients had ectopic atrial tachycardia (41.7%), followed by permanent junctional reciprocating tachycardia (20.8%), ventricular tachycardia (16.7%), and atrioventricular re-entrant tachycardia or atrioventricular nodal re-entrant tachycardia (10.4%). Pharmacologic treatment was the predominant therapy, but 70.8% of patients needed at least 1 ablation procedure. All patients demonstrated significant improvement in left ventricular ejection fraction after treatment, with most achieving at least near-normal ejection fractions in 80 days on average since presentation. In conclusion, TIC is overall a treatable condition with challenging diagnosis but generally has a favourable prognosis when diagnosed and treated appropriately. This article emphasizes the importance of considering TIC in the differential diagnosis of tachycardia in the context of reduced ventricular function, to recognize it and to enable targeted treatment initiation as soon as possible.

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.

Pulmonary artery banding to treat end-stage heart failure in infants and young children: A multicenter study

Background

Conventional treatment options for end-stage heart failure (ESHF) in children include heart transplantation (HT) and ventricular assist devices (VADs), both with significant drawbacks in the pediatric population. Pulmonary artery banding (PAB) has been effectively used as bridge to transplant or recovery in pediatric ESHF. We herein describe the early and mid-term clinical outcomes from a multicenter international experience.

Methods

This is a multicenter retrospective study including children admitted for ESHF caused by dilated cardiomyopathy and treated with PAB. The primary outcome was the freedom from death/VAD/HT.

Results

Thirty-one patients (median age 210 days [131-357]) with ESHF underwent PAB in 5 centers. Pediatric Interagency Registry for Mechanically Assisted Circulatory Support (PEDIMACS) score was I to III in 90%; 15 patients were intubated preoperatively. Preoperative left ventricular (LV) ejection fraction was <30% in 68%, with LV dilation in all cases. Postoperatively, median PAB gradient was 29 mm Hg (23-34), and complications occurred in 14 patients (45%), with 4 (13%) early deaths. Twenty-seven patients were successfully discharged home on anti-congestive therapy. At a median follow-up of 2.9 years, there were 1 late death and 3 HTs. Freedom from death/VAD/HT was 77.3% (95% confidence interval [CI] = 58-88.4%), 77.3% (95%CI=58-88.4%), and 73.2% (95%CI=53.2-85.5%) at 6 months, 1 year, and 2 years of follow-up, respectively. All 23 survivors with a native heart had gradual normalization of LV function and dimensions.

Conclusions

PAB can be an effective procedure to treat ESHF in selected infants, as alternative strategy for bridging to transplant or recovery.

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.

Subtle echocardiogram findings requiring further investigation: restrictive cardiomyopathy in a rare genetic condition

Mulibrey nanism (MN) is a extremely rare genetic condition first described in 1973, with around 150 cases reported worldwide. MN is characterised by growth delay and multiorgan manifestations, the most fatal being a combination restrictive-constrictive, perimyocardial heart disease that results in diastolic heart failure. We present a male toddler with MN who presented with recurrent episodes of hypoxia, feeding intolerance, and generalised swelling (anasarca) in the setting of subtle echocardiographic findings. A multidisciplinary and systematic diagnostic approach was used to determine the underlying aetiology. Invasive cardiac testing via right heart catheterisation revealed the final diagnosis of restrictive cardiomyopathy. Transplant decision-making was limited due to hepatic involvement. This case highlights the limitations of echocardiography in diagnosing restrictive cardiomyopathy, which has a preserved ejection fraction, as well the need for multidisciplinary involvement and a family-centred approach in treating patients with this rare condition.

Arrhythmias May Hide a Genetic Cardiomyopathy in Left Ventricular Hypertrabeculation in Children: A Single-Center Experience

BACKGROUND

Left ventricular hypertrabeculation (LVHT) is a myocardial disorder with different clinical manifestations, from total absence of symptoms to heart failure, arrhythmias, sudden cardiac death (SCD), and thromboembolic events. It is challenging to distinguish between the benign and pathological forms of LVHT. The aim of this study was to describe the arrhythmic manifestations of LVHT in a large group of pediatric patients and to correlate them with genetic results or other clinical markers.

METHODS

We retrospectively enrolled 140 pediatric patients with diagnosis of LVHT followed at our Institution from 2013 to 2023. Data regarding family history, instrumental exams, cardiac magnetic resonance, genetic testing and outcomes were collected. Most of them had isolated LVHT (80.7%); in other patients, mixed phenotypes (hypertrophic or dilated cardiomyopathy or congenital heart disease) were present.

RESULTS

Arrhythmias were found in 33 children (23.6%): 13 (9.3%) supraventricular tachyarrhythmias; 14 (10%) ventricular arrhythmias (five frequent PVCs (premature ventricular contractions), eight patients with ventricular tachycardia (VT), one ventricular fibrillation (VF)); two (1.4%) sinus node disfunctions; two (1.4%) complete atrio-ventricular blocks (AVB), three (2.1%) paroxysmal complete AVB, one (0.7%) severe I degree AVB. Three patients received an ICD (implantable cardioverter defibrillator). Comparison between LVHT patients with (33 pts) and without (107 pts) arrhythmias as regards genetic testing showed a statistical significance for the presence of class 4 or 5 genetic variants and arrhythmic manifestation (p = 0.037).

CONCLUSIONS

In our pediatric cohort with LVHT, good outcomes were observed, but arrhythmias were not so rare (23.6%); no SCD occurred.

Pediatric Extracorporeal Membrane Oxygenation in Restrictive and Hypertrophic Cardiomyopathy: A Single Center Experience

Patients with restrictive cardiomyopathy (RCM) and hypertrophic cardiomyopathy (HCM) were previously considered poor candidates for mechanical circulatory support due to technical limitations related to restrictive ventricular physiology and small ventricular size, limiting the ability to provide adequate flows and decompress the heart. Literature examining use of extracorporeal membrane oxygenation (ECMO) in this population consists of a single case series reporting no survivors. We report our experience providing ECMO in children with RCM or HCM at a large pediatric quaternary cardiac center. Between 2012 and 2022, five patients (four RCM, one HCM) were supported with seven ECMO runs. All patients were cannulated to ECMO with ongoing cardiopulmonary resuscitation. Four patients survived decannulation from ECMO (median support time 209 hr, interquartile range [IQR]: 48-265), of which three (60%) survived to hospital discharge after transitioning to a ventricular assist device (VAD) and undergoing orthotopic heart transplant (OHT). Two remain alive at long-term follow-up with normal or mildly impaired functional status. These findings suggest that while RCM and HCM have traditionally been considered contraindications to ECMO due to adverse outcomes, this population may be successfully supported with ECMO with survival comparable to international registry outcomes in select centers where VAD as a bridge to OHT is available.

Cardiomyopathy-Associated Chronic Heart Failure in Infants Aged <1 Year: A Prospective Observational Cohort Over 5 Years in Northern China

BACKGROUND

There have been few large-scale studies on the outcomes of cardiomyopathy-associated heart failure (HF) in infants aged <1 year. This study aimed to assess longitudinal echocardiographic outcomes of infants with HF secondary to cardiomyopathy who survived for >1 year.

METHODS AND RESULTS

A prospective observational study following 327 infant patients up to 5 years in 2 large pediatric heart centers in Northern China between January 2010 and December 2018. A total of 236 (72.2%) patients had reduced left ventricular ejection fraction (LVEF) (HF with reduced ejection fraction group; LVEF <40%), 91 (27.8%) patients had midrange LVEF (HF with midrange ejection fraction group; LVEF ≥40% but <55%). LVEF improved significantly within the first year and remained stable in years 2 through 5 for both groups. The HF with midrange ejection fraction group had a higher rate of LVEF normalization (hazard ratio, 1.65; P<0.001). Baseline LVEF ≥40%, baseline left ventricular end-diastolic diameter Z score <7.8, the absence of left bundle-branch block, and the absence of β-blocker use were 4 independent favorable predictors for future LVEF normalization. A total of 62.4% of enrolled patients were diagnosed with left ventricular noncompaction. No significant difference in LVEF normalization was found among the different types of cardiomyopathy studied.

CONCLUSIONS

A significant number of infants with cardiomyopathy who survived >1 year were found to improve with medical therapies during the first year of diagnosis. Poorer outcomes were associated with decreased LVEF and increased heart size at diagnosis baseline, the presence of left bundle-branch block and use of β blockers. The Northern Chinese pediatric population may have a high proportion of left ventricular noncompaction.

Genophenotypic correlates and long-term outcome prognosticators of left ventricular non-compaction in children

BACKGROUND

To investigate the outcomes, clinical prognosticators, and genetic profiles of pediatric left ventricular non-compaction (LVNC).

METHODS

All subjects were <18 years old, diagnosed with LVNC between January 2008 and December 2020. Whole-exome sequencing was undertaken. The primary endpoint was composite outcome, including death, heart transplant, and left ventricular assist device implantation.

RESULTS

Thirty-three patients were enrolled, males predominating (57.6%). Median age at diagnosis was 0.33 (0.1-7.2) years. Family history was documented in four (12.1%). Five (15.2%) had sustained arrhythmias. Mean follow-up period was 9.5 years, and 5- and 10-year event-free survival were 84.8% and 66.9%, respectively. Seven died of heart failure, four received heart transplants, and one required left ventricular assist device placement. Log of baseline NT-proBNP (adjusted odds ratio [aOR] = 4.4, p = 0.012) and lack of improvement in NT-proBNP (aOR = 41.2, p = 0.033) impacted the primary outcome most significantly. Eighteen out of 25 genetic testing (72%) revealed chromosomal anomalies, or pathogenic or likely pathogenic variants. Three genetic variants (PLEKHM2 p.G419R, RYR2 p.V2571A, and SCN5A p.M1676I) were significantly associated with the primary outcome (p = 1.52 × 10-6).

CONCLUSIONS

Pediatric LVNC is a rare disorder with variable genetic underpinnings. Baseline NT-proBNP values and lack of improvement in NT-proBNP levels were important predictors of poor long-term outcomes. Pathogenic genetic variants or chromosomal anomalies are not unusual.

Brazilian Guideline for Exercise Testing in Children and Adolescents - 2024

CLASSES OF RECOMMENDATION

LEVELS OF EVIDENCE

Abnormal left atrial strain and left atrial stiffness index are associated with adverse outcomes in children with cardiomyopathies: a pilot study

Conventional diastolic dysfunction parameters seem to be imperfect when applied to the pediatric cardiomyopathy population. The aim of this pilot study was to search for novel echocardiographic parameters associated with adverse outcomes in children with the most common cardiomyopathies. Fifty-six patients with pediatric cardiomyopathies (28 with dilated, 21 with hypertrophic, 7 with left ventricular non-compaction cardiomyopathy) and 28 healthy subjects were included in the study. Left atrial reservoir (LASr), conduit (LAScd) and contraction (LASct) strain, left atrial stiffness index (LASI), as well as conventional diastolic dysfunction parameters were measured using echocardiography. Adverse outcomes were defined as heart failure (including heart transplant) and arrhythmic endpoints. Patients with adverse outcomes presented with significantly lower LASr (16.68% ± 8.64% vs. 33.97% ± 9.99%, p-value < 0.001), lower LAScd (- 10.37% ± 5.83% vs. - 25.50% ± 9.24%, p-value < 0.001) and higher values of LASI (0.69 [IQR 0.34; 1.11] vs. 0.21 [IQR 0.16; 0.31], p-value < 0.001). LASr < 20%, LAScd ≥ - 12%, and LASI ≥ 0.26 were all associated with reduced survival. LASr, LAScd and LASI seem to be promising parameters in predicting adverse outcomes in the most common pediatric cardiomyopathies. Left atrial strain parameters and LASI are helpful in differentiating healthy control subjects from children with hypertrophic and dilated cardiomyopathies.

Cardiomyopathy in Children and Adolescents in the Era of Precision Medicine

In childhood and adolescence, cardiomyopathies have their own characteristics and are an important cause of heart failure, arrhythmias, sudden death, and indication for heart transplantation. Diagnosis is a challenge in daily practice due to its varied clinical presentation, heterogeneous etiologies, and limited knowledge of tools related to clinical and molecular genetics. However, it is essential to recognize the different phenotypes and prioritize the search for the etiology. Recent advances in precision medicine have made molecular diagnosis accessible, which makes it possible to individualize therapeutic approaches, stratify the prognosis, and identify individuals in the family who are at risk of developing the disease. The objective of this review is to emphasize the particularities of cardiomyopathies in pediatrics and how the individualized approach impacts the therapy and prognosis of the patient. Through a systematized approach, the five-stage protocol used in our service is presented. These stages bring together clinical evaluation for determining the morphofunctional phenotype, identification of etiology, classification, establishment of prognosis, and the search for personalized therapies.

Canadian Cardiovascular Society Clinical Practice Update on Contemporary Management of the Patient With Hypertrophic Cardiomyopathy

Numerous guidelines on the diagnosis and management of hypertrophic cardiomyopathy (HCM) have been published, by learned societies, over the past decade. Although helpful they are often long and less adapted to nonexperts. This writing panel was challenged to produce a document that grew as much from years of practical experience as it did from the peer-reviewed literature. As such, rather than produce yet another set of guidelines, we aim herein to deliver a concentrate of our own experiential learning and distill for the reader the essence of effective and appropriate HCM care. This Clinical Practice Update on HCM is therefore aimed at general cardiologists and other cardiovascular practitioners rather than for HCM specialists. We set the stage with a description of the condition and its clinical presentation, discuss the central importance of "obstruction" and how to look for it, review the role of cardiac magnetic resonance imaging, reflect on the appropriate use of genetic testing, review the treatment options for symptomatic HCM-crucially including cardiac myosin inhibitors, and deal concisely with practical issues surrounding risk assessment for sudden cardiac death, and management of the end-stage HCM patient. Uniquely, we have captured the pediatric experience on our panel to discuss appropriate differences in the management of younger patients with HCM. We ask the reader to remember that this document represents expert consensus opinion rather than dogma and to use their best judgement when dealing with the HCM patient in front of them.

A Review of Pediatric Cardiomyopathy

Though pediatric cardiomyopathy is rare in children, there is significant associated morbidity and mortality. Etiology varies from inborn errors of metabolism to familial genetic mutations and myocyte injury. Major classes include dilated, hypertrophic, restrictive, and non-compaction. Diagnosis generally involves a combination of clinical history and echocardiography. The use of cross-sectional imaging is gaining popularity. Management varies between subtype and may involve a combination of medical and surgical interventions depending on clinical status.

Biallelic NEXN variants and fetal onset dilated cardiomyopathy: two independent case reports and revision of literature

BACKGROUND

Dilated cardiomyopathy (DCM) is an etiologically heterogeneous group of diseases of the myocardium. With the rapid evolution in laboratory investigations, genetic background is increasingly determined including many genes with variable penetrance and expressivity. Biallelic NEXN variants are rare in humans and associated with poor prognosis: fetal and perinatal death or severe DCMs in infants.

CASE PRESENTATION

We describe two male infants with prenatal diagnosis of dilated cardiomyopathy with impaired ventricular contractility. One of the patients showed hydrops and polyhydramnios. Postnatally, a DCM with severely reduced systolic function was confirmed and required medical treatment. In patient 1, Whole Exome Sequencing (WES) revealed a homozygous NEXN variant: c.1156dup (p.Met386fs) while in patient 2 a custom Next Generation Sequencing (NGS) panel revealed the homozygous NEXN variant c.1579_1584delp. (Glu527_Glu528del). These NEXN variants have not been previously described. Unlike the unfavorable prognosis described for biallelic NEXN variants, we observed in both our patients a favorable clinical course over time.

CONCLUSION

This report might help to broaden the present knowledge regarding NEXN biallelic variants and their clinical expression. It might be worthy to consider the inclusion of the NEXN gene sequencing in the investigation of pediatric patients with DCM.

Clinical Characteristics and Outcomes of Dilated Cardiomyopathy in Chinese Children: A Single-Center Retrospective Study

BACKGROUND

The reported outcomes of pediatric dilated cardiomyopathy (DCM) have varied across studies. There are few outcome data concerning DCM in Chinese children. Therefore, we conducted a retrospective study to describe clinical features and determine risk factors for poor outcomes in children with DCM.

METHODS

We enrolled 121 children with DCM in our hospital from 2003 to 2021. General information and laboratory and echocardiographic data were collected and analyzed. Cox regression analysis was performed to determine risk factors for poor outcomes.

RESULTS

This study included 121 patients (69 males and 52 females). The median age at diagnosis was 10.8 years, and the follow-up time was 10.0 months. Eighty-two patients (67.8%) exhibited cardiac function classes III-IV at the time of diagnosis. Tachypnea was the most common symptom (78.5%). In echocardiography, the mean left ventricular end-diastolic dimension z score was 7.36 ± 2.73, and the left ventricular ejection fraction z score was -6.58 ± 2.17. The 1-, 2-, and 5-year survival rates were 51.2%, 43.8%, and 32.2%, respectively. Cox analysis revealed that cardiac function classes III-IV (hazard ratio [HR] = 1.801, 95% confidence interval [95% CI] = 1.030-3.149, p = 0.039) and calcium levels (HR = 0.219, 95% CI = 0.084-0.576, p = 0.002) were predictors of poor outcomes in children with DCM.

CONCLUSIONS

Children with DCM are at high risk of death. Cardiac function class III-IV and calcium levels were related to the prognosis of pediatric DCM patients.

Ventricular assist device support in paediatric patients with restrictive cardiomyopathy-clinical outcomes and haemodynamics

OBJECTIVES

Restrictive cardiomyopathy is rare and is generally associated with worse clinical outcomes compared to other cardiomyopathies. Ventricular assist device (VAD) support for these children is seldom applied and often hampered by the surgical difficulties.

METHODS

All paediatric (<19 years) patients with a restricted cardiomyopathy supported by a VAD from the EUROMACS database were included and compared to patients with a dilated cardiomyopathy (retrospective database analyses). Participating centres were retrospectively contacted to provide additional detailed echo and Swan Ganz measurements to analyse the effect of VAD support on pulmonary artery pressure and right ventricular function.

RESULTS

Forty-four paediatric VAD-supported patients diagnosed with restricted cardiomyopathy were included, with a median age at implantation of 5.0 years. Twenty-six of the 44 patient with a restricted cardiomyopathy survived to transplantation (59.1%), 16 died (36.4%) and 2 are still on ongoing VAD support (4.5%) after a median duration of support of 95.5 days (interquartile range 33.3-217.8). Transplantation probability after 1 and 2 years of VAD support in patients with a restricted cardiomyopathy were comparable to patients with a dilated cardiomyopathy (52.3% vs 51.4% and 59.5% vs 60.1%, P = 0.868). However, mortality probability was higher in the restricted cardiomyopathy cohort (35.8% vs 17.0% and 35.8% vs 19.0%, P = 0.005). Adverse event rates were high (cerebrovascular accident in 31.8%, pump thrombosis in 29.5%, major bleeding 25.0%, eventual biventricular support in 59.1%). In the atrially cannulated group, cerebrovascular accident and pump thrombosis occurred in twice as much patients (21.1% vs 40.0%, P = 0.595 and 15.8% vs 40.0%, P = 0.464; probably non-significant due to the small numbers). Pulmonary arterial pressures improved after implantation of a VAD, and 6 patients who were initially labelled as ineligible due to pulmonary hypertension could eventually be transplanted.

CONCLUSIONS

VAD support in children with a restricted cardiomyopathy is rarely performed. Mortality and adverse event rates are high. On the other hand, survival to cardiac transplantation was 59.1% with all patients surviving the 1st 30 days after cardiac transplantation. Pulmonary arterial pressures improved while on support, potentially making cardiac transplantation a viable option for previously ineligible children.

Children With Cardiac Disease and Heat Exposure: Catastrophic Converging Consequences?

The detrimental impact of extreme heat exposure on the health and well-being of children is widely acknowledged. The direct and indirect effects of climate change have led to an increased risk of certain cardiovascular events which may be particularly harmful to children who are born with, or develop, heart disease.

PURPOSE

To highlight the worrying paucity of investigative research aimed at differentiating how higher ambient temperatures further tax an already compromised cardiovascular system in children.

METHODS

This commentary describes basic thermoregulatory concepts relevant to the healthy pediatric population and summarizes common heart diseases observed in this population.

RESULTS

We describe how heat stress and exercise are important factors clinicians should more readily consider when treating children with heart disease. Countermeasures to physical inactivity are suggested for children, parents, clinicians, and policymakers to consider.

CONCLUSIONS

As sudden, excessive heat exposures continue to impact our rapidly warming world, vulnerable populations like children with underlying heart conditions are at greater heat health risk, especially when coupled with the negative physical activity and fitness trends observed worldwide.

Patterns of Left Ventricular Remodelling in Children and Young Patients with Hypertrophic Cardiomyopathy

Introduction: The aim of this study was to evaluate the age at onset, clinical course, and patterns of left ventricular (LV) remodelling during follow-up in children and young patients with hypertrophic cardiomyopathy (HCM). Methods: We included consecutive patients with sarcomeric or non-syndromic HCM below 18 years old. Three pre-specified patterns of LV remodelling were assessed: maximal LV wall thickness (MLVWT) thickening; MLVWT thinning with preserved LV ejection fraction; and MLVWT thinning with progressive reduction in LV ejection fraction (hypokinetic end-stage evolution). Results: Fifty-three patients with sarcomeric/non-syndromic HCM (mean age 9.4 ± 5.5 years, 68% male) fulfilled the inclusion criteria. In total, 32 patients (60%) showed LV remodelling: 3 patients (6%) exhibited MLVWT thinning; 16 patients (30%) showed MLVWT thickening; and 13 patients (24%) progressed to hypokinetic end-stage HCM. Twenty-one patients (40%) had no LV remodelling during follow-up. In multivariate analysis, MLVWT was a predictor of the hypokinetic end-stage remodelling pattern during follow-up (OR 1.17 [95%CI 1.01-1.36] per 1 mm increase, p-value 0.043), regardless of sarcomeric variants and New York Heart Association class. Two patients with sarcomeric HCM, showing a pattern of MLVWT regression during childhood, experienced progression during adolescence. Conclusions: Different patterns of LV remodelling were observed in a cohort of children with sarcomeric/non-syndromic HCM. Interestingly, a pattern of progressive MLVWT thinning during childhood, with new progression of MLVWT during adolescence, was noted. A better understanding of the remodelling mechanisms in children with sarcomeric HCM may be relevant to defining the timing and possible efficacy of new targeted therapies in the preclinical stage of the disease.

Unraveling the genetic tapestry of pediatric sarcomeric cardiomyopathies and masquerading phenocopies in Jordan

Pediatric cardiomyopathies are mostly attributed to variants in sarcomere-related genes. Unfortunately, the genetic architecture of pediatric cardiomyopathies has never been previously studied in Jordan. We sought to uncover the genetic landscape of 14 patients from nine families with several subtypes of pediatric cardiomyopathies in Jordan using Exome sequencing (ES). Our investigation identified pathogenic and likely pathogenic variants in seven out of nine families (77.8%), clustering in sarcomere-related genes. Surprisingly, phenocopies of sarcomere-related hypertrophic cardiomyopathies were evident in probands with glycogen storage disorder and mitochondrial-related disease. Our study underscored the significance of streamlining ES or expanding cardiomyopathy-related gene panels to identify plausible phenocopies of sarcomere-related cardiomyopathies. Our findings also pointed out the need for genetic testing in patients with cardiomyopathy and their at-risk family members. This can potentially lead to better management strategies, enabling early interventions, and ultimately enhancing their prognosis. Finally, our findings provide an initial contribution to the currently absent knowledge about the molecular underpinnings of cardiomyopathies in Jordan.

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.

Epidemiology of Pediatric Cardiomyopathy in a Mediterranean Population

BACKGROUND

Our knowledge regarding the epidemiology of pediatric cardiomyopathy is based on large national population studies reporting an annual incidence of 1 case per 100,000 children, with a higher incidence observed in infancy and among selected populations. The aim here is to document the epidemiology of pediatric cardiomyopathy in a Mediterranean population.

METHODS

Children younger than 18 years of age living on the Mediterranean island of Crete, Greece, who have been evaluated since the establishment of tertiary pediatric cardiology services (2002-2022) were included in this retrospective study.

RESULTS

A total of 40 children were included, corresponding to an average annual incidence of pediatric cardiomyopathy of 1.59 cases (95% CI: 1.4-2.3) and a prevalence of 26 cases per 100,000 children. In decreasing order of frequency, most cases corresponded to dilated (50%), followed by hypertrophic (42.5%), arrhythmogenic (5%), and restrictive (2.5%) cardiomyopathy. An etiology was identified in 40%, including a genetic diagnosis in 22.5%.

CONCLUSIONS

The incidence of pediatric cardiomyopathy in the Mediterranean island of Crete is higher compared with that reported previously for other Caucasian populations. Further study is needed to investigate the exact prevalence and specific genetic factors associated with the epidemiology of pediatric cardiomyopathy in Mediterranean populations.

Relationship between Baseline Serum Potassium and 1-Year Readmission in Pediatric Patients with Heart Failure: A Retrospective Cohort Study

Pediatric heart failure (HF) is associated with high readmission rates, but the optimal serum potassium range for this population remains unclear. In this single-center retrospective cohort study, 180 pediatric patients hospitalized for HF between January 2016 and January 2022 were stratified into low-potassium (<3.7 mmol/L), middle-potassium (3.7-4.7 mmol/L), and high-potassium (≥4.7 mmol/L) groups based on the distribution of potassium levels in the study population. The primary outcome was readmission for HF within 1 year of discharge. Cox regression and restricted cubic spline models were used to assess the association between potassium levels and 1-year HF readmission rates. Notably, 38.9% of patients underwent 1 or more 1-year readmissions for HF within 1 year. The high-potassium group had a significantly higher readmission frequency than the middle-potassium group. In multivariate Cox regression models, potassium levels of ≥4.7 mmol/L were independently associated with increased 1-year readmission risk. A J-shaped relationship was observed between baseline potassium levels and 1-year readmission risk, with the lowest risk at 4.1 mmol/L. In pediatric patients with HF, a serum potassium level ≥ 4.7 mmol/L was independently associated with increased 1-year readmission risk. Maintaining potassium levels within a narrow range may improve outcomes in this population.

Tachycardia-Induced Cardiomyopathy in an Infant with Atrial Flutter and Prolonged Recovery of Cardiac Function

Background: Tachycardia-induced cardiomyopathy (TIC) is caused by prolonged tachycardia, leading to left ventricular dilatation and systolic dysfunction with heart failure. Although TIC is more common in adults, it is rare in early infancy. Methods: Clinical testing was performed as part of medical evaluation and management. Next-generation sequencing (NGS) was conducted for a patient with TIC. A literature review on TIC was also conducted. Results: The case involved a 5-month-old infant referred to the hospital due to symptoms of heart failure lasting at least two months. The infant's heart rate was 200 beats per minute, the left ventricular ejection fraction fell below 14%, and electrocardiograms showed atrial flutter, suggesting TIC. After cardioversion, there was no recurrence of atrial flutter, and cardiac function improved 98 days after tachycardia arrest. The NGS did not identify any pathogenic variants. The literature review identified eight early infantile cases of TIC. However, no previous reports described a case with such a prolonged duration of TIC as ours. Conclusions: This is the first report of a case of prolonged TIC in a child with the documented time to recover normal cardiac function. The improvement of cardiac function depends on the duration of TIC. Early recognition and intervention in TIC are essential to improve outcomes for infantile patients, as timely treatment offers the potential for recovery.

Evaluation of new predictive scores for sudden cardiac death in childhood hypertrophic cardiomyopathy in a French cohort

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is rare in children, and sudden cardiac death (SCD) is difficult to predict. Two prognostic scores - HCM Risk-Kids and Precision Medicine for Cardiomyopathy (PRIMaCY) - were developed to assess the risk of SCD in the next 5 years in children with HCM.

AIMS

To test the ability of these scores to predict SCD in children with HCM. Also, to identify factors associated with a severe cardiac rhythmic event (SCRE) (ventricular fibrillation, sustained ventricular tachycardia, heart transplant for rhythmic reasons or SCD).

METHODS

Retrospective, multicentre, observational study at 10 medical centres in the Nord-Pas-de-Calais region, France.

RESULTS

This study included 72 paediatric patients with HCM during 2009-2019 who were followed for a median (interquartile range [IQR]) of 8.5 (5.0-16.2) years. Eleven patients (15.3%) presented with SCRE. HCM Risk-Kids was high, with a median (IQR) score of 6.2% (2.1-12.8%; significant threshold≥6.0%) and the PRIMaCY median (IQR) score was 7.1% (2.6-15.0%; significant threshold≥8.3%). The positive predictive value was only 27.1% (95% confidence interval [CI] 21.5-32.5%) for HCM Risk-Kids (with a threshold of≥6.0%) and 33.2% (95% CI 27.1-38.9%) for the PRIMaCY score (with a threshold of≥8.3%). The negative predictive values were 95.4% (95% CI 92.3-97.7%) and 93.0% (95% CI 89.8-96.2%), respectively. Three of 28 patients with an implantable cardioverter defibrillator (ICD) experienced complications (including inappropriate shocks).

CONCLUSION

HCM Risk-Kids and the PRIMaCY score have low positive predictive values to predict SCD in paediatric patients. If used alone, they could increase the rate of ICD implantation and thus ICD complications. Therefore, the scores should be used in combination with other data (genetic and magnetic resonance imaging results).