Cardiomyopathy Phenotypes and Outcomes for Children With Left Ventricular Myocardial Noncompaction: Results From the Pediatric Cardiomyopathy Registry

Biventricular noncompaction induced heart failure in premature newborn

Deep intertrabecular recesses and overly pronounced trabeculations in one ventricle are the hallmarks of noncompaction cardiomyopathy (NCCM), a rare congenital cardiomyopathy but very rarely right ventricle (RV), or both ventricles may be involved. We reported a 5-day-old preterm newborn with signs of congestive heart failure that the transthoracic echocardiography (TTE) revealed deep intertrabecular recesses perfused from the left ventricle (LV) and RV cavity, as well as significantly increased wall thickness of the right ventricles and hypertrabeculations in the apical and midventricular segments.

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.

The outcome of genetic and non-genetic pediatric cardiomyopathies

BACKGROUND

Pediatric cardiomyopathies (CMP) can be familial or idiopathic with increasing detection of genetic mutations. The study is a retrospective single-center review of cardiomyopathy patients from January 2011 to May 2020. Results of the genetic study, as well as the outcome, were reported. Patients were divided according to the type of CMP, age of presentation, and EF at presentation. Univariate and multivariate analysis and ROC and survival curves were done.

RESULTS

We reported 229 patients under 14 years of age with a diagnosis of cardiomyopathy, most commonly DCM (160 patients (70%)) followed by HCM (26.2%). 52% presented at 6 months of age or less and 119 (52%) required ICU admission at presentation. The genetic and or metabolic disorder was confirmed in 21.4% of patients, most commonly VLCAD defect (16, 7%) and ELAC2 gene defect (10, 4.4%). During the disease course, 88 patients (38.4%) died (48 with DCM, 39 with HCM, and 1 with RCM). An EF of 20% or less at presentation and presentation at 6 months of age or less carries a risk for mortality in patients with DCM and HCM, respectively (RR 3.88 and 2.06 and OR of 11.09 and 4.35, respectively). Death was more common among HCM patients especially patients with positive genetic abnormality compared with patients with DCM.

CONCLUSIONS

The mortality for CMP in children reaches up to 40%, (30% in DCM and 65% in HCM patients). Mortality was higher in those with HCM, DCM with EF of 20% or less, and HCM presented at 6 months of age or less. Whole-exome and/or whole-genome sequencing is advised for all patients of CMP and at-risk family members.

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.

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.

Progressive Left Ventricular Remodeling for Predicting Mortality in Children With Dilated Cardiomyopathy: The Pediatric Cardiomyopathy Registry

BACKGROUND

Pediatric dilated cardiomyopathy often leads to death or cardiac transplantation. We sought to determine whether changes in left ventricular (LV) end-diastolic dimension (LVEDD), LV end-diastolic posterior wall thickness, and LV fractional shortening (LVFS) over time may help predict adverse outcomes.

METHODS AND RESULTS

We studied children up to 18 years old with dilated cardiomyopathy, enrolled between 1990 and 2009 in the Pediatric Cardiomyopathy Registry. Changes in LVFS, LVEDD, LV end-diastolic posterior wall thickness, and the LV end-diastolic posterior wall thickness:LVEDD ratio between baseline and follow-up echocardiograms acquired ≈1 year after diagnosis were determined for children who, at the 1-year follow-up had died, received a heart transplant, or were alive and transplant-free. Within 1 year after diagnosis, 40 (5.0%) of the 794 eligible children had died, 117 (14.7%) had undergone cardiac transplantation, and 585 (73.7%) had survived without transplantation. At diagnosis, survivors had higher median LVFS and lower median LVEDD Z scores. Median LVFS and LVEDD Z scores improved among survivors (Z score changes of +2.6 and -1.1, respectively) but remained stable or worsened in the other 2 groups. The LV end-diastolic posterior wall thickness:LVEDD ratio increased in survivors only, suggesting beneficial reverse LV remodeling. The risk for death or cardiac transplantation up to 7 years later was lower when LVFS was improved at 1 year (hazard ratio [HR], 0.83; P=0.004) but was higher in those with progressive LV dilation (HR, 1.45; P<0.001).

CONCLUSIONS

Progressive deterioration in LV contractile function and increasing LV dilation are associated with both early and continuing mortality in children with dilated cardiomyopathy. Serial echocardiographic monitoring of these children is therefore indicated.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT00005391.

Left Ventricular Non-Compaction in Children: Aetiology and Diagnostic Criteria

Left ventricular non-compaction (LVNC) is a heterogeneous myocardial disorder characterized by prominent trabeculae protruding into the left ventricular lumen and deep intertrabecular recesses. LVNC can manifest in isolation or alongside other heart muscle diseases. Its occurrence among children is rising due to advancements in imaging techniques. The origins of LVNC are diverse, involving both genetic and acquired forms. The clinical manifestation varies greatly, with some cases presenting no symptoms, while others typically manifesting with heart failure, systemic embolism, and arrhythmias. Diagnosis mainly relies on assessing heart structure using imaging tools like echocardiography and cardiac magnetic resonance. However, the absence of a universally agreed-upon standard and limitations in diagnostic criteria have led to ongoing debates in the scientific community regarding the most reliable methods. Further research is crucial to enhance the diagnosis of LVNC, particularly in early life stages.

A Rare Case of an Infant With 1p36 Deletion Syndrome Presenting With Systolic Heart Failure Secondary to Severe Dilated Cardiomyopathy

1p36 deletion syndrome is a common terminal chromosomal deletion syndrome in humans. It is caused by the deletion of genetic material from a specific region in the short arm of chromosome 1. Symptoms range from seizure disorders, abnormalities of tone, visual and auditory disturbances. Cardiac abnormalities like left ventricular non-compaction (LVNC) and dilated cardiomyopathies (DCM) are commonly associated with this syndrome. This case report presents a 15-month-old female with dilated cardiomyopathy associated with 1p36 deletion syndrome, who has been followed from birth. Cardiac function was normal at birth with an ejection fraction of 65%. At three weeks of age, the patient presented with severe tachypnea, cyanosis, poor weight gain, and diaphoresis with feeding. Echocardiogram showed an ejection fraction of 22%. The patient was diagnosed with Modified Ross Heart Failure Class III. The patient was admitted to the cardiovascular intensive care unit where diuretics, phosphodiesterase inhibitors, and ionotropic agents were used to manage the heart failure. The patient relapsed two months later following a severe adenovirus infection. She was readmitted and heart failure medications were optimized. This patient has maintained a steady growth, meeting most milestones with no further relapse. The heterogeneity of 1p36 deletion syndrome presentation poses a diagnostic challenge for most clinicians. Cardiac involvements are very common and infants presenting with signs and symptoms of heart failure need to be screened for chromosomal abnormalities when other causes have been ruled out.

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.

Spectrum and Outcome of Prenatally Diagnosed Fetal Primary Cardiomyopathies-A Twenty-Year Overview

OBJECTIVE

to assess the course and outcome of fetuses affected by primary cardiomyopathy (CM).

METHODS

Retrospective study of 21 cases with prenatal diagnosis of a primary CM in one tertiary center over a period of 20 years. Charts were reviewed for echocardiographic findings, pregnancy outcome, and postnatal course. The utility of prenatal evaluation was discussed.

RESULTS

The mean gestational age (GA) at diagnosis was 26.7 (±5.1) weeks. A total of 33.3% (7/21) had associated anomalies. Genetic etiology was confirmed in 50.0% (10/20, with one case lost to follow up). The overall survival rate of the entire study population was 40% (8/20) including termination of pregnancy in 20% (4/20) and an intrauterine mortality rate of 5% (1/20). Of the initial survivors (n = 15), a neonatal and early infant mortality rate of 46.7% (7/15) was calculated. Prenatal isolated right ventricular involvement was the only identified significant parameter for survival (p = 0.035). Four phenotypical groups were identified: 42.9% (9/21) hypertrophic (HCM), 38.1% (8/21) dilated (DCM), 14.3% (3/21) isolated noncompaction (NCCM), and 4.8% (1/21) restrictive CM (RCM). Fetuses assigned to isolated NCCM revealed a 100% survival rate.

CONCLUSION

Prenatal detection is feasible but needs to a introduce classification method for better consulting and management practices. A poor outcome is still observed in many cases, but an increase in examiners' awareness may influence optimal multispecialized care.

Advances in symptomatic therapy for left ventricular non-compaction in children

Left ventricular non-compaction is a complex cardiomyopathy and the third largest childhood cardiomyopathy, for which limited knowledge is available. Both pathogenesis and prognosis are still under investigation. Currently, no effective treatment strategy exists to reduce its incidence or severity, and symptomatic treatment is the only clinical treatment strategy. Treatment strategies are constantly explored in clinical practice, and some progress has been made in coping with the corresponding symptoms because the prognosis of children with left ventricular non-compaction is usually poor if there are complications. In this review, we summarized and discussed the coping methods for different left ventricular non-compaction symptoms.

NON-COMPACTION CARDIOMYOPATHY: ISSUES, CONTRADICTIONS AND SEARCH FOR EFFECTIVE DIAGNOSTIC CRITERIA. LITERATURE REVIEW. PART 2

Active research of non-compaction cardiomyopathy (NCM) has been going on for more than 30 years. A significant amount of information has been accumulated that is familiar to a much larger number of specialists than in the most recent past. Despite this, numerous issues remain unresolved, ranging from classification (congenital or acquired, nosology or morphological phenotype) to the ongoing search for clear diagnostic criteria that separate NCM from physiological hypertrabecularity and secondary non-compaction myocardium with the background of existing chronic processes. Meanwhile, a high risk of adverse cardiovascular events in a certain group of people with NCM is quite high. These patients need timely and often quite aggressive therapy. This review of sources of scientific and practical information is devoted to the current aspects of the classification, extremely diverse clinical picture, extremely complex genetic and instrumental diagnosis of NCM, and the possibilities of its treatment. The purpose of this review is to analyze current ideas about the controversial problems of non-compaction cardiomyopathy. The material for its preparation is the numerous sources of databases Web Science, PubMed, Google Scholar, eLIBRARY. As a result of their analysis, the authors tried to identify and summarize the main problems of the NCM and identify the ways to resolve them.

Clinical profile and outcome of cardiomyopathies in infants and children seen at a tertiary centre

INTRODUCTION

Due to their rare prevalence and marked heterogeneity, pediatric cardiomyopathies (CMPs) are little known and scarcely reported. We report the etiology, clinical profile and outcome of a consecutive cohort of children diagnosed with CMP and followed at Meyer Children's Hospital over a decade.

PATIENTS AND METHODS

We retrospectively reviewed patients consecutively referred from May 2008 to May 2019 for pediatric onset CMP (<18 years). Heart disease caused by arrhythmic disorders, toxic agents, rheumatic conditions and maternal disease were excluded.

RESULTS

We enrolled 110 patients (65 males), diagnosed at a median age of 27 [4-134] months; 35% had an infant onset (<1 year of age). A positive family history was more often associated with childhood-onset (38.8%). Hypertrophic cardiomyopathy (HCM; 48 patients) was the most frequent phenotype, followed by dilated cardiomyopathy (DCM; 35 patients). While metabolic and idiopathic etiologies were preponderant in infants, metabolic and sarcomeric diseases were most frequent in the childhood-onset group. Major adverse cardiac events (MACE) occurred in 31.8% of patients, including hospitalization for acute heart failure in 25.5% of patients, most commonly due to DCM. Overall, the most severe outcomes were documented in patients with metabolic diseases.

CONCLUSIONS

In a consecutive cohort of pediatric patients with CMP, those with infantile onset and with a metabolic etiology had the worst prognosis. Overall, MACE occurred in 41% of the entire population, most commonly associated with DCM, inborn errors of metabolism and genetic syndromes. Systematic NGS genetic testing was critical for etiological diagnosis and management.

Case report: Myocardial noncompaction causing massive cerebral infarction in 1 patient with eyelid edema as an early manifestation and literature review

Objective

To summarize and analyze the early clinical manifestations, risk factors, treatment and prognosis of myocardial noncompaction in children, and to provide scientific basis for early and effective intervention.

Methods

Combined with a case of myocardial noncompaction with massive cerebral infarction in a child, the related research reports of myocardial noncompaction in children were analyzed retrospectively.

Results

Myocardial noncompaction in children is cardiomyopathy caused by abnormal myocardial compaction during embryonic development. Feeding intolerance, dyspnea, chest tightness, fatigue, eyelid edema and other non-specific manifestations may occur in the early stage. It is easy to miss the diagnosis and misdiagnosis in clinical diagnosis and treatment, leading to intractable heart failure, nausea and arrhythmia, thromboembolism and even sudden death and other serious complications. Early diagnosis, symptomatic treatment, control of complications and regular follow-up can prevent the occurrence of serious complications and reduce mortality.

Conclusion

There is no specific clinical manifestation in the early stage of myocardial noncompaction in children. If it is not detected early and treated symptomatically, the prognosis is poor and the mortality is high. Therefore, clinicians should fully improve the understanding of the early clinical manifestations of this disease, give early diagnosis and early intervention to children, reduce the occurrence of serious complications and improve the survival rate.

Left ventricular non-compaction in paediatrics: a novel semi-automated imaging technique bridging imaging findings and clinical outcomes

Aims

We set out to design a reliable, semi-automated, and quantitative imaging tool using cardiac magnetic resonance (CMR) imaging that captures LV trabeculations in relation to the morphologic endocardial and epicardial surface, or perimeter-derived ratios, and assess its diagnostic and prognostic utility.

Methods and results

We queried our institutional database between January 2008 and December 2018. Non-compacted (NC)-to-compacted (C) (NC/C) myocardium ratios were calculated and our tool was used to calculate fractal dimension (FD), total mass ratio (TMR), and composite surface ratios (SRcomp). NC/C, FD, TMR, and SRcomp were assessed in relation to LVNC diagnosis and outcomes. Univariate hazard ratios with cut-offs were performed using clinically significant variables to find ‘at-risk’ patients and imaging parameters were compared in ‘at-risk’ patients missed by Petersen Index (PI). Ninety-six patients were included. The average time to complete the semi-automated measurements was 3.90 min (SEM: 0.06). TMR, SRcomp, and NC/C were negatively correlated with LV ejection fraction (LVEF) and positively correlated with indexed LV end-systolic volumes (iLVESVs), with TMR showing the strongest correlation with LVEF (−0.287; P = 0.005) and SRcomp with iLVESV (0.260; P = 0.011). We found 29 ‘at-risk’ patients who were classified as non-LVNC by PI and hence, were missed. When compared with non-LVNC and ‘low-risk’ patients, only SRcomp differentiated between both groups (1.91 SEM 0.03 vs. 1.80 SEM 0.03; P = 0.019).

Conclusion

This method of semi-automatic calculation of SRcomp captured changes in at-risk patients missed by standard methods, was strongly correlated with LVEF and LV systolic volumes and may better capture outcome events.

Longitudinal Observational Study of Cardiac Outcome Risk Factor Prediction in Children, Adolescents, and Adults with Barth Syndrome

Barth Syndrome (BTHS) is an X-linked mitochondrial cardioskeletal myopathy caused by defects in TAFAZZIN, a gene responsible for cardiolipin remodeling. Altered mitochondrial levels of cardiolipin lead to cardiomyopathy (CM), muscle weakness, exercise intolerance, and mortality. Cardiac risk factors predicting outcome are unknown. Therefore, we conducted a longitudinal observational study to determine risk factors for outcome in BTHS. Subjects with minimum two evaluations (or one followed by death or transplant) were included. Cardiac size, function, and QTc data were measured by echocardiography and electrocardiography at 7 time points from 2002 to 2018. Analysis included baseline, continuous, and categorical variables. Categorical risk factors included prolonged QTc, abnormal right ventricle fractional area change (RV FAC), left ventricle (LV) or RV non-compaction, and restrictive CM phenotype. The association between variables and cardiac death or transplant (CD/TX) was assessed. Median enrollment age was 7 years (range 0.5-22; n = 44). Transplant-free survival (TFS) was 74.4% at 15 years from first evaluation. The cohort demonstrated longitudinal declines in LV size and stroke volume z-scores (end-diastolic volume, p = 0.0002; stroke volume p < 0.0001), worsening RV FAC (p = 0.0405), and global longitudinal strain (GLS) (p = 0.0001) with stable ejection (EF) and shortening (FS) fraction. CD/TX subjects (n = 9) displayed worsening LV dilation (p = 0.0066), EF (p ≤ 0.0001), FS (p = 0.0028), and RV FAC (p = .0032) versus stability in TFS. Having ≥ 2 categorical risk factors predicted CD/TX (p = 0.0073). Over 15 years, 25% of BTHS subjects progressed to CD/TX. Those with progressive LV enlargement, dysfunction, and multiple cardiac risk factors warrant increased surveillance and intense therapy.

Different Phenotypes of Sarcomeric MyBPC3-Cardiomyopathy in the Same Family: Hypertrophic, Left Ventricular Noncompaction and Restrictive Phenotypes (in Association with Sarcoidosis)

The same variants in sarcomeric genes can lead to different cardiomyopathies within the same family. This gave rise to the concept of a continuum of sarcomeric cardiomyopathies. However, the manifestations and evolution of these cardiomyopathies in pathogenic variant carriers, including members of the same family, remains poorly understood. We present a case of familial sarcomeric cardiomyopathy caused by heterozygous truncating pathogenic variant p.Q1233* in cardiac myosin-binding protein C (MyBPC3) gene. The proband was first diagnosed with restrictive cardiomyopathy combined with left ventricular noncompaction (LVNC) and sarcoidosis at the age of 64. The predominantly restrictive phenotype of cardiomyopathy is considered to be a result of interaction between LVNC and sarcoid myocarditis. His 39-year-old son and 35-year-old daughter have identical non-obstructive asymmetric hypertrophic cardiomyopathy. The risk of sudden cardiac death in the son is high due to myocardial fibrosis, ischemia and nonsustained VT. We assume that both phenotypes in the family may have originally been different or there may have been a gradual transformation of the hypertrophic phenotype into LVNC. Myocarditis is regarded as an important epigenomic modifier of sarcomeric cardiomyopathy. In the proband and his son, cardioverter-defibrillators were implanted, and the proband experienced appropriate shocks due to ventricular tachycardia/fibrillation. The proband was also treated with corticosteroids. His death at the age of 69 years occurred due to acute gastric hemorrhage accompanied by progressive heart failure. This report confirms the concept of the phenotypic continuum of sarcomeric cardiomyopathies and describes possible phenotypic patterns and their transformation over time.

Genetic Profile of Left Ventricular Noncompaction Cardiomyopathy in Children-A Single Reference Center Experience

Background: Left ventricular noncompaction cardiomyopathy (LVNC) is a rare cardiac disorder characterised by the presence of a two-layer myocardium with prominent ventricular trabeculation, intertrabecular deep depressions and an increased risk of heart failure, atrial and ventricular arrhythmias and systemic thromboembolic events in affected patients. The heterogeneous molecular aetiology solved in 10%–50% of patients more frequently involves sarcomeric, cytoskeletal or ion channel protein dysfunction—mainly related to causative MYH7, TTN or MYBPC3 variants. The aim of the study was to determine the molecular spectrum of isolated LVNC in a group of children examined in a single paediatric reference centre. Methods: Thirty-one paediatric patients prospectively diagnosed with LVNC by echocardiography and cardiovascular magnetic resonance examination were recruited into the study group. The molecular analysis included next-generation sequencing (gene panel or whole exome) and classic Sanger sequencing. All selected variants with high priority were co-segregated in the available parents. Results: We identified 16 distinct variants in 11 genes in 16 patients (52%), including 10 novel alterations. The most frequent defects in our cohort were found in the genes HCN4 (n = 4), MYH7 (n = 2) and PRDM16 (n = 2). Other likely disease-causing variants were detected in ACTC1, ACTN2, HCCS, LAMA4, MYH6, RBM20, TAFFAZIN and TTN. Patients with established molecular defects more often presented with arrhythmia, thromboembolic events and death, whereas the predominant symptoms in patients with no identified molecular defects were heart failure and the presence of late gadolinium enhancement. Conclusion: This study expands the genetic and clinical spectrum of childhood LVNC. Although the molecular aetiology of LVNC varies widely, the comprehensive testing of a wide panel of cardiomyopathy-related genes helped to identify underlying molecular defects in more than half of the children in the study group. The molecular spectrum in our cohort correlated with the occurrence of arrhythmia, death and a family history of cardiomyopathy. We confirmed that genetic testing is an integral part of the work-up and management LVNC in children.

Pediatric and adult dilated cardiomyopathy are distinguished by distinct biomarker profiles

BACKGROUND

Emerging evidence suggests that pediatric and adult dilated cardiomyopathy (DCM) represent distinct diseases. Few diagnostic tools exist for pediatric cardiologists to assess clinical status and prognosis. We hypothesized that pediatric DCM would have a unique biomarker profile compared to adult DCM and controls.

METHODS

We utilized a DNA aptamer array (SOMAScan) to compare biomarker profiles between pediatric and adult DCM. We simultaneously measured 1310 plasma proteins and peptides from 39 healthy children (mean age 3 years, interquartile range (IQR) 1-14), 39 ambulatory subjects with pediatric DCM (mean age 2.7 years, IQR 1-13), and 40 ambulatory adults with DCM (mean age 53 years, IQR 46-63).

RESULTS

Pediatric and adult DCM patients displayed distinct biomarker profiles, despite similar clinical characteristics. We identified 20 plasma peptides and proteins that were increased in pediatric DCM compared to age- and sex-matched controls. Unbiased multidimensionality reduction analysis suggested previously unrecognized heterogeneity among pediatric DCM subjects. Biomarker profile analysis identified four subgroups of pediatric DCM with distinguishing clinical characteristics.

CONCLUSIONS

These findings support the emerging concept that pediatric and adult DCM are distinct disease entities, signify the need to develop pediatric-specific biomarkers for disease prognostication, and challenge the paradigm that pediatric DCM should be viewed as a single disease.

IMPACT

Pediatric and adult DCM patients displayed distinct biomarker profiles, despite similar clinical characteristics and outcomes. Our findings suggest that pediatric DCM may be a heterogeneous disease with various sub-phenotypes, including differing biomarker profiles and clinical findings. These data provide prerequisite information for future prospective studies that validate the identified pediatric DCM biomarkers, address their diagnostic accuracy and prognostic significance, and explore the full extent of heterogeneity amongst pediatric DCM patients.

Left Ventricular Noncompaction in Children: The Role of Genetics, Morphology, and Function for Outcome

Left ventricular noncompaction (LVNC) is a ventricular wall anomaly morphologically characterized by numerous, excessively prominent trabeculations and deep intertrabecular recesses. Accumulating data now suggest that LVNC is a distinct phenotype but must not constitute a pathological phenotype. Some individuals fulfill the morphologic criteria of LVNC and are without clinical manifestations. Most importantly, morphologic criteria for LVNC are insufficient to diagnose patients with an associated cardiomyopathy (CMP). Genetic testing has become relevant to establish a diagnosis associated with CMP, congenital heart disease, neuromuscular disease, inborn error of metabolism, or syndromic disorder. Genetic factors play a more decisive role in children than in adults and severe courses of LVNC tend to occur in childhood. We reviewed the current literature and highlight the difficulties in establishing the correct diagnosis for children with LVNC. Novel insights show that the interplay of genetics, morphology, and function determine the outcome in pediatric LVNC.

Modeling Nonischemic Genetic Cardiomyopathies Using Induced Pluripotent Stem Cells

Purpose of Review

The advent of induced pluripotent stem cells (iPSC) has paved the way for new in vitro models of human cardiomyopathy. Herein, we will review existing models of disease as well as strengths and limitations of the system.

Recent Findings

Preclinical studies have now demonstrated that iPSCs generated from patients with both acquired or heritable genetic diseases retain properties of the disease in vitro and can be used as a model to study novel therapeutics. iPSCs can be differentiated in vitro into the cardiomyocyte lineage into cells resembling adult ventricular myocytes that retain properties of cardiovascular disease from their respective donor. iPSC pluripotency allows for them to be frozen, stored, and continually used to generate iPSC-derived myocytes for future experiments without need for invasive procedures or repeat myocyte isolations to obtain animal or human cardiac tissues.

Summary

While not without their limitations, iPSC models offer new ways for studying patient-specific cardiomyopathies. iPSCs offer a high-throughput avenue for drug development, modeling of disease pathophysiology in vitro, and enabling experimental repair strategies without need for invasive procedures to obtain cardiac tissues.

Dilated-Left Ventricular Non-Compaction Cardiomyopathy in a Pediatric Case with SPEG Compound Heterozygous Variants

Left Ventricular Non-Compaction (LVNC) is defined by the triad prominent myocardial trabecular meshwork, thin compacted layer, and deep intertrabecular recesses. LVNC associated with dilation is characterized by the coexistence of left ventricular dilation and systolic dysfunction. Pediatric cases with dilated-LVNC have worse outcomes than those with isolated dilated cardiomyopathy and adult patients. Herein, we report a clinical and genetic investigation using trio-based whole-exome sequencing of a pediatric case with early-onset dilated-LVNC. Compound heterozygous mutations were identified in the Striated Muscle Enriched Protein Kinase (SPEG) gene, a key regulator of cardiac calcium homeostasis. A paternally inherited mutation: SPEG; p.(Arg2470Ser) and the second variant, SPEG; p.(Pro2687Thr), is common and occurred de novo. Subsequently, Sanger sequencing was performed for the family in order to segregate the variants. Thus, the index case, his father, and both sisters carried the SPEG: p.(Arg2470Ser) variant. Only the index patient carried both SPEG variants. Both sisters, as well as the patient’s father, showed LVNC without cardiac dysfunction. The unaffected mother did not harbor any of the variants. The in silico analysis of the identified variants (rare and common) showed a decrease in protein stability with alterations of the physical properties as well as high conservation scores for the mutated residues. Interestingly, using the Project HOPE tool, the SPEG; p.(Pro2687Thr) variant is predicted to disturb the second fibronectin type III domain of the protein and may abolish its function. To our knowledge, the present case is the first description of compound heterozygous SPEG mutations involving a de novo variant and causing dilated-LVNC without neuropathy or centronuclear myopathy.

RBPMS is an RNA-binding protein that mediates cardiomyocyte binucleation and cardiovascular development

Noncompaction cardiomyopathy is a common congenital cardiac disorder associated with abnormal ventricular cardiomyocyte trabeculation and impaired pump function. The genetic basis and underlying mechanisms of this disorder remain elusive. We show that the genetic deletion of RNA-binding protein with multiple splicing (Rbpms), an uncharacterized RNA-binding factor, causes perinatal lethality in mice due to congenital cardiovascular defects. The loss of Rbpms causes premature onset of cardiomyocyte binucleation and cell cycle arrest during development. Human iPSC-derived cardiomyocytes with RBPMS gene deletion have a similar blockade to cytokinesis. Sequencing analysis revealed that RBPMS plays a role in RNA splicing and influences RNAs involved in cytoskeletal signaling pathways. We found that RBPMS mediates the isoform switching of the heart-enriched LIM domain protein Pdlim5. The loss of Rbpms leads to an abnormal accumulation of Pdlim5-short isoforms, disrupting cardiomyocyte cytokinesis. Our findings connect premature cardiomyocyte binucleation to noncompaction cardiomyopathy and highlight the role of RBPMS in this process.

A Comprehensive Assessment of Cardiomyopathies through Cardiovascular Magnetic Resonance: Focus on the Pediatric Population

Cardiomyopathies (CMPs) are a heterogeneous group of diseases that involve the myocardium and result in systolic or diastolic impairment of the cardiac muscle, potentially leading to heart failure, malignant arrhythmias, or sudden cardiac death. Occurrence in pediatric age is rare but has been associated with worse outcomes. Non-invasive cardiac imaging techniques, integrated with clinical, genetic, and electrocardiographic data, have shown a pivotal role in the clinical work-up of such diseases by defining structural alterations and assessing potential complications. Above all modalities, cardiovascular magnetic resonance (CMR) has emerged as a powerful tool complementary to echocardiography to confirm diagnosis, provide prognostic information and guide therapeutic strategies secondary to its high spatial and temporal resolution, lack of ionizing radiation, and good reproducibility. Moreover, CMR can provide in vivo tissue characterization of the myocardial tissue aiding the identification of structural pathologic changes such as replacement or diffuse fibrosis, which are predictors of worse outcomes. Large prospective randomized studies are needed for further validation of CMR in the context of childhood CMPs. This review aims to highlight the role of advanced imaging with CMR in CMPs with particular reference to the dilated, hypertrophic and non-compacted phenotypes, which are more commonly seen in children.

Noncompact Myocardium with Dilated Phenotype: Manifestations, Treatment and Outcomes in Comparison with Other Forms of Dilated Cardiomyopathy Syndrome

Aim. To study the place of NCM in the structure of DCM, its clinical features and influence on prognosis in comparison with other forms of DCM syndrome.

Methods. The NCM registry includes 125 patients, mean age 46.4±15.1 years, 74 men and 51 women, median follow-up 14 [4.0; 41.0] months. The DCM registry included 365 patients, mean age 46.4±15.1 years, 253 men and 112 women, median follow-up 14 [5; 43.75] months. The examination included electrocardiography (ECG), ECG Holter monitoring, echocardiography, blood anti-heart antibody level evaluation, and additionally cardiac computed tomography, magnetic resonance imaging, DNA diagnostics (in the MYH7, MYBPC3, TPM1, TNNI3, TNNT2, ACTC1, TAZ, ZASP (LDB3), MYL2, MYL3, DES, LMNA, EMD, TTR gene panel), coronary angiography, right ventricular endomyocardial biopsy.

Results. The proportion of patients with DCM phenotype in the NCM registry was 40% (n=49), another 11% (n=15) had NCM diagnosed simultaneously with acute/subacute myocarditis. Lethality in these subgroups was 12.2% and 33.3%, respectively, and was significantly higher than in asymptomatic, ischemic and arrhythmic variants of NCM. In the DCM registry, the proportion of patients with NСM was 21% (n=78), and increased left ventricular (LV) trabecularity was detected in another 18% (n=64). DCM patients with and without NСM did not differ by baseline echocardiographic parameters, heart failure class, and cardiotropic therapy. Pathogenic mutations were detected in 14% of DCM patients with NCM and only 3% of other patients with DCM (p<0.001). Only in patients without NCM the presence of mutations had a significant effect on lethality. The patients with NCM compared with the others DCM patients showed significantly lower increase in EF in early and late period (from 31.0±10.2 to 34.8±11.0 and 37.1±10.9% [р<0.05] vs from 31.8±9.7 to 38.8±11.3 and 42.3±12.4% [р<0.01] respectively), a greater incidence of premature ventricular   beats (1568 [105;7000] vs 543.5 [77.75; 3194], p<0.05), appropriate defibrillator shocks and sudden deaths (17.9 vs 5.9%, p<0.001), intracardiac thrombosis (21.8 vs 13.5%, p=0.069) despite a greater frequency of anticoagulants (73.1 vs 57.4%, p<0<05). There were no significant differences in death (19.2 vs 18.5%) and transplantation (7.7 vs 3.8%) between patients with and without NCM. There were no cases of NCM regression.

Conclusion. NCM is an independent form of DCM syndrome, which is characterized by higher frequency of pathogenic mutations, arrhythmic events, worse response to cardiotropic therapy, higher frequency of intracardiac thrombosis. The absence of mortality differences can be explained by the higher frequency of preventive interventions in this category of patients with DCM (prescription of anticoagulants, defibrillator implantation, heart transplantation).

Continuous Arrhythmia Monitoring in Pediatric and Adult Patients With Left Ventricular Noncompaction

Patients with left ventricular noncompaction (LVNC) are at risk of clinically significant arrhythmias and sudden death. We evaluated whether implantable loop recorders could detect significant arrhythmias that might be missed in these patients during annual Holter monitoring. Selected pediatric and adult patients with LVNC who consented to implantable loop recorder placement were monitored for 3 years (study duration, 10 April 2014-9 December 2019). Fourteen subjects were included (age range, 6.5-36.4 yr; 8 males). Of 13 patients who remained after one device extrusion, one underwent implantable cardioverter-defibrillator placement. Four patients (31%) had significant arrhythmias: atrial tachycardia (n=2), nonsustained ventricular tachycardia (n=1), and atrial fibrillation (n=1). All 4 events were clinically asymptomatic and not associated with left ventricular ejection fraction. In addition, a high frequency of benign arrhythmic patterns was detected. Implantable loop recorders enable continuous, long-term detection of important subclinical arrhythmias in selected patients who have LVNC. These devices may prove to be most valuable in patients who have LVNC and moderate or greater ventricular dysfunction.

Left Ventricular Noncompaction Is Associated with Valvular Regurgitation and a Variety of Arrhythmias

Left ventricular noncompaction (LVNC) is a type of cardiomyopathy characterized anatomically by prominent ventricular trabeculation and deep intertrabecular recesses. The mortality associated with LVNC ranges from 5% to 47%. The etiology of LVNC is yet to be fully understood, although decades have passed since its recognition as a clinical entity globally. Furthermore, critical questions, i.e., whether LVNC represents an acquired pathology or has a congenital origin and whether the reduced contractile function in LVNC patients is a cause or consequence of noncompaction, remain to be addressed. In this study, to answer some of these questions, we analyzed the clinical features of LVNC patients. Out of 9582 subjects screened for abnormal cardiac functions, 45 exhibit the characteristics of LVNC, and 1 presents right ventricular noncompaction (RVNC). We found that 40 patients show valvular regurgitation, 39 manifest reduced systolic contractions, and 46 out of the 46 present different forms of arrhythmias that are not restricted to be caused by the noncompact myocardium. This retrospective examination of LVNC patients reveals some novel findings: LVNC is associated with regurgitation in most patients and arrhythmias in all patients. The thickness ratio of the trabecular layer to compact layer negatively correlates with fractional shortening, and reduced contractility might result from LVNC. This study adds evidence to support a congenital origin of LVNC that might benefit the diagnosis and subsequent characterization of LVNC patients.

Left Ventricular Non-Compaction Cardiomyopathy - Left ventricular dilation and dysfunction at baseline portend the risk of death or heart transplantation

BACKGROUND

Left ventricular non-compaction (LVNC) is associated with genetic and phenotypic variability that influences outcomes. We aimed to identify risk factors for death or heart transplant (HTX) in a paediatric LVNC cohort.

METHODS

We reviewed patients < 18 years of age (2001 - 2018) with LVNC, either isolated (I-LVNC) or with dilated phenotype (D-LVNC) and at least mildly reduced ejection fraction (EF). Patients with dilated cardiomyopathy (DCM) were included as controls. Descriptive statistics, multivariate analysis, and time-to-event analysis were used.

RESULTS

We included 188 patients, 34 (18%) with I-LVNC, 37 (20%) with D-LVNC, and 117 (62%) with DCM. Overall median age at diagnosis = 1.08 years (IQR = 0.22 - 10.65) and median follow-up = 1.4 (IQR = 0.2 - 5.2) years. I-LVNC patients' median baseline LV ejection fraction (LVEF) was 47%, compared with D-LVNC 33%, and DCM 21% (p<0.0001). 62% of I-LVNC patients developed moderate to severe LV dysfunction during follow-up. The incidence of death or transplantation was 43.6% in the overall cohort. Freedom from death or transplantation at 10 years after diagnosis was 88.6% (95% CI, 76-100) for I-LVNC, 47% (95% CI, 29-65) for D-LVNC and 42.3% (95% CI, 33-52) for DCM. On multivariable analysis, baseline LVEF and LVEDD z-score were associated with death or transplantation. Patients with a baseline LVEDD z-score > 4 and moderate to severe LV dysfunction had a transplant free survival of 38%.

CONCLUSIONS

Baseline LV dilation and systolic dysfunction were independently associated with progression to death or HTX in LVNC patients.

Cardiomyopathies in Children and Systemic Disorders When Is It Useful to Look beyond the Heart?

Cardiomyopathy (CMP) is a rare disease in the pediatric population, with a high risk of morbidity and mortality. The genetic etiology of CMPs in children is extremely heterogenous. These two factors play a major role in the difficulties of establishing standard diagnostic and therapeutic protocols. Isolated CMP in children is a frequent finding, mainly caused by sarcomeric gene variants with a detection rate that can reach up to 50% of analyzed cohorts. Complex multisystemic forms of pediatric CMP are even more heterogenous. Few studies in literature take into consideration this topic as the main core since it represents a rarity (systemic CMP) within a rarity (pediatric population CMP). Identifying etiology in this cohort is essential for understanding prognosis, risk stratification, eligibility to heart transplantation and/or mechanical-assisted procedures, preventing multiorgan complications, and relatives' recurrence risk calculation. The previous points represent a cornerstone in patients' empowerment and personalized medical care approach. The aim of this work is to propose a new approach for an algorithm in the setting of the diagnostic framework of systemic pediatric CMP. On the other hand, during the literature review, we noticed a relatively common etiologic pattern in some forms of complex/multisystem CMP. In other words, certain syndromes such as Danon, Vici, Alström, Barth, and Myhre syndrome share a common pathway of directly or indirectly defective "autophagy" process, which appears to be a possible initiating/triggering factor for CMPs. This conjoint aspect could be important for possible prognostic/therapeutic implications in this category of patients. However, multicentric studies detailed functional and experimental models are needed prior to deriving conclusions.

Current and future treatment approaches for Barth syndrome

Barth Syndrome is an X-linked disorder of mitochondrial cardiolipin metabolism caused by pathogenic variants in TAFAZZIN with pleiotropic effects including cardiomyopathy, neutropenia, growth delay, and skeletal myopathy. Management requires a multidisciplinary approach to the organ-specific manifestations including specialists from cardiology, hematology, nutrition, physical therapy, genetics, and metabolism. Currently, treatment is centered on management of specific clinical features, and is not targeted toward remediating the underlying biochemical defect. However, two clinical trials have been recently undertaken which target the mitochondrial pathology of this disease: a study to examine the effects of elamipretide, a cardiolipin targeted agent, and a study to examine the effects of bezafibrate, a peroxisome proliferator-activated receptor (PPAR) agonist. Treatments to directly target the defective TAFAZZIN pathway are under development, including enzyme and gene therapies.

The clinical utility of pediatric cardiomyopathy genetic testing: From diagnosis to a precision medicine-based approach to care

Background

Pediatric-onset cardiomyopathies are rare yet cause significant morbidity and mortality in affected children. Genetic testing has a major role in the clinical evaluation of pediatric-onset cardiomyopathies, and identification of a variant in an associated gene can be used to confirm the clinical diagnosis and exclude syndromic causes that may warrant different treatment strategies. Further, risk-predictive testing of first-degree relatives can assess who is at-risk of disease and requires continued clinical follow-up.

Aim of Review

In this review, we seek to describe the current role of genetic testing in the clinical diagnosis and management of patients and families with the five major cardiomyopathies. Further, we highlight the ongoing development of precision-based approaches to diagnosis, prognosis, and treatment.

Key Scientific Concepts of Review

Emerging application of genotype-phenotype correlations opens the door for genetics to guide a precision medicine-based approach to prognosis and potentially for therapies. Despite advances in our understanding of the genetic etiology of cardiomyopathy and increased accessibility of clinical genetic testing, not all pediatric cardiomyopathy patients have a clear genetic explanation for their disease. Expanded genomic studies are needed to understand the cause of disease in these patients, improve variant classification and genotype-driven prognostic predictions, and ultimately develop truly disease preventing treatment.

2021 PACES Expert Consensus Statement on the Indications and Management of Cardiovascular Implantable Electronic Devices in Pediatric Patients: Developed in collaboration with and endorsed by the Heart Rhythm Society (HRS), the American College of Cardiology (ACC), the American Heart Association (AHA), and the Association for European Paediatric and Congenital Cardiology (AEPC) Endorsed by the Asia Pacific Heart Rhythm Society (APHRS), the Indian Heart Rhythm Society (IHRS), and the Latin American Heart Rhythm Society (LAHRS)

In view of the increasing complexity of both cardiovascular implantable electronic devices (CIEDs) and patients in the current era, practice guidelines, by necessity, have become increasingly specific. This document is an expert consensus statement that has been developed to update and further delineate indications and management of CIEDs in pediatric patients, defined as ≤21 years of age, and is intended to focus primarily on the indications for CIEDs in the setting of specific disease categories. The document also highlights variations between previously published adult and pediatric CIED recommendations and provides rationale for underlying important differences. The document addresses some of the deterrents to CIED access in low- and middle-income countries and strategies to circumvent them. The document sections were divided up and drafted by the writing committee members according to their expertise. The recommendations represent the consensus opinion of the entire writing committee, graded by class of recommendation and level of evidence. Several questions addressed in this document either do not lend themselves to clinical trials or are rare disease entities, and in these instances recommendations are based on consensus expert opinion. Furthermore, specific recommendations, even when supported by substantial data, do not replace the need for clinical judgment and patient-specific decision-making. The recommendations were opened for public comment to Pediatric and Congenital Electrophysiology Society (PACES) members and underwent external review by the scientific and clinical document committee of the Heart Rhythm Society (HRS), the science advisory and coordinating committee of the American Heart Association (AHA), the American College of Cardiology (ACC), and the Association for European Paediatric and Congenital Cardiology (AEPC). The document received endorsement by all the collaborators and the Asia Pacific Heart Rhythm Society (APHRS), the Indian Heart Rhythm Society (IHRS), and the Latin American Heart Rhythm Society (LAHRS). This document is expected to provide support for clinicians and patients to allow for appropriate CIED use, appropriate CIED management, and appropriate CIED follow-up in pediatric patients.

2021 PACES expert consensus statement on the indications and management of cardiovascular implantable electronic devices in pediatric patients

In view of the increasing complexity of both cardiovascular implantable electronic devices (CIEDs) and patients in the current era, practice guidelines, by necessity, have become increasingly specific. This document is an expert consensus statement that has been developed to update and further delineate indications and management of CIEDs in pediatric patients, defined as ≤21 years of age, and is intended to focus primarily on the indications for CIEDs in the setting of specific disease categories. The document also highlights variations between previously published adult and pediatric CIED recommendations and provides rationale for underlying important differences. The document addresses some of the deterrents to CIED access in low- and middle-income countries and strategies to circumvent them. The document sections were divided up and drafted by the writing committee members according to their expertise. The recommendations represent the consensus opinion of the entire writing committee, graded by class of recommendation and level of evidence. Several questions addressed in this document either do not lend themselves to clinical trials or are rare disease entities, and in these instances recommendations are based on consensus expert opinion. Furthermore, specific recommendations, even when supported by substantial data, do not replace the need for clinical judgment and patient-specific decision-making. The recommendations were opened for public comment to Pediatric and Congenital Electrophysiology Society (PACES) members and underwent external review by the scientific and clinical document committee of the Heart Rhythm Society (HRS), the science advisory and coordinating committee of the American Heart Association (AHA), the American College of Cardiology (ACC), and the Association for European Paediatric and Congenital Cardiology (AEPC). The document received endorsement by all the collaborators and the Asia Pacific Heart Rhythm Society (APHRS), the Indian Heart Rhythm Society (IHRS), and the Latin American Heart Rhythm Society (LAHRS). This document is expected to provide support for clinicians and patients to allow for appropriate CIED use, appropriate CIED management, and appropriate CIED follow-up in pediatric patients.

Spectrum of Clinical Features and Genetic Profile of Left Ventricular Noncompaction Cardiomyopathy in Children

Background: Left ventricular noncompaction (LVNC) is a genetically determined cardiomyopathy that occurs following a disruption of endomyocardial morphogenesis. The purpose of this study was to identify the clinical characteristics and genetic profile of children with LVNC. Methods: From February 2008 to July 2020, a total of 32 children (median 11.5 years) with LVNC were prospectively enrolled and followed up for a median of 4.02 years. Diagnosis was made based on characteristic features of LVNC in echocardiography and cardiovascular magnetic resonance (CMR). Patients’ clinical symptoms, family history, ECG, Holter ECG, and genetic tests were also evaluated. Results: The most common presenting symptom was heart failure (31% of children). ECG abnormalities were noted in 56% of patients. The most prominent features were ventricular arrhythmias, sinus bradycardia, and paroxysmal third-degree atrioventricular block. Most of the patients (94%) met the criteria for LVNC and CMR confirmed this diagnosis in 82% of cases. The molecular etiology was found in 53% of children. Conclusion: Although heart failure and arrhythmias were very frequent in our study group, thromboembolic events and genetic syndromes were rare. For the accurate and reliable assessment of children with LVNC, it is necessary to get to know their family history and detailed clinical profile.

Left Ventricular Myocardial Noncompaction with Advanced Atrioventricular Conduction Disorder and Ventricular Arrhythmias in a Young Patient: Role of MIB1 Gene

Left ventricular noncompaction (LVNC) is a structural abnormality of the left ventricle, usually described as an isolated condition, or sometimes associated with other structural cardiac diseases. LVNC is generally asymptomatic, although it may present conduction disorders, arrhythmias, and heart failure. Here, we present the case of a patient who came to our attention with a severe LVNC phenotype associated with advanced AV conduction disorder, and supraventricular and ventricular arrhythmias at young age, in which a novel MIB1, likely pathogenic, variation has been identified.

2021 PACES Expert Consensus Statement on the Indications and Management of Cardiovascular Implantable Electronic Devices in Pediatric Patients

In view of the increasing complexity of both cardiovascular implantable electronic devices (CIEDs) and patients in the current era, practice guidelines, by necessity, have become increasingly specific. This document is an expert consensus statement that has been developed to update and further delineate indications and management of CIEDs in pediatric patients, defined as ≤21 years of age, and is intended to focus primarily on the indications for CIEDs in the setting of specific disease categories. The document also highlights variations between previously published adult and pediatric CIED recommendations and provides rationale for underlying important differences. The document addresses some of the deterrents to CIED access in low- and middle-income countries and strategies to circumvent them. The document sections were divided up and drafted by the writing committee members according to their expertise. The recommendations represent the consensus opinion of the entire writing committee, graded by class of recommendation and level of evidence. Several questions addressed in this document either do not lend themselves to clinical trials or are rare disease entities, and in these instances recommendations are based on consenus expert opinion. Furthermore, specific recommendations, even when supported by substantial data, do not replace the need for clinical judgment and patient-specific decision-making. The recommendations were opened for public comment to Pediatric and Congenital Electrophysiology Society (PACES) members and underwent external review by the scientific and clinical document committee of the Heart Rhythm Society (HRS), the science advisory and coordinating committee of the American Heart Association (AHA), the American College of Cardiology, (ACC) and the Association for European Paediatric and Congenital Cardiology (AEPC). The document received endorsement by all the collaborators and the Asia Pacific Heart Rhythm Society (APHRS), the Indian Heart Rhythm Society (IHRS), and the Latin American Heart Rhythm Society (LAHRS). This document is expected to provide support for clinicians and patients to allow for appropriate CIED use, appropriate CIED management, and appropriate follow-up in pediatric patients.

2021 PACES Expert Consensus Statement on the Indications and Management of Cardiovascular Implantable Electronic Devices in Pediatric Patients

In view of the increasing complexity of both cardiovascular implantable electronic devices (CIEDs) and patients in the current era, practice guidelines, by necessity, have become increasingly specific. This document is an expert consensus statement that has been developed to update and further delineate indications and management of CIEDs in pediatric patients, defined as ≤21 years of age, and is intended to focus primarily on the indications for CIEDs in the setting of specific disease categories. The document also highlights variations between previously published adult and pediatric CIED recommendations and provides rationale for underlying important differences. The document addresses some of the deterrents to CIED access in low- and middle-income countries and strategies to circumvent them. The document sections were divided up and drafted by the writing committee members according to their expertise. The recommendations represent the consensus opinion of the entire writing committee, graded by class of recommendation and level of evidence. Several questions addressed in this document either do not lend themselves to clinical trials or are rare disease entities, and in these instances recommendations are based on consensus expert opinion. Furthermore, specific recommendations, even when supported by substantial data, do not replace the need for clinical judgment and patient-specific decision-making. The recommendations were opened for public comment to Pediatric and Congenital Electrophysiology Society (PACES) members and underwent external review by the scientific and clinical document committee of the Heart Rhythm Society (HRS), the science advisory and coordinating committee of the American Heart Association (AHA), the American College of Cardiology (ACC), and the Association for European Paediatric and Congenital Cardiology (AEPC). The document received endorsement by all the collaborators and the Asia Pacific Heart Rhythm Society (APHRS), the Indian Heart Rhythm Society (IHRS), and the Latin American Heart Rhythm Society (LAHRS). This document is expected to provide support for clinicians and patients to allow for appropriate CIED use, appropriate CIED management, and appropriate CIED follow-up in pediatric patients.

Hypertrabeculation; a phenotype with Heterogeneous etiology

Left ventricular hypertrabeculation (LVHT) is a phenotype with multiple etiologies and variable clinical presentation and significance. It is characterized by a 2-layer myocardium with an enlarged trabecular layer and a thinner compacted layer. The prevalence has been increasing due to advances in cardiac imaging. Initial attention was focused on the congenital noncompaction syndrome, and the presence of LVHT was always attributed to this etiology. However, due to the lack of consensus diagnostic criteria, LVHT has now been reported in a broad spectrum of cardiomyopathies, congenital heart diseases, monogenetic disorders, neuromuscular diseases, and even healthy individuals. LVHT is often associated with systolic dysfunction, arrhythmias, and thromboembolic events. Given the etiologic heterogeneity, the prognosis and outcomes are primarily determined by comorbidities, and treatment is dictated by known guidelines. We present hypertrabeculation (HT) as a phenotype and discuss the varied landscape in the classification, etiology, diagnosis, and management of the condition.

Left ventricular noncompaction in pediatric population: could cardiovascular magnetic resonance derived fractal analysis aid diagnosis?

BACKGROUND

Cardiovascular magnetic resonance (CMR) derived fractal analysis of the left ventricle (LV) has been shown in adults to be a useful quantitative measure of trabeculation with high reproducibility and accuracy for the diagnosis of LV non-compaction (LVNC). The aim of this study was to investigate the utility and feasibility of fractal analysis in children.

METHODS

Eighty-four subjects underwent CMR: (1) 28 patients with LVNC (as defined by the Petersen criteria with NC/C ratio [Formula: see text] 2.3); (2) 28 patients referred by clinicians for assessment of hyper-trabeculation and found not to qualify as LVNC (NC/C [Formula: see text] 1.8 and < 2.3); (3) 28 controls. The fractal scores for each group were presented as global and maximal fractal dimension as well as for 3 segments of the LV: basal, mid, and apical. Statistical comparison of the fractal scores between the 3 groups was performed.

RESULTS

Global fractal dimension (FD) was higher in the LVNC group than in the hyper-trabeculated group: 1.345 (SEM 0.053) vs 1.252 (SEM 0.034), p < 0.001 and higher in hyper-trabeculated group than in controls: 1.252 (SEM 0.034) vs 1.158 (SEM 0.038), p < 0.001. The highest maximum FD was in the apical portion of the LV in the LVNC group, (1.467; SEM 0.035) whereas it was in the mid ventricle in the hyper-trabeculated (1.327; SEM 0.025) and healthy groups (1.251; SEM 0.042). Fractal analysis showed lower intra- and interobserver variability than the Petersen and Jacquier methods.

CONCLUSIONS

It is technically feasible to perform fractal analysis in children using CMR and that it is quick, accurate and reproducible. Fractal scoring accurately distinguishes between LVNC, hyper-trabeculation and healthy controls as defined by the Petersen criteria.

Ventricular non-compaction review

Left ventricular non-compaction cardiomyopathy (LVNC) is a rare and unclassified cardiomyopathy that carries the potential to cause heart failure, arrhythmias, and embolic events within adults. The diagnosis of this cardiomyopathy can be based off a variety of echocardiographic, cardiac magnetic resonance (CMR), and computed tomography (CT) imaging criteria; none of which have been standardized to establish a firm diagnosis. This is further complicated by the observation from prior studies that LVNC may present as different forms of cardiomyopathy, each with its own subset of nuances that may change treatment strategies. Management of such cardiomyopathy has been debated in terms of anticoagulation, electrophysiologic studies to prevent arrhythmia, as well as heart failure prevention. Not enough data exists in regard to establishing firm guidelines for management. The following article aims to provide a comprehensive review in regard to the etiologies, pathogenesis, diagnostic criteria, management, and treatment of LVNC.

Noncompaction Cardiomyopathy-History and Current Knowledge for Clinical Practice

Noncompaction cardiomyopathy (NCCM) has gained increasing attention over the past twenty years, but in daily clinical practice NCCM is still rarely considered. So far, there are no generally accepted diagnostic criteria and some groups even refuse to acknowledge it as a distinct cardiomyopathy, and grade it as a variant of dilated cardiomyopathy or a morphological trait of different conditions. A wide range of morphological variants have been observed even in healthy persons, suggesting that pathologic remodeling and physiologic adaptation have to be differentiated in cases where this spongy myocardial pattern is encountered. Recent studies have uncovered numerous new pathogenetic and pathophysiologic aspects of this elusive cardiomyopathy, but a current summary and evaluation of clinical patient management are still lacking, especially to avoid mis- and overdiagnosis. Addressing this issue, this article provides an up to date overview of the current knowledge in classification, pathogenesis, pathophysiology, epidemiology, clinical manifestations and diagnostic evaluation, including genetic testing, treatment and prognosis of NCCM.

The Role of Speckle Tracking Echocardiography in the Evaluation of Common Inherited Cardiomyopathies in Children and Adolescents: A Systematic Review

Speckle tracking echocardiography (STE) has gained importance in the evaluation of adult inherited cardiomyopathies, but its utility in children is not well characterized. We conducted a systematic review to evaluate the role of STE in pediatric inherited cardiomyopathies. PubMed, EMBASE, Web of Science, Scopus, CENTRAL and CINAHL databases were searched up to May 2020, for terms related to inherited cardiomyopathies and STE. Included were dilated cardiomyopathy (DCM), hypertrophic cardiomyopathy (HCM), left ventricular non-compaction (LVNC) and arrhythmogenic cardiomyopathy (ACM). A total of 14 cohorts were identified, of which six were in DCM, four in HCM, three in LVNC and one in ACM. The most commonly reported STE measurements were left ventricular longitudinal strain (S_l), circumferential strain (S_c), radial strain (S_r) and rotation/torsion/twist. S_l, S_c and were abnormal in all DCM and LVNC cohorts, but not in all HCM. Apical rotation and twist/torsion were increased in HCM, and decreased in LVNC. Abnormal STE parameters were reported even in cohorts with normal non-STE systolic/diastolic measurements. STE in childhood cardiomyopathies can detect early changes which may not be associated with changes in cardiac function detectable by non-STE methods. Longitudinal and circumferential strain should be introduced in the cardiomyopathy echocardiography protocol, reflecting current practice in adults.

Left Ventricular Noncompaction-A Systematic Review of Risk Factors in the Pediatric Population

Left ventricular noncompaction (LVNC) is a heterogeneous, often hereditary group of diseases, which may have diverse clinical manifestations. This article reviews the risk factors for unfavorable outcomes of LVNC in children, as well as discuss the diagnostic methods and the differences between pediatric and adult LVNC. Through a systematic review of the literature, a total of 1983 articles were outlined; 23 of them met the inclusion criteria. In echocardiography the following have been associated with adverse outcomes in children: Left ventricular ejection fraction, end-diastolic dimension, left ventricular posterior wall compaction, and decreased strains. T-wave abnormalities and increased spatial peak QRS-T angle in ECG, as well as arrhythmia, were observed in children at greater risk. Cardiac magnetic resonance is a valuable tool to identify those with systolic dysfunction and late gadolinium enhancement. Genetic testing appears to help identify children at risk, because mutations in particular genes have been associated with worse outcomes. ECG and imaging tests, such as echocardiography and magnetic resonance, help outline risk factors for unfavorable outcomes of LVNC in children and in identifying outpatients who require more attention. Refining the current diagnostic criteria is crucial to avoid inadequate restrain from physical activity.