Asymmetric Myocardial Involvement as an Early Indicator of Cardiac Dysfunction in Pediatric Dystrophinopathies: A Study on Cardiac Magnetic Resonance (CMR) Parametric Mappings.

Dystrophinopathies, such as Duchenne and Becker muscular dystrophy, frequently lead to cardiomyopathy, being its primary cause of mortality. Detecting cardiac dysfunction early is crucial, but current imaging methods lack insight into microstructural remodeling. This study aims to assess the potential of cardiac magnetic resonance (CMR) parametric mappings for early detection of myocardial involvement in dystrophinopathies and explores whether distinct involvement patterns may indicate impending dysfunction. In this prospective study, 23 dystrophinopathy patients underwent CMR with tissue mappings. To establish a basis for comparison, a control group of 173 subjects was analyzed. CMR protocols included SSFP, T2-weighted and T1-weighted sequences pre and post gadolinium, and tissue mappings for native T1 (nT1), extracellular volume (ECV), and T2 relaxation times. The difference between the left ventricular posterior wall and the interventricular septum was calculated to reveal asymmetric myocardial involvement. Significant differences in LV ejection fraction (LVEF), myocardial mass, and late gadolinium enhancement confirmed abnormalities in patients. Tissue mappings: nT1 (p < 0.001) and ECV (p = 0.002), but not T2, displayed substantial variations, suggesting sensitivity to myocardial involvement. Asymmetric myocardial involvement in nT1 (p = 0.01) and ECV (p = 0.012) between septal and LV posterior wall regions was significant. While higher mapping values didn't correlate with dysfunction, asymmetric involvement in nT1 (ρ=-0.472, p = 0.023) and ECV (ρ=-0.460, p = 0.049) exhibited a significant negative correlation with LVEF. CMR mappings show promise in early myocardial damage detection in dystrophinopathies. Although mapping values may not directly correspond to dysfunction, the negative correlation between asymmetric involvement in nT1 and ECV with LVEF suggests their potential as early biomarkers. Larger, longitudinal studies are needed for a comprehensive understanding and improved risk stratification in dystrophinopathies.

New-onset heart failure in infants: when the aetiological diagnosis becomes a challenge.

This study aimed to report the findings of cardiac magnetic resonance imaging (CMR) with quantitative mappings in infants presenting with new-onset heart failure, as well as to assess the capabilities of endomyocardial biopsy (EMB) and CMR in detecting inflammatory cardiomyopathies and determining their etiology. In a prospective analysis of infants who underwent CMR with tissue mappings, EMB, and genetic testing, the sample was categorized into two groups: those with inflammatory cardiomyopathy and negative genetics (indicative of possible myocarditis) and those with positive genetics (indicative of possible dilated cardiomyopathy). All patients exhibited similar clinical presentations, echocardiographic dysfunction, and elevated troponins and NT-proBNP levels. Additionally, they all met the diagnostic criteria for inflammatory cardiomyopathy based on EMB findings (≥14 mononuclear cells, ≥7 T-lymphocytes/mm2). EMB results unveiled significant differences in the presence of inflammation and edema between the two groups, with higher troponin levels correlating with increased inflammation. Notably, when focusing on CMR, neither the classic criteria nor the 2018 Lake Louise criteria (LLC) could effectively differentiate between the two groups. Only late gadolinium enhancement (LGE) appeared to be associated with myocarditis in this cohort, while other LLC and tissue mappings did not exhibit a similar correlation. Importantly, there was no observed correlation between the inflammation detected through EMB and CMR. CONCLUSIONS: The onset of heart dysfunction in infants can result from either inherited factors or viral infections, both of which may involve inflammation. However, the precise role of EMB and CMR in determining the etiology of such cases remains poorly defined. While CMR demonstrates high sensitivity in detecting inflammation, our experience suggests that it may not effectively differentiate between these two groups. A comprehensive diagnostic approach is essential when addressing this challenge, which includes considering EMB (with attention to the number of T-lymphocytes and the presence of oedema), specific CMR criteria, notably LGE and tissue mappings, as well as the identification of viral agents in cardiac tissue and troponin levels. Additionally, genetic tests should be conducted when evaluating these patients. WHAT IS KNOWN: • EMB is the gold standard diagnostic test for myocarditis but it is not universally accepted. • The diagnostic value of the 2018-LLC in pediatric patients is still undefined. WHAT IS NEW: • Both EMB and CMR may show inflammation in infants with new-onset heart failure of any aetiology. • A global approach should be used when facing this diagnostic challenge, including the EMB (number of T-lymphocytes and oedema), some CMR criteria, specially LGE and mappings, the detection of viral agents in cardiac tissue and troponins. Genetic tests should also be performed when studying these patients.

Being exposed to the same trigger increases the risk of recurrence of takotsubo cardiomyopathy in children and can have fatal results: a case report.

Takotsubo cardiomyopathy has an incidence of 1% of acute coronary syndrome in the adult population, and the risk of recurrence is approximately 1.5% per year. However, only a few cases have been reported in children. Having a neurologic disorder and being exposed to the same trigger repeatedly have been associated with an increased risk.

Stress and coping strategies of families of pediatric solid organ transplant recipients in times of pandemic.

Objective: Pediatric solid organ transplantation (SOT) is a chronic condition that impacts the whole family system. The objective of this study is to evaluate psychopathology, family stress, and coping strategies in families of SOT recipients compared to families of healthy children and adolescents. Moreover, it analyzes if the stress related to the COVID-19 pandemic has had an additional impact on these families. Methods: The sample was recruited between May and July 2021, during the fourth and fifth wave of the pandemic in Spain. It consisted of 102 families, 51 with a pediatric recipient who had undergone a SOT (liver, kidney, heart, or lung) and 51 healthy controls, matched by child age and gender. A primary caregiver from each family answered an online sociodemographic questionnaire and different tests to evaluate family stress, depression, anxiety, coping strategies, and effects of the pandemic on the family. Results: Caregivers were mostly mothers (89.2%). Families of SOT recipients showed greater anxiety (U = 863.5, p = 0.003) and more total stress, stress related to childcare (t = -2.043; p = 0.045), and parent-child interaction stress (U = 355.5, p = 0.015). SOT families used more avoidance strategies, specifically denial (U = 889.5; p = 0.010) and abandonment of coping efforts (U = 1,013; p = 0.047), more religious strategies (U = 792.5; p = 0.031), and fewer social support coping strategies (t = 2.098; p = 0.038). No differences were found between groups in terms of exposure, impact, and distress more than 1 year after the start of the pandemic. Conclusion: SOT families showed clinical levels of anxiety, more parent-child interaction stress, more difficulties in taking care of their child, more avoidance and religious strategies, and less use of social support strategies, even 4 years after transplantation. The pandemic did not have an additional differential effect on SOT families. Caregivers of SOT patients can benefit from psychological interventions focused on parents' mental health, parent-child connectedness, skill building, and social support aid groups, with attention to multiculturalism and promoting a better balance between caregivers. There is a need for family interventions that are maintained over time. Strategies that offer this support to families through digital resources can facilitate adjustment to chronic illness, especially in pandemic times.

Short- and long-term survival of children treated with ventricular assist devices in Spain, based on 15 years' experience.

OBJECTIVES: To describe the use of ventricular assist devices (VAD) in children in Spain and to identify variables related to survival. METHODS: This is an observational cohort study of all children younger than 18 years of age who underwent an initial implantation of a VAD at any of the 6 paediatric heart transplant centres from May 2006 to December 2020. Subjects were identified retrospectively from each hospital's database. RESULTS: Paracorporeal VADs were implanted in 118 children [pulsatile (63%), continuous (30.5%) or both types (5.9%)]. Small children (<0.7 m2 of body surface area) comprised the majority of this cohort (63.3%). Overall, 67% survived to VAD explantation, and 64.9% survived to hospital discharge. Non-central nervous system haemorrhage (39%) and stroke (38.1%) were the most common complications. Body weight <5 kg, congenital heart disease, pre-implantation bilirubin >34 µmol/l and bridge to decision strategy were associated with a higher mortality at hospital discharge and in the long-term. Interagency registry for mechanically assisted circulatory support (INTERMACS) status 1 and cardiac arrest prior to VAD implantation were related to long-term mortality, whereas pre-implantation renal replacement therapy and extracorporeal membrane oxygenation were not related to mortality. CONCLUSIONS: In Spain, 67% of the VAD-supported children have been bridged to heart transplantation or to recovery. Body weight lower than 5 kg, congenital heart disease diagnosis, cholestatic liver dysfunction, bridge to decision as VAD strategy, INTERMACS-1 status and cardiac arrest were pre-implantation variables related to mortality, whereas pre-implantation renal replacement therapy and extracorporeal membrane oxygenation were not.

Myocardial tissue characterization by cardiovascular magnetic resonance T1 mapping and pericardial fat quantification in adolescents with morbid obesity. Cardiac dimorphism by gender.

PURPOSE: Changes in the myocardial extracellular matrix (ECM) identified using T1 mapping cardiovascular magnetic resonance (CMR) have been only reported in obese adults, but with opposite conclusions. The objectives are to assess the composition of the myocardial ECM in an obese pediatric population without type 2 diabetes by quantifying native T1 time, and to quantify the pericardial fat index (PFI) and their relationship with cardiovascular risk factors. METHODS: Observational case-control research of 25 morbidly obese adolescents and 13 normal-weight adolescents. Native T1 and T2 times (ms), left ventricular (LV) geometry and function, PFI (g/ht3) and hepatic fat fraction (HFF, %) were calculated by 1.5-T CMR. RESULTS: No differences were noticed in native T1 between obese and non-obese adolescents (1000.0 vs. 990.5 ms, p0.73), despite showing higher LV mass values (28.3 vs. 22.9 g/ht3, p0.01). However, the T1 mapping values were significantly higher in females (1012.7 vs. 980.7 ms, p < 0.01) while in males, native T1 was better correlated with obesity parameters, particularly with triponderal mass index (TMI) (r = 0.51), and inflammatory cells. Similarly, the PFI was correlated with insulin resistance (r = 0.56), highly sensitive C-reactive protein (r = 0.54) and TMI (r = 0.77). CONCLUSION: Female adolescents possess myocardium peculiarities associated with higher mapping values. In males, who are commonly more exposed to future non-communicable diseases, TMI may serve as a useful predictor of native T1 and pericardial fat increases. Furthermore, HFF and PFI appear to be markers of adipose tissue infiltration closely related with hypertension, insulin resistance and inflammation.

Case report: Removal of a subcutaneous implantable cardiac defibrillator in a pediatric patient with hypertrophic cardiomyopathy after a septal myectomy. Insights on current indications of type of ICD in children with hypertrophic cardiomyopathy and left ventricular tract obstruction.

Hypertrophic cardiomyopathy is a heart muscle disease with an annual incidence between 0.24 and 0.47/100000 in childhood. Sudden cardiac death is the most common cause of death in this population. Although some medical treatment can decrease the risk of sudden cardiac death, implantable cardioverter defibrillator continues to be the most reliable treatment. Different types of devices and programming strategies can be used in patients with hypertrophic cardiomyopathy depending on each center and specific patient condition. We report a pediatric patient affected with hypertrophic cardiomyopathy who had and ICD implantation in primary prevention. Four years later he developed symptomatic left ventricular outflow tract obstruction and a surgical septal myectomy was performed. After the myectomy the patient developed complete left bundle branch block on his 12 lead ECG, and unfortunately none of the S-ICD vectors were suitable after the myectomy and it had to be explanted and replaced for a new transvenous ICD.

Relationship Between Maximal Left Ventricular Wall Thickness and Sudden Cardiac Death in Childhood Onset Hypertrophic Cardiomyopathy.

BACKGROUND: Maximal left ventricular wall thickness (MLVWT) is a risk factor for sudden cardiac death (SCD) in hypertrophic cardiomyopathy (HCM). In adults, the severity of left ventricular hypertrophy has a nonlinear relationship with SCD, but it is not known whether the same complex relationship is seen in childhood. The aim of this study was to describe the relationship between left ventricular hypertrophy and SCD risk in a large international pediatric HCM cohort. METHODS: The study cohort comprised 1075 children (mean age, 10.2 years [±4.4]) diagnosed with HCM (1-16 years) from the International Paediatric Hypertrophic Cardiomyopathy Consortium. Anonymized, noninvasive clinical data were collected from baseline evaluation and follow-up, and 5-year estimated SCD risk was calculated (HCM Risk-Kids). RESULTS: MLVWT Z score was <10 in 598 (58.1%), ≥10 to <20 in 334 (31.1%), and ≥20 in 143 (13.3%). Higher MLVWT Z scores were associated with heart failure symptoms, unexplained syncope, left ventricular outflow tract obstruction, left atrial dilatation, and nonsustained ventricular tachycardia. One hundred twenty-two patients (71.3%) with MLVWT Z score ≥20 had coexisting risk factors for SCD. Over a median follow-up of 4.9 years (interquartile range, 2.3-9.3), 115 (10.7%) had an SCD event. Freedom from SCD event at 5 years for those with MLVWT Z scores <10, ≥10 to <20, and ≥20 was 95.6%, 87.4%, and 86.0, respectively. The estimated SCD risk at 5 years had a nonlinear, inverted U-shaped relationship with MLVWT Z score, peaking at Z score +23. The presence of coexisting risk factors had a summative effect on risk. CONCLUSIONS: In children with HCM, an inverted U-shaped relationship exists between left ventricular hypertrophy and estimated SCD risk. The presence of additional risk factors has a summative effect on risk. While MLVWT is important for risk stratification, it should not be used either as a binary variable or in isolation to guide implantable cardioverter defibrillator implantation decisions in children with HCM.

Clinical Features and Natural History of Preadolescent Nonsyndromic Hypertrophic Cardiomyopathy.

BACKGROUND: Up to one-half of childhood sarcomeric hypertrophic cardiomyopathy (HCM) presents before the age of 12 years, but this patient group has not been systematically characterized. OBJECTIVES: The aim of this study was to describe the clinical presentation and natural history of patients presenting with nonsyndromic HCM before the age of 12 years. METHODS: Data from the International Paediatric Hypertrophic Cardiomyopathy Consortium on 639 children diagnosed with HCM younger than 12 years were collected and compared with those from 568 children diagnosed between 12 and 16 years. RESULTS: At baseline, 339 patients (53.6%) had family histories of HCM, 132 (20.9%) had heart failure symptoms, and 250 (39.2%) were prescribed cardiac medications. The median maximal left ventricular wall thickness z-score was 8.7 (IQR: 5.3-14.4), and 145 patients (27.2%) had left ventricular outflow tract obstruction. Over a median follow-up period of 5.6 years (IQR: 2.3-10.0 years), 42 patients (6.6%) died, 21 (3.3%) underwent cardiac transplantation, and 69 (10.8%) had life-threatening arrhythmic events. Compared with those presenting after 12 years, a higher proportion of younger patients underwent myectomy (10.5% vs 7.2%; P = 0.045), but fewer received primary prevention implantable cardioverter-defibrillators (18.9% vs 30.1%; P = 0.041). The incidence of mortality or life-threatening arrhythmic events did not differ, but events occurred at a younger age. CONCLUSIONS: Early-onset childhood HCM is associated with a comparable symptom burden and cardiac phenotype as in patients presenting later in childhood. Long-term outcomes including mortality did not differ by age of presentation, but patients presenting at younger than 12 years experienced adverse events at younger ages.

Evolución del intervalo QTc en pacientes con infección SARS-CoV-2 tratados con fármacos antivirales / QTc interval prolongation in patients infected with SARS-CoV-2 and treated with antiviral drugs

Introducción: Muchos antivirales, como la hidroxicloroquina, se han utilizado para el tratamiento de COVID-19. La prolongación del QTc es un efecto adverso preocupante, escasamente estudiado en pediatría. Pacientes y métodos: Los pacientes pediátricos con COVID-19 que recibieron tratamiento antiviral se emparejaron (1:2) con controles no infectados ni expuestos al tratamiento. Se analizaron prospectivamente los electrocardiogramas basales, en las primeras 72 horas de tratamiento y posterior a 72 horas. Resultados: Once (22,9%) de 48 pacientes pediátricos ingresados por COVID-19 (marzo a julio del 2020) recibieron terapia antiviral. Todos presentaban patologías de base; destacando cardiopatías (4/11; 36,4%) e inmunosupresión (3/11; 27,3%); 5/11 (45,5%) recibían tratamiento de base con potencial efecto sobre el QTc. No hubo diferencias en el QTc basal entre casos y controles: 414,8 ms (49,2) vs. 416,5 ms (29,4) (p = 0,716). Se observó QTc prolongado basal en 2/11 casos y 2/22 controles. De los casos, 10/11 (90,9%) recibieron hidroxicloroquina, principalmente asociada a azitromicina (8/11; 72,7%); tres recibieron lopinavir/ritonavir, uno remdesivir. La mediana de incremento del QTc tras 72 horas fue de 28,9 ms (IQR 48,7) (p = 0,062); 4/11 (36,4%) presentaron un QTc largo, de los cuales en tres ≥ 500 ms. En uno se paró el tratamiento (QTc 510 ms) pero no se documentaron arritmias ventriculares. Conclusiones: El uso de fármacos antivirales causó un incremento del QTc tras 72 horas de tratamiento, considerándose un QTc largo en el 36,4% de los pacientes, aunque no se objetivaron eventos arrítmicos. El uso de hidroxicloroquina y antivirales requiere monitorización activa del QTc y se recomienda suspender el tratamiento si el QTc > 500 ms. (AU)

Introduction: Many antiviral agents, such as hydroxychloroquine, have been used to treat COVID-19, without being broadly accepted. QTc prolongation is a worrisome adverse effect, scarcely studied in pediatrics. Patients and methods: Pediatric patients affected from COVID-19 who received antivirals were matched (1:2) with controls not infected nor exposed. Electrocardiograms were prospectively analyzed at baseline, during the first 72 h in treatment and after 72 h. Results: Eleven (22.9%) out of 48 patients admitted due to COVID-19 (March–July 2020) received antiviral therapy. All had underlying diseases: congenital heart disease (4/11; 36.4%) and immunosuppression (3/11; 27.3%) stand out. 5/11 (45.5%) received treatment at baseline with a potential effect on QTc. There where no differences observed in the baseline QTc between cases and controls: 414.8 ms (49.2) vs. 416.5 ms (29.4) (p = 0.716). Baseline long QT was observed in 2/11 cases and 2/22. Among cases, 10/11 (90.9%) received hydroxychloroquine, mainly associated with azithromycin (8/11; 72.7%), 3 received lopinavir/ritonavir and one remdesivir. The median increase in QTc after 72 h under treatment was 28.9 ms (IQR 48.7) (p = 0.062). 4/11 (36.4%) patients had a long QTc at 72 h, resulting in 3 patients ≥500 ms; treatment was stopped in one (QTc 510 ms) but ventricular arrhythmias were not documented. Conclusions: The use of antivirals caused an increase on the QTc interval after 72 h of treatment, being the QTc long in 36.3% of the patients, although no arrhythmic events were observed. The use of hydroxychloroquine and antivirals requires active QTc monitoring and it is recommended to discontinue treatment if QTc >500 ms. (AU)

QTc interval prolongation in patients infected with SARS-CoV-2 and treated with antiviral drugs.

INTRODUCTION: Many antiviral agents, such as hydroxychloroquine, have been used to treat COVID-19, without being broadly accepted. QTc prolongation is a worrisome adverse effect, scarcely studied in pediatrics. PATIENTS AND METHODS: Paediatric patients affected from COVID-19 who received antivirals were matched (1:2) with controls not infected nor exposed. Electrocardiograms were prospectively analyzed at baseline, during the first 72 h of treatment and after 72 h. RESULTS: Eleven (22.9%) out of 48 patients admitted due to COVID-19 (March-July 2020) received antiviral therapy. All had underlying diseases: congenital heart disease (4/11; 36.4%) and immunosuppression (3/11; 27.3%) stand out. 5/11 (45.5%) received treatment at baseline with a potential effect on QTc. There where no differences observed in the baseline QTc between cases and controls: 414.8 ms (49.2) vs 416.5 ms (29.4), (P = .716). Baseline long QT was observed in 2/11 cases and 2/22. Among cases, 10/11 (90.9%) received hydroxychloroquine, mainly associated with azithromycin (8/11; 72.7%), 3 received lopinavir/ritonavir and one remdesivir. The median increase in QTc after 72 h under treatment was 28.9 ms [IQR 48.7] (P = .062). 4/11 (36.4%) patients had a long QTc at 72 h, resulting in 3 patients ≥500 ms; treatment was stopped in one (QTc 510 ms) but ventricular arrhythmias were not documented. CONCLUSIONS: The use of antivirals caused an increase on the QTc interval after 72 h of treatment, being the QTc long in 36.3% of the patients, although no arrhythmic events were observed. The use of hydroxychloroquine and antivirals requires active QTc monitoring and it is recommended to discontinue treatment if QTc > 500 ms.

Parvovirus B19 myocarditis in children: a diagnostic and therapeutic approach.

Parvovirus B19 is one of the most frequent causes of pediatric myocarditis, associating high mortality rates or need for cardiac transplantation. The aim of this study is to describe the clinical course of Parvovirus B19 myocarditis in children with emphasis on the role of endomyocardial biopsy and cardiac magnetic resonance, and the use of an innovative therapeutic strategy. Eleven patients and 12 episodes of polymerase chain reaction (PCR)-confirmed Parvovirus B19 myocarditis were prospectively collected for 14 years. Diagnosis was confirmed either histopathologically or by magnetic resonance. A life-threatening clinical presentation is described, similar to previous series, but with 83.3% overall survival without transplantation. We also present a case of recurrent myocarditis, which is extraordinarily rare. Electrocardiographic patterns presented chiefly peaked p waves, low QRS voltages, and negative T waves on inferior or lateral leads. Endomyocardial biopsy is the gold standard diagnostic test; alternatively magnetic resonance could be a useful diagnostic tool. A good concordance between myocardial and blood PCRs was observed. Seven patients received treatment with corticosteroids and beta interferon and all underwent a significant cardiac function improvement. CONCLUSION: A severe clinical presentation is reported, similar to previous reports but with better outcomes. Endomyocardial biopsy is the gold standard diagnostic test; alternatively magnetic resonance may be used. Both blood and myocardium PCR can be used in children to establish the microbiological etiology. Steroids with IFNß could be a useful therapeutic option, although further multicenter studies are needed to confirm these results. WHAT IS KNOWN: • Parvovirus B19 is one of the most frequent causes of myocarditis in children. It is associated with a fulminant clinical presentation. • Endomyocardial biopsy is the gold standard diagnostic test but it is an invasive procedure. WHAT IS NEW: • Myocarditis may recur in pediatrics, even it is extraordinarily rare. • IFNß with steroids may be a useful therapeutic option to improve the outcomes.

[QTc interval prolongation in patients infected with SARS-CoV-2 and treated with antiviral drugs]. / Evolución del intervalo QTc en pacientes con infección SARS-CoV-2 tratados con fármacos antivirales.

Introduction: Many antiviral agents, such as hydroxychloroquine, have been used to treat COVID-19, without being broadly accepted. QTc prolongation is a worrisome adverse effect, scarcely studied in pediatrics. Patients and methods: Pediatric patients affected from COVID-19 who received antivirals were matched (1:2) with controls not infected nor exposed. Electrocardiograms were prospectively analyzed at baseline, during the first 72 h in treatment and after 72 h. Results: Eleven (22.9%) out of 48 patients admitted due to COVID-19 (March-July 2020) received antiviral therapy. All had underlying diseases: congenital heart disease (4/11; 36.4%) and immunosuppression (3/11; 27.3%) stand out. 5/11 (45.5%) received treatment at baseline with a potential effect on QTc. There where no differences observed in the baseline QTc between cases and controls: 414.8 ms (49.2) vs. 416.5 ms (29.4) (p = 0.716). Baseline long QT was observed in 2/11 cases and 2/22. Among cases, 10/11 (90.9%) received hydroxychloroquine, mainly associated with azithromycin (8/11; 72.7%), 3 received lopinavir/ritonavir and one remdesivir. The median increase in QTc after 72 h under treatment was 28.9 ms (IQR 48.7) (p = 0.062). 4/11 (36.4%) patients had a long QTc at 72 h, resulting in 3 patients ≥500 ms; treatment was stopped in one (QTc 510 ms) but ventricular arrhythmias were not documented. Conclusions: The use of antivirals caused an increase on the QTc interval after 72 h of treatment, being the QTc long in 36.3% of the patients, although no arrhythmic events were observed. The use of hydroxychloroquine and antivirals requires active QTc monitoring and it is recommended to discontinue treatment if QTc >500 ms.

The role of the electrocardiographic phenotype in risk stratification for sudden cardiac death in childhood hypertrophic cardiomyopathy.

AIMS: The 12-lead electrocardiogram (ECG) is routinely performed in children with hypertrophic cardiomyopathy (HCM). An ECG risk score has been suggested as a useful tool for risk stratification, but this has not been independently validated. This aim of this study was to describe the ECG phenotype of childhood HCM in a large, international, multi-centre cohort and investigate its role in risk prediction for arrhythmic events. METHODS AND RESULTS: Data from 356 childhood HCM patients with a mean age of 10.1 years (±4.5) were collected from a retrospective, multi-centre international cohort. Three hundred and forty-seven (97.5%) patients had ECG abnormalities at baseline, most commonly repolarization abnormalities (n = 277, 77.8%); left ventricular hypertrophy (n = 240, 67.7%); abnormal QRS axis (n = 126, 35.4%); or QT prolongation (n = 131, 36.8%). Over a median follow-up of 3.9 years (interquartile range 2.0-7.7), 25 (7%) had an arrhythmic event, with an overall annual event rate of 1.38 (95% CI 0.93-2.04). No ECG variables were associated with 5-year arrhythmic event on univariable or multivariable analysis. The ECG risk score threshold of >5 had modest discriminatory ability [C-index 0.60 (95% CI 0.484-0.715)], with corresponding negative and positive predictive values of 96.7% and 6.7. CONCLUSION: In a large, international, multi-centre cohort of childhood HCM, ECG abnormalities were common and varied. No ECG characteristic, either in isolation or combined in the previously described ECG risk score, was associated with 5-year sudden cardiac death risk. This suggests that the role of baseline ECG phenotype in improving risk stratification in childhood HCM is limited.

Differences between genetic dilated cardiomyopathy and myocarditis in children presenting with severe cardiac dysfunction.

Acute myocarditis is an inflammatory disease of the myocardium, and it can present as severe heart failure in children. Differential diagnosis with genetic cardiomyopathy can be difficult. The objective of this study is to identify patterns of clinical presentation and to assess invasive and non-invasive measures to differentiate patients with acute myocarditis from patients with dilated genetic cardiomyopathy. We performed a retrospective descriptive study of all paediatric patients (0-16 years old) that presented with new-onset heart failure with left ventricle ejection fraction < 35% in whom we performed an endomyocardial biopsy (EMB) during the period from April 2007 to December 2020. The patients were classified into two groups: Group 1 included 18 patients with myocarditis. Group 2 included 9 patients with genetic cardiomyopathy. Findings favouring a diagnosis of myocarditis included a fulminant or acute presentation (77.8% vs 33.3%, p = 0.01), higher degree of cardiac enzyme elevation (p = 0.011), lower left ventricular dimension z-score (2.2 vs 5.4, p = 0.03) increase of ventricular wall thickness (88.8% vs 33.3%, p = 0.03) and oedema in the EMB. Seven (77.8%) patients with genetic cardiomyopathy had inflammation in the endomyocardial biopsy fulfilling the diagnostic criteria of inflammatory cardiomyopathy.Conclusion: Differentiating patients with a myocarditis from those with genetic cardiomyopathy can be challenging, even performing an EMB. Some patients with genetic cardiomyopathy fulfil the diagnostic criteria of inflammatory cardiomyopathy. Using invasive and non-invasive measures may be useful to develop a predictive model to differentiate myocarditis from genetic cardiomyopathy. What is Known: • Acute myocarditis could present with cardiogenic shock in paediatric patients. • Parvovirus B19 is the main cause of myocarditis in this population. What is New: • Current diagnostic criteria for myocarditis have limited use in paediatric patients presenting with new-onset heart failure. • Some patients with a genetic cardiomyopathy and a new-onset heart failure fulfill the diagnostic criteria of inflammatory cardiomyopathy.

Results of heart retransplantation: subanalysis of the Spanish Heart Transplant Registry.

INTRODUCTION AND OBJECTIVES: Heart retransplantation (ReHT) is controversial in the current era. The aim of this study was to describe and analyze the results of ReHT in Spain. METHODS: We performed a retrospective cohort analysis from the Spanish Heart Transplant Registry from 1984 to 2018. Data were collected on donors, recipients, surgical procedure characteristics, immunosuppression, and survival. The main outcome was posttransplant all-cause mortality or need for ReHT. We studied differences in survival according to indication for ReHT, the time interval between transplants and era of ReHT. RESULTS: A total of 7592 heart transplants (HT) and 173 (2.3%) ReHT were studied (median age, 52.0 and 55.0 years, respectively). Cardiac allograft vasculopathy was the most frequent indication for ReHT (42.2%) and 59 patients (80.8%) received ReHT >5 years after the initial transplant. Acute rejection and primary graft failure decreased as indications over the study period. Renal dysfunction, hypertension, need for mechanical ventilation or intra-aortic balloon pump and longer cold ischemia time were more frequent in ReHT. Median follow-up for ReHT was 5.8 years. ReHT had worse survival than HT (weighted HR, 1.43; 95%CI, 1.17-1.44; P<.001). The indication of acute rejection (HR, 2.49; 95%CI, 1.45-4.27; P<.001) was related to the worst outcome. ReHT beyond 5 years after initial HT portended similar results as primary HT (weighted HR, 1.14; 95%CI, 0.86-1.50; P<.001). CONCLUSIONS: ReHT was associated with higher mortality than HT, especially when indicated for acute rejection. ReHT beyond 5 years had a similar prognosis to primary HT.