Clinical Outcomes and Genetic Analyses of Restrictive Cardiomyopathy in Children.

BACKGROUND: Restrictive cardiomyopathy in children is rare and outcomes are very poor. However, little information is available concerning genotype-outcome correlations. METHODS: We analyzed the clinical characteristics and genetic testing, including whole exome sequencing, of 28 pediatric restrictive cardiomyopathy patients who were diagnosed from 1998 to 2021 at Osaka University Hospital in Japan. RESULTS: The median age at diagnosis (interquartile range) was 6 (2.25-8.5) years. Eighteen patients received heart transplantations and 5 patients were on the waiting list. One patient died while waiting for transplantation. Pathologic or likely-pathogenic variants were identified in 14 of the 28 (50%) patients, including heterozygous TNNI3 missense variants in 8 patients. TNNT2, MYL2, and FLNC missense variants were also identified. No significant differences in clinical manifestations and hemodynamic parameters between positive and negative pathogenic variants were detected. However, 2- and 5-year survival rates were significantly lower in patients with pathogenic variants (50% and 22%) compared with survival in patients without pathogenic variants (62% and 54%; P=0.0496, log-rank test). No significant differences were detected in the ratio of patients diagnosed at nationwide school heart disease screening program between positive and negative pathogenic variants. Patients diagnosed by school screening showed better transplant-free survival compared with patients diagnosed by heart failure symptoms (P=0.0027 in log-rank test). CONCLUSIONS: In this study, 50% of pediatric restrictive cardiomyopathy patients had pathogenic or likely-pathogenic gene variants, and TNNI3 missense variants were the most frequent. Patients with pathogenic variants showed significantly lower transplant-free survival compared with patients without pathogenic variants.

Como eu faço avaliação ecocardiográfica de pericardite constritiva / My approach to echocardiographic assessment for constrictive pericarditis

A pericardite constritiva (PC) é uma condição na qual a cicatrização e perda de elasticidade do pericárdio resultam em enchimento ventricular prejudicado, disfunção diastólica e insuficiência cardíaca direita. O diagnóstico dessa patologia é desafiador, sendo frequente a necessidade de técnicas de imagem multimodal, dentre as quais a ecocardiografia representa a modalidade de imagem inicial para a avaliação diagnóstica, além de permitir a diferenciação da PC da cardiomiopatia restritiva (CMR) e outras condições que mimetizam constrição. (AU)

Constrictive pericarditis (CP) is a condition in which scarring and loss of elasticity of the pericardium result in impaired ventricular filling, diastolic dysfunction, and right heart failure. The diagnosis of this pathology is challenging, with frequent need for multimodal imaging techniques, among which echocardiography represents the initial imaging modality for the diagnostic evaluation, in addition to allowing the differentiation of CP from restrictive cardiomyopathy (RCM) and other conditions that mimic constriction. (AU)

A rare case of sudden death due to endomyocardial fibrosis in Italy: A differential diagnosis with other causes of restrictive cardiomyopathy.

A 45-years-old Indonesian woman was admitted to the hospital with nausea, vomiting, abdominal pain and tachyarrhythmia. Atrial fibrillation was found at ECG, blood tests showed mild hepatic function alterations. Radiological exams showed bilateral pleural effusions, ascites, hepatomegaly. Systolic and diastolic functions of the left ventricle were found to be strongly compromised at US. Physical conditions and laboratory results worsened rapidly, followed by multi organ failure. Death occurred 28 hours after admission. An autopsy was performed to clarify the cause of death and investigated medical malpractice. External examination showed jaundice skin and at internal examination bilateral pleural and pericardial effusions, ascites, mild cardiomegaly, ventricular endocardial fibrosis, a thrombus in tight junction to the left ventricular wall and hepatic necrosis were observed. Histological investigations revealed a massive endomyocardial fibrosis, detected through Azan-Mallory and Verhoef-Van-Gieson stain, and confirmed the presence of hepatic and renal necrosis. Toxicological and microbiological investigations were negative. The cause of death was a global cardiac dysfunction caused by a restrictive cardiomyopathy in an Indonesian woman affected by an undiagnosed and asymptomatic endomyocardial fibrosis. In this case, autopsy and histopathological investigations were fundamental to diagnose an occult endomyocardial fibrosis, which is an idiopathic disorder of tropical and subtropical regions of the world. The not common incidence of this disease in our country and its unusual clinical onset were at first perceived as a medical malpractice from the relatives. Consequently, the clinical aspects of the case intertwine with the medicolegal implications concerning the undiagnosed disease and the causality with the patient's death.

Restrictive cardiomyopathy: definition and diagnosis.

Restrictive cardiomyopathy (RCM) is a heterogeneous group of diseases characterized by restrictive left ventricular pathophysiology, i.e. a rapid rise in ventricular pressure with only small increases in filling volume due to increased myocardial stiffness. More precisely, the defining feature of RCM is the coexistence of persistent restrictive pathophysiology, diastolic dysfunction, non-dilated ventricles, and atrial dilatation, regardless of ventricular wall thickness and systolic function. Beyond this shared haemodynamic hallmark, the phenotypic spectrum of RCM is wide. The disorders manifesting as RCM may be classified according to four main disease mechanisms: (i) interstitial fibrosis and intrinsic myocardial dysfunction, (ii) infiltration of extracellular spaces, (iii) accumulation of storage material within cardiomyocytes, or (iv) endomyocardial fibrosis. Many disorders do not show restrictive pathophysiology throughout their natural history, but only at an initial stage (with an evolution towards a hypokinetic and dilated phenotype) or at a terminal stage (often progressing from a hypertrophic phenotype). Furthermore, elements of both hypertrophic and restrictive phenotypes may coexist in some patients, making the classification challenge. Restrictive pathophysiology can be demonstrated by cardiac catheterization or Doppler echocardiography. The specific conditions may usually be diagnosed based on clinical data, 12-lead electrocardiogram, echocardiography, nuclear medicine, or cardiovascular magnetic resonance, but further investigations may be needed, up to endomyocardial biopsy and genetic evaluation. The spectrum of therapies is also wide and heterogeneous, but disease-modifying treatments are available only for cardiac amyloidosis and, partially, for iron overload cardiomyopathy.

Removal of cardiac AL amyloid with positive remodelling of cardiomyocytes and of restrictive cardiomyopathy.

Herein, we describe histological mobilization of light chain cardiac amyloid documented by sequential left ventricular endomyocardial biopsies. These findings were associated with positive remodelling of cardiomyocytes and of restrictive cardiomyopathy resulting from 14 courses of chemotherapy over 17 years of time. Histological and ultrastructural findings of light chain cardiac amyloid removal led to increase in cardiomyocyte dimension and electrocardiogram voltages, reduction of biventricular wall thickness with improvement of left ventricular diastolic function, and NYHA class shifting from III to I.

Clinical genetic testing in four highly suspected pediatric restrictive cardiomyopathy cases.

BACKGROUND: Restrictive cardiomyopathy (RCM) presents a high risk for sudden cardiac death in pediatric patients. Constrictive pericarditis (CP) exhibits a similar clinical presentation to RCM and requires differential diagnosis. While mutations of genes that encode sarcomeric and cytoskeletal proteins may lead to RCM, infection, rather than gene mutation, is the main cause of CP. Genetic testing may be helpful in the clinical diagnosis of RCM. METHODS: In this case series study, we screened for TNNI3, TNNT2, and DES gene mutations that are known to be etiologically linked to RCM in four pediatric patients with suspected RCM. RESULTS: We identified one novel heterozygous mutation, c.517C>T (substitution, position 517 C → T) (amino acid conversion, p.Leu173Phe), and two already known heterozygous mutations, c.508C>T (substitution, position 508, C → T) (amino acid conversion, p.Arg170Trp) and c.575G>A (substitution, position 575, G → A) (amino acid conversion, p.Arg192His), in the TNNI3 gene in three of the four patients. CONCLUSION: Our findings support the notion that genetic testing may be helpful in the clinical diagnosis of RCM.

Overview of Restrictive Cardiomyopathies.

Restrictive cardiomyopathy (RCM) includes a heterogeneous group of diseases that cause increased myocardial stiffness, leading to impaired ventricular relaxation and severe diastolic dysfunction. Given that it is the least common type of cardiomyopathy, it can be a diagnostic challenge due to its varied pathogenesis, clinical presentation, and diagnostic evaluation. In this review, we provide an overview of different etiologies of RCM and examine the diagnostic and treatment approaches for various types.

Restrictive cardiomyopathy: from genetics and clinical overview to animal modeling.

Restrictive cardiomyopathy (RCM), a potentially devastating heart muscle disorder, is characterized by diastolic dysfunction due to abnormal muscle relaxation and myocardial stiffness resulting in restrictive filling of the ventricles. Diastolic dysfunction is often accompanied by left atrial or bi-atrial enlargement and normal ventricular size and systolic function. RCM is the rarest form of cardiomyopathy, accounting for 2-5% of pediatric cardiomyopathy cases, however, survival rates have been reported to be 82%, 80%, and 68% at 1-, 2-, and 5-years after diagnosis, respectively. RCM can be idiopathic, familial, or secondary to a systemic disorder, such as amyloidosis, sarcoidosis, and hereditary hemochromatosis. Approximately 30% of cases are familial RCM, and the genes that have been linked to RCM are cTnT, cTnI, MyBP-C, MYH7, MYL2, MYL3, DES, MYPN, TTN, BAG3, DCBLD2, LNMA, and FLNC. Increased Ca2+ sensitivity, sarcomere disruption, and protein aggregates are some of the few mechanisms of pathogenesis that have been revealed by studies utilizing cell lines and animal models. Additional exploration into the pathogenesis of RCM is necessary to create novel therapeutic strategies to reverse restrictive cardiomyopathic phenotypes.

Natriuretic peptides to differentiate constrictive pericarditis and restrictive cardiomyopathy: A systematic review and meta-analysis.

Previous studies have shown that natriuretic peptide levels are increased in patients with restrictive cardiomyopathy (RCM) but not in constrictive pericarditis (CP). We performed a systematic review and meta-analysis to evaluate the diagnostic utility of B-type natriuretic peptide (BNP) and N-terminal pro-brain natriuretic peptide (NT-proBNP) to differentiate CP and RCM. We searched electronic databases from inception to January 07, 2021. Studies involving adult patients that assessed the utility of natriuretic peptides to differentiate CP and RCM were included. All meta-analyses were performed using a random-effects model. Seven studies (four case-control and three cohorts) involving 204 patients were included. The mean age ranged between 25.7 and 64.1 years and 77% of patients were men. BNP levels were significantly lower (standardized median difference [SMD], -1.48; 95% confidence interval [CI], -2.33 to -0.63) in patients with CP compared to RCM. The pooled area under the curve (AUC) of the BNP level was 0.81 (95% CI, 0.70-0.92). NT-proBNP (SMD, -0.86; 95% CI, -1.38 to -0.33) and log NT-proBNP (SMD, -1.89; 95% CI, -2.59 to -1.20) levels were significantly lower in patients with CP compared to RCM. Our review shows that BNP and NT-proBNP levels were significantly lower in patients with CP compared to RCM. The pooled AUC of BNP level showed a good diagnostic accuracy to differentiate both conditions.

Restrictive cardiomyopathy caused by diffuse calcification of the left ventricle after 20 years of haemodialysis.

Valvular and vascular calcifications are common among patients with end-stage renal disease, but diffuse calcification of the left ventricle is rarely reported. We report on a rare case of restrictive cardiomyopathy resulting from severe myocardial calcification and review the literature. A 77-year-old man was diagnosed with end-stage renal disease after having received regular haemodialysis for 20 years. He was referred to our emergency room due to exertional dyspnoea and exacerbated shortness of breath. A chest X-ray revealed severe pulmonary oedema and bilateral massive pleural effusion. Transthoracic echocardiography revealed impaired diastolic function of the left ventricle but preserved systolic function with a 50% ejection fraction. Repeat chest computed tomography demonstrated exacerbation of the calcification from the mitral annulus to the whole circular left ventricle. A coronary angiogram revealed non-significant stenosis, and right heart catheterisation demonstrated elevated pulmonary capillary wedge pressure. He was discharged after two weeks of conservative medication.

A Rare Case of Restrictive Cardiomyopathy Presenting With Large, Recurrent Pericardial Effusions.

The association between large pericardial effusion and restrictive cardiomyopathy (RCM) is uncommon and has seldom been described. We describe an uncommon case of a 31-year-old male with RCM who presented with large, recurrent pericardial effusion, heart failure, and echocardiographic findings showing progressive worsening of diastolic function even after total pericardiectomy who was eventually transferred for cardiac transplant evaluation.

Miocardiopatía restrictiva: la importancia de su diagnóstico precoz / Restrictive cardiomyopathy: Importance of early diagnosis

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Left ventricular strain-curve morphology to distinguish between constrictive pericarditis and restrictive cardiomyopathy.

AIMS: To distinguish between constrictive pericarditis (CP) and restrictive cardiomyopathy (RCM) using cardiac magnetic resonance feature tracking (CMR-FT) left ventricle (LV) diastolic time-strain curve patterns and myocardial strain. METHODS AND RESULTS: A total of 32 CP patients, 27 RCM patients, and 25 control subjects were examined by CMR-FT and analysed for global strain, segmental strain, and LV time-strain curve patterns in the longitudinal, circumferential, and radial directions. Speckle tracking echocardiography (STE) strain imaging was performed in some cases. The peak global longitudinal strain (GLS) and global circumferential strain (GCS) of the RCM group were lower than those of the CP group. GLS [median (interquartile range) CP vs. RCM: -11.15 (-12.85, -9.35) vs. -6.5 (-8.75, -4.85), P < 0.001] and GCS (CP vs. RCM: -16.89 ± 5.11 vs. -13.37 ± 5.79, P < 0.001). In circumferential and radial directions, the strain ratios of the LV lateral/septal wall (LW/SW) of the CP group were significantly lower than those of the RCM group at the basal and mid segments. The CS ratio of LW/SW at the basal segment [CP vs. RCM: 0.95 (0.85, 1.25) vs. 1.43 (1.18, 1.89), P < 0.001] and mid segment [CP vs. RCM: 1.05 (0.92, 1.15) vs. 1.18 (1.06, 1.49), P = 0.026]. The RS ratio of LW/SW at the basal segment [CP vs. RCM: 0.97 (0.76, 1.37) vs. 1.55 (1.08, 2.31), P = 0.006] and mid segment [CP vs. RCM: 0.95 (0.70, 1.28) vs. 1.79 (1.32, 2.92), P < 0.001]. In the longitudinal and circumferential directions, the characteristic 'plateau' pattern of time-strain curves could be seen in the CP but not in the RCM during the diastole. The GCS ratio of 0-50%/50-75% diastolic period of the CP was higher than that of the RCM [CP vs. RCM: 17.01 (8.67, 23.75) vs. 5.38 (1.93, 11.24), P = 0.001], while the GCS ratio of 50-75%/75-100% diastolic period was lower than that of the RCM [CP vs. RCM: 0.36 (0.15, 1.67) vs. 1.12 (0.70, 5.58), P < 0.001]. The peak GLS (sensitivity, 85%; specificity, 78%) and the GCS ratio of 0-50%/50-75% diastolic period (sensitivity, 88%; specificity, 73%) had higher differential diagnosis value. CONCLUSIONS: The CMR-FT could distinctly differentiate CP from RCM based on LV myocardial strain and LV time-strain curve patterns. The characteristic 'plateau' pattern of the time-strain curve is specific for CP and not RCM and this curve can also be duplicated by STE.

Features of myocardial injury detected by cardiac magnetic resonance in a patient with desmin-related restrictive cardiomyopathy.

Myocardial fibrosis detected by cardiac magnetic resonance (CMR) has been reported in patients with desmin-related myopathy, although its characteristics remain unclear. Here, we describe a case of desmin-related restrictive cardiomyopathy wherein CMR imaging revealed myocardial oedema, ischaemia, and fibrosis in the left ventricle; the different types and processes of myocardial injury were detected by CMR. Middle wall left ventricular enhancement may be a feature of late gadolinium enhancement, and the lateral wall is often involved in cases of myocardial injury. CMR is useful for the early detection of cardiac involvement and the prediction of prognosis in patients diagnosed with desmin-related myopathy.

A homozygous nonsense mutation in DCBLD2 is a candidate cause of developmental delay, dysmorphic features and restrictive cardiomyopathy.

DCBLD2 encodes discodin, CUB and LCCL domain-containing protein 2, a type-I transmembrane receptor that is involved in intracellular receptor signalling pathways and the regulation of cell growth. In this report, we describe a 5-year-old female who presented severe clinical features, including restrictive cardiomyopathy, developmental delay, spasticity and dysmorphic features. Trio-whole-exome sequencing and segregation analysis were performed to identify the genetic cause of the disease within the family. A novel homozygous nonsense variant in the DCBLD2 gene (c.80G > A, p.W27*) was identified as the most likely cause of the patient's phenotype. This nonsense variant falls in the extracellular N-terminus of DCBLD2 and thus might affect proper protein function of the transmembrane receptor. A number of in vitro investigations were performed on the proband's skin fibroblasts compared to normal fibroblasts, which allowed a comprehensive assessment resulting in the functional characterization of the identified DCBLD2 nonsense variant in different cellular processes. Our data propose a significant association between the identified variant and the observed reduction in cell proliferation, cell cycle progression, intracellular ROS, and Ca2 + levels, which would likely explain the phenotypic presentation of the patient as associated with lethal restrictive cardiomyopathy.

Reversal of pulmonary hypertension in paediatric patients with restrictive cardiomyopathy.

Left ventricular assist devices can reverse pulmonary hypertension in cardiac transplant candidates with heart failure with a reduced ejection fraction. Whether a similar approach is applicable in restrictive cardiomyopathy is uncertain. We report the successful implantation of a Medtronic HVAD left ventricular assist device in a bridge-to-candidacy concept in 2 paediatric patients with restrictive cardiomyopathy.

Diagnostic value of P-waves in children with idiopathic restrictive cardiomyopathy.

Restrictive cardiomyopathy (RCM) is a rare myocardial disease with an impaired diastolic function and poor prognosis. Almost all RCM patients are reported to have abnormal P-waves due to atrial overloading. This study aimed to reveal the characteristics of the P-waves in RCM patients and to suggest the diagnostic index of RCM in children with a 12-lead electrocardiogram (ECG). We retrospectively investigated 17 ECGs of children with idiopathic RCM during the initial visit at 15 institutes in Japan between 1979 and 2013. The RCM group was divided into four groups based on the age (elementary school [ES] and junior high school [JHS] students) and inception of the diagnosis (abnormal ECG on school-heart-screening [e-RCM] and some cardiovascular symptoms [s-RCM]), the ES/e-RCM (n = 5), ES/s-RCM (n = 4), JHS/e-RCM (n = 4), and JHS/s-RCM (n = 4) groups. As an aged-match control group, school-heart-screening ECGs of 1st-grade ES students (16,770 students) and 1st-grade JHS students (18,126 students) from Kagoshima in 2016 were adopted. For a comparison between the groups, we used the effect size "Hedge's g" by calculating the mean and standard deviation of the two groups. An effect size of 0.8 (or above) had an overlap of 53% (or less). The effect sizes of the sum of the absolute values of the forward and backward amplitudes in lead V1 (P1 + P2 V1) was the largest, and the ES/e-RCM, ES/s-RCM, JHS/e-RCM, and JHS/s-RCM were 15.8, 22.1, 9.4, and 10.3, respectively. A P1 + P2 V1 > 200 µV was able to rule in all RCM patients, thus, we proposed 200 µV as the cutoff value for screening purposes. In conclusion, the P1 + P2 V1 in the school-heart-screening may be useful for detecting asymptomatic or early-stage RCM in school-age children.