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

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

FLNC Associated Restrictive Cardiomyopathy and Hypertrabeculation, a Rare Association. / FLNC Associada a Cardiomiopatia Restritiva e Hipertrabeculação, uma Associação Rara.

A six-year-old girl with restrictive cardiomyopathy and hypertrabeculation, due to the early onset of her disease, whole exome sequencing was conducted, revealing the presence of a novel heterozygous missense variant in the FLNC gene. The same gene variant was also identified in her father, who, at an adult age, displayed normal imaging results and was symptom-free. This variant has not been reported in population databases or current medical literature and is classified as likely pathogenic.

Menina de seis anos com cardiomiopatia restritiva e hipertrabeculação na qual, devido ao início precoce da doença, foi realizado sequenciamento completo do exoma, revelando a presença de uma nova variante heterozigótica missense no gene FLNC. A mesma variante genética também foi identificada em seu pai, que, já adulto, apresentava resultados de imagem normais e não apresentava sintomas. Esta variante não foi relatada em bancos de dados populacionais ou na literatura médica atual e é classificada como provavelmente patogênica.

Biventricular assist device implant using biatrial cannulation for restrictive cardiomyopathy.

Preoperative calculations showed that the 9-mm inlet, 6-mm outlet, 25-cc pump chambers and 65-73 bpm would be optimal for a 5-year-old patient suffering from restrictive cardiomyopathy, with a body surface area of 0.59 m2 (1.5 L/min flow for a cardiac index of 2.5). After re-sternotomy and standard bicaval cannulation for cardiopulmonary bypass, the procedure was performed under normothermic conditions and on the beating heart. Biventricular support was established with the Berlin Heart Excor using biatrial cannulation. For left atrial cannulation, induced ventricular fibrillation was used. The 9-mm inlet cannulas were inserted into the left and right atria, respectively. The 6-mm outlet cannulas were implanted using 8-mm interposition vascular grafts for the aorta and the main pulmonary artery, respectively. Cannulas were tunnelled through the epigastric space, with systems crossing outside of the body. The 25-cc chambers were used for both right ventricular assist device and left ventricular assist device support, which subsequently showed full emptying and filling.

A novel multi-task machine learning classifier for rare disease patterning using cardiac strain imaging data.

To provide accurate predictions, current machine learning-based solutions require large, manually labeled training datasets. We implement persistent homology (PH), a topological tool for studying the pattern of data, to analyze echocardiography-based strain data and differentiate between rare diseases like constrictive pericarditis (CP) and restrictive cardiomyopathy (RCM). Patient population (retrospectively registered) included those presenting with heart failure due to CP (n = 51), RCM (n = 47), and patients without heart failure symptoms (n = 53). Longitudinal, radial, and circumferential strains/strain rates for left ventricular segments were processed into topological feature vectors using Machine learning PH workflow. In differentiating CP and RCM, the PH workflow model had a ROC AUC of 0.94 (Sensitivity = 92%, Specificity = 81%), compared with the GLS model AUC of 0.69 (Sensitivity = 65%, Specificity = 66%). In differentiating between all three conditions, the PH workflow model had an AUC of 0.83 (Sensitivity = 68%, Specificity = 84%), compared with the GLS model AUC of 0.68 (Sensitivity = 52% and Specificity = 76%). By employing persistent homology to differentiate the "pattern" of cardiac deformations, our machine-learning approach provides reasonable accuracy when evaluating small datasets and aids in understanding and visualizing patterns of cardiac imaging data in clinically challenging disease states.

Long-term prognostic value of big endothelin-1 and its combination with late gadolinium enhancement in patients with idiopathic restrictive cardiomyopathy.

BACKGROUND AND AIMS: Idiopathic restrictive cardiomyopathy (RCM) has a low incidence. This study aimed to determine the prognostic value of big endothelin-1 (ET-1) in idiopathic RCM. MATERIALS AND METHODS: We prospectively enrolled patients with idiopathic RCM from 2009 to 2017 and followed them up. The primary outcome was a composite of all-cause mortality and cardiac transplantation, and the secondary outcome was a composite of cardiac death and cardiac transplantation. RESULTS: Ninety-one patients were divided into the high big ET-1 (>0.85 pmol/L, n = 56) and low big ET-1 (≤0.85 pmol/L, n = 35) groups, and 87 of them completed the follow-up. Big ET-1 concentrations (hazard ratio: 1.756, 95 % confidence interval [CI]: 1.117-2.760) and late gadolinium enhancement (LGE) (hazard ratio: 3.851, 95 % CI: 1.238-11.981) were independent risk factors for the primary outcome. Big ET-1 concentrations (C-statistic estimation: 0.764, 95 % CI: 0.657-0.871) and the combination of LGE and big ET-1 concentrations (C-statistic estimation: 0.870, 95 % CI: 0.769-0.970) could accurately predict the 5-year transplant-free survival rate, and 0.85 pmol/L was a suitable cutoff for big ET-1. CONCLUSION: Big ET-1 and its combination with LGE may be useful to predict an adverse prognosis in patients with idiopathic RCM.

Pediatric Heart Transplantation in the Context of Severe Pulmonary Hypertension Secondary to Restrictive Cardiomyopathy-Case Report.

The aim of this study is to analyze the feasibility of performing an isolated heart transplant in patients with severe pulmonary hypertension as a result of restrictive cardiomyopathy. The results present the clinical course from the diagnosis of restrictive cardiomyopathy at the age of 2 until the heart transplant at 8 years old. Initially, the patient was considered for multiorgan transplantation, heart and lungs, due to extremely high pulmonary resistance. However, due to the prolonged waiting period for a donor and the worsening condition of the child, a decision was made to perforate the atrial septum with the implantation of an atrial flow regulator system. After conducting control hemodynamic measurements, the qualification was changed to an isolated heart transplant, accepting the high operative risk associated with the still elevated pulmonary resistance index of 4.9 Wood units. This study describes the medical problems that occurred during postoperative treatment. The patient underwent an orthotopic heart transplant in her eighth year of life. Postsurgery, complications were observed, including generalized seizures and heart transplant rejection reaction. Immunosuppressive therapies were applied, and efforts were made to combat anemia and electrolyte disorders. While the cardiovascular system and heart parameters improved, there were some difficulties in controlling heart rhythm and stabilizing electrolyte levels.

Pronóstico del trasplante cardiaco en pacientes con miocardiopatía hipertrófica y restrictiva. Análisis de un registro nacional / Prognosis after heart transplant in patients with hypertrophic and restrictive cardiomyopathy. A nationwide registry analysis

Introducción y objetivos: Existe controversia acerca de los resultados del trasplante cardiaco en pacientes con miocardiopatía hipertrófica (MCH) o restrictiva (MCR). Métodos: Análisis retrospectivo de receptores adultos de un primer trasplante cardiaco entre 1984 y 2021 incluidos en un registro nacional. La mortalidad al primer y quinto año postrasplante en receptores con MCH y MCR se comparó con la de receptores con miocardiopatía dilatada (MCD). Resultados: Se incluyó a 3.703 pacientes (3.112 MCD; 331 MCH y 260 MCR) con seguimiento mediano de 5,0 años (3,1-5,0). En comparación con la MCD, el riesgo ajustado de mortalidad a 1 año fue: MCH: hazard ratio (HR)=1,38; intervalo de confianza del 95% (IC95%), 1,07-1,78; p=0,01, MCR: HR=1,48; IC95%, 1,14-1,93; p=0,003. El riesgo ajustado a 5 años fue: MCH: HR=1,17; IC95%, 0,93-1,47; p=0,18; MCR: HR=1,52; IC95%, 1,22-1,89; p<0,001. En los últimos 20 años, la MCR mejoró significativamente la supervivencia a 1 año (R2 ajustada=0,95) y a 5 años (R2=0,88); la MCH mejoró la supervivencia a 5 años (R2=0,59) y a 1 año permaneció estable (R2=0,16). Conclusiones: Se asoció la MCR y la MCH a peor pronóstico precoz postrasplante que la MCD. La diferencia desfavorable se mantuvo para la supervivencia a 5 años solo para la MCR. Se observa una tendencia temporal a mejor pronóstico precoz y tardío para la MCR, y solo para el tardío en la MCH. (AU)

Introduction and objectives: Posttransplant outcomes among recipients with a diagnosis of hypertrophic cardiomyopathy (HCM) or restrictive cardiomyopathy (RCM) remain controversial. Methods: Retrospective analysis of a nationwide registry of first-time recipients undergoing isolated heart transplant between 1984 and 2021. One-year and 5-year mortality in recipients with HCM and RCM were compared with those with dilated cardiomyopathy (DCM). Results: We included 3703 patients (3112 DCM; 331 HCM; 260 RCM) with a median follow-up of 5.0 [3.1-5.0] years. Compared with DCM, the adjusted 1-year mortality risk was: HCM: HR, 1.38; 95%CI, 1.07-1.78; P=.01, RCM: HR, 1.48; 95%CI, 1.14-1.93; P=.003. The adjusted 5-year mortality risk was: HCM: HR, 1.17; 95%CI, 0.93-1.47; P=.18; RCM: HR, 1.52; 95%CI, 1.22-1.89; P<.001. Over the last 20 years, the RCM group showed significant improvement in 1-year survival (adjusted R2=0.95) and 5-year survival (R2=0.88); the HCM group showed enhanced the 5-year survival (R2=0.59), but the 1-year survival remained stable (R2=0.16). Conclusions: Both RCM and HCM were linked to a less favorable early posttransplant prognosis compared with DCM. However, at the 5-year mark, this unfavorable difference was evident only for RCM. Notably, a substantial temporal enhancement in both early and late mortality was observed for RCM, while for HCM, this improvement was mainly evident in late mortality. (AU)

Impaired Relaxation in Induced Pluripotent Stem Cell-Derived Cardiomyocytes with Pathogenic TNNI3 Mutation of Pediatric Restrictive Cardiomyopathy.

BACKGROUND: Restrictive cardiomyopathy (RCM) is characterized by impaired diastolic function with preserved ventricular contraction. Several pathogenic variants in sarcomere genes, including TNNI3, are reported to cause Ca2+ hypersensitivity in cardiomyocytes in overexpression models; however, the pathophysiology of induced pluripotent stem cell (iPSC)-derived cardiomyocytes specific to a patient with RCM remains unknown. METHODS AND RESULTS: We established an iPSC line from a pediatric patient with RCM and a heterozygous TNNI3 missense variant, c.508C>T (p.Arg170Trp; R170W). We conducted genome editing via CRISPR/Cas9 technology to establish an isogenic correction line harboring wild type TNNI3 as well as a homozygous TNNI3-R170W. iPSCs were then differentiated to cardiomyocytes to compare their cellular physiological, structural, and transcriptomic features. Cardiomyocytes differentiated from heterozygous and homozygous TNNI3-R170W iPSC lines demonstrated impaired diastolic function in cell motion analyses as compared with that in cardiomyocytes derived from isogenic-corrected iPSCs and 3 independent healthy iPSC lines. The intracellular Ca2+ oscillation and immunocytochemistry of troponin I were not significantly affected in RCM-cardiomyocytes with either heterozygous or homozygous TNNI3-R170W. Electron microscopy showed that the myofibril and mitochondrial structures appeared to be unaffected. RNA sequencing revealed that pathways associated with cardiac muscle development and contraction, extracellular matrix-receptor interaction, and transforming growth factor-ß were altered in RCM-iPSC-derived cardiomyocytes. CONCLUSIONS: Patient-specific iPSC-derived cardiomyocytes could effectively represent the diastolic dysfunction of RCM. Myofibril structures including troponin I remained unaffected in the monolayer culture system, although gene expression profiles associated with cardiac muscle functions were altered.

Generation of human induced pluripotent stem cell line from a patient with restrictive cardiomyopathy.

Restrictive cardiomyopathy (RCM) is a rare cardiomyopathy characterized by diastolic dysfunction, which affects cardiac systolic function. We successfully established human induced pluripotent stem cells (hiPSCs) from peripheral blood mononuclear cells of 24-year-old male with restrictive cardiomyopathy (RCM). The patient-derived hiPSCs carried heterozygous mutation of CRYAB gene (c.326A > G, p.D109G), which was consistent with clinical whole exon sequencing results. We confirmed the pluripotency, multipotential differentiation and karyotype of hiPSCs. The hiPSCs will be useful for studying the pathogenesis of RCM caused by CRYAB (c.326A > G) mutation.

Role of the Alpha-B-Crystallin Protein in Cardiomyopathic Disease.

Alpha-B-crystallin, a member of the small heat shock family of proteins, has been implicated in a variety of cardiomyopathies and in normal cardiac homeostasis. It is known to function as a molecular chaperone, particularly for desmin, but also interacts with a wide variety of additional proteins. The molecular chaperone function is also enhanced by signal-dependent phosphorylation at specific residues under stress conditions. Naturally occurring mutations in CRYAB, the gene that encodes alpha-B-crystallin, have been suggested to alter ionic intermolecular interactions that affect dimerization and chaperone function. These mutations have been associated with myofibrillar myopathy, restrictive cardiomyopathy, and hypertrophic cardiomyopathy and promote pathological hypertrophy through different mechanisms such as desmin aggregation, increased reductive stress, or activation of calcineurin-NFAT signaling. This review will discuss the known mechanisms by which alpha-B-crystallin functions in cardiac homeostasis and the pathogenesis of cardiomyopathies and provide insight into potential future areas of exploration.

Waitlist Outcomes in Candidates With Rare Causes of Heart Failure After Implementation of the 2018 French Heart Allocation Scheme.

BACKGROUND: In 2018, an algorithm-based allocation system for heart transplantation (HT) was implemented in France. Its effect on access to HT of patients with rare causes of heart failure (HF) has not been assessed. METHODS: In this national study, including adults listed for HT between 2018 and 2020, we analyzed waitlist and posttransplant outcomes of candidates with rare causes of HF (restrictive cardiomyopathy [RCM], hypertrophic cardiomyopathy, and congenital heart disease). The primary end point was death on the waitlist or delisting for clinical deterioration. Secondary end points included access to HT and posttransplant mortality. The cumulative incidence of waitlist mortality estimated with competing risk analysis and incidence of transplantation were compared between diagnosis groups. The association of HF cause with outcomes was determined by Fine-Gray or Cox models. RESULTS: Overall, 1604 candidates were listed for HT. At 1 year postlisting, 175 patients met the primary end point and 1040 underwent HT. Candidates listed for rare causes of HF significantly differed in baseline characteristics and had more frequent score exceptions compared with other cardiomyopathies (31.3%, 32.0%, 36.4%, and 16.7% for patients with hypertrophic cardiomyopathy, RCM, congenital heart disease, and other cardiomyopathies). The cumulative incidence of death on the waitlist and probability of HT were similar between diagnosis groups (P=0.17 and 0.40, respectively). The adjusted risk of death or delisting for clinical deterioration did not significantly differ between candidates with rare and common causes of HF (subdistribution hazard ratio (HR): hypertrophic cardiomyopathy, 0.51 [95% CI, 0.19-1.38]; P=0.18; RCM, 1.04 [95% CI, 0.42-2.58]; P=0.94; congenital heart disease, 1.82 [95% CI, 0.78-4.26]; P=0.17). Similarly, the access to HT did not significantly differ between causes of HF (hypertrophic cardiomyopathy: HR, 1.18 [95% CI, 0.92-1.51]; P=0.19; RCM: HR, 1.19 [95% CI, 0.90-1.58]; P=0.23; congenital heart disease: HR, 0.76 [95% CI, 0.53-1.09]; P=0.14). RCM was an independent risk factor for 1-year posttransplant mortality (HR, 2.12 [95% CI, 1.06-4.24]; P=0.03). CONCLUSIONS: Our study shows equitable waitlist outcomes among HT candidates whatever the indication for transplantation with the new French allocation scheme.

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.

Gene correction and overexpression of TNNI3 improve impaired relaxation in engineered heart tissue model of pediatric restrictive cardiomyopathy.

Research on cardiomyopathy models using engineered heart tissue (EHT) created from disease-specific induced pluripotent stem cells (iPSCs) is advancing rapidly. However, the study of restrictive cardiomyopathy (RCM), a rare and intractable cardiomyopathy, remains at the experimental stage because there is currently no established method to replicate the hallmark phenotype of RCM, particularly diastolic dysfunction, in vitro. In this study, we generated iPSCs from a patient with early childhood-onset RCM harboring the TNNI3 R170W mutation (R170W-iPSCs). The properties of R170W-iPSC-derived cardiomyocytes (CMs) and EHTs were evaluated and compared with an isogenic iPSC line in which the mutation was corrected. Our results indicated altered calcium kinetics in R170W-iPSC-CMs, including prolonged tau, and an increased ratio of relaxation force to contractile force in R170W-EHTs. These properties were reversed in the isogenic line, suggesting that our model recapitulates impaired relaxation of RCM, i.e., diastolic dysfunction in clinical practice. Furthermore, overexpression of wild-type TNNI3 in R170W-iPSC-CMs and -EHTs effectively rescued impaired relaxation. These results highlight the potential efficacy of EHT, a modality that can accurately recapitulate diastolic dysfunction in vitro, to elucidate the pathophysiology of RCM, as well as the possible benefits of gene therapies for patients with RCM.

Unveiling the structural and functional consequences of the p.D109G pathogenic mutation in human αB-Crystallin responsible for restrictive cardiomyopathy and skeletal myopathy.

αB-Crystallin (αB-Cry) is expressed in many tissues, and mutations in this protein are linked to various diseases, including cataracts, Alzheimer's disease, Parkinson's disease, and several types of myopathies and cardiomyopathies. The p.D109G mutation, which substitutes a conserved aspartate residue involved in the interchain salt bridges, with glycine leads to the development of both restrictive cardiomyopathy (RCM) and skeletal myopathy. In this study, we generated this mutation in the α-Cry domain (ACD) which is crucial for forming the active chaperone dimeric state, using site-directed mutagenesis. After inducing expression in the bacterial host, we purified the mutant and wild-type recombinant proteins using anion exchange chromatography. Various spectroscopic evaluations revealed significant changes in the secondary, tertiary, and quaternary structures of human αB-Cry caused by this mutation. Furthermore, this pathogenic mutation led to the formation of protein oligomers with larger sizes than those of the wild-type protein counterpart. The mutant protein also exhibited increased chaperone activity and decreased chemical, thermal, and proteolytic stability. Atomic force microscopy (AFM), transmission electron microscopy (TEM), and fluorescence microscopy (FM) demonstrated that p.D109G mutant protein is more prone to forming amyloid aggregates. The misfolding associated with the p.D109G mutation may result in abnormal interactions of human αB-Cry with its natural partners (e.g., desmin), leading to the formation of protein aggregates. These aggregates can interfere with normal cellular processes and may contribute to muscle cell dysfunction and damage, resulting in the pathogenic involvement of the p.D109G mutant protein in restrictive cardiomyopathy and skeletal myopathy.

Echocardiography-Based Deep Learning Model to Differentiate Constrictive Pericarditis and Restrictive Cardiomyopathy.

BACKGROUND: Constrictive pericarditis (CP) is an uncommon but reversible cause of diastolic heart failure if appropriately identified and treated. However, its diagnosis remains a challenge for clinicians. Artificial intelligence may enhance the identification of CP. OBJECTIVES: The authors proposed a deep learning approach based on transthoracic echocardiography to differentiate CP from restrictive cardiomyopathy. METHODS: Patients with a confirmed diagnosis of CP and cardiac amyloidosis (CA) (as the representative disease of restrictive cardiomyopathy) at Mayo Clinic Rochester from January 2003 to December 2021 were identified to extract baseline demographics. The apical 4-chamber view from transthoracic echocardiography studies was used as input data. The patients were split into a 60:20:20 ratio for training, validation, and held-out test sets of the ResNet50 deep learning model. The model performance (differentiating CP and CA) was evaluated in the test set with the area under the curve. GradCAM was used for model interpretation. RESULTS: A total of 381 patients were identified, including 184 (48.3%) CP, and 197 (51.7%) CA cases. The mean age was 68.7 ± 11.4 years, and 72.8% were male. ResNet50 had a performance with an area under the curve of 0.97 to differentiate the 2-class classification task (CP vs CA). The GradCAM heatmap showed activation around the ventricular septal area. CONCLUSIONS: With a standard apical 4-chamber view, our artificial intelligence model provides a platform to facilitate the detection of CP, allowing for improved workflow efficiency and prompt referral for more advanced evaluation and intervention of CP.

Prognosis after heart transplant in patients with hypertrophic and restrictive cardiomyopathy. A nationwide registry analysis.

INTRODUCTION AND OBJECTIVES: Posttransplant outcomes among recipients with a diagnosis of hypertrophic cardiomyopathy (HCM) or restrictive cardiomyopathy (RCM) remain controversial. METHODS: Retrospective analysis of a nationwide registry of first-time recipients undergoing isolated heart transplant between 1984 and 2021. One-year and 5-year mortality in recipients with HCM and RCM were compared with those with dilated cardiomyopathy (DCM). RESULTS: We included 3703 patients (3112 DCM; 331 HCM; 260 RCM) with a median follow-up of 5.0 [3.1-5.0] years. Compared with DCM, the adjusted 1-year mortality risk was: HCM: HR, 1.38; 95%CI, 1.07-1.78; P=.01, RCM: HR, 1.48; 95%CI, 1.14-1.93; P=.003. The adjusted 5-year mortality risk was: HCM: HR, 1.17; 95%CI, 0.93-1.47; P=.18; RCM: HR, 1.52; 95%CI, 1.22-1.89; P<.001. Over the last 20 years, the RCM group showed significant improvement in 1-year survival (adjusted R2=0.95) and 5-year survival (R2=0.88); the HCM group showed enhanced the 5-year survival (R2=0.59), but the 1-year survival remained stable (R2=0.16). CONCLUSIONS: Both RCM and HCM were linked to a less favorable early posttransplant prognosis compared with DCM. However, at the 5-year mark, this unfavorable difference was evident only for RCM. Notably, a substantial temporal enhancement in both early and late mortality was observed for RCM, while for HCM, this improvement was mainly evident in late mortality.

Clinical features, etiology, and survival in patients with restrictive cardiomyopathy: A single-center experience.

BACKGROUND: Numerous prognostic factors have been proposed for cardiac amyloidosis (CA). The knowledge about other subtypes of restrictive cardiomyopathy (RCM) is scant. AIMS: This study aimed to elucidate the etiology and prognostic factors of RCM as well as assess cardiac biomarkers: high-sensitive troponin T (hs-TnT), growth differentiation factor-15 (GDF-15), N-terminal pro-B-type natriuretic peptide (NT-proBNP), and soluble suppression of tumorigenicity 2, as mortality predictors in RCM. METHODS: We enrolled 36 RCM patients in our tertiary cardiac department. All patients were screened for CA. Genetic testing was performed in 17 patients without CA. RESULTS: Pathogenic or likely pathogenic gene variants were found in 86% of patients, including 5 novel variants. Twenty patients died, and 4 had a heart transplantation during the study. Median overall survival was 29 months (8-55). The univariate Cox models analysis indicated that systolic and diastolic blood pressure, GDF-15, hs-TnT, NT-proBNP, left ventricular stroke volume, the ratio of the transmitral early peak velocity (E) estimated by pulsed wave Doppler over the early mitral annulus velocity (e'), tricuspid annulus plane systolic excursion, early tricuspid valve annular systolic velocity, the presence of pulmonary hypertension, and pericardial effusion influenced survival (P <0.05). A worse prognosis was observed in patients with GDF-15 >1316 pg/ml, hs-TnT >42 ng/l, NT-proBNP >3383 pg/ml, and pericardial effusion >3.5 mm (Kaplan-Meier analysis, log-rank test, P <0.001). CONCLUSIONS: Genetic testing should be considered in every RCM patient where light-chain amyloidosis has been excluded. Survival remains poor regardless of etiology. Increased concentrations of GDF-15, hs-TNT, NT-proBNP, and pericardial effusion are associated with worse prognosis. Further studies are warranted.

Effects of diabetes mellitus on left ventricular function and deformation in patients with restrictive cardiomyopathies: a 3.0T CMR feature tracking study.

BACKGROUND: Diabetes mellitus (DM) is the most common metabolic disease worldwide and a major risk factor for adverse cardiovascular events, while the additive effects of DM on left ventricular (LV) deformation in the restrictive cardiomyopathy (RCM) cohort remain unclear. Accordingly, we aimed to investigate the additive effects of DM on LV deformation in patients with RCM. MATERIALS AND METHODS: One hundred thirty-six RCM patients without DM [RCM(DM-)], 46 with DM [RCM (DM+)], and 66 age- and sex-matched control subjects who underwent cardiac magnetic resonance (CMR) scanning were included. LV function, late gadolinium enhancement (LGE) type, and LV global peak strains (including radial, circumferential, and longitudinal directions) were measured. The determinant of reduced LV global myocardial strain for all RCM patients was assessed using multivariable linear regression analyses. The receiver operating characteristic curve (ROC) was performed to illustrate the relationship between DM and decreased LV deformation. RESULTS: Compared with the control group, RCM (DM-) and RCM(DM+) patients presented increased LV end-diastolic index and end-systolic volume index and decreased LV ejection fraction. LV GPS in all three directions and longitudinal PDSR progressively declined from the control group to the RCM(DM-) group to the RCM(DM+) group (all p < 0.05). DM was an independent determinant of impaired LV GPS in the radial, circumferential, and longitudinal directions and longitudinal PDSR (ß = - 0.217, 0.176, 0.253, and - 0.263, all p < 0.05) in RCM patients. The multiparameter combination, including DM, showed an AUC of 0.81(95% CI 0.75-0.87) to predict decreased LV GLPS and an AUC of 0.69 (95% CI 0.62-0.76) to predict decreased LV longitudinal PDSR. CONCLUSIONS: DM may have an additive deleterious effect on LV dysfunction in patients with RCM, especially diastolic dysfunction in RCM patients, indicating the importance of early identification and initiation of treatment of DM in patients with RCM.

Thyroid hormone induces restrictive cardiomyopathy in ß1-adrenoceptor knockout mice.

The purpose of this study was to characterize the role of ß1-AR signaling and its cross-talk between cardiac renin-angiotensin system and thyroid-hormone-induced cardiac hypertrophy. T3 was administered at 0.5 mg·kg-1·day-1 for 10 days in ß1-KOT3 and WTT3 groups, while control groups received vehicle alone. Echocardiography and myocardial histology was performed; cardiac and serum ANGI/ANGII and ANP and cardiac levels of p-PKA, p-ERK1/2, p-p38-MAPK, p-AKT, p-4EBP1, and ACE were measured. WTT3 showed decreased IVSTd and increased LVEDD versus WTsal (p < 0.05). ß1-KOT3 exhibited lower LVEDD and higher relative IVSTd versus ß1-KOsal, the lowest levels of ejection fraction, and the highest levels of cardiomyocyte diameter (p < 0.05). Cardiac ANP levels decreased in WTT3 versus ß1-KOT3 (p < 0.05). Cardiac ACE expression was increased in T3-treated groups (p < 0.05). Phosphorylated-p38 MAPK levels were higher in WTT3 versus WTsal or ß1-KOT3, p-4EBP1 was elevated in ß1-KO animals, and p-ERK1/2 was up-regulated in ß1-KOT3. These findings suggest that ß1-AR signaling is crucial for TiCH.