MYH7 R453C induced cardiac remodelling via activating TGF-ß/Smad2/3, ERK1/2 and Nox4/ROS/NF-κB signalling pathways.

Hypertrophic cardiomyopathy (HCM) is a monogenic cardiac disorder commonly induced by sarcomere gene mutations. However, the mechanism for HCM is not well defined. Here, we generated transgenic MYH7 R453C and MYH6 R453C piglets and found both developed typical cardiac hypertrophy. Unexpectedly, we found serious fibrosis and cardiomyocyte loss in the ventricular of MYH7 R453C, not MYH6 R453C piglets, similar to HCM patients. Then, RNA-seq analysis and western blotting identified the activation of ERK1/2 and PI3K-Akt pathways in MYH7 R453C. Moreover, we observed an increased expression of fetal genes and an excess of reactive oxygen species (ROS) in MYH7 R453C piglet models, which was produced by Nox4 and subsequently induced inflammatory response. Additionally, the phosphorylation levels of Smad2/3, ERK1/2 and NF-kB p65 proteins were elevated in cardiomyocytes with the MYH7 R453C mutation. Furthermore, epigallocatechin gallate, a natural bioactive compound, could be used as a drug to reduce cell death by adjusting significant downregulation of the protein expression of Bax and upregulated Bcl-2 levels in the H9C2 models with MYH7 R453C mutation. In conclusion, our study illustrated that TGF-ß/Smad2/3, ERK1/2 and Nox4/ROS pathways have synergistic effects on cardiac remodelling and inflammation in MYH7 R453C mutation.

Exploring Health-Related Quality of Life in Children With Hypertrophic Cardiomyopathy and Relationship to Physical Activity.

BACKGROUND: Hypertrophic cardiomyopathy is a burdensome condition that inflicts both physical and psychological impairment on those with the disease, negatively impacting health-related quality of life (HRQoL). Given the abundance of evidence suggesting a role of physical activity (PA) in modulating HRQoL in healthy populations of children, we sought to determine the relationship between HRQoL and PA in children diagnosed with hypertrophic cardiomyopathy. METHODS AND RESULTS: A multicenter prospective observational cohort study was conducted, with patients with hypertrophic cardiomyopathy aged 10 to 19 years being provided a wrist-worn activity tracker (Fitbit Charge HR) to wear for 14 days. Patients self-reported on Pediatric Quality of Life 4.0 quality of life inventory items, which were associated with PA metrics following covariate adjustment using linear regression. A total of 56 participants were recruited to the study. The median age at enrollment was 15.5 years (interquartile range, 13.8-16.8), and 16 out of 56 (29%) of the cohort were girls. The cohort reported decreased metrics of physical, psychosocial, and total summary scores compared with health reference populations, with scores comparable with that of published populations with chronic disease. Increased physical HRQoL scores were significantly associated with increased daily steps taken, distance traveled, and flights of stairs climbed. CONCLUSIONS: These results show that impaired PA correlates with reduced HRQoL in children with hypertrophic cardiomyopathy, suggesting PA may partially mediate HRQoL in this population.

Impaired longitudinal systolic-diastolic coupling and cardiac response to exercise in patients with hypertrophic cardiomyopathy.

BACKGROUND: In patients with hypertrophic cardiomyopathy (HCM), impaired augmentation of stroke volume and diastolic dysfunction contribute to exercise intolerance. Systolic-diastolic (S-D) coupling characterizes how systolic contraction of the left ventricle (LV) primes efficient elastic recoil during early diastole. Impaired S-D coupling may contribute to the impaired cardiac response to exercise in patients with HCM. METHODS: Patients with HCM (n = 25, age = 47 ± 9 years) and healthy adults (n = 115, age = 49 ± 10 years) underwent a cardiopulmonary exercise testing (CPET) and echocardiogram. S-D coupling was defined as the ratio of LV longitudinal excursion of the mitral annulus during early diastole (EDexc) and systole (Sexc) and compared between groups. Peak oxygen uptake (peak V̇O2) (Douglas bags), cardiac index (C2H2 rebreathe), and stroke volume index (SVi) were assessed during CPET. Linear regression was performed between S-D coupling and peak V̇O2, peak cardiac index, and peak SVi. RESULTS: S-D coupling was lower in HCM (Controls: 0.63 ± 0.08, HCM: 0.56 ± 0.10, p < 0.001). Peak V̇O2 and stroke volume reserve were lower in patients with HCM (Peak VO2 Controls: 28.5 ± 5.5, HCM: 23.7 ± 7.2 mL/kg/min, p < 0.001, SV reserve: Controls 39 ± 16, HCM 30 ± 18 mL, p = 0.008). In patients with HCM, S-D coupling was associated with peak V̇O2 (r = 0.47, p = 0.018), peak cardiac index (r = 0.60, p = 0.002), and peak SVi (r = 0.63, p < 0.001). CONCLUSION: Systolic-diastolic coupling was impaired in patients with HCM and was associated with fitness and the cardiac response to exercise. Inefficient S-D coupling may link insufficient stroke volume generation, diastolic dysfunction, and exercise intolerance in HCM.

Genetic Mutations and Mitochondrial Redox Signaling as Modulating Factors in Hypertrophic Cardiomyopathy: A Scoping Review.

Hypertrophic cardiomyopathy (HCM) is a heart condition characterized by cellular and metabolic dysfunction, with mitochondrial dysfunction playing a crucial role. Although the direct relationship between genetic mutations and mitochondrial dysfunction remains unclear, targeting mitochondrial dysfunction presents promising opportunities for treatment, as there are currently no effective treatments available for HCM. This review adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Extension for Scoping Reviews guidelines. Searches were conducted in databases such as PubMed, Embase, and Scopus up to September 2023 using "MESH terms". Bibliographic references from pertinent articles were also included. Hypertrophic cardiomyopathy (HCM) is influenced by ionic homeostasis, cardiac tissue remodeling, metabolic balance, genetic mutations, reactive oxygen species regulation, and mitochondrial dysfunction. The latter is a common factor regardless of the cause and is linked to intracellular calcium handling, energetic and oxidative stress, and HCM-induced hypertrophy. Hypertrophic cardiomyopathy treatments focus on symptom management and complication prevention. Targeted therapeutic approaches, such as improving mitochondrial bioenergetics, are being explored. This includes coenzyme Q and elamipretide therapies and metabolic strategies like therapeutic ketosis. Understanding the biomolecular, genetic, and mitochondrial mechanisms underlying HCM is crucial for developing new therapeutic modalities.

Novel Multiplexed Plasma Biomarker Panel Has Diagnostic and Prognostic Potential in Children With Hypertrophic Cardiomyopathy.

BACKGROUND: Hypertrophic cardiomyopathy (HCM) is defined clinically by pathological left ventricular hypertrophy. We have previously developed a plasma proteomics biomarker panel that correlates with clinical markers of disease severity and sudden cardiac death risk in adult patients with HCM. The aim of this study was to investigate the utility of adult biomarkers and perform new discoveries in proteomics for childhood-onset HCM. METHODS: Fifty-nine protein biomarkers were identified from an exploratory plasma proteomics screen in children with HCM and augmented into our existing multiplexed targeted liquid chromatography-tandem/mass spectrometry-based assay. The association of these biomarkers with clinical phenotypes and outcomes was prospectively tested in plasma collected from 148 children with HCM and 50 healthy controls. Machine learning techniques were used to develop novel pediatric plasma proteomic biomarker panels. RESULTS: Four previously identified adult HCM markers (aldolase fructose-bisphosphate A, complement C3a, talin-1, and thrombospondin 1) and 3 new markers (glycogen phosphorylase B, lipoprotein a and profilin 1) were elevated in pediatric HCM. Using supervised machine learning applied to training (n=137) and validation cohorts (n=61), this 7-biomarker panel differentiated HCM from healthy controls with an area under the curve of 1.0 in the training data set (sensitivity 100% [95% CI, 95-100]; specificity 100% [95% CI, 96-100]) and 0.82 in the validation data set (sensitivity 75% [95% CI, 59-86]; specificity 88% [95% CI, 75-94]). Reduced circulating levels of 4 other peptides (apolipoprotein L1, complement 5b, immunoglobulin heavy constant epsilon, and serum amyloid A4) found in children with high sudden cardiac death risk provided complete separation from the low and intermediate risk groups and predicted mortality and adverse arrhythmic outcomes (hazard ratio, 2.04 [95% CI, 1.0-4.2]; P=0.044). CONCLUSIONS: In children, a 7-biomarker proteomics panel can distinguish HCM from controls with high sensitivity and specificity, and another 4-biomarker panel identifies those at high risk of adverse arrhythmic outcomes, including sudden cardiac death.

Integrating Clinical Phenotype With Multiomics Analyses of Human Cardiac Tissue Unveils Divergent Metabolic Remodeling in Genotype-Positive and Genotype-Negative Patients With Hypertrophic Cardiomyopathy.

BACKGROUND: Hypertrophic cardiomyopathy (HCM) is caused by sarcomere gene mutations (genotype-positive HCM) in ≈50% of patients and occurs in the absence of mutations (genotype-negative HCM) in the other half of patients. We explored how alterations in the metabolomic and lipidomic landscape are involved in cardiac remodeling in both patient groups. METHODS: We performed proteomics, metabolomics, and lipidomics on myectomy samples (genotype-positive N=19; genotype-negative N=22; and genotype unknown N=6) from clinically well-phenotyped patients with HCM and on cardiac tissue samples from sex- and age-matched and body mass index-matched nonfailing donors (N=20). These data sets were integrated to comprehensively map changes in lipid-handling and energy metabolism pathways. By linking metabolomic and lipidomic data to variability in clinical data, we explored patient group-specific associations between cardiac and metabolic remodeling. RESULTS: HCM myectomy samples exhibited (1) increased glucose and glycogen metabolism, (2) downregulation of fatty acid oxidation, and (3) reduced ceramide formation and lipid storage. In genotype-negative patients, septal hypertrophy and diastolic dysfunction correlated with lowering of acylcarnitines, redox metabolites, amino acids, pentose phosphate pathway intermediates, purines, and pyrimidines. In contrast, redox metabolites, amino acids, pentose phosphate pathway intermediates, purines, and pyrimidines were positively associated with septal hypertrophy and diastolic impairment in genotype-positive patients. CONCLUSIONS: We provide novel insights into both general and genotype-specific metabolic changes in HCM. Distinct metabolic alterations underlie cardiac disease progression in genotype-negative and genotype-positive patients with HCM.

The abnormalities of free fatty acid metabolism in patients with hypertrophic cardiomyopathy, a single-center retrospective observational study.

BACKGROUND: Previous studies have shown the importance of energy deficiency and malfunctioning mitochondria in the pathophysiology of hypertrophic cardiomyopathy (HCM). There has been a little research into the relationship between plasma free fatty acids (FFA), one of the heart's main energy sources, and HCM. We evaluated its clinical importance in HCM to see if there was a link between plasma FFA metabolism and HCM. METHODS: In a single-center retrospective observational study, we investigated 420 HCM patients diagnosed at Beijing Anzhen Hospital between January 1, 2018, and December 31, 2022. Meanwhile, 1372 individuals without HCM (non-HCM) were recruited. 391 non-HCM patients were chosen as controls via a propensity score matching (PSM) study with a 1:1 ratio. RESULTS: FFA in HCM patients showed statistically significant correlations with creatinine (r = 0.115, p = 0.023), estimated GFR (r=-0.130, p = 0.010), BNP (r = 0.152, p = 0.007), LVEF (r=-0.227, p < 0.001), LVFS (r=-0.160, p = 0.002), and LAD (r = 0.112, p = 0.028). Higher FFA levels were found in HCM patients who had atrial fibrillation and NYHY functional classes III or IV (p = 0.015 and p = 0.022, respectively). In HCM patients, multiple linear regression analysis revealed that BNP and LVEF had independent relationships with increasing FFA (Standardized = 0.139, p = 0.013 and =-0.196, p < 0.001, respectively). CONCLUSIONS: Among HCM patients, the plasma FFA concentration was lower, and those with AF and NYHY functional class III or IV had higher FFA levels, and LVEF and BNP were independently associated with increasing FFA. The findings of the study should help inspire future efforts to better understand how energy deficiency contributes to hypertrophic cardiomyopathy (HCM) development.

A therapeutic leap: how myosin inhibitors moved from cardiac interventions to skeletal muscle myopathy solutions.

The myosin inhibitor mavacamten has transformed the management of obstructive hypertrophic cardiomyopathy (HCM) by targeting myosin ATPase activity to mitigate cardiac hypercontractility. This therapeutic mechanism has proven effective for patients with HCM independent of having a primary gene mutation in myosin. In this issue of the JCI, Buvoli et al. report that muscle hypercontractility is a mechanism of pathogenesis underlying muscle dysfunction in Laing distal myopathy, a disorder characterized by mutations altering the rod domain of ß myosin heavy chain. The authors performed detailed physiological, molecular, and biomechanical analyses and demonstrated that myosin ATPase inhibition can correct a large extent of muscle abnormalities. The findings offer a therapeutic avenue for Laing distal myopathy and potentially other myopathies. This Commentary underscores the importance of reevaluating myosin activity's role across myopathies in general for the potential development of targeted myosin inhibitors to treat skeletal muscle disorders.

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

BACKGROUND: Hypertrophic cardiomyopathy (HCM) is rare in children, and sudden cardiac death (SCD) is difficult to predict. Two prognostic scores - HCM Risk-Kids and Precision Medicine for Cardiomyopathy (PRIMaCY) - were developed to assess the risk of SCD in the next 5 years in children with HCM. AIMS: To test the ability of these scores to predict SCD in children with HCM. Also, to identify factors associated with a severe cardiac rhythmic event (SCRE) (ventricular fibrillation, sustained ventricular tachycardia, heart transplant for rhythmic reasons or SCD). METHODS: Retrospective, multicentre, observational study at 10 medical centres in the Nord-Pas-de-Calais region, France. RESULTS: This study included 72 paediatric patients with HCM during 2009-2019 who were followed for a median (interquartile range [IQR]) of 8.5 (5.0-16.2) years. Eleven patients (15.3%) presented with SCRE. HCM Risk-Kids was high, with a median (IQR) score of 6.2% (2.1-12.8%; significant threshold≥6.0%) and the PRIMaCY median (IQR) score was 7.1% (2.6-15.0%; significant threshold≥8.3%). The positive predictive value was only 27.1% (95% confidence interval [CI] 21.5-32.5%) for HCM Risk-Kids (with a threshold of≥6.0%) and 33.2% (95% CI 27.1-38.9%) for the PRIMaCY score (with a threshold of≥8.3%). The negative predictive values were 95.4% (95% CI 92.3-97.7%) and 93.0% (95% CI 89.8-96.2%), respectively. Three of 28 patients with an implantable cardioverter defibrillator (ICD) experienced complications (including inappropriate shocks). CONCLUSION: HCM Risk-Kids and the PRIMaCY score have low positive predictive values to predict SCD in paediatric patients. If used alone, they could increase the rate of ICD implantation and thus ICD complications. Therefore, the scores should be used in combination with other data (genetic and magnetic resonance imaging results).

Target population for a selective cardiac myosin inhibitor in hypertrophic obstructive cardiomyopathy: Real-life estimation from the French register of hypertrophic cardiomyopathy (REMY).

BACKGROUND: The efficacy of current pharmacological therapies in hypertrophic cardiomyopathy is limited. A cardiac myosin inhibitor, mavacamten, has recently been approved as a first-in-class treatment for symptomatic hypertrophic obstructive cardiomyopathy. AIMS: To assess the profile and burden of cardiac myosin inhibitor candidates in the hypertrophic cardiomyopathy prospective Register of hypertrophic cardiomyopathy (REMY) held by the French Society of Cardiology. METHODS: Data were collected at baseline and during follow-up from patients with hypertrophic cardiomyopathy enrolled in REMY by the three largest participating centres. RESULTS: Among 1059 adults with hypertrophic cardiomyopathy, 461 (43.5%) had obstruction; 325 (30.7%) of these were also symptomatic, forming the "cardiac myosin inhibitor candidates" group. Baseline features of this group were: age 58±15years; male sex (n=196; 60.3%); diagnosis-to-inclusion delay 5 (1-12)years; maximum wall thickness 20±6mm; left ventricular ejection fraction 69±6%; family history of hypertrophic cardiomyopathy or sudden cardiac death (n=133; 40.9%); presence of a pathogenic sarcomere gene mutation (n=101; 31.1%); beta-blocker or verapamil treatment (n=304; 93.8%), combined with disopyramide (n=28; 8.7%); and eligibility for septal reduction therapy (n=96; 29%). At the end of a median follow-up of 66 (34-106) months, 319 (98.2%) were treated for obstruction (n=43 [13.2%] received disopyramide), 46 (14.2%) underwent septal reduction therapy and the all-cause mortality rate was 1.9/100 person-years (95% confidence interval 1.4-2.6) (46 deaths). Moreover, 41 (8.9%) patients from the initial hypertrophic obstructive cardiomyopathy group became eligible for a cardiac myosin inhibitor. CONCLUSIONS: In this cohort of patients with hypertrophic cardiomyopathy selected from the REMY registry, one third were eligible for a cardiac myosin inhibitor.

Sex-Related Differences in Patients With Hypertrophic Cardiomyopathy Undergoing Alcohol Septal Ablation.

BACKGROUND: Previous studies have shown that women with hypertrophic obstructive cardiomyopathy (HCM) have worse long-term outcomes irrespective of intervention. However, the outcomes of patients undergoing alcohol septal ablation (ASA) based on sex have not been described. Hence, this study aimed to evaluate pressure changes and long-term mortality in patients with HCM undergoing ASA based on sex. METHODS AND RESULTS: This is a single-center retrospective study evaluating hemodynamic changes and long-term mortality in patients with HCM treated with ASA according to sex. A total of 259 patients were included (aged 68.4±11.9 years, 62.2% women). Women had higher age and baseline pressures at the time of ASA, with a greater percent reduction in mean left atrial pressure (men versus women: 2.2% versus 15.9%, respectively; P=0.02). Women had better survival (median survival rate of men versus women: 8.6 versus 12.5 years, respectively; P=0.011). On Cox multivariable regression, predictors of mortality were age (per group change <60 years, 61-70 years, 71-80 years, and >80 years; hazard ratio [HR], 1.45 [95% CI, 1.10-1.91], P=0.008), female sex (HR, 0.59 [95% CI, 0.35-0.99], P=0.048), chronic kidney disease (HR, 1.88 [95% CI, 1.06-3.33], P=0.031), and left ventricular outflow tract gradient reduction ≤86% (HR, 1.91 [95% CI, 1.14-3.19], P=0.014). CONCLUSIONS: Women with HCM undergoing ASA are older and have higher left-sided baseline pressures compared with men yet have better survival. Further studies exploring the mechanisms of differential outcomes according to sex in patients with HCM undergoing ASA are needed.

Hypertrophic cardiomyopathy in pregnancy: Nationwide analysis of patients characteristics and outcomes.

INTRODUCTION: Hypertrophic cardiomyopathy (HCM) poses unique challenges in the management of pregnant patients due to the complex interplay of physiological changes of pregnancy. Despite its relatively low prevalence among pregnant women, HCM can significantly impact maternal and fetal outcomes. This study aims to enhance understanding of pregnant patients with HCM and the associated outcomes through a nationwide analysis of patient characteristics and outcomes. METHODS: A retrospective analysis was conducted using data obtained from the Agency for Healthcare Research in Quality (AHRQ) Nationwide Inpatient Sample (NIS) database from January 2016 to December 2020. 3,599,855 pregnant patients without HCM and 187 pregnant patients with HCM were identified using International Classification of Disease (ICD) codes, and baseline characteristics, medical comorbidities, and outcomes were compared between the two groups. RESULTS: Significant differences were observed in baseline characteristics, including age distribution, racial composition, and prevalence of systemic organ disease, between pregnant women with and without HCM. Women with HCM had higher odds of experiencing maternal complications, such as acute heart failure and peripartum cardiomyopathy, as well as higher rates of fetal distress and obstetric interventions, including preterm delivery and caesarean section. CONCLUSION: Comprehensive cardiovascular assessment and risk stratification are essential in pregnant women with HCM to optimize maternal and fetal outcomes. Moreover, disparities in baseline characteristics and outcomes among black pregnant women with HCM highlight the need for a multifactorial approach to addressing pregnancy-related complications.

2024 AHA/ACC/AMSSM/HRS/PACES/SCMR Guideline for the Management of Hypertrophic Cardiomyopathy: A Report of the American Heart Association/American College of Cardiology Joint Committee on Clinical Practice Guidelines.

AIM: The "2024 AHA/ACC/AMSSM/HRS/PACES/SCMR Guideline for the Management of Hypertrophic Cardiomyopathy" provides recommendations to guide clinicians in the management of patients with hypertrophic cardiomyopathy. METHODS: A comprehensive literature search was conducted from September 14, 2022, to November 22, 2022, encompassing studies, reviews, and other evidence on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, the Agency for Healthcare Research and Quality, and other selected databases relevant to this guideline. Additional relevant studies, published through May 23, 2023, during the guideline writing process, were also considered by the writing committee and added to the evidence tables, where appropriate. STRUCTURE: Hypertrophic cardiomyopathy remains a common genetic heart disease reported in populations globally. Recommendations from the "2020 AHA/ACC Guideline for the Diagnosis and Treatment of Patients With Hypertrophic Cardiomyopathy" have been updated with new evidence to guide clinicians.

Hypertrophic cardiomyopathy and competitive sports: let 'em play?

PURPOSE OF REVIEW: Hypertrophic cardiomyopathy (HCM) is one of the most common cardiovascular genetic conditions. Although most patients with HCM typically do well clinically, there is a small but real incidence of sudden cardiac death. A diagnosis of HCM was previously a reason for complete exclusion in sports, particularly competitive sports.However, many of these recommendations are based on expert consensus, and much data has been published in the last decade furthering the scientific knowledge in this area, and allowing athletes who may have been previously excluded the potential to participate in strenuous activities and competitive sports. RECENT FINDINGS: With recent publications on participation in sports with HCM, as well as an emphasis on shared decision-making, more athletes with HCM are participating in competitive sports, even at a professional level. Even contact sports in the presence of an implantable cardioverter-defibrillator are no longer mutually exclusive in the current era. SUMMARY: Previous guidelines were likely overly restrictive for patients with HCM. Although there is a risk of sudden death that cannot be ignored, the potential for shared decision making as well as medical guidance are entering a new era in all aspects of medicine, particularly in sports participation.

Temporal trends, prevalence, predictors, and outcomes of heart failure in patients with hypertrophic cardiomyopathy in the United States: Insights from the national inpatient sample.

OBJECTIVES: This study aims to delineate the temporal trends, prevalence, predictors, and outcomes of HF among HCM patients using the National Inpatient Sample (NIS) database, with a focus on optimizing therapeutic strategies and healthcare resources. METHODS: We conducted a retrospective cohort analysis of anonymized data from the NIS spanning 2016 to 2019. The study population consisted of adults diagnosed with HCM based on specific ICD-10 diagnostic codes. Logistic regression was utilized to explore the association between HF and in-hospital mortality, adjusting for demographic and clinical factors. RESULTS: Our analysis included 215,505 individuals, with 97,875 (45.4 %) experiencing HF. Patients with HF exhibited a higher burden of comorbidities such as diabetes and renal failure, and had increased odds of mortality (OR 1.41). The study also highlighted significant demographic disparities, with marked differences in outcomes based on race and gender. The economic analysis revealed higher healthcare costs and longer hospital stays associated with HF. CONCLUSION: HF significantly impacts mortality, healthcare costs, and hospitalization length in HCM patients, with substantial demographic and clinical disparities. This study underscores the importance of tailored management strategies and the need for continuous surveillance and research to address the challenges posed by HF in HCM.