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Background: Alcohol septal ablation (ASA) is recommended for moderate to severe symptomatic patients with hypertrophic obstructive cardiomyopathy. The current guidelines don not recommend particular alcohol doses and the amount of alcohol injected into the septal artery is based more on the interventionalist's decision rather than on systematic evidence. Our objective is to execute a comprehensive assessment of the efficacy and safety of low alcohol doses (1-2 ml)) in comparison to large ones (2-4 ml)., Methods: Multiple databases, encompassing PubMed, WOS, Scopus, Embase, and Cochrane library were systemically assessed from inception to October 2023. Randomized controlled trials (RCTs) and observational studies comparing low-alcohol and high-alcohol dose in patients with HOCM was included. The main outcome was creatine kinase-MB (CK-MB). The secondary ones are septal thickness, left ventricular outflow pressure gradient, and atrioventricular (AV) block., Results: Eight studies, with a total of 1446 individuals, were finally involved in our investigation. low alcohol doses showed lower CK-MB levels relative to high ones (MD=-0.93, 95% CI [-1.15 to -0.72], P = 0.00001). Furthermore, in terms of septal thickness, left ventricular outflow pressure gradient, and AV block, neither of the two doses was preferred., Conclusion: We propose that the low alcohol dose is equally effective as the high dose. moreover, the low alcohol dose was associated with a lower CK-MB levels in comparison to the high one., Prospero Registration: CRD42024511537., (© 2024. The Author(s).)

Background: Hypertrophic cardiomyopathy (HCM) is a common inherited cardiac disease, and clinical and genetic family screening is recommended by guidelines., Objectives: This study sought to investigate the diagnostic yield of screening relatives of HCM patients and identify predictive factors for HCM development during long-term follow-up in relatives from gene-elusive families., Methods: This was a retrospective cohort study of families screened at clinics for inherited cardiomyopathies in Eastern Denmark, from 2006 to 2023., Results: We included 1,230 relatives (55% female; age: 42 ± 17 years) from 531 families. The combined clinical and genetic yield at baseline was 26% (n = 321). After 7 years (mean) of follow-up (6,762 person-years), 43 (4%) additional relatives developed HCM. The strongest predictors of developing HCM were carrying a likely pathogenic/pathogenic variant (HR: 4.58; 95% CI: 2.50-8.40; P < 0.001) and larger left ventricular maximum wall thickness (MWT) (HR: 2.21 per mm; 95% CI: 1.76-2.77 per mm; P < 0.001). In gene-elusive families, we found that an MWT of ≥10 mm represented the optimal classification threshold for developing HCM (area under the curve: 0.80), with only 2 (0.4%) relatives from gene-elusive families with an MWT of <10 mm developing HCM during follow-up., Conclusions: In HCM, the diagnostic yield of a single screening visit was 1 in 4, and the additional yield during 7 years of follow-up was 4%. Gene carriers and relatives from gene-elusive families with a baseline MWT of ≥10 mm were at the highest risk of developing HCM during follow-up. These findings may inform future recommendations on the management of relatives of HCM patients., Competing Interests: Funding Support and Author Disclosures The study was supported by Rigshospitalet Research Council. The funder had no part in the design of the study, the collection, analysis, or interpretation of data or publication. The authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2024 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Hypertrophic cardiomyopathy (HCM) is a prevalent genetic cardiovascular disease characterized by asymmetric thickening of the left ventricular wall, frequently occurring in families predisposed genetically. While HCM in twins is rare, it presents a unique opportunity to explore the disease's genetic and epigenetic underpinnings due to the phenotypic heterogeneity observed even among genetically identical individuals. This review collates and analyzes global clinical studies that focus on the twin phenomena in HCM. It explores the genetic foundations of HCM, examines the influence of environmental and epigenetic factors on disease expression, and emphasizes the crucial role of genetic screening in the early and differential diagnosis of HCM. By focusing on twin cases in HCM, this review aims to enhance our understanding of HCM's complex genetic background, which could lead to more personalized approaches in the management and treatment of this condition, thus drawing significant interest from researchers and clinicians alike.

Aims: Atrial fibrillation (AF) is the most common sustained arrhythmia among patients with hypertrophic cardiomyopathy (HCM), increasing symptom burden and stroke risk. We aimed to construct a plasma proteomics-based model to predict new-onset AF in patients with HCM and determine dysregulated signalling pathways., Methods and Results: In this prospective, multi-centre cohort study, we conducted plasma proteomics profiling of 4986 proteins at enrolment. We developed a proteomics-based machine learning model to predict new-onset AF using samples from one institution (training set) and tested its predictive ability using independent samples from another institution (test set). We performed a survival analysis to compare the risk of new-onset AF among high- and low-risk groups in the test set. We performed pathway analysis of proteins significantly (univariable P < 0.05) associated with new-onset AF using a false discovery rate (FDR) threshold of 0.001. The study included 284 patients with HCM (training set: 193, test set: 91). Thirty-seven (13%) patients developed AF during median follow-up of 3.2 years [25-75 percentile: 1.8-5.2]. Using the proteomics-based prediction model developed in the training set, the area under the receiver operating characteristic curve was 0.89 (95% confidence interval 0.78-0.99) in the test set. In the test set, patients categorized as high risk had a higher rate of developing new-onset AF (log-rank P = 0.002). The Ras-MAPK pathway was dysregulated in patients who developed incident AF during follow-up (FDR < 1.0 × 10-6)., Conclusion: This is the first study to demonstrate the ability of plasma proteomics to predict new-onset AF in HCM and identify dysregulated signalling pathways., Competing Interests: Conflict of interest: Y.J.S. has received research funding from Bristol Myers Squibb and consulting income from Bristol Myers Squibb and Moderna Japan. M.S.M. has received consulting income from Akcea, Alnylam, Eidos Therapeutics, Pfizer, Prothena, Novo Nordisk, and Intellia. All remaining authors have declared no conflicts of interest., (© The Author(s) 2024. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Hypertrophic cardiomyopathy (HCM) is the most common cardiomyopathy in cats. The diagnosis can be difficult, requiring advanced echocardiographic skills. Additionally, circulating biomarkers (N-terminal pro-B type natriuretic peptide and cardiac troponin I) have several limitations when used for HCM screening. In previous work, we identified interleukin 18 (IL-18), insulin-like growth factor binding protein 2 (IGFBP-2), brain-type glycogen phosphorylase B (PYGB), and WNT Family Member 5 A (WNT5A) as myocardial genes that show significant differential expression between cats with HCM and healthy cats. The products of these genes are released into the circulation, and we hypothesized that IL-18, IGFBP-2, PYGB, and WNT5A serum RNA and protein concentrations differ between healthy cats, cats with subclinical HCM, and those with HCM and congestive heart failure (HCM + CHF). Reverse transcriptase quantitative polymerase chain reaction (RTqPCR) and enzyme-linked immunosorbent assay (ELISA) were applied to evaluate gene and protein expression, respectively, in the serum of eight healthy controls, eight cats with subclinical HCM, and six cats with HCM + CHF. Serum IGFBP-2 RNA concentrations were significantly different among groups and were highest in cats with subclinical HCM. Compared to healthy controls, serum IL-18 and WNT5A gene expression were significantly higher in cats with HCM + CHF, and WNT5A was higher in cats with subclinical HCM. No differences were observed for PYGB. These results indicate that further investigation via large scale clinical studies for IGFBP-2, WNT5A, and IL-18 may be valuable in diagnosing and staging feline HCM., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Crown Copyright © 2024. Published by Elsevier Ltd. All rights reserved.)

Hypertrophic cardiomyopathy (HCM) patients with sarcomere mutations have an increased risk of heart failure and left ventricular (LV) systolic dysfunction. We hypothesize that sarcomere mutation carriers have abnormal myocardial contractility before LV dysfunction. Therefore, we aimed to associate myocardial contractility with identified sarcomere mutations and predict genotyped HCM patients with sarcomere mutation by three-dimensional speckle tracking imaging (3D-STI). A retrospective analysis of 117 HCM patients identified 32 genotype-positive (G +) and 85 genotype-negative (G-) patients. Genotype-positive patients had higher globe circumferential strain (GCS), globe longitudinal strain (GLS), and globe radial strain (GRS) (p < 0.05), and multivariate logistic regression revealed that these variables were associated with a positive genetic status (p < 0.05). After the propensity matches other possible influencing factors, we developed three models, named Model GCS, Model GLS, and Model GRS, which could identified genotype-positive HCM patients with excellent performance (AUC of 0.855, 0.833, and 0.870 respectively, all p < 0.001). Genotype-positive HCM patients show a higher myocardial hyper-contractility status than patients without sarcomere mutations. When combined with clinical and echocardiographic markers, the 3D-STI parameters can effectively identify the likelihood of genotype-positive HCM., (© 2024. Springer Nature Japan KK, part of Springer Nature.)

Hypertrophic obstructive cardiomyopathy (HOCM) is an autosomal dominant condition that still remains significantly under-diagnosed worldwide. Early detection through clinical evaluation, imaging, and familial history is crucial to prevent severe complications such as heart failure and sudden cardiac death. While cuddsnt management strategies primarily offer symptomatic relief through pharmacotherapy or invasive procedures, their effectiveness and accessibility are limited, revealing substantial gaps in care. The emergence of Mavacamten, a recently FDA-approved drug, could potentially revolutionize HOCM management as it addresses the underlying pathophysiology by inhibiting cardiac myosin ATPase, showing promise in reducing obstruction and improving cardiac function. Our review aims to assess mavacamten's efficacy, emphasizing the pivotal role of genetic testing in identifying at-risk individuals and guiding precise diagnoses for personalized treatments. Additionally, we aim to highlight disparities in access to advanced diagnostics and therapies, particularly affecting underserved populations globally and within communities, as well as explore the potential of artificial intelligence (AI) in enhancing early detection and monitoring treatment responses in HOCM. This review thus offers valuable insights to inform future research directions and clinical practices aimed at optimizing outcomes for individuals with HOCM., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background: Infantile hypertrophic cardiomyopathy (HCM) is a heterogeneous disorder. Apart from registries in high-income nations, there is a shortage of data on the aetiological basis of infantile HCM in low- and middle-income nations. This study attempts to characterise the phenotypic expression, genetic architecture and short-term clinical outcomes of infantile HCM from a South Asian tertiary referral centre., Methods: This study includes all infants from the Amrita HCM cohort between January 2011 and July 2021. Clinical history, ECG, echocardiographic data, and genetic analyses were evaluated., Results: 34 patients with infantile HCM were diagnosed at a median age of 3.7 months (IQR 1-6 months). Underlying aetiologies were RASopathy (n=13; 38%), non-syndromic (n=12; 35%) and inborn errors of metabolism (n=9; 27%). Genetic analysis was done in 20 patients (59%) with a yield of 90%. Clinical presentation included failure to thrive (n=29; 85%), dyspnoea on exertion (n=23; 68%) and clinical heart failure (n=24; 71%). Echo showed concentric left ventricular hypertrophy in 22 patients (65%), obstructive HCM in 11 patients (32%) and left ventricular systolic dysfunction in 6 patients (18%). The mortality rate was 10.0 deaths per 100 patient years over a median follow-up period of 3.1 years. The main risk markers for mortality were the age at diagnosis, gender and concentric Left ventricular hypertrophy., Conclusions: This cohort demonstrates the morphological, functional and genetical heterogeneity of infantile HCM, enunciating the need for integration of cardiology, metabolic and genetic services to achieve optimum outcomes in these patients., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Hypertrophic cardiomyopathy (HCM) is a heterogeneous disorder with varying risks of clinical outcomes, including sudden cardiac death (SCD). We aimed to identify distinct phenotypes among patients with HCM in relation to SCD risk factors, interpret their clinical characteristics, and examine their outcomes., Methods and Results: This retrospective study analyzed 1231 consecutive patients with HCM from 2 tertiary hospitals. We performed latent class analysis to categorize patients into phenotypic groups. Three distinct phenotypic groups were identified using latent class analysis. Group 1 (n=554) consisted of young patients with HCM with minimal SCD risk factors and favorable cardiac remodeling. Group 2 (n=114) comprised young patients with HCM and a high prevalence of SCD risk factors, whereas Group 3 (n=563) included older patients (median age, 68 years). Over a median 6.5-year follow-up, 34 SCD-related events, 131 cardiovascular events, 133 all-cause mortality events, and 70 noncardiovascular mortality events were observed. Group 2 exhibited the highest rate of SCD-related events (5-year SCD rate: Group 1 versus 2 versus 3: 0.8% versus 8.2% versus 4.0%, respectively, P <0.001), and cardiovascular events were more frequent in Groups 2 and 3 compared with Group 1. All-cause and noncardiovascular mortality were the most frequent in Group 3. A simplified decision tree was developed for the straightforward assignment of phenotypic group membership, demonstrating fair concordance., Conclusions: This study identified 3 distinct clinical phenotypes in patients with HCM, each associated with different SCD risks and outcomes. Data-driven phenotyping of patients with HCM offers effective risk stratification and may optimize patient management.

Hypertrophic cardiomyopathy (HCM) is the most common inherited heart disease that is characterized by left ventricular hypertrophy unexplained by secondary causes. Based on international epidemiological data, around 20,000-40,000 patients are expected to be affected in Austria. Due to the wide variety of clinical and morphological manifestations the diagnosis can be difficult and the disease therefore often goes unrecognized. HCM is associated with a substantial reduction in quality of life and can lead to sudden cardiac death, especially in younger patients. Early and correct diagnosis, including genetic testing, is essential for comprehensive counselling of patients and their families and for effective treatment. The latter is especially true as an effective treatment of outflow tract obstruction has recently become available in the form of a first in class cardiac myosin ATPase inhibitor, as a noninvasive alternative to established septal reduction therapies. The aim of this Austrian consensus statement is to summarize the recommendations of international guidelines with respect to the genetic background, pathophysiology, diagnostics and management in the context of the Austrian healthcare system and resources, and to present them in easy to understand algorithms., (© 2024. The Author(s).)

Background: Apical hypertrophic cardiomyopathy (ApHCM) is a variant of hypertrophic cardiomyopathy, with distinct clinical characteristics and outcomes. We aimed to clarify the natural history of patients with ApHCM and identify the risk of end-stage heart failure incidence., Methods and Results: This retrospective study was conducted on patients with hypertrophic cardiomyopathy in China between January 2009 and February 2024. Patients were stratified into ApHCM and non-ApHCM groups. The primary outcome was a composite of major adverse cardiovascular events, including all-cause deaths, heart failure hospitalization, sudden cardiac death, and ventricular tachycardia. The secondary outcome was the incidence of end-stage heart failure, defined as left ventricular ejection fraction <50%. Kaplan-Meier and univariable and multivariable Cox proportional analyses were applied. Adjustment variables were included for important baseline characteristics, comorbidities, and medication use. Of 5653 patients enrolled with hypertrophic cardiomyopathy, 584 (10.3%) had ApHCM and 5069 (89.7%) had non-ApHCM. During the median follow-up period of 4.6 years (1.6-8.0 years), major adverse cardiovascular events occurred in 32.2% (n=1808), with a lower incidence in patients with ApHCM than non-ApHCM (20.4% versus 33.3%, P <0.001). Non-ApHCM was an independent predictor of major adverse cardiovascular events (hazard ratio [HR], 1.65 [95% CI, 1.36-1.99]; P <0.001). In the serial cohort, patients with ApHCM exhibited a lower incidence of end-stage heart failure than those with non-ApHCM (12.4% versus 2.7%, P <0.001). Non-ApHCM was associated with a higher risk of end-stage heart failure development (HR, 2.31 [95% CI, 1.28-4.15]; P <0.001). In subgroup and sensitivity analysis, the results were consistent for our main and secondary outcomes., Conclusions: ApHCM is relatively common in hypertrophic cardiomyopathy and shows lower rates of all-cause mortality and heart failure hospitalizations than non-ApHCM.

Aims: Hypertrophic cardiomyopathy (HCM) is an autosomal dominant genetic cardiac disorder characterized by unexplained left ventricular hypertrophy. It can cause a wide spectrum of clinical manifestations, ranging from asymptomatic to heart failure and sudden cardiac death (SCD). Approximately half of HCM cases are caused by variants in sarcomeric proteins, including α-tropomyosin (TPM1). In this study, we aimed to characterize the clinical and molecular phenotype of HCM in an Iranian pedigree with SCD., Methods and Results: The proband and available family members underwent comprehensive clinical evaluations, including echocardiography, cardiac magnetic resonance (CMR) imaging and electrocardiography (ECG). Whole-exome sequencing (WES) was performed in all available family members to identify the causal variant, which was validated, and segregation analysis was conducted via Sanger sequencing. WES identified a novel missense variant, c.761A>G:p.D254G (NM&#95;001018005.2), in the TPM1 gene, in the proband, his father and one of his sisters. Bioinformatic analysis predicted it to be likely pathogenic. Clinical features in affected individuals were consistent with HCM., Conclusions: The identification of a novel TPM1 variant in a family with HCM and SCD underscores the critical role of genetic screening in at-risk families. Early detection of pathogenic variants can facilitate timely intervention and management, potentially reducing the risk of SCD in individuals with HCM., (© 2024 The Author(s). ESC Heart Failure published by John Wiley & Sons Ltd on behalf of European Society of Cardiology.)

Aims: The aim of this study was to investigate whether the H 2 FPEF score, which was developed to improve the diagnosis of heart failure (HF) with preserved ejection fraction, is associated with HF outcomes in patients with hypertrophic cardiomyopathy (HCM)., Methods and Results: Patients with HCM and preserved left ventricular ejection fraction (LVEF ≥50%) were included from a multicentre registry and the H 2 FPEF score was calculated. Patients were divided into three groups: low (0-1), intermediate (2-5) and high (6-9) H 2 FPEF score. The primary combined endpoint was a composite of all-cause death and HF admissions, while the secondary endpoints were all-cause death and HF admissions separately. A total of 955 patients were included (age 51 ± 17 years, 310 [32.5%] female). Patients with a high H 2 FPEF score (n = 105) were more often female, and presented with more symptoms and comorbidities. On echocardiography, patients with a high H 2 FPEF score had lower LVEF, more impaired diastolic function and more frequently left ventricular outflow tract obstruction. During follow-up (median 90 months [interquartile range 49-176]), 103 (11%) patients died and 57 (6%) patients had a first HF hospitalization. Event-free survival rate for the primary combined and secondary endpoints was lower for patients with an intermediate and high H 2 FPEF score. On multivariate Cox regression analysis, female sex (hazard ratio [HR] 1.670, 95% confidence interval [CI] 1.157-2.410; p = 0.006), Asian ethnicity (HR 6.711, 95% CI 4.076-11.048; p < 0.001), ischaemic heart disease (HR 1.732, 95% CI 1.133-2.650; p =  0.011), left atrial diameter (HR 1.028, 95% CI 1.005-1.051; p = 0.016) and intermediate (HR 2.757, 95% CI 1.612-4.713; p < 0.001) or high H 2 FPEF score (HR 3.689, 95% CI 1.908-7.134; p < 0.001) were independently associated with the primary combined endpoint., Conclusion: The H 2 FPEF score is independently associated with HF outcome in patients with HCM and may be considered for risk stratification., (© 2024 The Author(s). European Journal of Heart Failure published by John Wiley & Sons Ltd on behalf of European Society of Cardiology.)

This retrospective cohort study aimed to assess whether basal septal wall thickness (BSWT), anterior (AML) and posterior (PML) mitral leaflet length, or sex were associated with remaining left ventricular outflow tract obstruction (LVOTO) in patients with hypertrophic obstructive cardiomyopathy (HOCM) undergoing alcohol septal ablation (ASA). One hundred fifty-four patients who underwent ASA at the Karolinska University Hospital in Stockholm, Sweden, between 2009 and 2021, were included retrospectively. Anatomical and hemodynamic parameters were collected from invasive catheterization before and during ASA, and from echocardiography (ECHO) examinations before, during, and at 1-year follow-up after ASA. Linear and logistic regression models were used to assess the association between sex, BSWT, AML, PML, and outcome, which was defined as the remaining LVOTO (≥ 30 mmHg) after ASA. The median follow-up was 364 days (interquartile range 334-385 days). BSWT ≥ 23 mm (n = 13, 12%) was associated with remaining LVOTO at follow-up (p = 0.004). Elongated mitral valve leaflet length (either AML or PML) was present in 125 (90%) patients. Elongated AML (> 24 mm) was present in 67 (44%) patients, although AML length was not associated with remaining LVOTO at follow-up. Elongated PML (> 14 mm) was present in 114 (74%) patients and was not associated with remaining LVOTO at follow-up. No significant sex differences were observed regarding the remaining LVOTO. ECHO measurement of BSWT can be effectively used to select patients for successful ASA and identify those patients with a risk of incomplete resolution of LVOTO after ASA., (© 2024. The Author(s).)

Background: Catalogues of pathogenic genetic mutations in hypertrophic cardiomyopathy (HCM) are disproportionately small when compared to that of the size of the population with South Asian ancestry and their collective increased risk of heart disease., Methods: We conducted clinical exome sequencing of 200 HCM patients to identified cardiomyopathy-associated genetic mutations. The clinical and echocardiographic characteristics of genotype-positive and genotype-negative patients were compared, and the likelihood of detecting a positive genetic test result was evaluated. Allelic burden analysis was done to compare the minor allele frequencies (MAF) of the pathogenic or likely pathogenic (P/LP) variants and variants of uncertain significance (VUSs) identified in the cohort against various population genomics databases., Results: The genetic yield was 40% for P/LP variants, with MYBPC3 and MYH7 as the predominant sarcomere genes. Younger age-at-diagnosis, family history of HCM, asymmetric hypertrophic (ASH) pattern, the ratio of the interventricular septum to posterior wall thickness (IVS/PW ratio), left atrial (LA) dimensions, severe mitral regurgitation grade (MR grade), late gadolinium enhancement (LGE) detected fibrosis and absence of hypertension were associated with an increased likelihood of HCM-associated variants. Patients who experienced ventricular tachycardia and premature cardiovascular death were significantly likely to carry MYBPC3 or loss-of-function variants. LA and interventricular septal (IVS) dimensions were associated with MYH7 variants. The rare variant burden for P/LP variants and VUSs was significantly enriched in HCM cases compared to population controls., Conclusion: Our study provides a comprehensive evaluation of HCM-associated genetic mutations from an Indian population. The identified genotype-phenotype associations could improve the yield of targeted genetic testing in HCM., Competing Interests: Declaration of competing interest The authors declare that there is no conflict of interest., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Hereditary cardiomyopathies (CMPs), including arrhythmogenic cardiomyopathy (ACM), dilated cardiomyopathy (DCM), and hypertrophic cardiomyopathy (HCM), represent a group of heart disorders that significantly contribute to cardiovascular morbidity and mortality and are often driven by genetic factors. Recent advances in next-generation sequencing (NGS) technology have enabled the identification of rare variants in both well-established and minor genes associated with CMPs. Nowadays, a set of core genes is included in diagnostic panels for ACM, DCM, and HCM. On the other hand, despite their lesser-known status, variants in the minor genes may contribute to disease mechanisms and influence prognosis. This review evaluates the current evidence supporting the involvement of the minor genes in CMPs, considering their potential pathogenicity and clinical significance. A comprehensive analysis of databases, such as ClinGen, ClinVar, and GeneReviews , along with recent literature and diagnostic guidelines provides a thorough overview of the genetic landscape of minor genes in CMPs and offers guidance in clinical practice, evaluating each case individually based on the clinical referral, and insights for future research. Given the increasing knowledge on these less understood genetic factors, future studies are essential to clearly assess their roles, ultimately leading to improved diagnostic precision and therapeutic strategies in hereditary CMPs.

Competing Interests: Funding Support and Author Disclosures The VALOR-HCM study was funded by Bristol Myers Squibb. Dr Desai has served as a consultant for Bristol Myers Squibb, Cytokinetics, Tenaya, Edgewise and Viz.AI; and has received research support (to Cleveland Clinic) from Bristol Myers Squibb, Cytokinetics, and Tenaya. Dr Owens has served as a consultant for Bristol Myers Squibb, Cytokinetics, Pfizer, Biomarin, Tenaya, Lexicon, Stealth, Edgewise, and Renovacor; and has received grant support for research from Bristol Myers Squibb. Ms Wolski works for C5 Research and is an employee of Cleveland Clinic, which received payments for current research from Bristol Myers Squibb. Dr Geske has served as a consultant for Bristol Myers Squibb. Dr Saberi has served as a consultant for Bristol Myers Squibb and Cytokinetics. Dr Wang has received research grants (to institution) from Bristol Myers Squibb, Cytokinetics, and Abbott Vascular; has served on a consulting/advisory board for Bristol Myers Squibb; has served on steering committees for Bristol Myers Squibb and Cytokinetics; and has received speaker fees from Bristol Myers Squibb. Dr Sherrid has served as a consultant for Bristol Myers Squibb and Cytokinetics. Dr. Cremer works for C5 Research; and is an employee of Cleveland Clinic, which received payments for current research from Bristol Myers Squibb. Dr Lakdawala has received consulting fees from Bristol Myers Squibb, Pfizer, Tenaya, Cytokinetics, and Akros; and has received research support from Bristol Myers Squibb and Pfizer. Dr Tower-Rader has served as a consultant for Bristol Myers Squibb and Cytokinetics. Dr Fermin has received consulting/speaker fees from Bristol Myers Squibb and BridgeBio; and has served as a consultant for Pfizer. Dr Naidu has served as a consultant for Bristol Myers Squibb and Cytokinetics. Dr Smedira has served as a consultant for Bristol Myers Squibb. Ms McErlean and Sewell work for C5 Research; and are employees of Cleveland Clinic, which received payments for current research from Bristol Myers Squibb. Dr Zhong is an employee of and has stock ownership in Bristol Myers Squibb. Dr Wyrwich was employed by and had stock ownership in Bristol Myers Squibb at the time of the study. Drs Lampl and Sehnert are employed by and have stock ownership in Bristol Myers Squibb. Dr Nissen works for C5 Research; and is an employee of Cleveland Clinic, which received payments for current research from Bristol Myers Squibb. Dr Spertus has consulted for Bristol Myers Squibb and Cytokinetics; and holds the copyright to the KCCQ. Dr Schaff has reported that he has no relationships relevant to contents of this paper to disclose.

Competing Interests: Competing interests: None declared.

Background: The initial diagnostic markers are important for general practitioners to identify cats suspected of having cardiac disease, particularly hypertrophic cardiomyopathy (HCM)., Aim: The aim of this study is to investigate the indicators that suggest feline cardiac disease, especially HCM., Methods: This is a retrospective study, using the data from 354 cats, to identify various clinical parameters that indicate the presence of cardiac disease in cats in order to develop a model to predict the likelihood of HCM in cats. Among all the parameters gathered, heart sound and LA size are the most significant in predicting the likelihood of HCM in cats., Results: After undergoing statistical analysis, we created a formula that could help screen cats with HCM and normal cats before further diagnosis, such as echocardiography. The formula Y 1 = -3.637 +2.448 (LA size) +2.683 (murmur) +1.274 (gallop) is the fittest model with an area under curve from the ROC analysis of 0.889. A new set of data was used to validate the model. This predictive model has 40% accuracy but correctly predicts 90% of the truly normal cats, making this model beneficial in helping veterinarians exclude truly normal cats from cats suspected of having HCM., Conclusion: The model may assist in distinguishing normal cats from those suspected of having HCM. Further diagnosis with echocardiography remains the gold standard for the final diagnosis of cardiac diseases in cats., Competing Interests: The authors declare that there is no conflict of interest.

Takotsubo cardiomyopathy (TCM) is characterized by transient left ventricular dysfunction, diagnosed via echocardiography or left ventriculography. In most cases, TCM involves an emotional, physical, or combined trigger. Acute coronary syndrome is one of the most frequent misdiagnoses in TCM patients due to electrocardiogram (ECG) abnormalities and elevated cardiac biomarkers. Typically, coronary angiography reveals no stenosis or occlusion of the coronary arteries. Hypertrophic cardiomyopathy (HCM) is a distinct pathology characterized by a hypertrophied left ventricle with various phenotypes. However, some reports have described TCM cases mimicking obstructive-type HCM in some patients. We present a case of a female patient diagnosed with TCM based on clinical, laboratory, and imaging tests. Differentiating TCM from HCM was challenging due to ventriculography and echocardiography findings, as hyperdynamic contraction of the basal segments of the left ventricle caused an increased left ventricular outflow tract (LVOT) gradient and severe mitral valve regurgitation. Detailed evaluation and close echocardiographic follow-up are essential in such rare cases.

Numerous guidelines on the diagnosis and management of hypertrophic cardiomyopathy (HCM) have been published, by learned societies, over the past decade. Although helpful they are often long and less adapted to nonexperts. This writing panel was challenged to produce a document that grew as much from years of practical experience as it did from the peer-reviewed literature. As such, rather than produce yet another set of guidelines, we aim herein to deliver a concentrate of our own experiential learning and distill for the reader the essence of effective and appropriate HCM care. This Clinical Practice Update on HCM is therefore aimed at general cardiologists and other cardiovascular practitioners rather than for HCM specialists. We set the stage with a description of the condition and its clinical presentation, discuss the central importance of "obstruction" and how to look for it, review the role of cardiac magnetic resonance imaging, reflect on the appropriate use of genetic testing, review the treatment options for symptomatic HCM-crucially including cardiac myosin inhibitors, and deal concisely with practical issues surrounding risk assessment for sudden cardiac death, and management of the end-stage HCM patient. Uniquely, we have captured the pediatric experience on our panel to discuss appropriate differences in the management of younger patients with HCM. We ask the reader to remember that this document represents expert consensus opinion rather than dogma and to use their best judgement when dealing with the HCM patient in front of them., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: The prevalence of hypertrophic cardiomyopathy (HCM) can be silent and can present with sudden death as the first manifestation of this disease. The goal of this study was to evaluate any association between reported physical symptoms with the presence of suspected HCM., Method: The Anthony Bates Foundation has been performing screening echocardiography across the United States for prevention of sudden death since 2001. A total of 4120 subjects between the ages of 4 and 79 underwent echocardiographic screening. We evaluated any association between various symptoms and suspected HCM defined as any left ventricular wall thickness³ ≥15 mm., Results: The total prevalence of suspected HCM in the entire study population was 1.1%. The presence of physical symptoms was not associated with HCM (chest pain in 4.3% of participants with HCM vs. 9.9% of the control, P = 0.19, palpitation in 4.3% of participants with HCM vs. 7.3% of the control, P = 0.41, shortness of breath in 6.4% of participant with HCM vs. 11.7% of the control, P = 0.26, lightheadedness in 4.3% of participant with HCM vs. 13.1% of the control, P = 0.07, ankle swelling in 2.1% of participant with HCM vs. 4.0% of the control, P = 0.52, dizziness in 8.5% of participant with HCM vs. 12.2% of the control, P = 0.44)., Conclusions: Echocardiographic presence of suspected HCM is not associated with a higher prevalence of physical symptoms in the participants undergoing screening echocardiography., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Background: Hypertrophic cardiomyopathy (HCM) is a widespread hereditary cardiac pathology characterized by thickened heart walls and rearrangement of cardiomyocytes. Despite extensive research, the mechanisms underlying HCM development remain poorly understood, impeding the development of effective therapeutic and diagnostic strategies. Recent studies have suggested a polygenic nature of HCM development alongside monogenic forms. Transcriptomic profiling is a valuable tool for investigating such diseases. In this study, we propose a novel approach to study regulatory microRNAs (miRNAs) in the context of HCM, utilizing state-of-the-art data analysis tools., Methods and Results: Our method involves applying the Monte Carlo simulation and machine learning algorithm to transcriptomic data to generate high-capacity classifiers for HCM. From these classifiers, we extract key genes crucial for their performance, resulting in the identification of 16 key genes. Subsequently, we narrow down the pool of miRNAs by selecting those that may target the greatest number of key genes within the best models. We particularly focused on miR-124-3p, which we validated to have an association with HCM on an independent dataset. Subsequent investigation of its function revealed involvement of miR-124-3p in the RhoA signaling pathway., Conclusions: In this study we propose a new approach to analyze transcriptomic data to search for microRNAs associated with a disease. Using this approach for transcriptomic profiling data of patients with HCM, we identified miR-124-3p as a potential regulator of the RhoA signaling pathway in the pathogenesis of HCM., Competing Interests: Declaration of competing interest The authors declare that they have no conflict of interest., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background: In symptomatic obstructive hypertrophic cardiomyopathy (oHCM) patients, mavacamten is commercially approved to help improve left ventricular (LV) outflow tract (LVOT) gradients, symptoms, and reduce eligibility for septal reduction therapy (SRT) under the risk evaluation and mitigation strategy (REMS) program. We sought to prospectively report the initial real-world clinical experience with the use of commercially available mavacamten in a multi-hospital tertiary healthcare system., Methods: We studied the first 150 consecutive oHCM patients (mean age 65 years, 53% women, 83% on betablockers and 61% in New York Heart Association [NYHA] class III) who were initiated on 5 mg of mavacamten with dose titrations using symptom assessment and echocardiographic measurements of LVOT gradient and LV ejection fraction (LVEF) measurements. We measured changes in NYHA class, LVEF, LVOT gradients (resting and Valsalva) at baseline, 4, 8 and 12 weeks., Results: At 261 ± 143 days (range of 31-571 days), 69 (46%) patients had ≥1 NYHA class, and 27 (18%) additional patients had ≥2 NYHA class improvement. The mean Valsalva LVOT gradient decreased from 72 ± 43 mmHg at baseline to 29 ± 31 mmHg at 4 weeks, 29 ± 28 mmHg at 8 weeks and 30 ± 29 mmHg at 12 weeks (p < 0.001). At baseline, 100% patients had Valsalva LVOT gradients ≥30 mmHg, which reduced to 29% at 4 weeks, 28% at 8 weeks and 30% at 12 weeks. In 40 patients who reported no symptomatic improvement, the mean Valsalva LVOT gradient decreased from 73 ± 39 mmHg at baseline to 34 ± 27 mmHg at 4 weeks, 35 ± 28 mmHg at 8 weeks and 30 ± 24 mmHg at 12 weeks (P < 0.001). The mean LVEF at baseline was 66 ± 6% and changed to 64 ± 5% at 4 weeks, 63 ± 5% at 8 weeks and 62 ± 7% at 12 weeks (p < 0.0001). No patient underwent SRT, developed LVEF ≤30% or developed heart failure requiring admission. Three (2%) patients needed temporary interruption of mavacamten due to LVEF<50%., Conclusions: In a real-world study in symptomatic oHCM patients at a multi-hospital tertiary care referral center, we demonstrate the efficacy and safety, along with the logistic feasibility of prescribing mavacamten under the REMS program., Competing Interests: Declaration of competing interest Dr. Desai is a consultant and has research agreements with Bristol Myers Squibb, Cytokinetics, Tenaya, Viz-AI and Edgewise. No industry support was utilized in the conduct of this study. Dr. Emery is a consultant for Bristol Myers Squibb. Others have no conflicts of interest., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background: Although the optimal approach is debated, systematic genetic screening for hypertrophic cardiomyopathy (HCM) is recommended., Aims: The performance of this approach was tested in GEREMY, a HCM prospective observational French register., Methods: Screening was based on a 12-gene panel, including the Fabry disease (GLA) and the transthyretin (TTR) genes. In case of a negative result and according to the clinical profile, 17-80 gene panels of were used., Results: A 748 adult cohort was examined: 68.9 % male, 54.6 ± 18.1 years, 27.5 % with a HCM family history, maximal wall thickness 19.1 ± 4.8 mm. Pathogenic or likely pathogenic variants were identified in 296 (39.6 %) patients, localized 1) in sarcomeric genes in 233, most frequently MYBPC3 (150) and MYH7 (42), with 24 identified only by large panels, with multiple variants in 8 patients and 2) in non-sarcomeric genes in 63, identified only with large panels in 26, predominantly TTR (26) and GLA(9), representing 8.8 % and 3.0 % of positive studies, respectively. Performance was 57.1 % before 40 years and 68.6 % in case of FH (vs otherwise 28.7 % and 26.1 % respectively, p < 0.001). In patients with a negative study, 148 had variants of unknown significance and 95 had senile or AL amyloidosis., Conclusions: Systematic genetic screening with a limited panel showed good performance, with diagnosis of Fabry disease (∼1 %) and hereditary TTR amyloidosis (∼3.5 %). Larger targeted panels were conclusive in 35.3 % of patients, of which 12 % had a negative initial approach., Competing Interests: Declaration of competing interest Pr. Hagege has served as an advisor to Alnylam, Amicus, Bristol Myers Squibb, Cytokinetics, Gilead, Myokardia, Pfizer, Sanofi Genzyme, Tenaya., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

In children with hypertrophic cardiomyopathy (HCM), the genotype-phenotype association of abnormal electrocardiographic (ECG) features in the backdrop of gene positivity has not been well described. This study aimed to describe the abnormal ECG findings in children with HCM harboring who have genetic variants and determine the association with major adverse cardiac events (MACE). We retrospectively analyzed 81 variants-positive, phenotype-positive (V+P+), 66 variant-positive, phenotype-negative (V+P-), and 85 non-sarcomeric subjects. We analyzed ECG findings and clinical outcomes in the three groups of subjects. Repolarization abnormalities (ST and T wave changes) and pathologic Q waves were the most common abnormalities in variant and non-sarcomeric subjects. The V+P+ group showed higher occurrence of ST segment changes and T wave abnormalities compared to V+P- group. Independent predictors of MACE included ST segment changes (OR 3.54, CI 1.20-10.47, p = 0.022). T wave changes alone did not predict outcome (OR 2.13, CI 0.75-6.07, p = 0.157), but combined repolarization abnormalities (ST+T changes) were strong predictors of MACE (OR 5.84, CI 1.43-23.7, p = 0.014) than ST segment changes alone. Maximal wall z score by echocardiography was a predictor of MACE (OR 1.21, CI 1.07-1.37, p = 0.002). Despite the presence of significant myocardial hypertrophy (z score > 4.7), voltage criteria for LVH were much less predictive. In the non-sarcomeric group, RVH was significantly associated with MACE (OR 3.85, CI 1.08-13.73, p = 0.038). These abnormal ECG findings described on the platform of known genetic status and known myocardial hypertrophy may add incremental value to the diagnosis and surveillance of disease progression in children with HCM. Select ECG findings, particularly repolarization abnormalities, may serve as predictors of MACE in children., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Hypertrophic cardiomyopathy (HCM), a common cardiomyopathy in children, is an important cause of morbidity and mortality. Early recognition and appropriate management are important. An electrocardiogram (ECG) is often used as a screening tool in children to detect heart disease. The ECG patterns in children with HCM are not well described.ECGs collected from an international cohort of children, and adolescents (≤ 21 years) with HCM were reviewed. 482 ECGs met inclusion criteria. Age ranged from 1 day to 21 years, median 13 years. Of the 482 ECGs, 57 (12%) were normal. The most common abnormalities noted were left ventricular hypertrophy (LVH) in 108/482 (22%) and biventricular hypertrophy (BVH) in 116/482 (24%) Of the patients with LVH/BVH (n = 224), 135 (60%) also had a strain pattern (LVH in 83, BVH in 52). Isolated strain pattern (in the absence of criteria for hypertrophy) was seen in 43/482 (9%). Isolated pathologic Q waves were seen in 71/482 (15%). Pediatric HCM, 88% have an abnormal ECG. The most common ECG abnormalities were LVH or BVH with or without strain. Strain pattern without hypertrophy and a pathologic Q wave were present in a significant proportion (24%) of patients. Thus, a significant number of children with HCM have ECG abnormalities that are not typical for "hypertrophy". The presence of the ECG abnormalities described above in a child should prompt further examination with an echocardiogram to rule out HCM., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

This case report concerns a 48-year-old man with a history of ischemic stroke at the age of 41 who reported cardiac hypertrophy, registered in his twenties when explained by increased physical activity. Family history was positive for a mother with permanent atrial fibrillation from her mid-thirties. At the age of 44, he had a first episode of persistent atrial fibrillation, accompanied by left atrial thrombosis while on a direct oral anticoagulant. He presented at our clinic at the age of 45 with another episode of persistent atrial fibrillation and decompensated heart failure. Echocardiography revealed a dilated left atrium, reduced left ventricular ejection fraction, and an asymmetric left ventricular hypertrophy. Cardiac magnetic resonance was positive for a cardiomyopathy with diffuse fibrosis, while slow-flow phenomenon was present on coronary angiography. Genetic testing by whole-exome sequencing revealed three variants in the patient, c.309C > A, p.His103Gln in the ACTC1 gene, c.116T > G, p.Leu39Ter in the PLN gene, and c.5827C > T, p.His1943Tyr in the SCN5A gene, the first two associated with hypertrophic cardiomyopathy and the latter possibly with familial atrial fibrillation. This case illustrates the need for advanced diagnostics in unexplained left ventricular hypertrophy, as hypertrophic cardiomyopathy is often overlooked, leading to potentially debilitating health consequences.

Objective: This pilot study sought to investigate the utility and acceptability of the KardiaMobile 6-lead ECG (KM6LECG) as a tool for remote monitoring in children with inherited cardiac conditions., Design: A single-centre prospective cohort study. Children underwent standard clinical evaluation including a 12-lead ECG and a KM6LECG in the clinic. Participants recorded KM6LECGs monthly at home for 3 months. Families completed a questionnaire on their experience., Setting: Great Ormond Street Hospital Centre for Inherited Cardiovascular Diseases., Participants: 64 children: 22 with hypertrophic cardiomyopathy (HCM); 22 with long QT syndrome and 20 unaffected siblings (controls)., Main Outcome Measures: Comparison of data extracted from the clinic 12-lead ECG and supervised KM6LECG, and the supervised and unsupervised KM6LECG recording., Results: Of 64 children (35% female, mean age 12 years), 58 had a baseline 12-lead ECG and appropriate baseline KM6LECG. In children with HCM, abnormalities in ventricular depolarisation/repolarisation in the limb leads of the 12-lead ECG were reliably reproduced. From the whole cohort, there was a strong positive correlation between the corrected QT interval from the 12-lead ECG and baseline KM6LECG (intraclass correlation coefficient=0.839) and baseline KM6LECG with an unsupervised KM6LECG (intraclass correlation coefficient=0.736). Suspected 'lead' misplacement impacted 18% of unsupervised recordings. Overall, the acceptability of the KM6LECG to families was good., Conclusions: The KM6LECG provides an accurate tool for assessing some ECG abnormalities associated with paediatric inherited cardiovascular disease and may provide a useful at-home adjunct to face-to-face clinical care of children requiring ECG assessment., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Hypertrophic cardiomyopathy (HCM) is an inherited heart disease that can lead to sudden cardiac death. Impact of genetic testing for the prognosis and treatment of patients with HCM needs to be improved. We conducted a systematic review and meta-analysis to investigate the characteristics and outcomes associated with sarcomere genotypes in index patients with HCM., Methods: A systematic search was conducted in Medline, Embase, and Cochrane Library up to Dec 31, 2023. Data on clinical characteristics, morphological and imaging features, outcomes and interventions were collected from published studies and pooled using a random-effects meta-analysis., Results: A total of 30 studies with 10,825 HCM index patients were included in the pooled analyses. The frequency of sarcomere genes in HCM patients was 41%. Sarcomere mutations were more frequent in women (p < 0.00001), and were associated with lower body mass index (26.1 ± 4.7 versus 27.5 ± 4.3; p = 0.003) and left ventricular ejection fraction (65.7% ± 10.1% vs. 67.1% ± 8.6%; p = 0.03), less apical hypertrophy (6.5% vs. 20.1%; p < 0.0001) and left ventricular outflow tract obstruction (29.1% vs. 33.2%; p = 0.03), greater left atrial volume index (43.6 ± 21.1 ml/m 2 vs. 37.3 ± 13.0 ml/m 2 ; p = 0.02). Higher risks of ventricular tachycardia (23.4% vs. 14.1%; p < 0.0001), syncope (18.3% vs. 10.9%; p = 0.01) and heart failure (17.3% vs. 14.6%; p = 0.002) were also associated with sarcomere mutations., Conclusions: Sarcomere mutations are more frequent in women, and are associated with worse clinical characteristics and poor outcomes., Competing Interests: Declaration of competing interest The authors have no conflicts of interest to declare., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background: Patients with obstructive hypertrophic cardiomyopathy (oHCM) have a substantial humanistic, clinical, and economic burden due to the array of symptoms and complications associated with the disease. The objective of this review was to identify key evidence gaps related to oHCM, specifically in Europe, North America, and Japan., Methods: A targeted literature review was conducted using PubMed to identify English-language studies published between 2012 and 2022 assessing patients with HCM/oHCM in France, Germany, Italy, Spain, the United Kingdom (UK), the United States (US), Canada, and Japan. Outcomes of interest were epidemiology, natural history, pathophysiology, management, and clinical, economic, and humanistic burden. Identified studies were assessed qualitatively to characterize evidence gaps., Results: Among 2,262 abstracts and 531 full-text articles screened, 178 articles were included from PubMed searches. An additional 16 unique studies were identified via a supplemental Google Scholar search initially conducted in January 2023 and updated in July 2024. Disease natural history, pathophysiology, and management were well documented globally. Significant evidence gaps were noted for the epidemiology, treatment, and burden of oHCM. Although multiple US studies were identified on the clinical, economic, and humanistic burden of oHCM, and one clinical burden study was found for Japan, there was a lack of evidence for France, Germany, Italy, Spain, the UK, and Canada., Conclusions: Major evidentiary gaps exist for the epidemiology, treatment, and burden of oHCM. Future research should address these gaps, with a specific focus on generating real-world evidence for Canada and European countries that will support the evaluation of emerging therapies in these regions., (© 2024. The Author(s).)

Pathogenic variation in genes encoding proteins of the cardiac sarcomere is responsible for 30%-40% of cases of hypertrophic cardiomyopathy. The main clinical utility of genetic testing is to provide diagnostic confirmation and facilitation of family screening. It also assists in the detection of aetiologies, which require distinct monitoring and treatment approaches. Other clinical applications, including the use of genetic information to inform risk prediction models, have been limited by the challenge of establishing robust genotype-phenotype correlations with actionable consequences, but new data on the interaction between rare and common genetic variation, as well as the emergence of therapies targeting disease-specific pathogenic mechanisms, herald a new era for genetic testing in routine practice., (© The Author(s) 2024. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Rest imaging in hypertrophic cardiomyopathy may underestimate or miss left ventricular outflow tract obstruction, leading to suboptimal management decisions that negatively affect symptomatic patients. The 2024 hypertrophic cardiomyopathy guidelines describe exercise stress testing as an important tool to determine overall exercise tolerance and latent, exercise-provoked left ventricular outflow tract obstruction., Competing Interests: Funding Support and Author Disclosures Dr Husaini has received honoraria from Bristol Myers Squibb. Dr Bach has received institutional research funding but no personal fees for conducting clinical trials from MyoKardia, Inc, and Cytokinetics, Inc. Dr Cresci is on the Data Monitoring Committees for the SEQUOIA-HCM, MAPLE-HCM, and ACACIA-HCM trials (Cytokinetics)., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Aficamten, a novel cardiac myosin inhibitor, reversibly reduces cardiac hypercontractility in obstructive hypertrophic cardiomyopathy. We present a prespecified analysis of the pharmacokinetics, pharmacodynamics, and safety of aficamten in SEQUOIA-HCM (Safety, Efficacy, and Quantitative Understanding of Obstruction Impact of Aficamten in HCM)., Methods and Results: A total of 282 patients with obstructive hypertrophic cardiomyopathy were randomized 1:1 to daily aficamten (5-20 mg) or placebo between February 1, 2022, and May 15, 2023. Aficamten dosing targeted the lowest effective dose for achieving site-interpreted Valsalva left ventricular outflow tract gradient <30 mm Hg with left ventricular ejection fraction (LVEF) ≥50%. End points were evaluated during titration (day 1 to week 8), maintenance (weeks 8-24), and washout (weeks 24-28), and included major adverse cardiac events, new-onset atrial fibrillation, implantable cardioverter-defibrillator discharges, LVEF <50%, and treatment-emergent adverse events. At week 8, 3.6%, 12.9%, 35%, and 48.6% of patients achieved 5-, 10-, 15-, and 20-mg doses, respectively. Baseline characteristics were similar across groups. Aficamten concentration increased by dose and remained stable during maintenance. During the treatment period, LVEF decreased by -0.9% (95% CI, -1.3 to -0.6) per 100 ng/mL aficamten exposure. Seven (4.9%) patients taking aficamten underwent per-protocol dose reduction for site-interpreted LVEF <50%. There were no treatment interruptions or heart failure worsening for LVEF <50%. No major adverse cardiovascular events were associated with aficamten, and treatment-emergent adverse events were similar between treatment groups, including atrial fibrillation., Conclusions: A site-based dosing algorithm targeting the lowest effective aficamten dose reduced left ventricular outflow tract gradient with a favorable safety profile throughout SEQUOIA-HCM., Registration: URL: https://www.clinicaltrials.gov; Unique Identifier: NCT05186818.

COQ7 pathogenetic variants cause primary CoQ 10 deficiency and a clinical phenotype of encephalopathy, peripheral neuropathy, or multisystemic disorder. Early diagnosis is essential for promptly starting CoQ 10 supplementation. Here, we report novel compound heterozygous variants in the COQ7 gene responsible for a prenatal onset (20 weeks of gestation) of hypertrophic cardiomyopathy and intestinal dysmotility in a Bangladesh consanguineous family with two affected siblings. The main clinical findings were dysmorphisms, recurrent intestinal occlusions that required ileostomy, left ventricular non-compaction cardiomyopathy, ascending aorta dilation, arterial hypertension, renal dysfunction, diffuse skin desquamation, axial hypotonia, neurodevelopmental delay, and growth retardation. Exome sequencing revealed compound heterozygous rare variants in the COQ7 gene, c.613&#95;617delGCCGGinsCAT (p.Ala205HisfsTer48) and c.403A>G (p.Met135Val). In silico analysis and functional in vitro studies confirmed the pathogenicity of the variants responsible for abolished activities of complexes I + III and II + III in muscle homogenate, severe decrease of CoQ 10 levels, and reduced basal and maximal respiration in patients' fibroblasts. The first proband deceased at 14 months of age, whereas supplementation with a high dose of CoQ 10 (30 mg/kg/day) since the first days of life modified the clinical course in the second child, showing a recovery of milestones acquirement at the last follow-up (18 months of age). Our study expands the clinical spectrum of primary CoQ 10 deficiency due to COQ7 gene defects and highlights the essential role of multidisciplinary and combined approaches for a timely diagnosis., (© 2024. The Author(s).)

Purpose of Review: Hypertrophic cardiomyopathy (HCM) is a common inherited cardiac condition with potential for severe complications including sudden cardiac death. Early diagnosis allows appropriate risk stratification and prompt intervention to minimise the potential for adverse outcomes. The implications of poorly coordinated screening are significant, either missing relatives at high-risk or burdening low-risk individuals with a diagnosis associated with reduced life expectancy. We aim to guide clinicians through the diagnostic pathway through to novel treatment options. Several conditions mimic the condition, and we discuss the phenocopies and how to differentiate from HCM., Recent Findings: We summarise the latest developments informing clinical decision making in the modern era of myosin inhibitors and future gene editing therapies. Early identification will enable prompt referral to specialist centres. A diagnostic flowchart is included, to guide the general cardiology and heart failure clinician in important decision making regarding the care of the HCM patient and importantly their relatives at risk. We have highlighted the importance of screening because genotype-positive/phenotype-negative patients are likely to have the most to gain from novel therapies., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Aims: In an era of evolving diagnostic possibilities, existing diagnostic systems are not fully sufficient to promptly recognize patients with early-stage hypertrophic cardiomyopathy (HCM) without symptomatic and instrumental features. Considering the sudden death of HCM, developing a novel diagnostic model to clarify the patients with early-stage HCM and the immunological characteristics can avoid misdiagnosis and attenuate disease progression., Methods and Results: Three hundred eighty-five samples from four independent cohorts were systematically retrieved. The weighted gene co-expression network analysis, differential expression analysis (|log2(foldchange)| > 0.5 and adjusted P < 0.05), and protein-protein interaction network were sequentially performed to identify HCM-related hub genes. With a machine learning algorithm, the least absolute shrinkage and selection operator regression algorithm, a stable diagnostic model was developed. The immune-cell infiltration and biological functions of HCM were also explored to characterize its underlying pathogenic mechanisms and the immune signature. Two key modules were screened based on weighted gene co-expression network analysis. Pathogenic mechanisms relevant to extracellular matrix and immune pathways have been discovered. Twenty-seven co-regulated genes were recognized as HCM-related hub genes. Based on the least absolute shrinkage and selection operator algorithm, a stable HCM diagnostic model was constructed, which was further validated in the remaining three cohorts (n = 385). Considering the tight association between HCM and immune-related functions, we assessed the infiltrating abundance of various immune cells and stromal cells based on the xCell algorithm, and certain immune cells were significantly different between high-risk and low-risk groups., Conclusions: Our study revealed a number of hub genes and novel pathways to provide potential targets for the treatment of HCM. A stable model was developed, providing an efficient tool for the diagnosis of HCM., (© 2024 The Authors. ESC Heart Failure published by John Wiley & Sons Ltd on behalf of European Society of Cardiology.)

Three cats were presented for unusual collapsing episodes. Echocardiography revealed a hypertrophic cardiomyopathy (HCM) phenotype in each cat. Continuous electrocardiographic monitoring showed that the clinical signs coincided with periods of severe ST-segment elevation in each cat. The first cat was treated with amlodipine and diltiazem but did not improve and was euthanized due to poor quality of life. Postmortem examination revealed cardiac lymphoma without obstructive coronary disease. The second cat was thought to have cardiac lymphoma, based on pericardial effusion cytology, and was euthanized before starting therapy. The third cat was diagnosed with HCM and left ventricular outflow tract obstruction and was treated with atenolol and diltiazem. This treatment reduced the frequency of episodic clinical signs, but the cat subsequently developed congestive heart failure and was euthanized. This case series describes clinical signs associated with severe ST elevation in cats with an HCM phenotype, and their outcomes. Continuous electrocardiographic monitoring was necessary to detect transient ST elevation in each case., Competing Interests: Conflict of Interest Statement The authors do not have any conflict of interest to disclose., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Despite substantial advances in the management of hypertrophic cardiomyopathy, advanced heart failure remains a major cause of morbidity in this patient population. This narrative review presents the case of a patient with hypertrophic obstructive cardiomyopathy who underwent alcohol septal ablation to frame a discussion of modern therapies for hypertrophic cardiomyopathy. The current treatment landscape includes medications, both old and new, and surgical and procedural interventions to relieve mechanical obstruction. Several promising new modalities for relieving obstruction are in the nascent stages of development., (© 2024 The Authors. Published by The Texas Heart Institute®.)

Competing Interests: Dr Coats has received fees from Alnylam, Cytokinetics, Pfizer, and Roche Diagnostics. The other author reports no conflicts.

Apical hypertrophic cardiomyopathy (ApHCM) is an HCM variant, affecting frequently males in midlife. It is characterized by apical obliteration and persistent diastolic contraction, often resulting in microvascular ischaemia. We report five cases of ApHCM, with evidence of intramyocardial calcification on echocardiogram. On cardiac magnetic imaging (MRI), a hypointense component at early gadolinium enhancement (EGE) sequences, compatible with calcium, and a deep layer, with hyperintensity at late gadolinium enhancement (LGE) sequences, referable to fibrosis, suggest an endomyocardial fibrosis (EMF) diagnosis. EMF pathologic hallmark is endocardium and myocardium scarring, evolving to dystrophic calcification. It is found only in few ApHCM patients. Our series is the largest one described until now. Analysing patients' history, coexistent inflammatory triggers were evident in all of them, so their co-morbidities could represent a further cause of small vessel disease, in the context of ischaemic microvascular stress due to hypertrophy, leading to fibrosis and dystrophic calcification. This series could demonstrate the relation between apical fibrosis/calcification and microvascular ischaemia due to hypertrophy and inflammatory triggers., (© 2024 The Authors. ESC Heart Failure published by John Wiley & Sons Ltd on behalf of European Society of Cardiology.)

Background: Hypertrophic cardiomyopathy (HCM) is believed to have low overall mortality rate, that could be influenced by gender, particularly among probands. We aimed to evaluate the survival rates and possible gender differences in a homogeneous cohort of HCM proband patients, referred for genetic testing, from the same geographical area, without differences in medical care access nor clinical referral pathways., Methods: we compared the mortality rates of a cohort of consecutive HCM probands referred for genetic testing (2000-2022), from a Spanish region (xxx1) with a centralized genetic testing pathway, with its control reference population by Ederer II method. Gender differences were analyzed., Results: Among the 649 HCM probands included in this study, there were significantly more men than women (61.3% vs 38.7, p < 0.05), with an earlier diagnosis (53.5 vs 61.1 years old, p < 0.05). Clinical evolution or arrhythmogenic HCM profile did no show no significant gender differences. Mean follow up was 9,8 years ±6,6 SD (9,9 ± 7 vs 9,6 ± 6,1, p = 0.59). No statistically significant differences in observed mortality, expected survival and excess mortality were found in the general HCM proband cohort. However, we found a significant excess mortality in female probands with HCM. No additional differences in analysis by genetic status were identified., Conclusion: Expected survival in our HCM probands did not differ from its reference population. However, despite no gender differences in phenotype severity were identified, proband HCM women did present a diagnosis delay and worse mortality outcomes., Competing Interests: Declaration of competing interest There are no conflicts of interest. This research was funded by Instituto de Salud Carlos III (ISCIII) (grant number PI22/00705). All patients signed the informed consent (local Ethical Committee approval CEImPA 2022.254)., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The pathophysiology of TTS is still elusive. This viewpoint proposes that TTS is an acute coronary syndrome, engendered by an ASNS/catecholamine-induced LVOTO, which results in an enhanced wall stress and afterload-based supply/demand mismatch, culminating in a segmental myocardial ischemic injury state, in susceptible individuals. Such individuals are felt to be particularly women with chronic hypertension, known or latent HCM, or non-HCM segmental myocardial hypertrophy, and certain structural abnormalities involving the LV and the MV apparatus. Recommendations are provided to explore further this hypothesis, while maintaining our focus on all other advanced TTS pathophysiology hypotheses for all patients, or those who do not experience LVOTO, men, the young, and patients with reverse, mid-ventricular, or right ventricular TTS, in whom more prolonged hyperadrenergic stimulation and/or larger amounts of blood-ridden catecholamines, segmental particularities of cardiac innervation and/or density of α-, and β-adrenergic receptors, pheochromocytoma, neurological chronic or acute comorbidities/catastrophies, coronary epicardial/microvascular vasospasm, and CMD., Competing Interests: Declaration of competing interest I can assure you that there are no conflicts of interest in connection with the submission of my manuscript, entitled “Left Ventricular Outflow Tract Obstruction/Hypertrophic Cardiomyopathy/Takotsubo Syndrome: A New Hypothesis of Takotsubo Syndrome Pathophysiology”., (Copyright © 2024 Elsevier Inc. All rights reserved.)