2020 AHA/ACC Guideline for the Diagnosis and Treatment of Patients With Hypertrophic Cardiomyopathy: Executive Summary: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

Supraventricular ectopic activity predicts postoperative atrial fibrillation, new-onset atrial fibrillation, and worse survival in obstructive hypertrophic cardiomyopathy

BACKGROUND

Supraventricular ectopic activity (SVEA) is a marker of foci that may initiate atrial fibrillation (AF) and is associated with worse survival. The types and frequencies of SVEA for predicting postoperative AF (POAF), new-onset AF, and clinical outcomes in obstructive hypertrophic cardiomyopathy (oHCM) remain unknown.

METHODS AND RESULTS

Our study consecutively recruited 961 patients with oHCM. All patients underwent a 24-h Holter monitor before surgery. POAF incidence was 20.7% and increased with the burden of premature atrial contractions (PACs). Multivariable analysis showed that supraventricular tachycardia (SVT) was independently associated with POAF, with the model including SVT yielding the largest area under the curve (AUC) [0.710, 95% CI 0.670-0.750] for predicting POAF. During a median follow-up of 2.9 years, 12 deaths, 60 new-onset AF, and 139 composite endpoints were observed. A Spearman correlation indicated a linear relationship between the incidence of new-onset AF and composite endpoints with PAC frequency. The Kaplan-Meier survival curves demonstrated that patients with PACs >200 beats/day had significantly higher cumulative rates of new-onset AF [HR 3.13, (95% CI 1.74-5.62), P < 0.001] and composite endpoints [HR 2.00, (95% CI 1.30-3.06), P = 0.002] than their counterparts. Adding PACs >200 beats/day to the multivariable model significantly improved net reclassification improvement (NRI) and integrated discrimination improvement (IDI) for predicting new-onset AF (NRI = 0.264, IDI = 0.033) and composite endpoints (NRI = 0.233, IDI = 0.014).

CONCLUSION

The incidence of POAF was 20.7%, increasing with PACs severity. Furthermore, PACs burden was positively associated with a higher incidence of adverse events. Specially, PACs >200 beats/day may best predict a higher incidence of new-onset AF and worse survival.

Variant sub-tiering, disease-gene associations and strictness of clinical criteria improves the interpretation of variants of uncertain significance in hereditary cardiomyopathies and rhythm disorders

Besides the ClinGen's efforts to standardize the ACMG/AMP criteria and European initiatives aimed at monitoring quality standards, molecular diagnostics of hereditary cardiomyopathies and heart rhythm disorders (HCHRDs) remains strongly influenced by the local strategies developed to overcome the variables in which genetic testing is requested. This is a monocentric study on the clinical and molecular findings of 363 pedigrees with various HCHRDs. ACMG/AMP criteria were adapted according to the ClinGen's material and internal specifications. Phenotypes were reviewed according to known disease-gene associations and the concurrence of multiple variants in the same individual. Relatives were studied when available and the significance of selected variants was supported by RNA- studies before reporting. One or more (likely) pathogenic variants were found in 80 pedigrees (22.0%), while 96 (26.4%) displayed one or more variants of uncertain significance (VUS) only. The 132 identified VUS were sub-tiered according to the Bayesian score in three categories presenting distinguishable patterns of selected criteria. VUS_high showed profiles of key molecular criteria and resembled deleterious variants according to the combinations of assigned criteria, while the VUS_low category displayed a high chance of conflicting combinations of criteria and unsupported disease-gene associations. Reclassification to likely pathogenic by the application of applicable clinical criteria (PVS1_Strength, PP1 and PP4) was accessible to VUS_high and a few VUS_mid only. This work supports the combined need to (i) introduce VUS sub-tiering, (ii) consider known disease-gene associations, (iii) stringently apply clinical criteria and (iv) incorporate RNA data to improve the clinical significance of genetic testing in HCHRDs.

Arrhythmias and Sudden Death: What is New in Hypertrophic Cardiomyopathy?

Hypertrophic cardiomyopathy (HCM) is a complex genetic disorder that has garnered significant attention because of its diverse manifestations, including arrhythmias and heightened risk of sudden cardiac death. Advances in precision diagnostics, such as genetic testing and cardiac imaging with late gadolinium enhancement, have refined HCM diagnosis, enabling targeted therapeutic and risk stratification approaches. AF, prevalent in HCM, exacerbates symptoms and stroke risk, while ventricular arrhythmias pose a direct threat to survival. Catheter ablation offers symptom relief in AF patients with HCM, yet recurrence remains high because of unique myocardial changes, highlighting the need for refined patient selection and long-term monitoring. The risk of sudden cardiac death in HCM, particularly in younger individuals, underscores the importance of precise risk stratification tools such as the European Society of Cardiology HCM Risk-SCD model. The expanding role of ICDs and emerging pharmacological agents, including myosin inhibitors, marks a shift toward more individualised management of HCM. This review integrates recent developments in arrhythmia management, targeted therapies and risk assessment, offering a comprehensive perspective on HCM tailored to improve clinical outcomes through a precision-medicine lens.

Correlation between left ventricular hypertrophy, myocardial fibrosis, and left atrial function in non-obstructive hypertrophic cardiomyopathy: insights from CMR-FT imaging

Nonobstructive hypertrophic cardiomyopathy (NOHCM) is associated with left ventricular (LV) hypertrophy and myocardial fibrosis, which progressively impair left atrial (LA) function. This study evaluated the impact of LV hypertrophy and fibrosis on LA dysfunction using cardiac magnetic resonance (CMR) imaging and feature-tracking (FT) strain analysis in 99 NOHCM patients, who were stratified into four groups based on the extent of late gadolinium enhancement (LGE): no fibrosis (LGE < 7%), mild fibrosis (7% ≤ LGE < 15%), moderate fibrosis (15% ≤ LGE < 30%), and severe fibrosis (LGE ≥ 30%). LA functional parameters, including reservoir strain (εs), conduit strain (εe), and pump strain (εa), showed significant reductions with increasing LGE burden (P < 0.05), with functional decline detectable even in mild fibrosis cases despite preserved LV ejection fraction. LV morphological and functional indices, such as global peak wall thickness (GPWT), LV end-systolic volume (LVESV), and LGE percentage, negatively correlated with LA strain metrics (r = -0.2 to -0.7, P < 0.05). Strain analysis demonstrated high reproducibility (ICC > 0.75). These findings highlight the clinical significance of CMR-FT as a sensitive and reliable tool for early detection of LA dysfunction in NOHCM patients, even before significant LV structural changes occur. The ability of CMR-FT to identify subtle changes in LA mechanics could provide valuable insights for risk stratification and guide early intervention strategies, ultimately improving clinical outcomes in this patient population.

Advancing Sports Cardiology: Integrating Artificial Intelligence with Wearable Devices for Cardiovascular Health Management

Sports cardiology focuses on athletes' cardiovascular health, yet sudden cardiac death remains a significant concern despite preventative measures. Prolonged physical activity leads to notable cardiovascular adaptations, known as the athlete's heart, which can resemble certain pathological conditions, complicating accurate diagnoses and potentially leading to serious consequences such as unnecessary exclusion from sports or missed treatment opportunities. Wearable devices, including smartwatches and smart glasses, have become prevalent for monitoring health metrics, offering potential clinical applications for sports cardiologists. These gadgets are capable of spotting exercise-induced arrhythmias, uncovering hidden heart problems, and offering crucial information for training and recovery, to minimize exercise-related cardiac incidents and enhance heart health care. However, concerns about data accuracy and the actionable value of the obtained information persist. A major challenge lies in the integration of artificial intelligence with wearables, research gaps remain regarding their ability to provide real-time, reliable, and clinically relevant insights. Combining artificial intelligence with wearable devices can improve how data is managed and used in sports cardiology. Artificial intelligence, particularly machine learning, can classify, predict, and draw inferences from the data collected by wearables, revolutionizing patient data usage. Despite artificial intelligence's proven effectiveness in managing chronic conditions, the limited research on its application in sports cardiology, particularly regarding wearables, creates a critical gap that needs to be addressed. This review examines commercially available wearables and their applications in sports cardiology, exploring how artificial intelligence can be integrated into wearable technology to advance the field.

Exploring the Current Status of Risk Stratification in Hypertrophic Cardiomyopathy: From Risk Models to Promising Techniques

Improving clinical prediction of sudden cardiac death is a crucial step in the management of patients with hypertrophic cardiomyopathy. However, finding the optimal method for risk evaluation has been challenging, given the complexity and the wide variation in clinical phenotypes. This is particularly important, as these patients are often of younger age and defibrillator implantation is associated with a low but tangible long-term risk of adverse events. A number of risk factors, including degree of hypertrophy, presence of syncope and family history of sudden cardiac death, have typically been considered to indicate a higher risk. The European risk score for prediction of sudden cardiac death is widely used; however, it may not apply well in patients with specific forms of the condition, such as those with extreme hypertrophy. Increasing evidence suggests that the presence and extent of myocardial fibrosis assessed with cardiac magnetic resonance imaging should be considered in clinical decision-making. Some research suggests that integrating electrophysiological studies into traditional risk assessment models may further optimize risk prediction and significantly improve accuracy in detecting high risk patients. Novel cardiac imaging techniques, better understanding of the genetic substrate and artificial intelligence-based algorithms may prove promising for risk refinement. The present review article provides an updated and in-depth viewpoint.

Sociodemographic Disparities in Obtaining Cardiac MRI: Black, White, and Shades of Gray

PURPOSE OF REVIEW

Despite growing recommendations for CMR utilization in heart disease evaluation, access remains limited by geography and socioeconomic status. In this review we discuss the role of CMR in addressing health disparities, review barriers to CMR access, and finally propose solutions to increasing CMR testing globally and in the U.S.

RECENT FINDINGS

CMR testing is higher prevalence in academic and urban centers in the Northeast and Midwest and remains sparser in Southern and rural areas which face a high burden of cardiovascular mortality. Globally, CMR is also limited in low- and middle-income countries. Barriers to CMR access include bias in physician referrals based on race, patient income, insurance status, language barriers, health literacy, and disparities in the multimodal cardiovascular imaging workforce. A multimodal approach involving policy makers, hospital systems, cardiologists, and health care personnel is essential to improving national and global barriers to accessing CMR.

Clinical and Genetic Heterogeneity of HCM: The Possible Role of a Deletion Involving MYH6 and MYH7

BACKGROUND/OBJECTIVES

Pediatric hypertrophic cardiomyopathy (HCM) is the most common genetic myocardial disorder in children and a leading cause of sudden cardiac death (SCD) among the young. Its phenotypic variability, driven by incomplete penetrance and variable expressivity, presents significant challenges in diagnosis and clinical management.

METHODS

In this study, we report a unique case of a 16-month-old female diagnosed with HCM caused by a rare genetic deletion. Molecular analysis was performed using a multigene panel and chromosomal microarray analysis (CMA).

RESULTS

Molecular tests identified a 30 kb deletion encompassing the MYH6 and MYH7 genes. These genes are critical components of sarcomeric architecture, with known associations to HCM and other cardiomyopathies.

CONCLUSIONS

This case underscores the clinical and genetic heterogeneity of HCM, highlighting the importance of considering genomic deletions involving key sarcomeric genes in the diagnostic evaluation.

Recent Clinical Updates of Hypertrophic Cardiomyopathy and Future Therapeutic Strategies

Hypertrophic cardiomyopathy (HCM) is the most prevalent inherited cardiomyopathy transmitted in an autosomal dominant manner to offspring. It is characterized by unexplained asymmetrical hypertrophy primarily affecting the left ventricle and interventricular septum while potentially causing obstruction within the left ventricular outflow tract (LVOT). The clinical manifestations of HCM are diverse, ranging from asymptomatic to severe heart failure (HF) and sudden cardiac death. Most patients present with obvious symptoms of left ventricular outflow tract obstruction (LVOTO). The diagnosis of HCM mainly depends on echocardiography and other imaging examinations. In recent years, myosin inhibitors have undergone clinical trials and gene therapy, which is expected to become a new treatment for HCM, has been studied. This article summarizes recent clinical updates on the epidemiology, pathogenesis, diagnostic methods, treatment principles, and complication prevention and treatment of HCM, to provide new ideas for follow-up research.

Pathogenic genes and clinical prognosis in hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is an autosomal dominant inherited cardiomyopathy characterized by left ventricular hypertrophy. It is one of the chief causes of sudden cardiac death in younger people and athletes. Molecular-genetic studies have confirmed that the vast majority of HCM is caused by mutations in genes encoding sarcomere proteins. HCM has a relatively wide phenotypic heterogeneity, varying from asymptomatic to sudden cardiac death, because of the many different mutations and pathogenic genes underlying it. Many studies have explored the clinical symptoms and prognosis of HCM, emphasizing the importance of genotype in evaluating patient prognosis and guiding the clinical management of HCM. To elaborate the main pathogenic genes and phenotypic prognosis in HCM to promote a better understanding of this genetic disease. Retrospective analysis of literature to evaluate the association between underlying gene mutations and clinical phenotypes in HCM patients. As sequencing technology advances, the pathogenic gene mutation spectrum and phenotypic characteristics of HCM are gradually becoming clearer. HCM is a widespread inherited disease with a highly variable clinical phenotype. The precise mechanisms linking known pathogenic gene mutations and the clinical course of this heterogeneous condition remain elusive.

Advances in genetic diagnosis and therapy of hereditary heart disease: a bibliometric review from 2004 to 2024

Hereditary heart disease (HHD) is a series of cardiac disorders associated with monogenic or polygenic abnormalities and is one of the leading causes of sudden death, particularly in young adults. The updated European Cardiology guideline for cardiomyopathies provides the first comprehensive summary of genotyping, imaging, and therapy recommendations for inherited cardiomyopathies, but still lacks a comprehensive discussion of research advances and future trends in genetic diagnosis and therapy of HHD. Our research aims to fill this gap. Bibliometric analysis software (CiteSpace 6.3.R1, VOSviewer 1.6.18, and Scimago Graphica) was used to analyze the general information, trends, and emerging foci of HHD in the past 20 years, including author, country, institution, keyword, and so on. There were 5,757 publications were screened and aggregated in the database, including 1876 reviews and 3,881 articles. Hypertrophic cardiomyopathy (HCM), arrhythmogenic cardiomyopathy (ACM), Brugada syndrome (BrS), myocardial amyloidosis, and Fabry disease (FD) were the main types of HHD that were explored in greater depth. Moreover, new diagnostic methods, clinical cohorts, and genetically targeted therapies for HHD patients are key research hotspots. The relationship between the pathogenicity of genes and prognosis will become increasingly important for therapy.

The Effect of Coronary Artery Disease on the Prognosis of Hypertrophic Cardiomyopathy: A Multi-Center Cohort Study

Background

There is a shortage of patients with hypertrophic cardiomyopathy (HCM) with concurrent coronary artery disease (CAD), and the influence of CAD on the prognosis of patients with HCM is uncertain. This real-world cohort study was conducted to evaluate the prognosis of patients with patients with CAD.

Methods

This cohort study of patients with HCM was conducted from May 2003 to September 2021. The total number of patients enrolled was 2167, and the mean follow-up period was 6.4 years (interquartile range 2.8-9.5 years). Sudden cardiac death (SCD), cardiovascular death, and all-cause mortality were assessed as outcomes. Using logistic regression, nine indicators were selected for 1:1 propensity score matching (PSM). Additionally, Kaplan-Meier survival curves and Cox proportional hazards regression analyses were used to assess the impact of CAD on the prognosis of patients with HCM.

Results

During an average of 6.4 years of follow-up, of the 2167 patients enrolled, 446 (20.6%) died. The patients were classified into two groups: CAD (n = 480) and non-CAD (n = 1,687). After imputation of missing values using the mean and 1:1 propensity score matching, there was no difference in SCD (log-rank χ2 = 0.4, p = 0.540), cardiovascular death (log-rank χ2 = 0.1, p = 0.995) and all-cause mortality (log-rank χ2 = 0.1, p = 0.776) between the CAD and non-CAD groups. After imputation of missing values using the median and 1:1 propensity score matching, patients with and without CAD were not significantly different in terms of SCD (log-rank χ2 = 0.1, p = 0.948), cardiovascular death (log-rank χ2 = 0.1, p = 0.811), and all-cause mortality (log-rank χ2 = 0.5, p = 0.499). In the Cox analysis, CAD was not a significant independent predictor of SCD, cardiovascular death, or all-cause mortality in patients with HCM.

Conclusions

In this study, it was observed that there was no statistically significant disparity in mortality rates between patients diagnosed with HCM who concurrently had CAD and those who did not exhibit CAD. This finding underscores the notion that the presence of CAD did not exert a notable influence on the incidence of SCD, cardiovascular death, or all-cause mortality, thereby emphasizing the complexity and multifaceted nature of mortality risk factors in HCM patients.

Natural history and clinical outcomes of patients with hypertrophic cardiomyopathy from thin filament mutations

Hypertrophic cardiomyopathy (HCM) due to thick filament variants is more common; however, HCM due to thin filament variants (HCM-Thin) may be associated with a more malignant phenotype with an increased risk of sudden cardiac death. The aim of this study was to review all the published cases of HCM-Thin to better understand the natural history and clinical outcomes of this disease. A literature review of HCM-Thin identified 21 studies with a total of 177 patients that were suitable for analysis. There were three outcomes of interest, which included a heart failure composite, a ventricular arrhythmia composite and a heart failure and arrhythmia composite outcome. Kaplan-Meier (KM) survival analyses for freedom from each of the abovementioned composite outcomes were completed for the entire cohort and stratified by age of onset and sarcomeric variant. The heart failure composite occurred in 24 (13.6%) patients, the ventricular arrhythmia composite occurred in 30 patients (16.9%) and the combined heart failure and arrhythmia composite occurred in 50 patients (28.2%). In regard to left ventricular ejection fraction (LVEF), the majority of patients were preserved (LVEF > 50%) compared with mildly reduced (LVEF 41%-50%) and reduced (LVEF ≤ 40%) (respectively 26.6% vs. 0.6% vs. 3.4%). The median maximal left ventricular wall thickness (LVWT) was 19.0 mm [interquartile range (IQR) 5.3]. Only 10.7% of the cohort had evidence of left ventricular outflow tract (LVOT) obstruction. Those with paediatric-onset HCM had earlier onset and were at higher risk for each endpoint than their adult counterparts. When stratified by genetic variant, patients with TNNI3 and TPM1 were at a higher risk of the heart failure composite endpoint and the combined heart failure and arrhythmia composite endpoint in comparison with those with the other genetic variants. HCM-Thin is associated with significant morbidity and mortality, with a high arrhythmia burden despite low rates of cardiac obstruction and mild hypertrophy. The paediatric onset of disease and certain sarcomeric variants appear to be associated with a worse prognosis than their adult-onset and other sarcomeric variant counterparts. HCM-Thin seems to have a distinct phenotype, which may require a different management approach.

Echocardiographic Diagnosis of Hypertrophic Cardiomyopathy by Machine Learning

Objective

To develop machine learning tools for automated hypertrophic cardiomyopathy (HCM) case recognition from echocardiographic metrics, aiming to identify HCM from standard echocardiographic data with high performance.

Patients and Methods

Four different random forest machine learning models were developed using a case-control cohort composed of 5548 patients with HCM and 16,973 controls without HCM, from January 1, 2004, to March 15, 2019. Each patient with HCM was matched to 3 controls by sex, age, and year of echocardiography. Ten-fold crossvalidation was used to train the models to identify HCM. Variables included in the models were demographic characteristics (age, sex, and body surface area) and 16 standard echocardiographic metrics.

Results

The models were differentiated by global, average, individual, or no strain measurements. Area under the receiver operating characteristic curves (area under the curve) ranged from 0.92 to 0.98 for the 4 separate models. Area under the curves of model 2 (using left ventricular global longitudinal strain; 0.97; 95% CI, 0.95-0.98), 3 (using averaged strain; 0.96; 95% CI, 0.94-0.97), and 4 (using 17 individual strains per patient; 0.98; 95% CI, 0.97-0.99) had comparable performance. By comparison, model 1 (no strain data; 0.92; 95% CI, 0.90-0.94) had an inferior area under the curve.

Conclusion

Machine learning tools that analyze echocardiographic metrics identified HCM cases with high performance. Detection of HCM cases improved when strain data was combined with standard echocardiographic metrics.

Influencing and prognostic factors of end-stage hypertrophic cardiomyopathy

AIMS

End-stage hypertrophic cardiomyopathy (ES-HCM) is a disease with severe complications and a poor prognosis. This study aimed to explore the influencing and prognostic factors of ES-HCM.

METHODS AND RESULTS

A total of 1282 patients with HCM who were hospitalized for the first time at Fujian Medical University Union Hospital between 1 January 2013 and 30 September 2021 were recorded. The patients with HCM and left ventricular ejection fraction (LVEF) < 50% were defined as having ES-HCM, and a control group (LVEF ≥ 50%) was generated from the collected medical records of HCM. The patients were matched in a ratio of 4:1 based on age and sex. Logistic regression analysis was used to determine the influencing factors of ES-HCM. Kaplan-Meier survival analysis was performed to analyse the clinical outcomes of ES-HCM patients. A total of 250 inpatients with HCM were enrolled in the study; 50 patients had ES-HCM, and 200 had HCM with LVEF ≥ 50%. The mean age of the patients at enrolment was 62.5 ± 10.3 years, and 215 patients (215/250, 86.0%) were male. The median follow-up time of the patients was 2.8 (1.4-5.4) years. The incidence of all-cause death and cardiovascular death in patients with ES-HCM was higher than those in patients with HCM and LVEF ≥ 50% (22/50 [44.0%] vs. 13/200 [6.5%]; 12/50 [24.0%] vs. 4/200 [2.0%], all P < 0.001). Multivariate logistic regression analysis showed that the influencing factors associated with ES-HCM included age at first symptom onset (odds ratio [OR] = 0.95, 95% CI [0.90, 1.00], P = 0.042), New York Heart Association (NYHA) class (OR = 7.73, 95% CI [2.93, 20.41], P < 0.001), heart rate (OR = 1.07, 95% CI [1.02, 1.12], P = 0.003), QRS duration (OR = 1.03, 95% CI [1.00, 1.05], P = 0.020), left ventricular end-diastolic diameter (LVEDD) (OR = 1.15, 95% CI [1.04, 1.28], P = 0.006), left atrial anteroposterior diameter (LAD) (OR = 1.13, 95% CI [1.03, 1.24], P = 0.012), and maximum left ventricular wall thickness (MLVWT) (OR = 0.80, 95% CI [0.68, 0.93], P = 0.005). Among the 50 patients with ES-HCM, NYHA class (P < 0.001) and heart rate (P = 0.017) were each associated with a higher likelihood and earlier occurrence of heart transplantation or all-cause mortality in univariate analyses.

CONCLUSIONS

The influencing factors for ES-HCM included the age at first symptom onset, NYHA class, heart rate, QRS duration, LVEDD, LAD, and MLVWT. Both NYHA class and heart rate were related to the prognosis of ES-HCM.

Cardiac hypertrophy in polycythemia vera: A case report and review of literature

BACKGROUND

The combination of polycythemia vera (PV) with pathological cardiac hypertrophy is uncommon. In this study, we describe a case of PV accompanied by pathological cardiac hypertrophy. It is hypothesized that the pronounced cardiac hypertrophy in this patient has a strong connection with PV.

CASE SUMMARY

In 2021, a 34-year-old Chinese man experienced chest constriction, shortness of breath, and palpitations during vigorous activity. Each episode lasted several minutes and resolved spontaneously following cessation of vigorous activity. He occasionally experienced syncope and vertigo without a headache. He underwent cardiac magnetic resonance imaging and was diagnosed with "hypertrophic cardiomyopathy (HCM)". He was discharged after receiving symptomatic treatment, which resulted in an improvement. He presented to our department with chest constriction, shortness of breath, and respiratory distress for one month while climbing to the second floor in 2023. His blood pressure was 180/100 mmHg at the time of admittance, and he was receiving antihypertensive treatment. He had a history of PV for 2 years without treatment. Symptomatic treatment was implemented concurrently with the administration of hydroxyurea upon admission. Good blood pressure control was observed during the long-term follow-up, and echocardiography did not reveal any progression of myocardial hypertrophy.

CONCLUSION

Clinicians managing PV patients should remain highly vigilant regarding the risks of thrombosis and cardiovascular complications, particularly in those with refractory hypertension.

Aficamten and Cardiopulmonary Exercise Test Performance: A Substudy of the SEQUOIA-HCM Randomized Clinical Trial

Importance

Impaired exercise capacity is a cardinal manifestation of obstructive hypertrophic cardiomyopathy (HCM). The Phase 3 Trial to Evaluate the Efficacy and Safety of Aficamten Compared to Placebo in Adults With Symptomatic Obstructive HCM (SEQUOIA-HCM) is a pivotal study characterizing the treatment effect of aficamten, a next-in-class cardiac myosin inhibitor, on a comprehensive set of exercise performance and clinical measures.

Objective

To evaluate the effect of aficamten on exercise performance using cardiopulmonary exercise testing with a novel integrated measure of maximal and submaximal exercise performance and evaluate other exercise measures and clinical correlates.

Design, Setting, and Participants

This was a prespecified analysis from SEQUOIA-HCM, a double-blind, placebo-controlled, randomized clinical trial. Patients were recruited from 101 sites in 14 countries (North America, Europe, Israel, and China). Individuals with symptomatic obstructive HCM with objective exertional intolerance (peak oxygen uptake [pVO2] ≤90% predicted) were included in the analysis. Data were analyzed from January to March 2024.

Interventions

Randomized 1:1 to aficamten (5-20 mg daily) or matching placebo for 24 weeks.

Main Outcomes and Measures

The primary outcome was change from baseline to week 24 in integrated exercise performance, defined as the 2-component z score of pVO2 and ventilatory efficiency throughout exercise (minute ventilation [VE]/carbon dioxide output [VCO2] slope). Response rates for achieving clinically meaningful thresholds for change in pVO2 and correlations with clinical measures of treatment effect (health status, echocardiographic/cardiac biomarkers) were also assessed.

Results

Among 282 randomized patients (mean [SD] age, 59.1 [12.9] years; 115 female [40.8%], 167 male [59.2%]), 263 (93.3%) had core laboratory-validated exercise testing at baseline and week 24. Integrated composite exercise performance improved in the aficamten group (mean [SD] z score, 0.17 [0.51]) from baseline to week 24, whereas the placebo group deteriorated (mean [SD] z score, -0.19 [0.45]), yielding a placebo-corrected improvement of 0.35 (95% CI, 0.25-0.46; P <.001). Further, aficamten treatment demonstrated significant improvements in total workload, circulatory power, exercise duration, heart rate reserve, peak heart rate, ventilatory efficiency, ventilatory power, and anaerobic threshold (all P <.001). In the aficamten group, large improvements (≥3.0 mL/kg per minute) in pVO2 were more common than large reductions (32% and 2%, respectively) compared with placebo (16% and 11%, respectively). Improvements in both components of the primary outcome, pVO2 and VE/VCO2 slope throughout exercise, were significantly correlated with improvements in symptom burden and hemodynamics (all P <.05).

Conclusions and Relevance

This prespecified analysis of the SEQUOIA-HCM randomized clinical trial found that aficamten treatment improved a broad range of exercise performance measures. These findings offer valuable insight into the therapeutic effects of aficamten.

Trial Registration

ClinicalTrials.gov Identifier: NCT05186818.

Exome sequencing data reanalysis of 200 hypertrophic cardiomyopathy patients: the HYPERGEN French cohort 5 years after the initial analysis

Background

Approximately half of hypertrophic cardiomyopathy (HCM) patients lack a precise genetic diagnosis. The likelihood of identifying clinically relevant variants increased over time.

Methods

In this study, we conducted a gene-centric reanalysis of exome data of 200 HCM cases 5 years after the initial analysis. This reanalysis prioritized genes with a matched HCM entry in the OMIM database and recently emerging HCM-associated genes gathered using a text mining-based literature review. Further classification of the identified genes and variants was performed using the Clinical Genome Resource (ClinGen) resource and American College of Medical Genetics and Genomics (ACMG) guidelines to assess the robustness of gene-disease association and the clinical actionability of the prioritized variants.

Results

As expected, the majority of patients carried variants in MYBPC3 and MYH7 genes, 26% (n = 51) and 8% (n = 16), respectively, in accordance with the initial analysis. The vast majority of pathogenic (P) and likely pathogenic (LP) variants were found in MYBPC3 (22 out of 40 variants) and MYH7 (8 out of 16 variants) genes. Three genes-not included in the initial analysis-were identified: SVIL, FHOD3, and TRIM63. Considering only patients with unique variants in the last three genes, there was a 9% enhancement in variant identification. Importantly, SVIL variant carriers presented apical and septal HCM, aortopathies, and severe scoliosis for one patient. Ten patients (5%) carried variants in the FHOD3 gene, six in hotspot regions (exons 12 and 15). We identified seven variants within the TRIM63 gene in 12 patients (6%). Homozygous variants were detected in 2.5% of the cohort in MYBPC3 (n = 1), MYL3 (n = 1), and TRIM63 (n = 3) genes.

Conclusion

Our study revealed that no variants were found in the ACTC1, TPM1, and TNNI3 genes in the HYPERGEN cohort. However, we identified variants in five out of the eight HCM core genes, with a high prevalence in young patients. We identified variants in three recent HCM-associated genes (SVIL, FHOD3, and TRIM63) in 35 patients, with 18 patients carrying unique variants (9%). Our results further emphasize the usefulness of exome data reanalysis, particularly in genotype-negative patients.

Cardiopulmonary Fitness and Personalized Exercise Prescription in Patients With Hypertrophic Cardiomyopathy

BACKGROUND

Patients with hypertrophic cardiomyopathy (HCM) are generally restricted regarding participation in competitive sports based on the potential risk of sudden cardiac death and malignant arrhythmias. As a result, they are often inactive and experience the negative consequences of a sedentary lifestyle. Hence, the need arises to strike the right balance between these 2 extremes through personalized exercise prescription. The aims of this study were (1) to assess the characteristics of patients with HCM practicing regular aerobic physical activity compared with sedentary patients; (2) to perform a personalized moderate-intensity exercise prescription and evaluate its effects.

METHODS AND RESULTS

Patients with HCM were evaluated through clinical assessment, ECG, ambulatory ECG monitoring, echocardiography, and cardiopulmonary testing. A personalized moderate-intensity exercise prescription was performed, and the same investigations were repeated. Physically active patients with HCM demonstrated better cardiopulmonary functional capacity than sedentary patients (oxygen consumptionpeak/kg 32.9±7.4 versus 25.2±7.4 mL/min per kg P≤0.0001, ventilation/carbon dioxide production slope 26.7±4.3 versus 29.9±5.2 P=0.004), with similar prevalence of ventricular arrhythmias (P=0.43). Sedentary subjects showed a borderline higher prevalence of obesity (P=0.07) than physically active subjects. Moderate-intensity exercise prescription led to improved cardiopulmonary fitness without occurrence of adverse events.

CONCLUSIONS

Patients with HCM practicing regular aerobic exercise have a better functional capacity in the absence of relevant events than sedentary patients. Conversely, a sedentary lifestyle led to a deterioration of cardiopulmonary functional capacity and fitness. The tailored moderate-intensity personalized exercise prescription appears to be a feasible approach in carefully selected patients with HCM to counterbalance the negative effects of sedentary behavior without significant major events.

A Machine Learning Approach to Gene Expression in Hypertrophic Cardiomyopathy

BACKGROUND/OBJECTIVES

Hypertrophic cardiomyopathy (HCM) is a common heart disorder characterized by the thickening of the heart muscle, particularly in the left ventricle, which increases the risk of cardiac complications. This study aims to analyze the expression of apoptosis-regulating genes (CASP8, CASP9, CASP3, BAX, and BCL2) in blood samples from HCM patients, to better understand their potential as biomarkers for disease progression.

METHODS

Quantitative real-time PCR (qPCR) was used to evaluate gene expression in blood samples from 93 HCM patients. The correlation between apoptosis-regulating genes was conducted and clinical parameters were integrated for feature importance and clustering analysis.

RESULTS

Most patients exhibited significant downregulation of CASP8, CASP9, and CASP3. In contrast, BAX expression was elevated in 71 out of 93 patients, while BCL2 was increased in 55 out of 93 patients. Correlation analysis revealed weak negative correlations between the BAX/BCL2 ratio and CASP gene expression.

CONCLUSIONS

These findings suggest that reduced expression of apoptotic genes may indicate a protective cellular mechanism, which could serve as a biomarker for disease progression. Further studies are needed to investigate the potential for therapeutic modulation of these pathways to improve patient outcomes.

Recurrent atrial flutter after radiofrequency ablation for atrial fibrillation in a patient with hypertrophic obstructive cardiomyopathy undergoing repetitive transcoronary ablation of septal hypertrophy

INTRODUCTION

We described the clinical characteristics of a patient with hypertrophic obstructive cardiomyopathy (HOCM) who had undergone transcoronary ablation of septal hypertrophy (TASH) twice and developed atrial flutter after radiofrequency ablation for atrial fibrillation (AF) due to pulmonary vein reconnection. This case of HOCM is unique because of its complex complications and multiple complex atrial arrhythmias. The treatment of HOCM was successful and the postoperative follow-up results was good.

METHODS AND RESULTS

A 71-year-oldfemale, developed exertional dyspnea with palpitations 12 years ago, with a valid diagnosis of HOCM according to the echocardiography which showed an absolute increase in the interventricular septum thickness (22.8 mm). She underwent two rounds of TASH and only the second round was successful. During a visit due to recurrent palpitations, the patient was diagnosed with AF based on electrocardiographic examination. Circumferential pulmonary vein isolation (CPVI) was performed to treat AF. However, the recurrence of atrial flutter was detected on her electrocardiograms (ECGs) three years after the operation. Since the patient had an interstitial lung injury, there were relative contraindications for antiarrhythmic drugs. Due to restrictive use of antiarrhythmic drugs and continuous palpitation, the patient agreed to receive a second radiofrequency ablation. Left-sided macroreentrant circuits were identified via high-density mapping and successful ablation was performed at the isthmus.

CONCLUSIONS

Performing catheter ablation and TASH respectively in patients with HOCM associated with AF would be tricky. But taking such a comprehensive and respective clinical treatment would be beneficial to patients in the long term.

Clonal haematopoiesis is associated with major adverse cardiovascular events in patients with hypertrophic cardiomyopathy

AIMS

The heterogeneous phenotype of hypertrophic cardiomyopathy (HCM) is still not fully understood. Clonal haematopoiesis (CH) is emerging as a cardiovascular risk factor potentially associated with adverse clinical events. The prevalence, phenotype and outcomes related to CH in HCM patients were evaluated.

METHODS AND RESULTS

Patients with HCM and available biospecimens from the Peter Munk Cardiac Centre Cardiovascular Biobank were subjected to targeted sequencing for 35 myeloid genes associated with CH. CH prevalence, clinical characteristics, morphological phenotypes assessed by echocardiogram and cardiac magnetic resonance and outcomes were assessed. All patients were evaluated for a 71-plex cytokines/chemokines, troponin I and B-type natriuretic peptide analysis. Major adverse cardiovascular events (MACE) were defined as appropriate implantable cardioverter-defibrillator shock, stroke, cardiac arrest, orthotopic heart transplant and death. Among the 799 patients, CH was found in 183 (22.9%) HCM patients with sarcomeric germline mutations. HCM patients with CH were more symptomatic and with a higher burden of fibrosis than those without CH. CH was associated with MACE in those HCM patients with sarcomeric germline mutations (adjusted hazard ratio [HR] 6.89, 95% confidence interval [CI] 1.78-26.6; p = 0.005), with the highest risk among those that had DNMT3A, TET2 and ASXL1 mutations (adjusted HR 5.76, 95% CI 1.51-21.94; p = 0.010). Several cytokines (IL-1ra, IL-6, IL-17F, TGFα, CCL21, CCL1, CCL8, and CCL17), and troponin I were upregulated in gene-positive HCM patients with CH.

CONCLUSIONS

These results indicate that CH in patients with HCM is associated with worse clinical outcomes. In the absence of CH, gene-positive patients with HCM have lower rates of MACE.

Comparing cryoballoon and contact-force guided radiofrequency ablation in pulmonary vein isolation for atrial fibrillation in patients with hypertrophic cardiomyopathy

BACKGROUND

Pulmonary vein isolation (PVI) employing cryoballoon (CB) or contact force-guided radiofrequency (CF-RF) catheter ablation has been established as an effective strategy for managing atrial fibrillation (AF). However, its efficacy in hypertrophic cardiomyopathy (HCM) remains to be further explored.

METHODS

This retrospective study analyzed 60 consecutive AF patients with HCM (average age 67 ± 10 years; 41 men) who were consecutively admitted to our hospital from January 2014 to December 2022 and underwent initial PVI.

RESULTS

The patients were treated with CB (26 patients) or CF-RF (34 patients). Successful PVI was achieved in both groups without significant complications. In the CF-RF group, additional ablations were performed on the cavotricuspid isthmus (14.7% of patients) and the anterior line (2.9%). The CB group benefited from reduced procedural times (93 ± 31 vs. 165 ± 60 min, p < 0.05) and decreased saline irrigation requirements (77.5 ± 31.4 vs. 870 ± 281.9 mL, p < 0.0001). Using a contrast medium was exclusive to the CB group (33.8 ± 4.2 mL). In a 12-month follow-up, the atrial tachyarrhythmia recurrence-free rates in the CB and CF-RF groups were comparable (77% and 76%, respectively; p = 0.63 according to the log-rank test). Notably, pulmonary vein reconnection was prevalent in most (7 out of 8) patients requiring a secondary ablation procedure.

CONCLUSION

PVI is feasible as a strategy for AF in patients with HCM employing either CB or CF-RF techniques. While the recurrence-free rates were comparable in both groups, differences were noted in procedure duration, saline usage, and the need for a contrast medium.

Mavacamten for Obstructive Hypertrophic Cardiomyopathy: Rationale for Clinically Guided Dose Titration to Optimize Individual Response

Mavacamten is the first and only cardiac myosin inhibitor approved in 5 continents for the treatment of adults with symptomatic New York Heart Association class II and III obstructive hypertrophic cardiomyopathy. An evidence-based rationale was used to develop individualized mavacamten dosing, guided by commonly used clinical parameters. Echocardiography is recommended as part of routine clinical assessment of patients with hypertrophic cardiomyopathy, and left ventricular (LV) outflow tract gradient and LV ejection fraction are parameters that can be readily assessed and monitored by echocardiography. Therefore, an echocardiography-based, clinically guided dose-titration strategy was developed to optimize patient benefit from mavacamten for the treatment of symptomatic obstructive hypertrophic cardiomyopathy while minimizing the risk of LV ejection fraction reduction. Results from clinical trials paired with extensive modeling and simulation analyses support a dose-titration and monitoring strategy based on serial echocardiographic measures of Valsalva LV outflow tract gradient and LV ejection fraction. This dosing approach allows for the identification of the lowest individualized mavacamten dose and exposure required to provide improvements in LV outflow tract obstruction, functional capacity, and symptoms. Mavacamten is primarily metabolized by CYP2C19 (cytochrome P450 2C19), and CYP2C19 metabolizer phenotype has an effect on mavacamten exposure. Therefore, this approach has also been demonstrated to provide a favorable safety profile irrespective of patients' CYP2C19 metabolizer status. The dose-titration strategy includes additional considerations for the potential onset of systolic dysfunction in the context of intercurrent illness, and for the potential of drug-drug interactions with inhibitors and substrates of cytochrome P450 enzymes. This posology is reflected in the mavacamten US prescribing information.

Safety and Effectiveness of Mavacamten Use in Hypertrophic Obstructive Cardiomyopathy: A Systematic Review and Meta-Analysis

Hypertrophic obstructive cardiomyopathy (HOCM) is a complex genetic cardiac disease that causes left ventricular hypertrophy and obstruction of the outflow tract. Mavacamten, a novel cardiac myosin inhibitor, has emerged as a potentially beneficial therapeutic option. This meta-analysis aimed to determine whether mavacamten is effective and safe for use in patients with HOCM. A systematic literature search was performed in PubMed and the Cochrane Central Register of Controlled Trials to identify randomized controlled trials (RCTs) that compared mavacamten to placebo in patients with HOCM. The primary objectives were changes in the gradients associated with the Valsalva maneuver and resting left ventricular outflow tract (LVOT). Alterations in the left atrial volume index (LAVI), left ventricular mass index (LVMI), and NT-proBNP level were secondary outcomes. Safety outcomes were also evaluated. Random effects models were used in the meta-analysis. Two RCTs comprising 332 patients were included. Mavacamten significantly reduced the Valsalva LVOT gradient (mean difference (MD) = -54.94 mmHg; 95% CI: -70.32, -39.56; P = 0.13) and resting LVOT gradient (MD = -42.44 mmHg; 95% CI: -67.52, -17.36; P<0.001) compared to placebo. Significant improvements were also observed in LAVI (MD = -7.18 mL/m²; 95% CI: -11.00, -3.37; P = 0.24) and NT-proBNP levels (RR = 0.58; 95% CI: 0.39, 0.84; P<0.001). LVMI showed a trend toward reduction (MD = -19.15 g/m²; 95% CI: -41.98, 3.69; P<0.001). Mavacamten demonstrated a favorable safety profile with few reported adverse events. This meta-analysis aimed to demonstrate the efficacy and short-term safety of mavacamten in patients with HOCM. Considerable improvement was observed in the LVOT gradients, cardiac remodeling measures, and indicators of cardiac stress when mavacamten was administered. Based on this data, mavacamten appears to offer the potential for a paradigm shift in the management of HOCM. However, studies conducted over an extended period are required to validate its long-term effectiveness and safety profile.

Evaluation of the 2021 ESC recommendations for family screening in hereditary transthyretin cardiac amyloidosis

AIMS

The 2021 European Society of Cardiology (ESC) screening recommendations for individuals carrying a pathogenic transthyretin amyloidosis variant (ATTRv) are based on expert opinion. We aimed to (i) determine the penetrance of ATTRv cardiomyopathy (ATTRv-CM) at baseline; (ii) examine the value of serial evaluation; and (iii) establish the yield of first-line diagnostic tests (i.e. electrocardiogram, echocardiogram, and laboratory tests) as per 2021 ESC position statement.

METHODS AND RESULTS

We included 159 relatives (median age 55.6 [43.2-65.9] years, 52% male) at risk for ATTRv-CM from 10 centres. The primary endpoint, ATTRv-CM diagnosis, was defined as the presence of (i) cardiac tracer uptake in bone scintigraphy; or (ii) transthyretin-positive cardiac biopsy. The secondary endpoint was a composite of heart failure (New York Heart Association class ≥II) and pacemaker-requiring conduction disorders. At baseline, 40/159 (25%) relatives were diagnosed with ATTRv-CM. Of those, 20 (50%) met the secondary endpoint. Indication to screen (≤10 years prior to predicted disease onset and absence of extracardiac amyloidosis) had an excellent negative predictive value (97%). Other pre-screening predictors for ATTRv-CM were infrequently identified variants and male sex. Importantly, 13% of relatives with ATTRv-CM did not show any signs of cardiac involvement on first-line diagnostic tests. The yield of serial evaluation (n = 41 relatives; follow-up 3.1 [2.2-5.2] years) at 3-year interval was 9.4%.

CONCLUSIONS

Screening according to the 2021 ESC position statement performs well in daily clinical practice. Clinicians should adhere to repeating bone scintigraphy after 3 years, as progressing to ATTRv-CM without signs of ATTRv-CM on first-line diagnostic tests or symptoms is common.

It has been 30 years since the first alcohol septal ablation for hypertrophic obstructive cardiomyopathy was performed

No abstract available.

Midterm Outcomes of Percutaneous Intramyocardial Septal Radiofrequency Ablation for Hypertrophic Cardiomyopathy: A Single-Center, Observational Study

BACKGROUND

Percutaneous intramyocardial septal radiofrequency ablation (PIMSRA) has been reported to be safe and effective at midterm follow-up to treat drug-refractory hypertrophic obstructive cardiomyopathy in a single center. However, data from other centers are lacking. This retrospective cohort study aimed to investigate the efficacy and safety of PIMSRA from another independent center.

METHODS AND RESULTS

PIMSRA was performed in 76 patients with hypertrophic obstructive cardiomyopathy in our center from April 2020 to June 2023. The primary outcome was the reduction of left ventricular outflow tract gradient after 6 months or more post-PIMSRA. Secondary outcomes were periprocedural major adverse clinical events. Sixty-one patients returned to the hospital for follow-up 6 to 30 (median, 14) months after the procedure. At the last follow-up of the 61 patients, the maximum septal thickness decreased from a median of 23.6 (interquartile range, 20.5-26.4) to 19.1 (interquartile range, 16.0-22.1) mm (P<0.001) and the left ventricular outflow tract peak gradient at rest decreased from a median of 70.0 (interquartile range, 29.1-107.5) to 20.0 (interquartile range, 10.8-48.8) mm Hg (P<0.001). The percentage of patients with symptoms of New York Heart Association functional class III/IV decreased from 51% to 0%. Of all 76 patients, there was no in-hospital or 30-day death, no right or left branch block, and no permanent pacemaker implantation. Six (8%) patients had pericardial effusion, with 1 experiencing cardiac tamponade and ventricular fibrillation, and 1 (1%) patient developed septal branch aneurysm that was treated with coil occlusion.

CONCLUSIONS

PIMSRA allows for the reduction in the left ventricular outflow tract gradient and enhances symptomatic improvement, with a limited incidence of adverse events and complications among patients with hypertrophic obstructive cardiomyopathy.

Eighteen-Month Real-World Experience Using Mavacamten for Treatment of Obstructive Hypertrophic Cardiomyopathy in a Racially Diverse Population

BACKGROUND

Patients with obstructive hypertrophic cardiomyopathy have increased symptomatic burden. Mavacamten was recently approved for treatment of obstructive hypertrophic cardiomyopathy based on 2 randomized controlled trials. However, its use under real-world conditions and in diverse populations is under-studied.

METHODS AND RESULTS

This was a prospective observational cohort study of patients seen at the Johns Hopkins HCM center and prescribed mavacamten for obstructive hypertrophic cardiomyopathy between July 7, 2022 and January 6, 2024. Patients were followed longitudinally, with serial echocardiography and clinical evaluation as mandated by the risk evaluation and mitigation strategy program. Sixty-six patients received mavacamten (mean age 59 years, 47% male, 29% non-White [Black, Hispanic/Latino, Asian, Native Hawaiian or Pacific Islander], 47% obese). Before treatment, all patients had New York Heart Association class II (51.5%) or III (48.5%) heart failure symptoms. Initial maximum peak left ventricular outflow tract gradient was 107±46 mm Hg. Median treatment duration was 9 months. For patients on mavacamten after ≥6 months (n=43), symptoms improved by ≥1 New York Heart Association class in 72% of patients, and peak left ventricular outflow tract gradient decreased by 80±46 mm Hg, eliminating hemodynamically significant left ventricular outflow tract obstruction in 79.1% of patients. Mavacamten was temporarily discontinued in 3 patients due to left ventricular ejection fraction decrease <50%. There were no medication-related adverse events. Effectiveness and safety were similar between White and non-White patients, but symptomatic relief was attenuated in patients with body-mass index ≥35 kg/m2.

CONCLUSIONS

Mavacamten was effective and safe when used under real-world conditions in a racially diverse population of symptomatic patients with obstructive hypertrophic cardiomyopathy. Patients with comorbid obesity were less likely to experience symptomatic improvement while on mavacamten.

Machine learning-driven diagnostic signature provides new insights in clinical management of hypertrophic cardiomyopathy

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.

Discontinuation of afterload-reducing drugs decreases left ventricular outflow tract obstruction in hypertrophic obstructive cardiomyopathy

Background

Hypertrophic cardiomyopathy (HCM), the most common genetic heart disease, is classified into hypertrophic non-obstructive and hypertrophic obstructive cardiomyopathy (HOCM). Patients with HOCM and coexisting heart failure or arterial hypertension are often prescribed afterload-reducing drugs. Although recommended in current guidelines, data on the direct effect of discontinuing afterload-reducing medication are scarce. This study aims to demonstrate the benefit of discontinuing afterload-reducing medication in HOCM patients.

Methods

This monocentric retrospective analysis included 24 patients with HOCM with afterload-reducing medication, including angiotensin-converting enzyme inhibitors, angiotensin-1 receptor blocker and dihydropyridine-calcium channel blocker, at their first outpatient visit. Effects of discontinuing this medication on LVOTO were examined compared to patients with persistent use despite medical advice.

Results

16 patients discontinued their afterload-reducing drugs, resulting in a significant decrease in median LVOT gradient from 86.5 [60.5-109.3] mmHg to 61.5 [28.3-97.50] mmHg (p = 0.0004). In 6 patients, beta-blocker therapy was initiated simultaneously, or the dose was increased. Regardless, LVOT gradient reduction was also significant in the remaining 10 patients (p = 0.001). The gradient was not changed significantly in the 8 patients continuing their afterload-reducing medication.

Conclusions

Discontinuation of afterload-reducing drugs significantly decreases LVOTO. Our study underscores the significance of abstaining from afterload-reducing drugs in HOCM patients, particularly in patients with concomitant hypertension or heart failure. According to recently published European guidelines, HOCM patients should preferably be treated with beta-blockers or non-dihydropyridine-calcium channel blockers.

Hypersynchrony in sarcomeric hypertrophic cardiomyopathy: description and mechanistic approach using multimodal electro-mechanical non-invasive cartography (HSYNC study)

Background

Little is known about left ventricular (LV) sequences of contraction and electrical activation in hypertrophic cardiomyopathy (HCM). A better understanding of the underlying relation between mechanical and electrical activation may allow the identification of predictive response criteria to right ventricular DDD pacing in obstructive patients.

Objective

To describe LV mechanical and electrical activation sequences in HCM patients compared to controls.

Materials and methods

We prospectively studied, in 40 HCM patients (20 obstructive and 20 non-obstructive) and 20 healthy controls: (1) mechanical activation using echocardiography at rest and cardiac magnetic resonance imaging, (2) electrical activation using 3-dimensional electrocardiographic mapping (ECM).

Results

In echocardiography, healthy controls had a physiological apex-to-base delay (ABD) during contraction (23.8 ± 16.2 ms). Among the 40 HCM patients, 18 HCM patients presented a loss of this ABD (<10 ms, defining hypersynchrony) more frequently than controls (45% vs. 5%, p = 0.017). These patients had a lower LV end-diastolic volume (71.4 ± 9.7 ml/m2 vs. 82.4 ± 14.8 ml/m2, p = 0.01), lower native T1 values (988 ± 32 ms vs. 1,028 ± 39 ms, p = 0.001) and tended to have lower LV mass (80.7 ± 23.7 g/m2 vs. 94.5 ± 25.3 g/m2, p = 0.08) compared with HCM patients that had a physiological contraction sequence. There was no significant relation between ABD and LV outflow tract obstruction. While HCM patients with a physiological contraction sequence presented an ECM close to those encountered in controls, patients with a loss of ABD presented a particular pattern of ECM with the first potential more frequently occurring in the postero-basal region.

Conclusion

The LV contraction sequence can be modified in HCM patients, with a loss of the physiological ABD, and is associated with smaller LV dimensions and a particular pattern of ECM. Further research is needed to determine whether this pattern is related to an electrical substrate or is the consequence of the hypertrophied heart's specific geometry.

Clinical trial registration

ClinicalTrial.gov: NCT02559726.

An overview of the treatments for hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is a very prevalent inherited disease with a wide global distribution and a prevalence rate of approximately 0.2% in the general population. Left ventricular hypertrophy (LVH) caused by sarcomere mutation is the primary reason of HCM. The histopathology feature is that cardiomyocyte hypertrophy, myocyte disorder and myocardial fibrosis lead to diminished diastolic function, left ventricular outflow tract obstruction (LVOTO) and arrhythmia, all of which result in serious cardiac complications. Previously, HCM was considered a malignant disease that was almost untreatable. With the improvement of medical standards and increasing awareness of HCM, it has become a highly treatable disease in contemporary times, with a significant decrease in mortality rates. However, there are still significant unmet requirements in the therapy of HCM. This paper draws on more than 100 references from the past four decades and summarizes current advances in the treatment of HCM. The article will review the pathogenesis and types, recent development in pharmacotherapy, invasive treatments and gene therapies, as well as dilemma and future development of HCM.

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.

Lifestyle Intervention Improves Parasympathetic Activity in Hypertrophic Cardiomyopathy

Background A limited number of studies have investigated the effects of lifestyle interventions in hypertrophic cardiomyopathy (HCM). This study evaluated the effect of a novel lifestyle intervention incorporating physical activity (PA) and dietary nitrate supplementation on heart rate variability (HRV) and haemodynamic measures in HCM.

Methods

Twenty-eight individuals with HCM were randomised into either the intervention or control group. Frequency-domain HRV measures including low frequency power (LF), high frequency power (HF) and LF/HF were recorded at rest using bioimpedance. Non-invasive haemodynamic variables were recorded at rest using bioreactance. Participants in the intervention group consumed 6 mmol of nitrate daily (concentrated beetroot juice) and were instructed to increase and maintain daily PA by ≥ 2000 steps/day above baseline for 16 weeks. Control group participants retained their usual lifestyle and monitored daily step counts.

Results

There was a significant increase in post-intervention HF power (7.54 ± 2.14 vs 8.78 ± 1.60 ms2, P < .01) and LF power (6.89 ± 2.33 vs 8.17 ± 1.55, P < .01) in the intervention but not in the control group. Resting mean arterial blood pressure (MABP) in the intervention group significantly reduced at follow-up (108 ± 6 vs 102 ± 7 mmHg, P < .01).

Conclusions

A novel lifestyle intervention including PA and dietary nitrate supplementation enhanced parasympathetic activity and resting MABP in HCM.

Invasive Cardiac Hemodynamics in Apical Hypertrophic Cardiomyopathy

BACKGROUND

Symptomatic limitations in apical hypertrophic cardiomyopathy may occur because of diastolic dysfunction with resultant elevated left ventricular filling pressures, cardiac output limitation to exercise, pulmonary hypertension (PH), valvular abnormalities, and/or arrhythmias. In this study, the authors aimed to describe invasive cardiac hemodynamics in a cohort of patients with apical hypertrophic cardiomyopathy.

METHODS AND RESULTS

Patients presenting to a comprehensive hypertrophic cardiomyopathy center with apical hypertrophic cardiomyopathy were identified (n=542) and those who underwent invasive hemodynamic catheterization (n=47) were included in the study. Of these, 10 were excluded due to postmyectomy status or incomplete hemodynamic data. The mean age was 56±18 years, 16 (43%) were women, and ejection fraction was preserved (≥50%) in 32 (91%) patients. The most common indication for catheterization was dyspnea (48%) followed by suspected PH (13%), and preheart transplant evaluation (10%). Elevated left ventricular filling pressures at rest or exercise were present in 32 (86%) patients. PH was present in 30 (81%) patients, with 6 (20%) also having right-sided heart failure. Cardiac index was available in 25 (86%) patients with elevated resting filling pressures. Of these, 19 (76%) had reduced cardiac index and all 6 with right-sided heart failure had reduced cardiac index. Resting hemodynamics were normal in 8 of 37 (22%) patients, with 5 during exercise; 3 of 5 (60%) patients had exercise-induced elevation in left ventricular filling pressures.

CONCLUSIONS

In patients with apical hypertrophic cardiomyopathy undergoing invasive hemodynamic cardiac catheterization, 86% had elevated left ventricular filling pressures at rest or with exercise, 81% had PH, and 20% of those with PH had concomitant right-sided heart failure.

Cardiovascular Magnetic Resonance-Based Tissue Characterization in Patients With Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is a common hereditable cardiomyopathy that affects between 1:200 to 1:500 of the general population. The role of cardiovascular magnetic resonance (CMR) imaging in the management of HCM has expanded over the past 2 decades to become a key informant of risk in this patient population, delivering unique insights into tissue health and its influence on future outcomes. Numerous mature CMR-based techniques are clinically available for the interrogation of tissue health in patients with HCM, inclusive of contrast and noncontrast methods. Late gadolinium enhancement imaging remains a cornerstone technique for the identification and quantification of myocardial fibrosis with large cumulative evidence supporting value for the prediction of arrhythmic outcomes. T1 mapping delivers improved fidelity for fibrosis quantification through direct estimations of extracellular volume fraction but also offers potential for noncontrast surrogate assessments of tissue health. Water-sensitive imaging, inclusive of T2-weighted dark blood imaging and T2 mapping, have also shown preliminary potential for assisting in risk discrimination. Finally, emerging techniques, inclusive of innovative multiparametric methods, are expanding the utility of CMR to assist in the delivery of comprehensive tissue characterization toward the delivery of personalized HCM care. In this narrative review we summarize the contemporary landscape of CMR techniques aimed at characterizing tissue health in patients with HCM. The value of these respective techniques to identify patients at elevated risk of future cardiovascular outcomes are highlighted.

Transaortic septal myectomy at the time of aortic valve replacement for severe aortic stenosis: a case series of 55 cases

Introduction

Symptomatic aortic valve stenosis (AS) is associated with asymmetric basal septal hypertrophy (ABSH) in 10% of cases. In this cohort, it has been suggested that rectification of the left ventricular outflow tract obstruction (LVOTO) by concomitant septal myectomy (CSM) can improve the results of aortic valve replacement (AVR).

Objective

This study aims to present the technique of AVR with CSM for severe AS with ABSH and to determine the associated early and late post-operative outcomes.

Methods

Fifty-five patients were prospectively recruited to undergo AVR with CSM between 2011 and 2021 at two centres. The primary outcomes were mortality within 30 days, incidence of post-operative ventricular septal defects (VSD) and prosthetic valve sizing. The secondary outcomes were in-hospital complications, permanent pacemaker implantation (PPI), survival at 15 months and changes on transthoracic echocardiogram.

Results

Post-operative mortality was 1.8% and this figure was unchanged at 15-month follow-up. No patients developed a post-operative VSD. Intra-operatively, it was found that in 94.6% cases the direct valve sizing increased by one, when compared to the measurement made before CSM. The indexed effective orifice area (iEOA) was > 85 cm2/m2 in 96.4% and no patients had an iEOA ≤ 0.75 cm2/m2. Four patients (7.3%) required PPI due to complete atrioventricular block.

Conclusion

AVR with CSM is a simple technique that can be utilised in severe AS with ABSH. There does not appear to be an increase in mortality or incidence of iatrogenic VSDs. Importantly, CSM allows for the implantation of a larger aortic valve compared to measurements made before CSM.

The Revolution of Cardiac Myosin Inhibitors in Patients With Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is the most common genetic cardiomyopathy worldwide and causes significant morbidity and mortality. For decades, medical treatment options have been limited and untargeted, with frequent need for invasive interventions not readily accessible to many HCM patients. More recently, our understanding of the genetic basis and pathophysiologic mechanism of HCM has grown significantly, leading to the discovery of a new class of medications, cardiac myosin inhibitors (CMIs), that shift myosin into the super-relaxed state to counteract the hypercontractility in HCM. Subsequent clinical trials have proven the mechanism and efficacy of CMIs in humans with obstructive HCM, and additional trials are under way in patients with nonobstructive HCM. With favourable results in the completed clinical trials and ongoing research on the horizon, CMIs represent a bright new era in the targeted management of HCM. This review is focused on the discovery of CMIs, provides a summary of the results of clinical trials to date, provides clinicians with a roadmap for implementing CMIs into practice, and identifies gaps in our current understanding as well as areas of ongoing investigation.

Fever Unveiling a Hidden Cardiac Condition: A Case of Pediatric Hypertrophic Obstructive Cardiomyopathy

This case report presents the clinical management of a 18-month-old female child who presented with fever, cough, and cold symptoms for eight days. Despite initial treatment with antipyretic syrup, the persistence of symptoms prompted further evaluation, revealing signs of hypertrophic obstructive cardiomyopathy (HOCM) on echocardiography. The patient was subsequently initiated on beta-blocker therapy and supportive care, leading to clinical improvement and eventual discharge. This case underscores the importance of considering cardiac etiologies in pediatric patients presenting with nonspecific symptoms. It highlights the role of timely diagnosis and multidisciplinary management in optimizing outcomes for affected individuals. Further research and awareness efforts are warranted to enhance diagnostic capabilities and refine treatment strategies for pediatric cardiac conditions like HOCM.

Current perspectives of sudden cardiac death management in hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is an autosomal dominant disorder characterized by left ventricular hypertrophy. Sudden cardiac death (SCD) is a rare but the most catastrophic complication in patients with HCM. Implantable cardioverter-defibrillators (ICDs) are widely recognized as effective preventive measures for SCD. Individualized risk stratification and early intervention in HCM can significantly improve patient prognosis. In this study, we review the latest findings regarding pathogenesis, risk stratification, and prevention of SCD in HCM patients, highlighting the clinic practice of cardiovascular magnetic resonance imaging for SCD management.

Myocardial bridging in obstructive hypertrophic cardiomyopathy: a risk factor for myocardial fibrosis

BACKGROUND

Myocardial bridging (MB) is common in patients with hypertrophic cardiomyopathy (HCM). There are sparse data on the impact of MB on myocardial fibrosis in HCM. This study was designed to evaluate the relationship between MB and myocardial fibrosis in patients with obstructive HCM.

METHODS

In this cohort study, retrospective data were collected from a high-volume HCM center. Patients with obstructive HCM who underwent septal myectomy and preoperative cardiac magnetic resonance (CMR) were screened from 2011 to 2018.

RESULTS

Finally, 492 patients were included in this study, with an average age of 45.7 years. Of these patients, 76 patients had MB. MB occurred mostly in the left anterior descending artery (73/76). The global extent of late gadolinium enhancement (LGE) was correlated with the degree of systolic compression (r = 0.33, p = 0.003). Multivariable linear regression analysis revealed that the degree of systolic compression was an independent risk factor for LGE (β = 0.292, p = 0.007). The LGE fraction of basal and mid anteroseptal segments in patients with severe MB (compression ratio ≥ 80%) was significantly greater than that in patients with mild to moderate MB (compression ratio < 80%). During a median follow-up of 28 (IQR: 15-52) months, 15 patients died. Kaplan-Meier analysis did not identify differences in all-cause death (log-rank p = 0.63) or cardiovascular death (log-rank p = 0.72) between patients undergoing MB-related surgery and those without MB.

CONCLUSIONS

MB with severe systolic compression was significantly associated with a high extent of fibrosis in patients with obstructive HCM. Concomitant myotomy or coronary artery bypass grafting might provide excellent survival similar to that of patients without MB. Identification of patients with severe MB and providing comprehensive management might help improve the prognosis of patients with HCM.

Effect of Mavacamten in Women Compared With Men With Obstructive Hypertrophic Cardiomyopathy: Insights From EXPLORER-HCM

BACKGROUND

Compared with men, women with hypertrophic cardiomyopathy (HCM) have a higher incidence of heart failure and worse outcomes. We investigated baseline clinical and echocardiographic characteristics and response to mavacamten among women compared with men in the EXPLORER-HCM study (Clinical Study to Evaluate Mavacamten [MYK-461] in Adults With Symptomatic Obstructive Hypertrophic Cardiomyopathy).

METHODS

A prespecified post hoc analysis of sex from the blinded, randomized EXPLORER-HCM trial of mavacamten versus placebo in symptomatic patients with obstructive HCM was performed. Baseline characteristics were compared with t tests for continuous variables (expressed as mean values) and χ2 tests for categorical variables. Prespecified primary, secondary, and exploratory end points and echocardiographic measurements from baseline to end of treatment (week 30) were analyzed with ANCOVA for continuous end points and a generalized linear model with binomial distribution for binary end points, with adjustment for each outcome's baseline value, New York Heart Association class, β-blocker use, and ergometer type.

RESULTS

At baseline, women (n=102) were older (62 years versus 56 years; P<0.0001), had lower peak oxygen consumption (16.7 mL·kg-1·min-1 versus 21.3 mL·kg-1·min-1; P<0.0001), were more likely to be assigned New York Heart Association class III (42% versus 17%; P<0.0001), had worse health status (Kansas City Cardiomyopathy Questionnaire-Clinical Summary Score 64 versus 75; P<0.0001), and had higher baseline plasma NT-proBNP (N-terminal pro-B-type natriuretic peptide) levels (1704 ng/L versus 990 ng/L; P=0.004) than men (n=149). After 30 weeks of mavacamten treatment, similar improvements were observed in women and men in the primary composite end point (percentage difference on mavacamten versus placebo, 22% versus 19%, respectively; P=0.759) and in the secondary end points of change in postexercise left ventricular outflow tract gradient (-42.4 mm Hg versus -33.6 mm Hg; P=0.348), change in peak oxygen consumption (1.2 mL·kg-1·min-1 versus 1.6 mL·kg-1·min-1; P=0.633), and percentage achieving ≥1 New York Heart Association class improvement (41% versus 28%; P=0.254). However, women had greater improvement in health status (Kansas City Cardiomyopathy Questionnaire-Clinical Summary Score 14.8 versus 6.1; P=0.026) and in the exploratory end point of NT-proBNP levels (-1322 ng/L versus -649 ng/L; P=0.0008).

CONCLUSIONS

Although at baseline women with symptomatic obstructive HCM enrolled in EXPLORER-HCM were older and had worse heart failure and health status than men, treatment with mavacamten resulted in similar improvements in the primary and most secondary EXPLORER-HCM end points and greater improvements in health status and NT-proBNP.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT03470545.

A MYH7 variant in a five-generation-family with hypertrophic cardiomyopathy

Background: Hypertrophic cardiomyopathy (HCM) is a genetic condition with a prevalence of 1:500-1:3 000. Variants in genes encoding sarcomeric proteins are mainly responsible for the disease. MYH7 gene encoding a myosin heavy chain beta, together with MYPBC3 gene are the two most commonly affected genes. The clinical presentation of this disease varies widely between individuals. This study aims to report a variant of MYH7 responsible for HCM in a five-generation family with a history of cardiac problems. Methods: The diagnosis was established according to the European Society of Cardiology HCM criteria based on two-dimensional Doppler echocardiography or cardiovascular magnetic resonance. Genetic analysis was performed using next-generation-sequencing and Sanger method. Results: The medical history of the presented family began with a prenatal diagnosis of HCM in the first child of a family with previously healthy parents. Five generations of the family had a long history of sudden cardiac death and cardiac problems. A NM_000257.4:c.2342T>A (p.Leu781Gln) variant was detected in the MYH7 gene. It was heterozygous in the proband and in all affected individuals in a large family. The variant was present in 10 affected members of the family, and was absent in 7 members. The clinical course of the disease was severe in several members of the family: three family members died of sudden cardiac death, one patient required heart transplantation, three underwent septal myectomy, and three required implantable cardioverter defibrillator (ICD) implantation. Conclusion: Herein, we report a MYH7 variant responsible for HCM. Familial HCM is inherited primarily in autosomal dominant mode, which is in accordance with our study. However, the presented family showed a broad clinical spectrum of HCM. Out of 10 family members with positive genetic testing 8 had severe presentation of the disease and 2 had a mild phenotype. This suggests that the severity of the disease may depend on other factors, most likely genetic.

Deficiency of Transcription Factor Sp1 Contributes to Hypertrophic Cardiomyopathy

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is the most prevalent monogenic heart disorder. However, the pathogenesis of HCM, especially its nongenetic mechanisms, remains largely unclear. Transcription factors are known to be involved in various biological processes including cell growth. We hypothesized that SP1 (specificity protein 1), the first purified TF in mammals, plays a role in the cardiomyocyte growth and cardiac hypertrophy of HCM.

METHODS

Cardiac-specific conditional knockout of Sp1 mice were constructed to investigate the role of SP1 in the heart. The echocardiography, histochemical experiment, and transmission electron microscope were performed to analyze the cardiac phenotypes of cardiac-specific conditional knockout of Sp1 mice. RNA sequencing, chromatin immunoprecipitation sequencing, and adeno-associated virus experiments in vivo were performed to explore the downstream molecules of SP1. To examine the therapeutic effect of SP1 on HCM, an SP1 overexpression vector was constructed and injected into the mutant allele of Myh6 R404Q/+ (Myh6 c. 1211C>T) HCM mice. The human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) from a patient with HCM were used to detect the potential therapeutic effects of SP1 in human HCM.

RESULTS

The cardiac-specific conditional knockout of Sp1 mice developed a typical HCM phenotype, displaying overt myocardial hypertrophy, interstitial fibrosis, and disordered myofilament. In addition, Sp1 knockdown dramatically increased the cell area of hiPSC-CMs and caused intracellular myofibrillar disorganization, which was similar to the hypertrophic cardiomyocytes of HCM. Mechanistically, Tuft1 was identified as the key target gene of SP1. The hypertrophic phenotypes induced by Sp1 knockdown in both hiPSC-CMs and mice could be rescued by TUFT1 (tuftelin 1) overexpression. Furthermore, SP1 overexpression suppressed the development of HCM in the mutant allele of Myh6 R404Q/+ mice and also reversed the hypertrophic phenotype of HCM hiPSC-CMs.

CONCLUSIONS

Our study demonstrates that SP1 deficiency leads to HCM. SP1 overexpression exhibits significant therapeutic effects on both HCM mice and HCM hiPSC-CMs, suggesting that SP1 could be a potential intervention target for HCM.

Role of Biomarkers of Myocardial Injury to Predict Adverse Outcomes in Hypertrophic Cardiomyopathy

BACKGROUND

Serum troponins and CK-MB (creatine kinase-MB) are readily detectable and reliable cardiac-specific biomarkers of subclinical myocardial injury. This study explores the roles of cTnI (cardiac troponin I) and CK-MB in hypertrophic cardiomyopathy (HCM).

METHODS

This study included 1045 patients with HCM who had baseline cTnI and CK-MB measurements at Fuwai Hospital between 1999 and 2019. Patients were excluded if they had undergone percutaneous coronary intervention or coronary artery bypass grafting, or had renal failure. Five end points were studied: all-cause death, cardiovascular death, noncardiovascular death, sudden cardiac death, and other cardiovascular death. Cox regression was used to assess the associations of cTnI and CK-MB levels with outcomes.

RESULTS

Nine hundred seventy patients with available follow-up data were finally analyzed (mean age, 49.3 years; 36.4% female). During the median 4.3-year follow-up period, 87 patients reached the end points. Higher cTnI (per 0.05 ng/mL increase) and CK-MB (per 1 IU/L increase) levels were associated with increased risks of all-cause death (cTnI: adjusted hazard ratio [HR], 1.038, P<0.001; CK-MB: adjusted HR, 1.021, P=0.004), cardiovascular death (cTnI: adjusted HR, 1.040, P<0.001; CK-MB: adjusted HR, 1.025, P=0.006), and sudden cardiac death (cTnI: adjusted HR, 1.045, P<0.001; CK-MB: adjusted HR, 1.032, P=0.001). Patients with elevated levels of both cTnI and CK-MB had worse prognoses than patients with an elevated level of either biomarker alone and patients who did not have an elevated level of either biomarker. Addition of the binary indicator elevation of both cTnI and CK-MB significantly improved the discrimination and reclassification abilities of the standard HCM Risk- sudden cardiac death model (C statistics: P=0.002; net reclassification improvement, 0.652; integrated discrimination improvement, 0.064).

CONCLUSIONS

Comprehensive evaluations of biomarkers of myocardial injury, cTnI and CK-MB, have considerable value for predicting adverse outcomes among patients with HCM. Routine cTnI and CK-MB assessments may help to guide implantable cardioverter defibrillator implantation for primary prevention in HCM.

A Young Pregnant Person With Old Myocardial Infarction

This case report presents the electrocardiogram findings of a pregnant patient in their 30s with a family history of hypertrophic obstructive cardiomyopathy.

Novel Magnetic Resonance Imaging Tools for Hypertrophic Cardiomyopathy Risk Stratification

Hypertrophic cardiomyopathy (HCM) is a common genetic disorder with a well described risk of sudden cardiac death; however, risk stratification has remained a challenge. Recently, novel parameters in cardiac magnetic resonance imaging (CMR) have shown promise in helping to improve upon current risk stratification paradigms. In this manuscript, we have reviewed novel CMR risk markers and their utility in HCM. The results of the review showed that T1, extracellular volume, CMR feature tracking, and other miscellaneous novel CMR variables have the potential to improve sudden death risk stratification and may have additional roles in diagnosis and prognosis. The strengths and weaknesses of these imaging techniques, and their potential utility and implementation in HCM risk stratification are discussed.

RAF1 mutation leading to hypertrophic cardiomyopathy in a Chinese family with a history of sudden cardiac death: A diagnostic insight into Noonan syndrome

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is predominantly caused by mutations in sarcomeric genes. However, a subset of cases is attributed to genetic disorders unrelated to sarcomeric genes, such as Noonan syndrome (NS) and other RASopathies. In this study, we present a family with a history of sudden cardiac death (SCD) and focus on two adults with syndromic left ventricular hypertrophy (LVH).

METHODS

Clinical evaluations, including echocardiography, were conducted to assess cardiac manifestations. Whole-exome sequencing was performed to identify potential genetic variants underlying syndromic LVH in the study participants.

RESULTS

Whole-exome sequencing revealed a missense variant in the RAF1 gene, c.782C>T (p.Pro261Leu). This variant confirmed the diagnosis of NS in the affected individuals.

CONCLUSION

The findings of this study underscore the importance of family history investigation and genetic testing in diagnosing syndromic LVH. By identifying the underlying genetic cause, clinicians can better understand the etiology of RAS-HCM and its association with SCD in young adults.

Real-world candidacy to mavacamten in a contemporary hypertrophic obstructive cardiomyopathy population

AIMS

In the EXPLORER-HCM trial, mavacamten reduced left ventricular outflow tract obstruction (LVOTO) and improved functional capacity of symptomatic hypertrophic obstructive cardiomyopathy (HOCM) patients. We sought to define the potential use of mavacamten by comparing real-world HOCM patients with those enrolled in EXPLORER-HCM and assessing their eligibility to treatment.

METHODS AND RESULTS

We collected information on HOCM patients followed up at 25 Italian HCM outpatient clinics and with significant LVOTO (i.e. gradient ≥30 mmHg at rest or ≥50 mmHg after Valsalva manoeuvre or exercise) despite pharmacological or non-pharmacological therapy. Pharmacological or non-pharmacological therapy resolved LVOTO in 1044 (61.2%) of the 1706 HOCM patients under active follow-up, whereas 662 patients (38.8%) had persistent LVOTO. Compared to the EXPLORER-HCM trial population, these real-world HOCM patients were older (62.1 ± 14.3 vs. 58.5 ± 12.2 years, p = 0.02), had a lower body mass index (26.8 ± 5.3 vs. 29.7 ± 4.9 kg/m2 , p < 0.0001) and a more frequent history of atrial fibrillation (21.5% vs. 9.8%, p = 0.027). At echocardiography, they had lower left ventricular ejection fraction (LVEF, 66 ± 7% vs. 74 ± 6%, p < 0.0001), higher left ventricular outflow tract gradients at rest (60 ± 27 vs. 52 ± 29 mmHg, p = 0.003), and larger left atrial volume index (49 ± 16 vs. 40 ± 12 ml/m2 , p < 0.0001). Overall, 324 (48.9%) would have been eligible for enrolment in the EXPLORER-HCM trial and 339 (51.2%) for treatment with mavacamten according to European guidelines.

CONCLUSIONS

Real-world HOCM patients differ from the EXPLORER-HCM population for their older age, lower LVEF and larger atrial volume, potentially reflecting a more advanced stage of the disease. About half of real-world HOCM patients were found eligible to mavacamten.