Aficamten for Symptomatic Obstructive Hypertrophic Cardiomyopathy.

BACKGROUND: One of the major determinants of exercise intolerance and limiting symptoms among patients with obstructive hypertrophic cardiomyopathy (HCM) is an elevated intracardiac pressure resulting from left ventricular outflow tract obstruction. Aficamten is an oral selective cardiac myosin inhibitor that reduces left ventricular outflow tract gradients by mitigating cardiac hypercontractility. METHODS: In this phase 3, double-blind trial, we randomly assigned adults with symptomatic obstructive HCM to receive aficamten (starting dose, 5 mg; maximum dose, 20 mg) or placebo for 24 weeks, with dose adjustment based on echocardiography results. The primary end point was the change from baseline to week 24 in the peak oxygen uptake as assessed by cardiopulmonary exercise testing. The 10 prespecified secondary end points (tested hierarchically) were change in the Kansas City Cardiomyopathy Questionnaire clinical summary score (KCCQ-CSS), improvement in the New York Heart Association (NYHA) functional class, change in the pressure gradient after the Valsalva maneuver, occurrence of a gradient of less than 30 mm Hg after the Valsalva maneuver, and duration of eligibility for septal reduction therapy (all assessed at week 24); change in the KCCQ-CSS, improvement in the NYHA functional class, change in the pressure gradient after the Valsalva maneuver, and occurrence of a gradient of less than 30 mm Hg after the Valsalva maneuver (all assessed at week 12); and change in the total workload as assessed by cardiopulmonary exercise testing at week 24. RESULTS: A total of 282 patients underwent randomization: 142 to the aficamten group and 140 to the placebo group. The mean age was 59.1 years, 59.2% were men, the baseline mean resting left ventricular outflow tract gradient was 55.1 mm Hg, and the baseline mean left ventricular ejection fraction was 74.8%. At 24 weeks, the mean change in the peak oxygen uptake was 1.8 ml per kilogram per minute (95% confidence interval [CI], 1.2 to 2.3) in the aficamten group and 0.0 ml per kilogram per minute (95% CI, -0.5 to 0.5) in the placebo group (least-squares mean between-group difference, 1.7 ml per kilogram per minute; 95% CI, 1.0 to 2.4; P<0.001). The results for all 10 secondary end points were significantly improved with aficamten as compared with placebo. The incidence of adverse events appeared to be similar in the two groups. CONCLUSIONS: Among patients with symptomatic obstructive HCM, treatment with aficamten resulted in a significantly greater improvement in peak oxygen uptake than placebo. (Funded by Cytokinetics; SEQUOIA-HCM ClinicalTrials.gov number, NCT05186818.).

Efficacy and Safety of Aficamten in Symptomatic Nonobstructive Hypertrophic Cardiomyopathy: Results From the REDWOOD-HCM Trial, Cohort 4.

BACKGROUND: This open-label phase 2 trial evaluated the safety and efficacy of aficamten in patients with nonobstructive hypertrophic cardiomyopathy (nHCM). METHODS: Patients with symptomatic nHCM (left ventricular outflow tract obstruction gradient ≤ 30 mmHg, left ventricular ejection fraction [LVEF] ≥ 60%, N-terminal pro-B-type natriuretic peptide [NT-proBNP] > 300 pg/mL) received aficamten 5-15 mg once daily (doses adjusted according to echocardiographic LVEF) for 10 weeks. RESULTS: We enrolled 41 patients (mean ± SD age 56 ± 16 years; 59% female). At Week 10, 22 (55%) patients experienced an improvement of ≥ 1 New York Heart Association class; 11 (29%) became asymptomatic. Clinically relevant improvements in Kansas City Cardiomyopathy Questionnaire Clinical Summary Scores occurred in 22 (55%) patients. Symptom relief was paralleled by reductions in NT-proBNP levels (56%; P < 0.001) and high-sensitivity cardiac troponin I (22%; P < 0.005). Modest reductions in LVEF (mean ± SD) of -5.4% ± 10 to 64.6% ± 9.1 were observed. Three (8%) patients had asymptomatic reduction in LVEF < 50% (range: 41%-48%), all returning to normal after 2 weeks of washout. One patient with prior history of aborted sudden cardiac death experienced a fatal arrhythmia during the study. CONCLUSIONS: Aficamten administration for symptomatic nHCM was generally safe and was associated with improvements in heart failure symptoms and cardiac biomarkers. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT04219826.

Emergency Department Use and Hospital Mortality Among Heart Transplant Recipients in the United States.

BACKGROUND: Annual heart transplant (HT) volumes have increased, as have post-HT outpatient care needs. Data on HT-related emergency department (ED) visits are limited. METHODS AND RESULTS: A retrospective analysis of 177 450 HT patient ED visits from the 2009 to 2018 Nationwide Emergency Department Sample was conducted. HT recipients, primary diagnoses, and comorbidities associated with ED visits were identified via International Classification of Diseases, Ninth Revision (ICD-9) and International Classification of Diseases, Tenth Revision (ICD-10) codes. Multivariable logistic regression was used to predict outcomes of hospital admission and death. HT volumes and HT-related ED visits increased from 2009 to 2018. Infection was the most common primary diagnosis (24%), and cardiac primary diagnoses represented 10% of encounters. Hospital admissions occurred in 48% of visits, but overall mortality was low (1.6%). Length of stay was 3.1 days (interquartile range, 1.6-5.9 days), and comorbidity burden was high: 42% had hypertension, 38% had diabetes, and 31% had ≥2 comorbidities. Those aged ≥65 years had significantly higher odds of admission (odds ratio [OR], 2.14 [95% CI, 1.97-2.33]) and death (OR, 2.06 [95% CI, 1.61-2.62]). Comorbidities increased odds of admission (OR, 1.62 [95% CI, 1.51-1.75]) but not death. Renal primary diagnosis had the highest risk of admission (OR, 4.1 [95% CI, 3.6-4.6]), but cardiac primary diagnosis had the highest odds of death (OR, 11.6 [95% CI, 9.1-14.8]). CONCLUSIONS: HT-related ED visits increased from 2009 to 2018 with high admission rates but low in-hospital mortality, suggesting an opportunity to improve prehospital care. Older patients and those with cardiac primary diagnoses had the highest risk of death. The observed contrast between predictors of admission and mortality signals a need for further study to improve risk stratification and outpatient care strategies.

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, ß-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.

Exercise Capacity in Patients With Obstructive Hypertrophic Cardiomyopathy: SEQUOIA-HCM Baseline Characteristics and Study Design.

Patients with obstructive hypertrophic cardiomyopathy (oHCM) have increased risk of arrhythmia, stroke, heart failure, and sudden death. Contemporary management of oHCM has decreased annual hospitalization and mortality rates, yet patients have worsening health-related quality of life due to impaired exercise capacity and persistent residual symptoms. Here we consider the design of clinical trials evaluating potential oHCM therapies in the context of SEQUOIA-HCM (Safety, Efficacy, and Quantitative Understanding of Obstruction Impact of Aficamten in HCM). This large, phase 3 trial is now fully enrolled (N = 282). Baseline characteristics reflect an ethnically diverse population with characteristics typical of patients encountered clinically with substantial functional and symptom burden. The study will assess the effect of aficamten vs placebo, in addition to standard-of-care medications, on functional capacity and symptoms over 24 weeks. Future clinical trials could model the approach in SEQUOIA-HCM to evaluate the effect of potential therapies on the burden of oHCM. (Safety, Efficacy, and Quantitative Understanding of Obstruction Impact of Aficamten in HCM [SEQUOIA-HCM]; NCT05186818).

Cardiac Remodeling in Subclinical Hypertrophic Cardiomyopathy: The VANISH Randomized Clinical Trial.

Importance: Valsartan has shown promise in attenuating cardiac remodeling in patients with early-stage sarcomeric hypertrophic cardiomyopathy (HCM). Genetic testing can identify individuals at risk of HCM in a subclinical stage who could benefit from therapies that prevent disease progression. Objective: To explore the potential for valsartan to modify disease development, and to characterize short-term phenotypic progression in subclinical HCM. Design, Setting, and Participants: The multicenter, double-blind, placebo-controlled Valsartan for Attenuating Disease Evolution in Early Sarcomeric Hypertrophic Cardiomyopathy (VANISH) randomized clinical trial was conducted from April 2014 to July 2019 at 17 sites in 4 countries (Brazil, Canada, Denmark, and the US), with 2 years of follow-up. The prespecified exploratory VANISH cohort studied here included sarcomere variant carriers with subclinical HCM and early phenotypic manifestations (reduced E' velocity, electrocardiographic abnormalities, or an increased left ventricular [LV] wall thickness [LVWT] to cavity diameter ratio) but no LV hypertrophy (LVH). Data were analyzed between March and December 2022. Interventions: Treatment with placebo or valsartan (80 mg/d for children weighing <35 kg, 160 mg/d for children weighing ≥35 kg, or 320 mg/d for adults aged ≥18 years). Main Outcomes and Measures: The primary outcome was a composite z score incorporating changes in 9 parameters of cardiac remodeling (LV cavity volume, LVWT, and LV mass; left atrial [LA] volume; E' velocity and S' velocity; and serum troponin and N-terminal prohormone of brain natriuretic peptide levels). Results: This study included 34 participants, with a mean (SD) age of 16 (5) years (all were White). A total of 18 participants (8 female [44%] and 10 male [56%]) were randomized to valsartan and 16 (9 female [56%] and 7 male [44%]) were randomized to placebo. No statistically significant effects of valsartan on cardiac remodeling were detected (mean change in composite z score compared with placebo: -0.01 [95% CI, -0.29 to 0.26]; P = .92). Overall, 2-year phenotypic progression was modest, with only a mild increase in LA volume detected (increased by 3.5 mL/m2 [95% CI, 1.4-6.0 mL/m2]; P = .002). Nine participants (26%) had increased LVWT, including 6 (18%) who developed clinically overt HCM. Baseline LA volume index (LAVI; 35 vs 28 mL/m2; P = .01) and average interventricular septum thickness (8.5 vs 7.0 mm; P = .009) were higher in participants who developed HCM. Conclusions and Relevance: In this exploratory cohort, valsartan was not proven to slow progression of subclinical HCM. Minimal changes in markers of cardiac remodeling were observed, although nearly one-fifth of patients developed clinically overt HCM. Transition to disease was associated with greater baseline interventricular septum thickness and LAVI. These findings highlight the importance of following sarcomere variant carriers longitudinally and the critical need to improve understanding of factors that drive disease penetrance and progression. Trial Registration: ClinicalTrials.gov Identifier: NCT01912534.

Predicted Deleterious Variants in Cardiomyopathy Genes Prognosticate Mortality and Composite Outcomes in UK Biobank.

BACKGROUND: Inherited cardiomyopathies present with broad variation of phenotype. Data are limited regarding genetic screening strategies and outcomes associated with predicted deleterious variants in cardiomyopathy-associated genes in the general population. OBJECTIVES: The authors aimed to determine the risk of mortality and composite cardiomyopathy-related outcomes associated with predicted deleterious variants in cardiomyopathy-associated genes in the UK Biobank. METHODS: Using whole exome sequencing data, variants in dilated, hypertrophic, and arrhythmogenic right ventricular cardiomyopathy-associated genes with at least moderate evidence of disease causality according to ClinGen Expert Panel curations were annotated using REVEL (≥0.65) and ANNOVAR (predicted loss-of-function) considering gene-disease mechanisms. Genotype-positive and genotype-negative groups were compared using time-to-event analyses for the primary (all-cause mortality) and secondary outcomes (diagnosis of cardiomyopathy; composite outcome of diagnosis of cardiomyopathy, heart failure, arrhythmia, stroke, and death). RESULTS: Among 200,619 participants (age at recruitment 56.46 ± 8.1 years), 5,292 (2.64%) were found to host ≥1 predicted deleterious variants in cardiomyopathy-associated genes (CMP-G+). After adjusting for age and sex, CMP-G+ individuals had higher risk for all-cause mortality (HR: 1.13 [95% CI: 1.01-1.25]; P = 0.027), increased risk for being diagnosed with cardiomyopathy later in life (HR: 5.75 [95% CI: 4.58-7.23]; P < 0.0001), and elevated risk for composite outcome (HR: 1.29 [95% CI: 1.20-1.39]; P < 0.0001) than CMP-G- individuals. The higher risk for being diagnosed with cardiomyopathy and composite outcomes in the genotype-positive subjects remained consistent across all cardiomyopathy subgroups. CONCLUSIONS: Adults with predicted deleterious variants in cardiomyopathy-associated genes exhibited a slightly higher risk of mortality and a significantly increased risk of developing cardiomyopathy, and cardiomyopathy-related composite outcomes, in comparison with genotype-negative controls.

Common- and rare-variant genetic architecture of heart failure across the allele frequency spectrum.

Heart failure (HF) is a complex trait, influenced by environmental and genetic factors, that affects over 30 million individuals worldwide. Historically, the genetics of HF have been studied in Mendelian forms of disease, where rare genetic variants have been linked to familial cardiomyopathies. More recently, genome-wide association studies (GWAS) have successfully identified common genetic variants associated with risk of HF. However, the relative importance of genetic variants across the allele-frequency spectrum remains incompletely characterized. Here, we report the results of common- and rare-variant association studies of all-cause heart failure, applying recently developed methods to quantify the heritability of HF attributable to different classes of genetic variation. We combine GWAS data across multiple populations including 207,346 individuals with HF and 2,151,210 without, identifying 176 risk loci at genome-wide significance (p < 5×10-8). Signals at newly identified common-variant loci include coding variants in Mendelian cardiomyopathy genes (MYBPC3, BAG3), as well as regulators of lipoprotein (LPL) and glucose metabolism (GIPR, GLP1R), and are enriched in cardiac, muscle, nerve, and vascular tissues, as well as myocyte and adipocyte cell types. Gene burden studies across three biobanks (PMBB, UKB, AOU) including 27,208 individuals with HF and 349,126 without uncover exome-wide significant (p < 3.15×10-6) associations for HF and rare predicted loss-of-function (pLoF) variants in TTN, MYBPC3, FLNC, and BAG3. Total burden heritability of rare coding variants (2.2%, 95% CI 0.99-3.5%) is highly concentrated in a small set of Mendelian cardiomyopathy genes, and is lower than heritability attributable to common variants (4.3%, 95% CI 3.9-4.7%) which is more diffusely spread throughout the genome. Finally, we demonstrate that common-variant background, in the form of a polygenic risk score (PRS), significantly modifies the risk of HF among carriers of pathogenic truncating variants in the Mendelian cardiomyopathy gene TTN. These findings suggest a significant polygenic component to HF exists that is not captured by current clinical genetic testing.

Left Ventricular Systolic Dysfunction in Patients Diagnosed With Hypertrophic Cardiomyopathy During Childhood: Insights From the SHaRe Registry.

BACKGROUND: The development of left ventricular systolic dysfunction (LVSD) in hypertrophic cardiomyopathy (HCM) is rare but serious and associated with poor outcomes in adults. Little is known about the prevalence, predictors, and prognosis of LVSD in patients diagnosed with HCM as children. METHODS: Data from patients with HCM in the international, multicenter SHaRe (Sarcomeric Human Cardiomyopathy Registry) were analyzed. LVSD was defined as left ventricular ejection fraction <50% on echocardiographic reports. Prognosis was assessed by a composite of death, cardiac transplantation, and left ventricular assist device implantation. Predictors of developing incident LVSD and subsequent prognosis with LVSD were assessed using Cox proportional hazards models. RESULTS: We studied 1010 patients diagnosed with HCM during childhood (<18 years of age) and compared them with 6741 patients with HCM diagnosed as adults. In the pediatric HCM cohort, median age at HCM diagnosis was 12.7 years (interquartile range, 8.0-15.3), and 393 (36%) patients were female. At initial SHaRe site evaluation, 56 (5.5%) patients with childhood-diagnosed HCM had prevalent LVSD, and 92 (9.1%) developed incident LVSD during a median follow-up of 5.5 years. Overall LVSD prevalence was 14.7% compared with 8.7% in patients with adult-diagnosed HCM. Median age at incident LVSD was 32.6 years (interquartile range, 21.3-41.6) for the pediatric cohort and 57.2 years (interquartile range, 47.3-66.5) for the adult cohort. Predictors of developing incident LVSD in childhood-diagnosed HCM included age <12 years at HCM diagnosis (hazard ratio [HR], 1.72 [CI, 1.13-2.62), male sex (HR, 3.1 [CI, 1.88-5.2), carrying a pathogenic sarcomere variant (HR, 2.19 [CI, 1.08-4.4]), previous septal reduction therapy (HR, 2.34 [CI, 1.42-3.9]), and lower initial left ventricular ejection fraction (HR, 1.53 [CI, 1.38-1.69] per 5% decrease). Forty percent of patients with LVSD and HCM diagnosed during childhood met the composite outcome, with higher rates in female participants (HR, 2.60 [CI, 1.41-4.78]) and patients with a left ventricular ejection fraction <35% (HR, 3.76 [2.16-6.52]). CONCLUSIONS: Patients with childhood-diagnosed HCM have a significantly higher lifetime risk of developing LVSD, and LVSD emerges earlier than for patients with adult-diagnosed HCM. Regardless of age at diagnosis with HCM or LVSD, the prognosis with LVSD is poor, warranting careful surveillance for LVSD, especially as children with HCM transition to adult care.

Frequency and clinicoeconomic impact of delays to definitive diagnosis of obstructive hypertrophic cardiomyopathy in the United States.

AIMS: The diagnostic history in the years leading up to the definitive diagnosis of patients with obstructive hypertrophic cardiomyopathy (HCM) has not been studied. METHODS: Patients with a delay in the definitive diagnosis of obstructive HCM from January 2009 to March 2019 were identified in the US IBM MarketScan Commercial and Medicare Supplemental Databases if they had an alternative diagnosis indicating a misdiagnosis during the 24 months before the definitive obstructive HCM diagnosis. Resource use and costs associated with the delay were estimated during the same period. RESULTS: Of 3,888 eligible patients with obstructive HCM, 59.5% had a delay in definitive diagnosis. Patients received a mean of 4.0 misdiagnoses before the definitive obstructive HCM diagnosis, most of which were other cardiovascular conditions. Consequently, 15.7% of patients may have received inappropriate treatment. Approximately 78.4% of patients visited a cardiologist (mean 4.7 visits) before the definitive obstructive HCM diagnosis. Additionally, 26.8% and 32.1% of patients had an inpatient and emergency room visit, respectively. Annualized healthcare costs associated with the delay were $4,379 per patient. LIMITATIONS: The current study used administrative claims data for a commercially insured population. Therefore, the results may not be generalizable to other populations (e.g. those insured by Medicare or Medicaid and the uninsured). Like other database studies, the current study may have suffered from miscoding or undercoding, which may have caused misclassification of patients. Owing to insufficient data, the study could not evaluate all potential consequences of a delay in definitive diagnosis. CONCLUSIONS: Most patients with obstructive HCM had a delay of ≤ 2 years before receiving the definitive diagnosis. The diagnostic journey involved multiple potential misdiagnoses, predominantly cardiovascular, as well as a substantial clinical and economic burden on patients and the healthcare system.

Clinical Outcomes, Resource Utilization, and Treatment Over the Disease Course of Symptomatic Obstructive Hypertrophic Cardiomyopathy in the United States.

We sought to describe the clinical outcomes, resource utilization, and treatment options for patients with symptomatic obstructive hypertrophic cardiomyopathy (HCM) over the course of their disease. Adults with obstructive HCM who were symptomatic were identified from the IBM MarketScan Commercial and Medicare supplemental database (January 2009 to March 2019). The index date was the initial obstructive HCM diagnosis date. Patients were required to have ≥12-month continuous eligibility before and after the index date. Incidence rates (IRs) and cumulative risk of cardiovascular events, healthcare resource utilization, and pharmacotherapy were assessed after index and compared with matched controls. Among 4,617 eligible patients with obstructive HCM, 2,917 (63.2%, mean age 60, 47.2% women) were symptomatic at index date. The most common cardiovascular events were atrial fibrillation/flutter (IR:1.421 per person-year [PPY], heart failure (IR: 0.895 PPY), and dyspnea (IR:0.797 PPY). Patients incurred higher resource use with frequent tests and monitoring, hospitalizations (0.454 PPY), and emergency room visits (0.611 PPY). The use of pharmacotherapy increased from 61.2% in the 6-month preindex period to 83.9% in the 6-month postindex period and remained stable after diagnosis. These events ranged from 3 to over 60-fold higher compared with controls, with the largest difference observed in arrhythmic events. The majority of patients were symptomatic at the time of obstructive HCM diagnosis, resulting in significantly increased cardiovascular complications and frequent disease monitoring after diagnosis versus controls. In conclusion, healthcare resource utilization was substantial, and these findings suggest a higher clinical and economic burden over the disease course among patients with symptomatic obstructive HCM, despite current treatment.

Effects of Mavacamten on Measures of Cardiopulmonary Exercise Testing Beyond Peak Oxygen Consumption: A Secondary Analysis of the EXPLORER-HCM Randomized Trial.

Importance: Mavacamten, a cardiac myosin inhibitor, improved peak oxygen uptake (pVO2) in patients with symptomatic obstructive hypertrophic cardiomyopathy (HCM) in the EXPLORER-HCM study. However, the full extent of mavacamten's effects on exercise performance remains unclear. Objective: To investigate the effect of mavacamten on exercise physiology using cardiopulmonary exercise testing (CPET). Design, Setting, and Participants: Exploratory analyses of the data from the EXPLORER-HCM study, a randomized, double-blind, placebo-controlled, phase 3 trial that was conducted in 68 cardiovascular centers in 13 countries. In total, 251 patients with symptomatic obstructive HCM were enrolled. Interventions: Patients were randomly assigned in a 1:1 ratio to mavacamten or placebo. Main Outcomes and Measures: The following prespecified exploratory cardiovascular and performance parameters were assessed with a standardized treadmill or bicycle ergometer test protocol at baseline and week 30: carbon dioxide output (VCO2), minute ventilation (VE), peak VE/VCO2 ratio, ventilatory efficiency (VE/VCO2 slope), peak respiratory exchange ratio (RER), peak circulatory power, ventilatory power, ventilatory threshold, peak metabolic equivalents (METs), peak exercise time, partial pressure of end-tidal carbon dioxide (PETCO2), and VO2/workload slope. Results: Two hundred fifty-one patients were enrolled. The mean (SD) age was 58.5 (11.9) years and 59% of patients were male. There were significant improvements with mavacamten vs placebo in the following peak-exercise CPET parameters: peak VE/VCO2 ratio (least squares [LS] mean difference, -2.2; 95% CI, -3.05 to -1.26; P < .001), peak METs (LS mean difference, 0.4; 95% CI, 0.17-0.60; P < .001), peak circulatory power (LS mean difference, 372.9 mL/kg/min × mm Hg; 95% CI, 153.12-592.61; P = .001), and peak PETCO2 (LS mean difference, 2.0 mm Hg; 95% CI, 1.12-2.79; P < .001). Mavacamten also improved peak exercise time compared with placebo (LS mean difference, 0.7 minutes; 95% CI, 0.13-1.24; P = .02). There was a significant improvement in nonpeak-exercise CPET parameters, such as VE/VCO2 slope (LS mean difference, -2.6; 95% CI, -3.58 to -1.52; P < .001) and ventilatory power (LS mean difference, 0.6 mm Hg; 95% CI, 0.29-0.90; P < .001) favoring mavacamten vs placebo. Conclusions and Relevance: Mavacamten improved a range of CPET parameters beyond pVO2, indicating consistent and broad benefits on maximal exercise capacity. Although improvements in peak-exercise CPET parameters are clinically meaningful, the favorable effects of mavacamten on submaximal exertional tolerance provide further insights into the beneficial impact of mavacamten in patients with obstructive HCM. Trial Registration: ClinicalTrials.gov Identifier: NCT03470545.

Sex Differences in Left Ventricular Assist Device-related Emergency Department Encounters in the United States.

BACKGROUND: There is a paucity of data regarding sex differences in the profiles and outcomes of ambulatory patients on left ventricular assist device (LVAD) support who present to the emergency department (ED). METHODS AND RESULTS: We performed a retrospective analysis of 57,200 LVAD-related ED patient encounters from the 2010 to 2018 Nationwide Emergency Department Sample. International Classification of Diseases Clinical Modification, Ninth Revision and Tenth Revision, codes identified patients aged 18 years or older with LVADs and associated primary and comorbidity diagnoses. Clinical characteristics and outcomes were stratified by sex and compared. Multivariable logistic regression was used to evaluate predictors of hospital admission and death. Female patient encounters comprised 27.2% of ED visits and occurred at younger ages and more frequently with obesity and depression (all P < .01). There were no sex differences in presentation for device complication, stroke, infection, or heart failure (all P > .05); however, female patient encounters were more often respiratory- and genitourinary or gynecological related (both P < .01). After adjustment for age group, diabetes, depression, and hypertension, male patient encounters had a 38% increased odds of hospital admission (95% confidence interval 1.20-1.58), but there was no sex difference in the adjusted odds of death (odds ratio 1.11, 95% confidence interval 0.86-1.45). CONCLUSIONS: Patient encounters of females on LVAD support have significantly different comorbidities and outcomes compared with males. Further inquiry into these sex differences is imperative to improve long-term outcomes.

Frequency, Penetrance, and Variable Expressivity of Dilated Cardiomyopathy-Associated Putative Pathogenic Gene Variants in UK Biobank Participants.

BACKGROUND: There is a paucity of data regarding the phenotype of dilated cardiomyopathy (DCM) gene variants in the general population. We aimed to determine the frequency and penetrance of DCM-associated putative pathogenic gene variants in a general adult population, with a focus on the expression of clinical and subclinical phenotype, including structural, functional, and arrhythmic disease features. METHODS: UK Biobank participants who had undergone whole exome sequencing, ECG, and cardiovascular magnetic resonance imaging were selected for study. Three variant-calling strategies (1 primary and 2 secondary) were used to identify participants with putative pathogenic variants in 44 DCM genes. The observed phenotype was graded DCM (clinical or cardiovascular magnetic resonance diagnosis); early DCM features, including arrhythmia or conduction disease, isolated ventricular dilation, and hypokinetic nondilated cardiomyopathy; or phenotype-negative. RESULTS: Among 18 665 individuals included in the study, 1463 (7.8%) possessed ≥1 putative pathogenic variant in 44 DCM genes by the main variant calling strategy. A clinical diagnosis of DCM was present in 0.34% and early DCM features in 5.7% of individuals with putative pathogenic variants. ECG and cardiovascular magnetic resonance analysis revealed evidence of subclinical DCM in an additional 1.6% and early DCM features in an additional 15.9% of individuals with putative pathogenic variants. Arrhythmias or conduction disease (15.2%) were the most common early DCM features, followed by hypokinetic nondilated cardiomyopathy (4%). The combined clinical/subclinical penetrance was ≤30% with all 3 variant filtering strategies. Clinical DCM was slightly more prevalent among participants with putative pathogenic variants in definitive/strong evidence genes as compared with those with variants in moderate/limited evidence genes. CONCLUSIONS: In the UK Biobank, ≈1 of 6 of adults with putative pathogenic variants in DCM genes exhibited early DCM features potentially associated with DCM genotype, most commonly manifesting with arrhythmias in the absence of substantial ventricular dilation or dysfunction.

Management of Type 2 Diabetes in Stage C Heart Failure with Reduced Ejection Fraction.

Type 2 diabetes is an increasingly common comorbidity of stage C heart failure with reduced ejection fraction (HFrEF). The two diseases are risk factors for each other and can bidirectionally independently worsen outcomes. The regulatory requirement of cardiovascular outcomes trials for antidiabetic agents has led to an emergence of novel therapies with robust benefits in heart failure, and clinicians must now ensure they are familiar with the management of patients with concurrent diabetes and stage C HFrEF. This review summarises the current evidence for the management of type 2 diabetes in stage C HFrEF, recapitulating data from landmark heart failure trials regarding the use of guideline-directed medical therapy for heart failure in patients with diabetes. It also provides a preview of upcoming clinical trials in these populations.

Treatment Changes, Healthcare Resource Utilization, and Costs Among Patients with Symptomatic Obstructive Hypertrophic Cardiomyopathy: A Claims Database Study.

INTRODUCTION: There is limited evidence on therapies for obstructive hypertrophic cardiomyopathy (HCM), and data regarding treatment patterns and cost are scarce. This study assessed treatment patterns and economic outcomes in patients with symptomatic obstructive HCM. METHODS: Adults with symptomatic obstructive HCM as per study design and treated with pharmacotherapies [beta blockers (BBs), calcium channel blockers (CCBs), BB + CCB, or disopyramide] or procedures (septal reduction therapy, heart transplantation, implantable cardioverter-defibrillator, and pacemaker implantation) were identified from the IBM® MarketScan® Commercial and Medicare Supplemental database (January 2009-March 2019). Patients had 12-month continuous eligibility before and after (study period) treatment initiation (index treatment). Healthcare resource utilization (HRU), costs, and treatment changes were assessed. RESULTS: Of the 4883 patients included in the analysis, 85% received pharmacotherapies (BB 52.5%; CCB 11.7%; BB + CCB 17.7%; disopyramide 2.4%) and 15.7% underwent procedures. During the study period, 38, 34, and 100% of all patients had ≥ 1 inpatient stay, emergency room (ER) visit, and outpatient visit, respectively; mean total healthcare costs were US$53,053. Patients undergoing procedures had the highest HRU and costs across groups. Among patients receiving pharmacotherapies, HRU was lowest with BBs and highest with disopyramide. Treatment changes were observed in 43.8% of patients receiving pharmacotherapies. CONCLUSIONS: Patients experienced high rates of treatment changes, and the economic burden associated with symptomatic obstructive HCM increased as therapy escalated. More effective therapies are needed to stabilize or decrease the economic burden of obstructive HCM.

Inflammation and Immune Response in Arrhythmogenic Cardiomyopathy: State-of-the-Art Review.

Arrhythmogenic cardiomyopathy (ACM) is a primary disease of the myocardium, predominantly caused by genetic defects in proteins of the cardiac intercalated disc, particularly, desmosomes. Transmission is mostly autosomal dominant with incomplete penetrance. ACM also has wide phenotype variability, ranging from premature ventricular contractions to sudden cardiac death and heart failure. Among other drivers and modulators of phenotype, inflammation in response to viral infection and immune triggers have been postulated to be an aggravator of cardiac myocyte damage and necrosis. This theory is supported by multiple pieces of evidence, including the presence of inflammatory infiltrates in more than two-thirds of ACM hearts, detection of different cardiotropic viruses in sporadic cases of ACM, the fact that patients with ACM often fulfill the histological criteria of active myocarditis, and the abundance of anti-desmoglein-2, antiheart, and anti-intercalated disk autoantibodies in patients with arrhythmogenic right ventricular cardiomyopathy. In keeping with the frequent familial occurrence of ACM, it has been proposed that, in addition to genetic predisposition to progressive myocardial damage, a heritable susceptibility to viral infections and immune reactions may explain familial clustering of ACM. Moreover, considerable in vitro and in vivo evidence implicates activated inflammatory signaling in ACM. Although the role of inflammation/immune response in ACM is not entirely clear, inflammation as a driver of phenotype and a potential target for mechanism-based therapy warrants further research. This review discusses the present evidence supporting the role of inflammatory and immune responses in ACM pathogenesis and proposes opportunities for translational and clinical investigation.