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The modern description of hypertrophic cardiomyopathy is credited to the London pathologist, Robert Donald Teare who likened the disease to 'a tumour of the heart' and published his observations in the British Heart Journal 50 years ago. Teare recognised asymmetrical hypertrophy and myocyte disarray as a familial condition associated with premature and sudden death in young people. He rightly deserves the accolade for bringing a poorly understood, but well recognised phenomenon into the public domain. Thick and heavy hearts had been of interest and investigation to physicians and pathologists for many centuries. This article reviews the early history of hypertrophic cardiomyopathy and reflects on several centuries of progress in our understanding of the condition. [ABSTRACT FROM AUTHOR]

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.) [ABSTRACT FROM AUTHOR]

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.

Background and Aims: The role of biomarker testing in the management of obstructive hypertrophic cardiomyopathy (oHCM) is not well defined. This pre-specified analysis of SEQUOIA-HCM (NCT05186818) sought to define the associations between clinical characteristics and baseline concentrations of N-terminal pro-B-type natriuretic peptide (NT-proBNP) and high-sensitivity cardiac troponin I (hs-cTnI), and to evaluate effect of treatment with aficamten on biomarker concentrations., Methods: Cardiac biomarkers were measured at baseline and serially throughout the study. Regression analyses determined predictors of baseline NT-proBNP and hs-cTnI concentrations, and to evaluate whether early changes in these biomarkers relate to later changes in left ventricular outflow tract gradient (LVOT-G), other echocardiographic measures, health status, and functional capacity., Results: Baseline concentration of NT-proBNP was associated with LVOT-G and measures of diastolic function, while hs-cTnI was associated with left ventricular thickness. Within 8 weeks of treatment with aficamten, NT-proBNP was reduced by 79% (95% CI 83%-76%, P < .001) and hs-cTnI by 41% (95% CI 49%-32%, P < .001); both biomarkers reverted to baseline after washout. Reductions in NT-proBNP and hs-cTnI by 24 weeks were strongly associated with a lowering of LVOT-G, improvement in health status, and increased peak oxygen uptake. NT-proBNP reduction strongly correlated with the majority of improvements in exercise capacity. Furthermore, the change in NT-proBNP by Week 2 was associated with the 24-week change in key endpoints., Conclusions: NT-proBNP and hs-cTnI concentrations are associated with key variables in oHCM. Serial measurement of NT-proBNP and hs-cTnI appears to reflect clinical response to aficamten therapy., (© The Author(s) 2024. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Background: A primary goal in treating obstructive hypertrophic cardiomyopathy (oHCM) is to improve patients' health status: their symptoms, function, and quality of life. The health status benefits of aficamten, a novel cardiac myosin inhibitor, have not been comprehensively described., Objectives: This study sought to determine the effect of aficamten on patient-reported health status, including symptoms of fatigue, shortness of breath, chest pain, physical and social limitations, and quality of life., Methods: SEQUOIA-HCM (Phase 3 Trial to Evaluate the Efficacy and Safety of Aficamten Compared to Placebo in Adults With Symptomatic oHCM) randomized symptomatic adults with oHCM to 24 weeks of aficamten (n = 142) or placebo (n = 140), followed by a 4-week washout. The Kansas City Cardiomyopathy Questionnaire (KCCQ) and Seattle Angina Questionnaire 7-item (SAQ7) were serially administered. Changes in mean KCCQ-Overall Summary Score (KCCQ-OSS) and SAQ7-Summary Score (SAQ7-SS) from baseline to 24 weeks and following treatment withdrawal were compared using linear regression adjusted for baseline scores and randomization strata. Proportions of patients with clinically important changes were compared., Results: Among 282 participants, the mean age was 59 ± 13 years, 115 (41%) were female, and 223 (79%) were White. Baseline KCCQ-OSS (69.3 ± 20.1 vs 67.3 ± 18.8) and SAQ7-SS (72.0 ± 21.0 vs 72.4 ± 18.3) were similar between aficamten and placebo groups. Treatment with aficamten, compared with placebo, improved both the mean KCCQ-OSS (13.3 ± 16.3 vs 6.1 ± 12.6; mean difference: 7.9; 95% CI: 4.8-11.0; P < 0.001) and SAQ7-SS (11.6 ± 17.4 vs 3.8 ± 14.4; mean difference: 7.8; 95% CI: 4.7-11.0; P < 0.001) at 24 weeks, with benefits emerging within 4 weeks. No heterogeneity in treatment effect was found across subgroups. A much larger proportion of participants experienced a very large health status improvement (≥20 points) with aficamten vs placebo (KCCQ-OSS: 29.7% vs 12.4%, number needed to treat: 5.8; SAQ7-SS: 31.2% vs 13.9%, number needed to treat: 5.8). Participants' health status worsened significantly more after withdrawal from aficamten than placebo (KCCQ-OSS: -16.2 ± 19.0 vs -3.0 ± 9.6; P < 0.001; SAQ7-SS: -17.4 ± 21.4 vs -2.5 ± 13.3), further confirming a causal effect of aficamten., Conclusions: In patients with symptomatic oHCM, treatment with aficamten resulted in markedly improved health status, including significant improvement in chest pain-related health status, than placebo. (Phase 3 Trial to Evaluate the Efficacy and Safety of Aficamten Compared to Placebo in Adults With Symptomatic oHCM [SEQUOIA-HCM]; NCT05186818)., Competing Interests: Funding Support and Author Disclosures The SEQUOIA-HCM study was funded by Cytokinetics, Incorporated. Study design and data analysis were supported by the funder and aided by coauthors. Manuscript drafting was completed independently but reviewed by the funder. Dr Sherrod has received support from the National Heart, Lung, and Blood Institute (award number T32HL110837). Dr Saberi has received consultant/advisor fees from Bristol Myers Squibb; and has received research grants from Bristol Myers Squibb, Cytokinetics, Novartis, and Actelion Pharmaceuticals. Dr Nassif has received research and grant support from AstraZeneca and Cytokinetics; and has received consulting/advisory fees from Vifor and Cytokinetics. Dr Coats has received speaker fees from Alnylam and Pfizer; and has received advisory fees from Cytokinetics and Roche Diagnostics. Dr Garcia-Pavia has received speaker fees from Pfizer, AstraZeneca, Novo Nordisk, Ionis, BridgeBio, Bristol Myers Squibb, Intellia, and Alnylam; has received consultant/advisor fees from Pfizer, Alnylam, MyoKardia/Bristol Myers Squibb, Cytokinetics, Neuroimmune, Intellia, Ionis, BridgeBio, Lexeo, Rocket, Attralus, and AstraZeneca; and has received research/educational grants to his institution from Pfizer, AstraZeneca, Novo Nordisk, BridgeBio, and Alnylam. Dr Januzzi has received funding from the Hutter Family Professorship; has served as a board member for Imbria Pharmaceuticals; has served as a Director at Jana Care; has received grant support from Abbott, Applied Therapeutics, HeartFlow, Innolife, and Roche Diagnostics; has received consulting income from Abbott, Beckman, Bristol Myers Squibb, Boehringer Ingelheim, Janssen, Novartis, Pfizer, Merck, Roche Diagnostics, and Siemens; and has participated in clinical endpoint committees/Data Safety Monitoring Boards for Abbott, AbbVie, CVRx, Intercept, and Takeda. Dr Lewis has received research funding from the National Institutes of Health (R01-HL 151841, R01-HL131029, and R01-HL159514), American Heart Association (15GPSGC-24800006), Amgen, Cytokinetics, Applied Therapeutics, AstraZeneca, and SoniVie; has received honoraria for Advisory Boards from Pfizer, Merck, Boehringer Ingelheim, Novartis, American Regent, Cyclerion, Cytokinetics, and Amgen; and has received royalties from UpToDate for scientific content authorship related to exercise physiology. Dr Maron has received consultant/advisor fees from Imbria, Edgewise, and BioMarin; and has received Steering Committee fees for SEQUIOA-HCM from Cytokinetics, Incorporated. Dr Olivotto has received Speakers Bureau fees from Bristol Myers Squibb, Amicus, and Genzyme; has received consultant/advisor fees from Bristol Myers Squibb, Cytokinetics, Sanofi Genzyme, Amicus, Bayer, Tenaya, Rocket Pharma, and Lexeo; and has received research grant funding from Bristol Myers Squibb, Cytokinetics, Sanofi Genzyme, Amicus, Bayer, Menarini International, Chiesi, and Boston Scientific. Drs Butzner, Jacoby, Heitner, Kupfer, Malik, and Meng, and Ms Wohltman are employees of Cytokinetics Incorporated; and hold stock in Cytokinetics Incorporated. Dr Spertus has provided consultative services on patient-reported outcomes and evidence evaluation to Alnylam, AstraZeneca, Bayer, Merck, Janssen, Bristol Myers Squibb, 4DT Medical, Terumo, Cytokinetics, Imbria, and United Healthcare; holds research grants from Bristol Myers Squibb, and Janssen; owns the copyrights to the Seattle Angina Questionnaire, Kansas City Cardiomyopathy Questionnaire, and Peripheral Artery Questionnaire; and has served on the Board of Directors for Blue Cross Blue Shield of Kansas City. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Obstructive hypertrophic cardiomyopathy (oHCM) is characterized by left ventricular (LV) hypertrophy, LV outflow tract obstruction, and left atrial dilation, which can be associated with progressive heart failure, atrial fibrillation, and stroke. Aficamten is a next-in-class cardiac myosin inhibitor that reduces outflow tract obstruction by modulating cardiac contractility, with the potential to reverse pathological remodeling and, in turn, reduce cardiovascular events., Objectives: This study sought to investigate the effect of aficamten on cardiac remodeling compared with placebo using cardiovascular magnetic resonance (CMR) and its association with key clinical endpoints in the SEQUOIA-HCM (Safety, Efficacy, and Quantitative Understanding of Obstruction Impact of Aficamten in HCM) CMR substudy., Methods: SEQUOIA-HCM was a phase 3 double-blind, placebo-controlled trial for adults with symptomatic oHCM who were randomized 1:1 to 24 weeks of aficamten (dose range: 5-20 mg) or placebo. Eligible participants were offered enrollment in the CMR substudy with studies performed at baseline and week 24. Image analysis was performed in a blinded fashion by a core laboratory., Results: Of the 282 randomized patients, 57 (20%) participated in the substudy, and of those, 50 (88%) completed both baseline and week 24 CMR. Baseline characteristics of the CMR cohort were similar to the overall study population. Of these 50 patients, 21 received aficamten and 29 received placebo. Relative to placebo, patients receiving aficamten demonstrated significant reductions (Δ least-squares mean) in LV mass index (-15 g/m 2 ; 95% CI: -25 to -6 g/m 2 ; P = 0.001), maximal LV wall thickness (-2.1 mm; 95% CI: -3.1 to -1.1 mm; P < 0.001), left atrial volume index (-13 mL/m 2 ; 95% CI: -19 to -7 mL/m 2 ; P < 0.001), native T1 relaxation time (-37 ms; 95% CI: -69 to -5 ms; P = 0.026), indexed extracellular volume fraction (-3.9 g/m 2 ; 95% CI: -7.0 to -0.9 g/m 2 ; P = 0.014), and indexed myocyte mass (-14 g/m 2 ; 95% CI: -23 to -4 g/m 2 ; P = 0.004), while there were no significant changes in LV chamber volumes, LV replacement fibrosis (late gadolinium enhancement mass -0.7 g; 95% CI: -2.9 to 1.6 g; P = 0.54), or extracellular volume (0.7%; 95% CI: -2.2% to 3.6%; P = 0.61)., Conclusions: The CMR substudy of SEQUOIA-HCM demonstrated that treatment with aficamten relative to placebo for 24 weeks resulted in favorable cardiac remodeling. These changes, particularly with regard to LV mass, wall thickness, and left atrial size, could potentially lead to reduced cardiovascular events including heart failure and atrial fibrillation with longer follow-up. (Phase 3 Trial to Evaluate the Efficacy and Safety of Aficamten Compared to Placebo in Adults With Symptomatic oHCM [SEQUOIA-HCM]; NCT05186818)., Competing Interests: Funding Support and Author Disclosures The SEQUOIA-HCM study was funded by Cytokinetics. Dr Masri has received research grants from Pfizer, Ionis, Attralus, and Cytokinetics; and has received fees from Cytokinetics, Bristol Myers Squibb, Eidos/BridgeBio, Pfizer, Ionis, Lexicon, Attralus, Alnylam, Haya, Alexion, Akros, Prothena, BioMarin, AstraZeneca, and Tenaya. Dr Coats has received speaker fees from Alnylam and Roche; and has received advisory fees from Cytokinetics. Dr Hegde has received fees paid to institution for core lab services from Bristol Myers Squibb and Cytokinetics. Dr Lee has received research grants through his employer, the University of Glasgow, from AstraZeneca, Boehringer Ingelheim, and Roche Diagnostics; and is a member of a Trial Steering Committee for Cytokinetics and the Clinical Endpoints Committee for Bayer. Dr Maron has received consulting/advisor fees from Imbria, Edgewise, and Biomarin; and has recevied steering committee fees for SEQUIOA-HCM from Cytokinetics. Dr Michels has received research grant support through her employer, the Erasmus Medical Center, from Bristol Myers Squibb; and has received fees from Cytokinetics, Bristol Myers Squibb, and Alnylam. Dr Olivotto has received research grants from Bristol Myers Squibb, Cytokinetics, Amicus, Genzyme, Shire Takeda, Menarini International, Chiesi, and Boston Scientific; and has received fees from Bristol Myers Squibb, Cytokinetics, Amicus, Genzyme, Shire Takeda, Menarini International, Chiesi, Boston Scientific, Tenaya, Rocket Pharma, and Lexeo. Dr Oreziak has received investigator fees from Cytokinetics and MyoKardia/Bristol Myers Squibb. Dr Jacoby, Dr Heitner, Dr Kupfer, Dr Malik, Ms Meng, and Ms Wohltman are employees of and own stock in Cytokinetics. Dr Solomon has received consulting/advisor fees from Abbott, Action, Akros, Alnylam, Amgen, Arena, AstraZeneca, Bayer, Boehringer Ingelheim, Bristol Myers Squibb, Cardior, Cardurion, Corvia, Cytokinetics, Daiichi-Sankyo, GlaxoSmithKline, Lilly, Merck, MyoKardia, Novartis, Roche, Theracos, Quantum Genomics, Cardurion, Janssen, Cardiac Dimensions, Tenaya, Sanofi Pasteur, Dinaqor, Tremeau, CellProThera, Moderna, American Regent, Sarepta, Lexicon, Anacardio, Akros, and Puretech Health; and has received research grants from Actelion, Alnylam, Amgen, AstraZeneca, Bellerophon, Bayer, Bristol Myers Squibb, Celladon, Cytokinetics, Eidos, Gilead, GlaxoSmithKline, Ionis, Lilly, Mesoblast, MyoKardia, National Institutes of Health/National Heart, Lung, and Blood Institute, Neurotronik, Novartis, Novo Nordisk, Respicardia, Sanofi Pasteur, Theracos, and US2.AI. Dr Kramer has received research grants from Bristol Myers Squibb and Eli Lilly; and has served as a consultant for Eli Lilly. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Aficamten, a next-in-class cardiac myosin inhibitor, improved peak oxygen uptake (pVO 2 ) and lowered resting and Valsalva left ventricular outflow (LVOT) gradients in adults with symptomatic obstructive hypertrophic cardiomyopathy (oHCM) in SEQUOIA-HCM (Phase 3 Trial to Evaluate the Efficacy and Safety of Aficamten Compared to Placebo in Adults With Symptomatic oHCM), a phase 3, multicenter, randomized, double-blinded, placebo-controlled study., Objectives: The authors sought to evaluate the effect of aficamten on echocardiographic measures of cardiac structure and function in SEQUOIA-HCM., Methods: Serial echocardiograms were performed over 28 weeks in patients randomized to receive placebo or aficamten in up to 4 individually titrated escalating doses (5-20 mg daily) over 24 weeks based on Valsalva LVOT gradients and left ventricular ejection fraction (LVEF)., Results: Among 282 patients (mean age 59 ± 13 years; 41% female, 79% White, 19% Asian), mean LVEF was 75% ± 6% with resting and Valsalva LVOT gradients of 55 ± 30 mm Hg and 83 ± 32 mm Hg, respectively. Over 24 weeks, aficamten significantly lowered resting and Valsalva LVOT gradients, and improved left atrial volume index, lateral and septal e' velocities, and lateral and septal E/e' (all P ≤ 0.001). LV end-systolic volume increased and wall thickness decreased (all P ≤ 0.003). Aficamten resulted in a mild reversible decrease in LVEF (-4.8% [95% CI: -6.4 to -3.3]; P < 0.001) and absolute LV global circumferential strain (-3.7% [95% CI: 1.8-5.6]; P < 0.0010), whereas LV global longitudinal strain was unchanged. Several measures, including LVEF, LVOT gradients, and E/e' returned to baseline following washout. Among those treated with aficamten, improved pVO 2 and reduction in N-terminal pro-B-type natriuretic peptide (NT-proBNP) were associated with improvement in lateral e' velocity and septal and lateral E/e' (all P < 0.03), whereas improvement in Kansas City Cardiomyopathy Questionnaire Clinical Summary Scores (KCCQ-CSS) was associated with a decrease in both LVOT gradients (all P < 0.001)., Conclusions: Compared with placebo, patients receiving aficamten demonstrated significant improvement in LVOT gradients and measures of LV diastolic function, and several of these measures were associated with improvements in pVO 2 , KCCQ-CSS, and NT-proBNP. A modest decrease in LVEF occurred yet remained within normal range. These findings suggest aficamten improved multiple structural and physiological parameters in oHCM without significant adverse changes in LV systolic function. (Phase 3 Trial to Evaluate the Efficacy and Safety of Aficamten Compared to Placebo in Adults With Symptomatic oHCM [SEQUOIA-HCM]; NCT05186818)., Competing Interests: Funding Support and Author Disclosures The SEQUOIA-HCM trial is funded by Cytokinetics, Incorporated. Representatives of Cytokinetics have been involved in the design and conduct of the study reported in this paper. Study design and data analysis was supported by the funder and aided by coauthors. Manuscript drafting was completed independently but reviewed by the funder. Dr Wang is supported by a ACC/Merck Research Fellowship. Dr Hegde’s and Dr Wang’s institutions have received fees for core lab services from Cytokinetics and Bristol Myers Squibb. Dr Masri has received research grants from Pfizer, Ionis, Attralus, and Cytokinetics; and has received fees from Cytokinetics, BMS, Eidos/BridgeBio, Pfizer, Ionis, Lexicon, Attralus, Alnylam, Haya, Alexion, Akros, Prothena, BioMarin, AstraZeneca, and Tenaya. Dr Nassif has received research and grant support from AstraZeneca and Cytokinetics; and has received consulting/advisory fees from Vifor and Cytokinetics. Dr Barriales-Villa has received consultant/advisor fees from MyoKardia/Bristol Myers Squibb. Dr Cardim has received speaker fees from Cytokinetics and Bristol Myers Squibb. Dr Coats has received speaker fees from Alnylam and Pfizer; and has received advisory fees from Cytokinetics and Roche Diagnostics. Dr Kramer has received research grants from Cytokinetics, BMS, and Eli Lilly; and is a consultant for Eli Lilly. Dr Maron has received consultant/advisor fees from Imbria and Takeda; and has received steering committee fees for SEQUOIA-HCM from Cytokinetics, Incorporated. Dr Michels’ institution has received a research grant from Bristol Myers Squibb; has received consultant/ advisor fees from Cytokinetics and Bristol Myers Squibb/Myokardia and Alnylam; and has received speaker fees from Bristol Myers Squibb and Pfizer. Dr Olivotto has received research grants from Bristol Myers Squibb, Cytotinetics, Sanofi, Benzyme, Amicus, Bayer, Menarini International, Chiesi, and Boston Scientific; has received consulting fees from Bristol Myers Squibb, Amicus, Sanofi, and Genzyme; and has served as an Advisory Board member for Cytokinetics, Bristol Myers Squibb, Chiesi, and Rocket Pharma. Dr Saberi has received consultant/advisor fees from Bristol Myers Squibb; and has received research grants from Cytokinetics, Bristol Myers Squibb, Cytokinetics, Novartis, and Actelion Pharmaceuticals. Drs Jacoby, Heitner, Kupfer, Meng, and Malik, and Ms Wohltman are employees of and hold stock in Cytokinetics, Incorporated. Dr Solomon has received research grants from Alexion, Alnylam, Applied Therapeutics, AstraZeneca, Bellerophon, Bayer, BMS, Boston Scientific, Cytokinetics, Edgewise, Eidos/Bridgebio, Gossamer, GSK, Ionis, Lilly, NIH/NHLBI, Novartis, NovoNordisk, Respicardia, Sanofi Pasteur, Tenaya, Theracos, and US2.AI; and has consulted for Abbott, Action, Akros, Alexion, Alnylam, Amgen, Arena, AstraZeneca, Bayer, BMS, Cardior, Cardurion, Corvia, Cytokinetics, GSK, Lilly, Novartis, Roche, Theracos, Quantum Genomics, Tenaya, Sanofi-Pasteur, Dinaqor, Tremeau, CellProThera, Moderna, American Regent, Sarepta, Lexicon, Anacardio, Akros, and Valo. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

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

Proteomics studies often explore phenotypic differences between whole organs and systems. Within the heart, more subtle variation exists. To date, differences in the underlying proteome are only described between whole cardiac chambers. This study, using the bovine heart as a model, investigates inter-regional differences and assesses the feasibility of measuring detailed, cross-tissue variance in the cardiac proteome. Using a bovine heart, we created a two-dimensional section through a plane going through two chambers. This plane was further sectioned into 4 × 4 mm cubes and analysed using label-free proteomics. We identified three distinct proteomes. When mapped to the extracted sections, the proteomes corresponded largely to the outer wall of the right ventricle and secondly to the outer wall of the left ventricle, right atrial appendage, tricuspid and mitral valves, modulator band, and parts of the left atrium. The third separate proteome corresponded to the inner walls of the left and right ventricles, septum, and left atrial appendage. Differential protein abundancies indicated differences in energy metabolism between regions. Data analyses of the mitochondrial proteins revealed a variable pattern of abundances of complexes I-V between the proteomes, indicating differences in the bioenergetics of the different cardiac sub-proteomes. Mapping of disease-associated proteins interestingly showed desmoglein-2, for which defects in this protein are known to cause Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy, which was present predominantly in the outer wall of the left ventricle. This study highlights that organs can have variable proteomes that do not necessarily correspond to anatomical features.

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

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., (Crown Copyright © 2024. Published by Elsevier Inc. All rights reserved.)

Hypertrophic cardiomyopathy (HCM) is characterized by abnormal growth of the myocardium with myofilament disarray and myocardial hyper-contractility, leading to left ventricular hypertrophy and fibrosis. Where culprit genes are identified, they typically relate to cardiomyocyte sarcomere structure and function. Multi-modality imaging plays a crucial role in the diagnosis, monitoring, and risk stratification of HCM, as well as in screening those at risk. Following the recent publication of the first European Society of Cardiology (ESC) cardiomyopathy guidelines, we build on previous reviews and explore the roles of electrocardiography, echocardiography, cardiac magnetic resonance (CMR), cardiac computed tomography (CT), and nuclear imaging. We examine each modality's strengths along with their limitations in turn, and discuss how they can be used in isolation, or in combination, to facilitate a personalized approach to patient care, as well as providing key information and robust safety and efficacy evidence within new areas of research.

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)., Competing Interests: Funding Support and Author Disclosures The SEQUOIA-HCM trial is funded by Cytokinetics, Incorporated. Representatives of Cytokinetics have been involved in the design and conduct of the study reported in this manuscript. Dr Coats has received speaker fees from Alnylam and Roche, and advisory fees from Cytokinetics. Dr Maron has received consultant/advisor fees from Imbria and Takeda, and Steering Committee fees for SEQUOIA-HCM from Cytokinetics, Incorporated. Dr Olivotto has received Speakers Bureau fees from Boston Scientific, Amicus, and Novartis; consultant/advisor fees from Bristol Myers Squibb, Cytokinetics, Sanofi Genzyme, Amicus, Bayer, Tenaya, and Rocket Pharma; and research grant funding from Bristol Myers Squibb, Cytokinetics, Sanofi Genzyme, Amicus, Bayer, Menarini International, and Boston Scientific. Dr Lee has received research grants to his institution from AstraZeneca and Boehringer Ingelheim, and Clinical Endpoint Committee fees from Bayer. Dr Arad has received consultant and lecture fees from Bristol Myers Squibb. Dr Cardim is on the advisory boards for Bristol Myers Squibb and Cytokinetics. Dr Düngen has received grants from Novartis, CSL Behring, and Cytokinetics. Dr Garcia-Pavia has received Speakers Bureau fees from Pfizer, AstraZeneca, NovoNordisk, Bristol Myers Squibb, BridgeBio, Ionis, and Alnylam; consultant/advisor fees from Pfizer, Alnylam, MyoKardia/Bristol Myers Squibb, Cytokinetics, Neurimmune, BridgeBio, Attralus, Intellia, Rocket Pharma, Lexeo Therapeutics, and AstraZeneca; and research/educational grants to his institution from Pfizer, BridgeBio, NovoNordisk, AstraZeneca, and Alnylam. Dr Hagège has received consultant/advisor fees from Alnylam, Amicus Therapeutics, Bayer, MyoKardia/Bristol Myers Squibb, Pfizer, and Sanofi Genzyme; and Steering Committee fees for SEQUOIA-HCM from Cytokinetics, Incorporated. Dr Lewis has received research funding from the National Institutes of Health (R01-HL 151841, R01-HL131029, and R01-HL159514), American Heart Association (15GPSGC-24800006), Amgen, Cytokinetics, Applied Therapeutics, AstraZeneca, and SoniVie; honoraria for advisory boards from Pfizer, Merck, Boehringer Ingelheim, Novartis, American Regent, Cyclerion, Cytokinetics, and Amgen; and royalties from UpToDate for scientific content authorship related to exercise physiology. Dr Michels’ institution has received a research grant from Bristol Myers Squibb. Dr Michels has received consultant/advisor fees from Cytokinetics and Bristol Myers Squibb/Myokardia; and Speakers Bureau fees from Bristol Myers Squibb and Pfizer. Dr Oreziak has received investigator fees from Bristol Myers Squibb/MyoKardia; consultant/advisor fees from Biotronik Polska, Abbott Polska; and traveling fees from Hammermed. Dr Owens has received consultant/advisor fees from Cytokinetics, Bristol Myers Squibb/MyoKardia, and Pfizer. Dr Tfelt-Hansen is a consultant for Leo Pharma, MicroPort, and Johnson and Johnson. Dr Watkins has received consultant/advisor fees from Cytokinetics, BioMarin, and BridgeBio. Dr Heitner, Dr Jacoby, Dr Kupfer, Dr Malik, Dr Meng, and Ms Wohltman are employees of Cytokinetics, Incorporated and hold stock in Cytokinetics, Incorporated. Dr Masri has received consultant/advisor fees from Tenaya, Attralus, Cytokinetics, Bristol Myers Squibb, Eidos, Pfizer, Lexicon, Alnylam, Haya, Intellia, and Ionis; and research grants from Ionis, Akcea, Pfizer, Cytokinetics, Ultromics, and the Wheeler Foundation. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

These guidelines form an update of the BSE guideline protocol for the assessment of restrictive cardiomyopathy (Knight et al. in Echo Res Prac, 2013). Since the original recommendations were conceived in 2013, there has been an exponential rise in the diagnosis of cardiac amyloidosis fuelled by increased clinician awareness, improvements in cardiovascular imaging as well as the availability of new and effective disease modifying therapies. The initial diagnosis of cardiac amyloidosis can be challenging and is often not clear-cut on the basis of echocardiography, which for most patients presenting with heart failure symptoms remains the first-line imaging test. The role of a specialist echocardiographer will be to raise the suspicion of cardiac amyloidosis when appropriate, but the formal diagnosis of amyloid sub-type invariably requires further downstream testing. This document seeks to provide a focused review of the literature on echocardiography in cardiac amyloidosis highlighting its important role in the diagnosis, prognosis and screening of at risk individuals, before concluding with a suggested minimum data set, for use as an aide memoire when reporting., (© 2023. British Society of Echocardiography.)

Background: Rapidly accelerated fibrosarcoma B-type (BRAF) and mitogen-activated extracellular signal-regulated kinase (MEK) inhibitors have revolutionized treatment for patients with BRAF-mutated melanoma. Although left ventricular systolic dysfunction associated with these therapies has been reported in clinical trials, the real-world incidence is poorly defined, as are risk factors for its development., Objectives: This study sought to characterize the incidence, time course, and risk factors for cancer therapy-related cardiac dysfunction (CTRCD) in patients with melanoma receiving BRAF and MEK inhibitors., Methods: Patients with melanoma treated with BRAF and MEK inhibitors at a cancer hospital network between June 1, 2017, and June 30, 2020, were included retrospectively. CTRCD was defined as mild, moderate, or severe according to International Cardio-Oncology Society (ICOS) definitions. Baseline cardiotoxicity risk stratification was performed using the Heart Failure Association/ICOS tool., Results: Of the 63 patients included, 27% developed CTRCD (17% mild and 10% moderate). No patients developed severe CTRCD or symptomatic heart failure. CTRCD occurred most frequently in patients considered to be at "low" and "medium" baseline risk of cardiotoxicity (82%). The baseline left ventricular ejection fraction and global longitudinal strain were not different in patients who developed moderate CTRCD vs those who did not. Left ventricular internal diameters in diastole and systole were larger in patients who developed moderate CTRCD compared with those who did not (left ventricular internal diameter in diastole: 4.9 ± 0.6 cm vs 4.3 ± 0.6 cm; P = 0.023; left ventricular internal diameter in systole: 3.3 ± 0.4 cm vs 2.8 ± 0.5 cm; P = 0.039)., Conclusions: BRAF and MEK inhibitor-associated CTRCD is common. The utility of the Heart Failure Association/ICOS risk stratification tool appears limited in this group, and better risk prediction tools are needed. The long-term consequences of CTRCD, particularly mild CTRCD, warrant evaluation in larger prospective studies., Competing Interests: Drs Glen and Lang are supported by an unrestricted grant from Roche Diagnostics. Drs Petrie and Lang are supported by a British Heart Foundation Centre of Research Excellence grant (RE/18/6/34217). Dr Petrie has received research funding from Boehringer Ingelheim, Roche, SQ Innovations, AstraZeneca, Novartis, Novo Nordisk, Medtronic, Boston Scientific, Pharmacosmos, and 3R LifeSciences; and is a consultant and on clinical trials committees for Boehringer Ingelheim, Novartis, Roche, Corvia, AstraZeneca, Novo Nordisk, Medtronic, Abbvie, Bayer, Takeda, Cardiorentis, Pharmacosmos, and Siemens. Dr Lang has received speaker fees from Roche, Pfizer, and Novartis., (© 2023 The Authors.)

Hereditary transthyretin-mediated amyloidosis (hATTR) is challenging to diagnose early owing to the heterogeneity of clinical presentation, which differs according to the TTR gene variant and its penetrance in each individual. The TTR variants seen most frequently in the UK and Ireland (T80A, V142I and V50M) differ to those commonly occurring in other geographic locations and warrant a specific consideration for diagnosis and genetic testing. In addition, recent availability of treatment for this condition has reinforced the need for a more consistent approach to the management of patients, including access to specialist services, genetic testing and counselling, and clinical investigation for families living in the UK and Ireland. A multidisciplinary panel of experts from the UK and Ireland was convened to identify the current challenges, provide recommendations, and develop a consensus for the diagnosis and screening of people with, or at risk of, hATTR. Over a series of meetings, experts shared their current practices and drafted, refined and approved a consensus statement. This consensus statement provides recommendations for three different groups: (1) people with symptoms raising a possibility of hATTR amyloidosis; (2) people with biopsy-confirmed hATTR amyloidosis; and (3) people without symptoms who may have hATTR amyloidosis (i.e. relatives of people with identified TTR variants). For each group, recommendations are made for the required steps for the diagnosis and follow-up of symptomatic patients, and for guidance on the specialist support for counselling and pre-symptomatic genetic testing of at-risk individuals. This guidance is intended to be practical and based on available evidence. The aim is for regional amyloid specialist centres to provide timely diagnosis, clinical screening, and treatment for individuals and their families with hATTR amyloidosis., (© 2022. The Author(s).)

In 2022, the British Cardiovascular Society celebrates the centenary of its foundation. Starting out as a small group of government-appointed physicians interested in heart disease, the Cardiac Club has grown and adapted to represent all those working in cardiovascular care and research. The historical stages of the organisation's development are outlined, alongside major innovations in science and technology providing context for a rapidly changing medical world. Only a small part of the history of cardiology in Britain is told, with greater emphasis on describing the broader need for services, skilled workforce, healthcare policy and continuing education. Above all, the history of the British Cardiovascular Society is a story of people and places. The people are those with vision, attitude and leadership to improve the care of communities across the world. The places are those that enabled conversation, innovation and freedom to bring about change. It is hard to believe the remarkable progress in diagnosis, prevention and treatment of heart disease over 100 years, but a thriving modern Society must be the greatest legacy of its founders., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

Importance: Hypertrophic cardiomyopathy causes limiting symptoms in patients, mediated partly through inefficient myocardial energy use. There is conflicting evidence for therapy with inhibitors of myocardial fatty acid metabolism in patients with nonobstructive hypertrophic cardiomyopathy., Objective: To determine the effect of oral therapy with trimetazidine, a direct inhibitor of fatty acid β-oxidation, on exercise capacity in patients with symptomatic nonobstructive hypertrophic cardiomyopathy., Design, Setting, and Participants: This randomized, placebo-controlled, double-blind clinical trial at The Heart Hospital, University College London Hospitals, London, United Kingdom was performed between May 31, 2012, and September 8, 2014. The trial included 51 drug-refractory symptomatic (New York Heart Association class ≥2) patients aged 24 to 74 years with a maximum left ventricular outflow tract gradient 50 mm Hg or lower and a peak oxygen consumption during exercise of 80% or less predicted value for age and sex. Statistical analysis was performed from March 1, 2016 through July 4, 2018., Interventions: Participants were randomly assigned to trimetazidine, 20 mg, 3 times daily (n = 27) or placebo (n = 24) for 3 months., Main Outcomes and Measures: The primary end point was peak oxygen consumption during upright bicycle ergometry. Secondary end points were 6-minute walk distance, quality of life (Minnesota Living with Heart Failure questionnaire), frequency of ventricular ectopic beats, diastolic function, serum N-terminal pro-brain natriuretic peptide level, and troponin T level., Results: Of 49 participants who received trimetazidine (n = 26) or placebo (n = 23) and completed the study, 34 (70%) were male; the mean (SD) age was 50 (13) years. Trimetazidine therapy did not improve exercise capacity, with patients in the trimetazidine group walking 38.4 m (95% CI, 5.13 to 71.70 m) less than patients in the placebo group at 3 months after adjustment for their baseline walking distance measurements. After adjustment for baseline values, peak oxygen consumption was 1.35 mL/kg per minute lower (95% CI, -2.58 to -0.11 mL/kg per minute; P = .03) in the intervention group after 3 months., Conclusions and Relevance: In symptomatic patients with nonobstructive hypertrophic cardiomyopathy, trimetazidine therapy does not improve exercise capacity. Pharmacologic therapy for this disease remains limited., Trial Registration: ClinicalTrials.gov identifier: NCT01696370.

Background: Hypertrophic cardiomyopathy (HCM) is characterized by a complex phenotype that is only partly explained by the biological effects of individual genetic variants. The aim of this study was to use proteomic analysis of myocardial tissue to explore the postgenomic phenotype., Methods: Label-free proteomic analysis was used initially to compare protein profiles in myocardial samples from 11 patients with HCM undergoing surgical myectomy with control samples from 6 healthy unused donor hearts. Differentially expressed proteins of interest were validated in myocardial samples from 65 unrelated individuals (HCM [n=51], controls [n=7], and aortic stenosis [n=7]) by the development and use of targeted multiple reaction monitoring-based triple quadrupole mass spectrometry., Results: In this exploratory study, 1586 proteins were identified with 151 proteins differentially expressed in HCM samples compared with controls ( P<0.05). Protein expression profiling showed that many proteins identified in the initial discovery study were associated with metabolism, muscle contraction, calcium regulation, and oxidative stress. Proteins downregulated in HCM versus controls included creatine kinase M-type, fructose-bisphosphate aldolase A, and phosphoglycerate mutase ( P<0.001). Proteins upregulated in HCM included lumican, carbonic anhydrase 3, desmin, α-actin skeletal, and FHL1 (four and a half LIM domain protein 1; P<0.01). Myocardial lumican concentration correlated with the left atrial area (ρ=0.34, P=0.015), late gadolinium enhancement on cardiac magnetic resonance imaging ( P=0.03) and the presence of a pathogenic sarcomere mutation ( P=0.04)., Conclusions: The myocardial proteome of HCM provides supporting evidence for dysregulation of metabolic and structural proteins. The finding that lumican is raised in HCM hearts provides insight into the myocardial fibrosis that characterizes this disease.

Aims: The burden of cardiovascular disease is increasing worldwide, which has to be reflected by cardiovascular (CV) research in Europe. CardioScape, a FP7 funded project initiated by the European Society of Cardiology (ESC), identified where CV research is performed, how it is funded and by whom. It could be transformed into an on-line and up-to-date resource of great relevance for researchers, funding bodies and policymakers and could be a role model for mapping CV research funding in Europe and beyond., Methods and Results: Relevant funding bodies in 28 European Union (EU) countries were identified by a multistep process involving experts in each country. Projects above a funding threshold of 100 k€ during the period 2010-2012 were included using a standard questionnaire. Results were classified by experts and an adaptive text analysis software to a CV-research taxonomy, integrating existing schemes from ESC journals and congresses. An on-line query portal was set up to allow different users to interrogate the database according to their specific viewpoints., Conclusion: CV-research funding varies strongly between different nations with the EU providing 37% of total available project funding and clear geographical gradients exist. Data allow in depth comparison of funding for different research areas and led to a number of recommendations by the consortium. CardioScape can support CV research by aiding researchers, funding agencies and policy makers in their strategic decisions thus improving research quality if CardioScape strategy and technology becomes the basis of a continuously updated and expanded European wide publicly accessible database.

Competing Interests: Competing interests: None declared.

Background: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a myocardial disease with an increased risk for ventricular arrhythmias. The condition, which occurs in Boxer dogs, shares phenotypic features with the human disease arrhythmogenic cardiomyopathy (ACM) suggesting its potential as a natural animal model. However, there are currently no universally accepted clinical criteria to diagnose ARVC in Boxer dogs. We aimed to identify diagnostic criteria for ARVC in Boxer dogs defining a more uniform and consistent phenotype., Methods and Results: Clinical records from 264 Boxer dogs from a referral veterinary hospital were retrospectively analysed. ARVC was initially diagnosed according to the number of ventricular premature complexes (VPCs) in the 24-hour-Holter-ECG in the absence of another obvious cause. Dogs diagnosed this way had more VPCs, polymorphic VPCs, couplets, triplets, VTs and R-on-T-phenomenon and syncope, decreased right ventricular function and dilatation in comparison to a control group of all other Boxer dogs seen by the Cardiology Service over the same period. Presence of couplets and R-on-T-phenomenon on a 24h-ECG were identified as independent predictors of the diagnosis. A diagnosis based on ≥100 VPCs in 24 hours, presence of couplets and R-on-T phenomenon on a 24h-ECG was able to select Boxer dogs with a phenotype most similar to human ACM., Conclusion: We suggest the diagnosis of ARVC in Boxer dogs requires two out of the three following criteria: presence of ≥ 100 VPCs, presence of couplets or R-on-T-phenomenon on a 24 h-ECG. This results in a uniform phenotype similar to that described in human ACM and may result in the adoption of the term ACM for this analogous condition in Boxer dogs.

Background: Exercise testing is performed in patients with hypertrophic cardiomyopathy to evaluate blood pressure response, a risk factor for sudden cardiac death. The prognostic role of exercise gas exchange variables is unknown., Methods and Results: Between 1998 and 2010, 1898 patients (age 47±15 years, range 16-86 years; 67% male) with hypertrophic cardiomyopathy underwent cardiopulmonary exercise testing. A total of 178 (9.4%) patients reached the primary end point of all-cause mortality or heart transplant (death/transplant) during a median follow-up of 5.6 years (interquartile range 2.6-8.9), giving an annual event rate of 1.6% per person year. Peak oxygen consumption (adjusted hazard ratio [HR] 0.82, 95% confidence interval [CI] 0.77-0.88, P<0.001), ventilatory efficiency (adjusted HR 1.10, 95% CI 1.00-1.22, P=0.049), and ventilatory anaerobic threshold (adjusted HR 0.82, 95% CI 0.70-0.96, P=0.016) were predictors of the primary outcome after correction for age, sex, left atrial size, nonsustained ventricular tachycardia, and ejection fraction. The overall adjusted death/transplant estimates for patients in the lowest quartile with peak oxygen consumption ≤15.3 mL/kg/min were 14% at 5 years and 31% at 10 years. Peak oxygen consumption (HR 0.81, 95% CI 0.77-0.86, P<0.01) and ventilation to carbon dioxide production (HR 1.10, 95% CI 1.08-1.13, P<0.001) were predictors of death because of heart failure or transplantation but not sudden cardiac death or implantable cardioverter defibrillator shocks., Conclusions: Cardiopulmonary exercise testing provides prognostic information in patients with hypertrophic cardiomyopathy. Submaximal exercise parameters, such as ventilatory efficiency and anaerobic threshold, measured alone or in combination with peak oxygen consumption, predict death from heart failure., (© 2015 American Heart Association, Inc.)

Aims: Plasma volume (PV) expansion hallmarks worsening chronic heart failure (CHF) but no non-invasive means of quantifying volume status exists. Because weight and haematocrit are related to PV, they can be used to calculate relative PV status (PVS). We tested the validity and prognostic utility of calculated PVS in CHF patients., Methods and Results: First, we evaluated the agreement between calculated actual PV (aPV) and aPV levels measured using (125)Iodine-human serum albumin. Second, we derived PVS as: [(calculated aPV - ideal PV)/ideal PV] × 100%. Third, we assessed the prognostic implications of PVS in 5002 patients from the Valsartan in Heart Failure Trial (Val-HeFT), and validated this in another 246 routine CHF outpatients. On analysis, calculated and measured aPV values correlated significantly in 119 normal subjects and 30 CHF patients. In the Val-HeFT cohort, mean (+SD) PVS was -9 ± 8% and related to volume biomarkers such as brain natriuretic peptide (BNP). Over 2 years, 977 (20%) patients died. Plasma volume status was associated with death and first morbid events in a 'J-shaped' fashion with the highest risk seen with a PVS > -4%. Stratification into PVS quartiles confirmed that a PVS > -4% was associated with increased mortality (unadjusted hazard ratio 1.65, 95% confidence interval 1.44-1.88, χ(2)  = 54, P < 0.001) even after adjusting for 22 variables, including brain natriuretic peptide. These results were mirrored in the validation cohort., Conclusions: Relative PVS calculated from simple clinical indices reflects the degree to which patients have deviated from their ideal PV and independently relates to outcomes. The utility of PVS-driven CHF management needs further evaluation., (© 2014 The Authors. European Journal of Heart Failure © 2014 European Society of Cardiology.)

Cardiomyopathies are an important cause of sudden cardiac death in young people and are responsible for arrhythmias and premature heart failure in all age groups. Although many cardiomyopathies are inherited, biochemical markers are a fundamental part of the diagnostic work-up and are useful in the prognostic assessment of disease. In this article, the authors review the rationale and evidence for important biomarkers according to their role in patient management. Emerging biomarkers are briefly reviewed, alongside modern scientific approaches to biomarker discovery.

Background: An elevated red cell distribution width (RDW) and iron deficiency (ID) at baseline predict enhanced mortality in chronic heart failure (CHF), but little is known about the prognostic implications of their temporal trends. We sought to determine the survival implications of temporal changes in RDW and evolving ID in patients with CHF., Methods: The relation between red cell indices on first consultation and over time with mortality in 274 stable patients with systolic CHF was analysed. The combination of a rising RDW with a falling mean cell volume (MCV) over time defined evolving ID., Results: Over a median 12 month period, 51% and 23% of patients had a rise in RDW and evolving ID, respectively. After a median follow-up of 27 months, 60 (22%) patients died. A rising RDW predicted enhanced all-cause mortality (unadjusted HR for 1% per week rise 9.27, 95% CI 3.58 to 24.00, P<0.0001) independently and incrementally to baseline RDW, with an absolute increase >0.02% per week optimally predictive. Evolving ID also related to higher rates of mortality (HR 2.78, 95% CI 1.64 to 4.73, P<0.001) and was prognostically worse than a rising RDW alone (P<0.005). Patients with evolving ID who maintained their Hb levels over time had a 2-fold greater risk of death than those whose Hb levels declined without evolving ID., Conclusions: An expanding RDW and evolving iron deficiency over time predict an amplified risk of death in CHF and should be utilised for risk stratification and/or therapeutically targeted to potentially improve outcomes., (Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.)

Aims: To determine the relation between serum concentrations of N-terminal pro-brain natriuretic peptide (NT-proBNP) and prognosis in patients with hypertrophic cardiomyopathy (HCM)., Methods and Results: In total, 847 patients (53 ± 15 years; 67% male) with HCM (28% with left ventricular outflow tract obstruction ≥ 30 mmHg at rest) were followed for 3.5 years (IQR 2.5-4.5 years). The median NT-proBNP concentration was 78 pmol/L (range < 5-1817 pmol/L and IQR 31-183 pmol/L). Sixty-eight patients (8%) reached the primary endpoint of all-cause mortality or cardiac transplantation. NT-proBNP concentration predicted long-term survival from the primary endpoint [area under the receiver operating characteristic curve of 0.78 (95% confidence interval 0.73-0.84)]. A serum concentration of ≥ 135 pmol/L was associated with an annual event rate of 6.1% (95% CI 4.4-7.7). Three independent predictors of primary outcome were identified in a multivariable Cox model: New York Heart Association class III/IV (HR 2.10, 95% CI 1.21-3.65, P = 0.008), ejection fraction (HR 0.98, 95% CI 0.96-1.00, P = 0.035), log NT-proBNP (HR 2.04, 95% CI 1.56-2.66, P < 0.001). Log NT-proBNP was a significant predictor of heart failure (HF) and transplant-related deaths (n = 23; HR 3.03, 95% CI 1.99-4.60, P < 0.001) but not sudden death or appropriate implantable cardioverter defibrillator shock (n = 11; HR 1.54, 95% CI 0.91-2.60, P = 0.111). In patients with ejection fraction ≥ 50% (n = 673), log NT-proBNP remained an independent predictor of the primary outcome (HR 2.11, 95% CI 1.54-2.90, P < 0.001)., Conclusion: In patients with HCM, elevated NT-proBNP concentration is a strong predictor of overall prognosis, particularly HF-related death and transplantation.

Hypertrophic cardiomyopathy is a common inherited heart muscle disorder associated with sudden cardiac death, arrhythmias and heart failure. Genetic mutations can be identified in approximately 60% of patients; these are commonest in genes that encode proteins of the cardiac sarcomere. Similar to other Mendelian diseases these mutations are characterized by incomplete penetrance and variable clinical expression. Our knowledge of this genetic diversity is rapidly evolving as high-throughput DNA sequencing technology is now used to characterize an individual patient's disease. In addition, the genomic basis of several multisystem diseases associated with a hypertrophic cardiomyopathy phenotype has been elucidated. Genetic biomarkers can be helpful in making an accurate diagnosis and in identifying relatives at risk of developing the condition. In the clinical setting, genetic testing and genetic screening should be used pragmatically with appropriate counseling. Here we review the current role of genetic biomarkers in hypertrophic cardiomyopathy, highlight recent progress in the field and discuss future challenges.

Enzyme replacement therapy has the potential to delay or reverse adverse cardiac remodeling in Anderson-Fabry disease (AFD); however, the current indications for enzyme replacement therapy rely on detecting relatively advanced features of the disease. We aimed to determine the relation between the serum N-terminal pro-brain natriuretic peptide (NT-proBNP) concentration and cardiac abnormalities in patients with AFD. We hypothesized that it might help to detect early disease. NT-proBNP was measured under at rest conditions in 117 patients with AFD (age 48 ± 15 years, 46.2% men). All patients underwent clinical evaluation with electrocardiography and echocardiography. The median NT-proBNP concentration was 24 pmol/L (range <5 to 6,059). Of the 117 patients, 67 (57%) had elevated, age-corrected, NT-proBNP levels. In the 56 patients (48%) with normal echocardiographic findings, the NT-proBNP levels were greater than the age-predicted cutoffs in 10 of 25 patients with abnormal electrocardiographic findings and 3 of 31 patients with normal electrocardiographic findings (p <0.05). On multiple regression analysis, age, creatinine, left atrial volume index, E/Ea, and the presence of abnormal electrocardiographic findings were independently associated with log NT-proBNP (R(2) = 0.67, p <0.05). In conclusion, NT-proBNP concentrations were elevated in patients with AFD and early cardiac involvement, suggesting its measurement could assist in decisions regarding the timing of enzyme replacement therapy., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Hypertrophic cardiomyopathy is a heterogeneous clinical syndrome with a wide spectrum of pathophysiologic consequences. Most cases are inherited and caused by sarcomeric protein gene mutations, although phenocopies are often encountered. Genomic research and family studies have improved our recognition of the disease and understanding of its natural history; however, tenuous links exist between genotype and phenotype and thus far have done little to alter clinical management. Surgery and, more recently, implantable cardiac defibrillators have had an impact on sudden cardiac death rates, with improved short- and medium-term survival. Therefore, managing heart failure has become increasingly challenging. Although heart failure due to fibrosis and a progressive loss of contractile function is common, treatment remains largely empiric. Case series and animal studies suggest that biventricular pacing and renin-angiotensin-aldosterone system modifiers may be useful in some patients, but there is a need for large prospective randomized controlled trials to study these and other treatments. Risk stratification and eligibility for sports participation remain hot topics, but one of the greatest challenges is the management of a growing cohort of asymptomatic gene carriers identified during family screening. Ultimately, major advances in treatment and disease prevention will come from a better understanding of the genomic, proteomic, and metabolomic profiles of individual patients.