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Hypertrophic cardiomyopathy (HCM) is the major contributor to morbidity and mortality in Noonan syndrome (NS). Gain-of-function variants in RAF1 are associated with high prevalence of HCM. Among these, NM_002880.4:c.770C > T, NP_002871.1:p.(Ser257Leu) accounts for approximately half of cases and has been reported as associated with a particularly severe outcome. Nevertheless, comprehensive studies on cases harboring this variant are missing. To precisely define the phenotype associated to the RAF1:c.770C > T, variant, an observational retrospective analysis on patients carrying the c.770C > T variant was conducted merging 17 unpublished patients and literature-derived ones. Data regarding prenatal findings, clinical features and cardiac phenotypes were collected to provide an exhaustive description of the associated phenotype. Clinical information was collected in 107 patients. Among them, 92% had HCM, mostly diagnosed within the first year of life. Thirty percent of patients were preterm and 47% of the newborns was admitted in a neonatal intensive care unit, mainly due to respiratory complications of HCM and/or pulmonary arterial hypertension. Mortality rate was 13%, mainly secondary to HCM-related complications (62%) at the average age of 7.5 months. Short stature had a prevalence of 91%, while seizures and ID of 6% and 12%, respectively. Two cases out of 75 (3%) developed neoplasms. In conclusion, patients with the RAF1:c.770C > T pathogenic variant show a particularly severe phenotype characterized by rapidly progressive neonatal HCM and high mortality rate suggesting the necessity of careful monitoring and early intervention to prevent or slow down the progression of HCM., (© 2024. The Author(s), under exclusive licence to European Society of Human Genetics.)

Hypertrophic cardiomyopathy (HCM) is a common myocardial disease defined by increased left ventricular wall thickness unexplained by loading conditions. HCM frequently is caused by pathogenic variants in sarcomeric protein genes, but several other syndromic, metabolic, infiltrative, and neuromuscular diseases can result in HCM phenocopies. This review summarizes the current understanding of these HCM mimics, highlighting their importance across the life course. The central role of a comprehensive, multiparametric diagnostic approach and the potential of precision medicine in tailoring treatment strategies are emphasized., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: A minority of patients with hypertrophic cardiomyopathy (HCM) presents advanced heart failure (HF) during their clinical course, in the context of left ventricular (LV) remodeling with reduced LV ejection fraction (LVEF), or of severe diastolic dysfunction without impaired LVEF. Aim of this study was to describe a multicentric end stage (ES) HCM population and analyze clinical course and outcome among its different phenotypes., Methods: Data of all HCM patients from 7 Italian referral centres were retrospectively evaluated. ES was diagnosed in presence of: LVEF <50% (ES-rEF) or NYHA functional class ≥II with severe diastolic dysfunction (ES-pEF). Outcomes were: HCM-related and all-cause mortality; combined arrhythmic events; advanced HF treatments., Results: Study population included 331 ES patients; 87% presented ES-rEF and 13% ES-pEF. At ES recognition, patients with ES-pEF were more commonly females, had more frequently NYHA III/IV, atrial fibrillation and greater maximal LV wall thickness. Over a median follow-up of 5.6 years, 83 (25%) patients died, 46 (15%) experienced arrhythmic events and (26%) 85 received advanced HF treatments. Incidence of HCM-related and all-cause mortality, and of combined arrhythmic events did not differ in ES-pEF and ES-rEF patients, but ES-pEF patients were less likely to receive advanced HF treatments. Older age at ES recognition was an independent predictor of increased HCM-related mortality (p = 0.01) and reduced access to advanced HF treatments (p < 0.0001)., Conclusions: Two different HCM-ES phenotypes can be recognized, with ES-pEF showing distinctive features at ES recognition and receiving less frequently advanced HF treatments. Older age at ES recognition has a major impact on outcomes., Competing Interests: Declaration of competing interest All Authors report no conflicts of interest related to the present work. All authors take responsibility for all aspects of the reliability and freedom from bias of the data presented and their discussed interpretation., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background and Aim: Atrial fibrillation (AF) is the most common sustained arrhythmia in hypertrophic cardiomyopathy (HCM) with significant effects on outcome. We aim to compare the left atrial (LA) diameter measurement with HCM-AF Score in predicting atrial fibrillation (AF) development in HCM., Methods: From the regional cohort of the Campania Region, Italy, 519 HCM patients (38% women, age45 ± 17 years) without history of AF, were enrolled in the study. The primary clinical endpoint was the development of AF, defined as at least 1 episode documented by ECG., Results: During the follow-up (mean 8 ± 6, IQ range 2.5-11.2 years), 99 patients (19%) developed AF. Patients who developed AF were more symptomatic, had higher prevalence of ICD implantation, had larger LA diameter, greater left ventricular (LV) maximal wall thickness and LV outflow tract obstruction (p < 0.01). Both LA diameter and HCM-AF score were higher in patients who developed AF versus those who did not (LA diameter 49 ± 7 versus 43 ± 6 mm; HCM-AF score 22 ± 4 versus 19 ± 4; p < 0.0001); however, ROC curve analysis demonstrated that LA diameter had a significant greater area under the curve than HCM-AF Score (p < 0.0001). At 5 years follow-up, a LA diameter > 46 mm, showed a similar accuracy in predicting AF development of HCM-AF score ≥ 22, which identifies patients at high risk to develop AF., Conclusion: Our analysis shows that LA diameter, a worldwide and simple echocardiographic measure, is capable alone to predict AF development in HCM patients., (Copyright © 2023 Elsevier Ireland Ltd. All rights reserved.)

Aims: In the EXPLORER-HCM trial, mavacamten reduced left ventricular outflow tract obstruction (LVOTO) and improved functional capacity of symptomatic hypertrophic obstructive cardiomyopathy (HOCM) patients. We sought to define the potential use of mavacamten by comparing real-world HOCM patients with those enrolled in EXPLORER-HCM and assessing their eligibility to treatment., Methods and Results: We collected information on HOCM patients followed up at 25 Italian HCM outpatient clinics and with significant LVOTO (i.e. gradient ≥30 mmHg at rest or ≥50 mmHg after Valsalva manoeuvre or exercise) despite pharmacological or non-pharmacological therapy. Pharmacological or non-pharmacological therapy resolved LVOTO in 1044 (61.2%) of the 1706 HOCM patients under active follow-up, whereas 662 patients (38.8%) had persistent LVOTO. Compared to the EXPLORER-HCM trial population, these real-world HOCM patients were older (62.1 ± 14.3 vs. 58.5 ± 12.2 years, p = 0.02), had a lower body mass index (26.8 ± 5.3 vs. 29.7 ± 4.9 kg/m 2 , p < 0.0001) and a more frequent history of atrial fibrillation (21.5% vs. 9.8%, p = 0.027). At echocardiography, they had lower left ventricular ejection fraction (LVEF, 66 ± 7% vs. 74 ± 6%, p < 0.0001), higher left ventricular outflow tract gradients at rest (60 ± 27 vs. 52 ± 29 mmHg, p = 0.003), and larger left atrial volume index (49 ± 16 vs. 40 ± 12 ml/m 2 , p < 0.0001). Overall, 324 (48.9%) would have been eligible for enrolment in the EXPLORER-HCM trial and 339 (51.2%) for treatment with mavacamten according to European guidelines., Conclusions: Real-world HOCM patients differ from the EXPLORER-HCM population for their older age, lower LVEF and larger atrial volume, potentially reflecting a more advanced stage of the disease. About half of real-world HOCM patients were found eligible to mavacamten., (© 2023 The Authors. European Journal of Heart Failure published by John Wiley & Sons Ltd on behalf of European Society of Cardiology.)

Background: Malonyl-CoA decarboxylase deficiency (MLYCDD) is an ultra-rare inherited metabolic disorder, characterized by multi-organ involvement manifesting during the first few months of life. Our aim was to describe the clinical, biochemical, and genetic characteristics of patients with later-onset MLYCDD., Methods: Clinical and biochemical characteristics of two patients aged 48 and 29 years with a confirmed molecular diagnosis of MLYCDD were examined. A systematic review of published studies describing the characteristics of cardiovascular involvement of patients with MLYCDD was performed., Results: Two patients diagnosed with MLYCDD during adulthood were identified. The first presented with hypertrophic cardiomyopathy and ventricular pre-excitation and the second with dilated cardiomyopathy (DCM) and mild-to-moderate left ventricular (LV) systolic dysfunction. No other clinical manifestation typical of MLYCDD was observed. Both patients showed slight increase in malonylcarnitine in their plasma acylcarnitine profile, and a reduction in malonyl-CoA decarboxylase activity. During follow-up, no deterioration of LV systolic function was observed. The systematic review identified 33 individuals with a genetic diagnosis of MLYCDD (median age 6 months [IQR 1-12], 22 males [67%]). Cardiovascular involvement was observed in 64% of cases, with DCM the most common phenotype. A modified diet combined with levocarnitine supplementation resulted in the improvement of LV systolic function in most cases. After a median follow-up of 8 months, 3 patients died (two heart failure-related and one arrhythmic death)., Conclusions: For the first time this study describes a later-onset phenotype of MLYCDD patients, characterized by single-organ involvement, mildly reduced enzyme activity, and a benign clinical course., (Copyright © 2023 Elsevier Masson SAS. All rights reserved.)

Background: We aimed to examine clinical features and outcomes of consecutive molecularly characterized patients with Noonan syndrome with multiple lentigines and hypertrophic cardiomyopathy., Methods: A retrospective, longitudinal multicenter cohort of consecutive children and adults with a genetic diagnosis of Noonan syndrome with multiple lentigines and hypertrophic cardiomyopathy between 2002 and 2019 was assembled. We defined a priori 3 different patterns of left ventricular remodeling during follow-up: (1) an increase in ≥15% of the maximal left ventricular wall thickness (MLVWT), both in mm and z -score (progression); (2) a reduction ≥15% of the MLVWT, both in mm and z -score (absolute regression); (3) a reduction ≥15% of the MLVWT z -score with a stable MLVWT in mm (relative regression). The primary study end point was a composite of cardiovascular death, heart transplantation, and appropriate implantable cardioverter defibrillator-shock., Results: The cohort comprised 42 patients with Noonan syndrome with multiple lentigines and hypertrophic cardiomyopathy, with a median age at diagnosis of 3.5 (interquartile range, 0.2-12.3) years. Freedom from primary end point was 92.7% (95% CI, 84.7%-100%) 1 year after presentation and 80.9% (95% CI, 70.1%-90.7%) at 5 years. Patients with MLVWT z -score >13.7 showed reduced survival compared with those with <13.7. During a median follow-up of 3.7 years (interquartile range, 2.6-7.9), absolute regression was the most common type of left ventricular remodeling (n=9, 31%), followed by progression (n=6, 21%), and relative regression (n=6, 21%)., Conclusions: These findings provide insights into the natural history of left ventricular hypertrophy, and can help inform clinicians regarding risk stratification and clinical outcomes in patients with Noonan syndrome with multiple lentigines and hypertrophic cardiomyopathy., Competing Interests: Disclosures None.

Hypertrophic cardiomyopathy is a myocardial disease defined by an increased left ventricular wall thickness not solely explained by abnormal loading conditions. It is often genetically determined, with sarcomeric gene mutations accounting for around 50% of cases. Several conditions, including syndromic, metabolic, infiltrative, and neuromuscular diseases, may present with left ventricular hypertrophy, mimicking the hypertrophic cardiomyopathy phenotype but showing a different pathophysiology, clinical course, and outcome. Despite being rare, they are collectively responsible for a large proportion of patients presenting with hypertrophic heart disease, and their timely diagnosis can significantly impact patients' management. The understanding of disease pathophysiology has advanced over the last few years, and several therapeutic targets have been identified, leading to a new era of tailored treatments applying to different etiologies associated with left ventricular hypertrophy. This review aims to provide an overview of the existing and emerging therapies for the principal causes of hypertrophic heart disease, discussing the potential impact on patients' management and clinical outcome., Competing Interests: Disclosures None.

Cardiomyopathies are mostly determined by genetic mutations affecting either cardiac muscle cell structure or function. Nevertheless, cardiomyopathies may also be part of complex clinical phenotypes in the spectrum of neuromuscular (NMD) or mitochondrial diseases (MD). The aim of this study is to describe the clinical, molecular, and histological characteristics of a consecutive cohort of patients with cardiomyopathy associated with NMDs or MDs referred to a tertiary cardiomyopathy clinic. Consecutive patients with a definitive diagnosis of NMDs and MDs presenting with a cardiomyopathy phenotype were described. Seven patients were identified: two patients with ACAD9 deficiency ( Patient 1 carried the c.1240C>T (p.Arg414Cys) homozygous variant in ACAD9 ; Patient 2 carried the c.1240C>T (p.Arg414Cys) and the c.1646G>A (p.Ar549Gln) variants in ACAD9 ); two patients with MYH7 -related myopathy ( Patient 3 carried the c.1325G>A (p.Arg442His) variant in MYH7 ; Patient 4 carried the c.1357C>T (p.Arg453Cys) variant in MYH7 ); one patient with desminopathy ( Patient 5 carried the c.46C>T (p.Arg16Cys) variant in DES ); two patients with mitochondrial myopathy ( Patient 6 carried the m.3243A>G variant in MT-TL1 ; Patient 7 carried the c.253G>A (p.Gly85Arg) and the c.1055C>T (p.Thr352Met) variants in MTO1 ). All patients underwent a comprehensive cardiovascular and neuromuscular evaluation, including muscle biopsy and genetic testing. This study described the clinical phenotype of rare NMDs and MDs presenting as cardiomyopathies. A multidisciplinary evaluation, combined with genetic testing, plays a main role in the diagnosis of these rare diseases, and provides information about clinical expectations, and guides management.

Several treatments have demonstrated safety and effectiveness in the treatment of patients with hypertrophic cardiomyopathy; however, no drug has been shown to modify the natural history of the disease or to decrease maximal wall thickness. Improvement in our knowledge of the physiopathology of the disease has permitted the development of new therapeutical approaches, including sarcomere modulators and gene therapy. A sarcomere modulator - mavacamten - has been shown to improve exercise capacity, left ventricular outflow tract obstruction, New York Heart Association functional class and health status in a phase 3 trial. Gene therapy - although still far from human experimentation - also has promising characteristics that may radically revolutionize the treatment of hypertrophic cardiomyopathy in the future. This therapy is currently approved for the treatment of select haematological malignancies, inherited retinal dystrophy and spinal muscular atrophy, and could potentially correct the genetic alterations of the most frequent sarcomeric forms of hypertrophic cardiomyopathy. This review provides an overview of current conventional therapies for the management of patients with hypertrophic cardiomyopathy, discusses emerging therapeutic approaches and presents future perspectives., (Copyright © 2022 Elsevier Masson SAS. All rights reserved.)

Aims: To evaluate the role of bisoprolol to control symptoms and left ventricular outflow tract obstruction (LVOTO) in a consecutive cohort of adults with hypertrophic cardiomyopathy (HCM)., Methods and Results: In this retrospective study, patients with HCM with an LVOT gradient ≥50 mmHg after Valsalva manoeuvre and New York Heart Association (NYHA) class II-III symptoms were assigned to receive bisoprolol (starting at 1.25 mg daily). The initial dose was increased every two weeks to achieve the target in LVOT gradient <30 mmHg or the maximum tolerated dose. The primary endpoint was the achievement of a LVOT gradient <30 mmHg and ≥ 1 NYHA class improvement. The secondary endpoints were proportion of patients with LVOT gradient <30 mmHg or < 50 mmHg, proportion of patients with ≥1 NYHA class improvement, and change from baseline in LVOT gradient. Between December 2001 and December 2020, 92 patients were enrolled into the study. Sixteen (17%) patients on bisoprolol met the primary endpoint. Bisoprolol reduced the LVOT gradient to less than 30 mmHg in 33 (36%) patients, to less than 50 mmHg in 57 (62%), and improved NYHA class in 30 (33%). The mean reduction of LVOT gradient on bisoprolol was 28 (±14) mmHg and the percentage reduction was 42 (±21) %. In 35 (38%) patients, bisoprolol did not reduce the gradient to less than 50 mmHg requiring disopyramide and/or myectomy to achieve this goal., Conclusion: Treatment with bisoprolol was well-tolerated and effective in relieving obstruction and improving symptoms in a significant proportion of patients with symptomatic obstructive HCM., (Copyright © 2022 Elsevier B.V. All rights reserved.)

RASopathies are multisystemic disorders caused by germline mutations in genes linked to the RAS/mitogen-activated protein kinase pathway. Diagnosis of RASopathy can be triggered by clinical clues ("red flags") which may direct the clinician toward a specific gene test. Compared with sarcomeric hypertrophic cardiomyopathy, hypertrophic cardiomyopathy in RASopathies (R-HCM) is associated with higher prevalence of congestive heart failure and shows increased prevalence and severity of left ventricular outflow tract obstruction. Biventricular involvement and the association with congenital heart disease, mainly pulmonary stenosis, have been commonly described in R-HCM. The aim of this review is to assess the prevalence and unique features of R-HCM and to define the available therapeutic options., Competing Interests: Disclosure The authors declare that they have no conflict of interest., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Fabry disease (FD, OMIM 301500) is an X-linked lysosomal storage disease caused by pathogenic variants in the GLA gene. Cardiac involvement is common in FD and is responsible for impaired quality of life and premature death. The classic cardiac involvement is a nonobstructive form of hypertrophic cardiomyopathy, usually manifesting as concentric left ventricular hypertrophy, with subsequent arrhythmogenic intramural fibrosis. Treatment of patients with FD should be directed to prevent the disease progression to irreversible organ damage and organ failure. The aim of this review is to describe the current state of knowledge regarding cardiovascular involvement in FD, focusing on clinical and instrumental features, cardiovascular management, and targeted therapy., Competing Interests: Disclosure The authors have nothing to disclose. D.P. Germain is a consultant for Sanofi Genzyme and Takeda., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Mitochondrial diseases (MD) include an heterogenous group of systemic disorders caused by sporadic or inherited mutations in nuclear or mitochondrial DNA (mtDNA), causing impairment of oxidative phosphorylation system. Hypertrophic cardiomyopathy is the dominant pattern of cardiomyopathy in all forms of mtDNA disease, being observed in almost 40% of the patients. Dilated cardiomyopathy, left ventricular noncompaction, and conduction system disturbances have been also reported. In this article, the authors discuss the current clinical knowledge on MD, focusing on diagnosis and management of mitochondrial diseases caused by mtDNA mutations., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Hypertrophic cardiomyopathy (HCM) is a group of heterogeneous disorders that are most commonly passed on in a heritable manner. It is a relatively rare disease around the globe, but due to increased rates of consanguinity within the Kingdom of Saudi Arabia, we speculate a high incidence of undiagnosed cases. The aim of this paper is to elucidate a systematic approach in dealing with HCM patients and since HCM has variable presentation, we have summarized differentials for diagnosis and how different subtypes and genes can have an impact on the clinical picture, management and prognosis. Moreover, we propose a referral multi-disciplinary team HCM-Family Unit in Saudi Arabia and an integrated role in a network between King Faisal Hospital and Inherited and Rare Cardiovascular Disease Unit-Monaldi Hospital, Italy (among the 24 excellence centers of the European Reference Network (ERN) GUARD-Heart).   Graphical Abstract.

Introduction: This study aimed to validate the increased wall thickness (IWT) score, a multiparametric echocardiographic score to facilitate diagnosis of cardiac amyloidosis (CA), in an independent population of patients with increased LV wall thickness suspicious for CA., Methods: Between January 2019 and December 2020, 152 consecutive patients with increased LV wall thickness suspicious for CA were included. For all patient, the multiparametric echocardiographic score (IWT score) was calculated. To validate the diagnostic accuracy of an IWT score ≥ 8 to predict the diagnosis of CA, sensibility (Se), specificity (Sp), positive predictive value (PPV), negative predictive value (NPV), and predictive accuracy (PA) were calculated., Results: Among the 152 patients included in the study, 50 (33%) were diagnosed as CA, 25 (16%) had severe aortic stenosis, 25 (16%) had hypertensive remodeling, and 52 (34%) had hypertrophic cardiomyopathy. Among the 50 and 102 patients with and without CA, 19 (38%) and 1 (1%) showed an IWT score ≥ 8, respectively. Overall, the diagnostic accuracy of an IWT score ≥ 8 for the diagnosis of CA in our population was the following: Se 38% (95%CI 25-53%); Sp 99% (95%CI 95-100%); PPV 95% (95%CI 72-99%); NPV 77% (95%CI 73-80%); PA 79% (95%CI 72-85%)., Conclusions: This study reports the first external validation of the IWT score for the diagnosis of CA in patients with increased LV wall thickness. A score ≥ 8 showed a high Sp, PPV and PA, suggesting that the IWT score can be used to identify CA patients in those with increased LV wall thickness., (Copyright © 2021 Elsevier B.V. All rights reserved.)

We evaluated the impact of weight loss (WL) using a Mediterranean diet and mild-to-moderate-intensity aerobic exercise program, on clinical status of obese, symptomatic patients with hypertrophic cardiomyopathy (HCM). Compared with nonresponders, responders showed a significant reduction of left atrial diameter, left atrial volume index (LAVI), E/E'average, pulmonary artery systolic pressure (PASP), and a significant increase in Vo 2max (%) and peak workload. Body mass index changes correlated with reduction in left atrial diameter, LAVI, E/E'average, PASP, and increase of Vo 2max (mL/Kg/min), Vo 2max (%), peak workload. Mediterranean diet and aerobic exercise is associated with clinical-hemodynamic improvement in obese symptomatic HCM patients., Competing Interests: Disclosure The authors have nothing to disclose., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Introduction: We sought to determine prevalence and predictive accuracy of clinical markers (red flags, RF), known to be associated with specific systemic disease in a consecutive cohort of patients with hypertrophic cardiomyopathy (HCM)., Methods: We studied 129 consecutive patients (23.7 ± 20.9 years, range 0-74 years; male/female 68%/32%). Pre-specified RF were categorized into five domains: family history; signs/symptoms; electrocardiography; imaging; and laboratory. Sensitivity (Se), specificity (Sp), negative predictive value (NPV), positive predictive value (PPV), and predictive accuracy of RF were analyzed in the genotyped population., Results: In the overall cohort of 129 patients, 169 RF were identified in 62 patients (48%). Prevalence of RF was higher in infants (78%) and in adults >55 years old (58%). Following targeted genetic and clinical evaluation, 94 patients (74%) had a definite diagnosis (sarcomeric HCM or specific causes of HCM). We observed 14 RF in 13 patients (21%) with sarcomeric gene disease, 129 RF in 34 patients (97%) with other specific causes of HCM, and 26 RF in 15 patients (45%) with idiopathic HCM (p < 0.0001). Non-sarcomeric causes of HCM were the most prevalent in ages <1yo and > 55yo. Se, Sp, PPV, NPV and PA of RF were 97%, 70%, 55%, 98% and 77%, respectively. Single and clinical combination of RF (clusters) had an high specificity, NPV and predictive accuracy for the specific etiologies (syndromes/metabolic/infiltrative disorders associated with HCM)., Conclusions: An extensive diagnostic work up, focused on analysis of specific diagnostic RF in patients with unexplained LVH facilitates a clinical diagnosis in 74% of patients with HCM., (Copyright © 2019 Elsevier B.V. All rights reserved.)