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Aims: In the clinical practice, the right ventricular (RV) manifestations have received less attention in hypertrophic cardiomyopathy (HCM). This paper aimed to evaluate the risk prediction value and genetic characteristics of RV involvement in HCM patients., Methods and Results: A total of 893 patients with HCM were recruited. RV hypertrophy, RV obstruction, and RV late gadolinium enhancement were evaluated by echocardiography and/or cardiac magnetic resonance. Patients with any of the above structural abnormalities were identified as having RV involvement. All patients were followed with a median follow-up time of 3.0 years. The primary endpoint was cardiovascular death; the secondary endpoints were all-cause death and heart failure (HF)-related death. Survival analyses were conducted to evaluate the associations between RV involvement and the endpoints. Genetic testing was performed on 669 patients. RV involvement was recognized in 114 of 893 patients (12.8%). Survival analyses demonstrated that RV involvement was an independent risk factor for cardiovascular death (P = 0.002), all-cause death (P = 0.011), and HF-related death (P = 0.004). These outcome results were then confirmed by a sensitivity analysis. Genetic testing revealed a higher frequency of genotype-positive in patients with RV involvement (57.0% vs. 31.0%, P < 0.001), and the P/LP variants of MYBPC3 were more frequently identified in patients with RV involvement (30.4% vs. 12.0%, P < 0.001). Logistic analyses indicated the independent correlation between RV involvement and these genetic factors., Conclusion: RV involvement was an independent risk factor for cardiovascular death, all-cause death and HF-related death in HCM patients. Genetic factors might contribute to RV involvement in HCM., (© The Author(s) 2022. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Patients with hypertrophic cardiomyopathy (HC) caused by compound variants have severe clinical manifestations, but significant clinical heterogeneity remains. Clinical diversity in these patients may result from different combinations of variants. We analyzed the role of cis-compound variants in a Chinese HC pedigree. Exome sequencing was performed in the proband. Identified variants were detected with bi-directional Sanger sequencing in a pedigree that comprised 3 generations and 28 family members. Follow-up was performed for 16 years. Two missense variants (c.2465T>C, p.Met822Thr; c.4258C>T, p.Arg1420Trp) were identified in the MYH7 gene. These variants were absent in our 761 in-house people without HC and predicted to be pathogenic.Both variants were detected in 11 family members, thus they were believed to inherit cis. In the 11 members, only 5 developed HC, the other 6 were asymptomatic variant carriers with an abnormal electrocardiogram. The HC members had mild hypertrophy with a maximum left ventricular wall thickness of 13 to 21 mm and showed a low incidence of cardiovascular events. In conclusion, the cis-compound variants of Met822Thr and Arg1420Trp in MYH7 are causal but relatively benign, variants associated with familial HC. This finding suggests that different types of compound variants might need to be analyzed for a genotype-phenotype study., Competing Interests: Disclosures The authors have no conflicts of interest to declare., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Background Myocardial replacement fibrosis is one of the major histologic features of hypertrophic cardiomyopathy (HCM), but its characteristics have not been well delineated. Purpose To clarify the characteristics of replacement fibrosis in HCM and to evaluate the prognostic value of the regional extent of fibrosis. Materials and Methods This prospective study evaluated participants with HCM who underwent contrast-enhanced cardiac MRI from March 2011 to April 2019. For each participant, global and 16-segment extent of late gadolinium enhancement (LGE) in the left ventricle (LV) at cardiac MRI was analyzed. The primary end point was all-cause death. Results Among the 798 study participants enrolled (median age, 49 years [interquartile range {IQR}: 38-59 years]; 508 men), 588 (74%) underwent whole-exome sequencing. Thirty-five participants (4%) experienced death from any cause during a median follow-up of 2.9 years (IQR: 1.5-4.7 years). Spearman analysis showed weak correlations between the extent of LGE and wall thickness (LGE of global LV and maximal LV wall thickness, r = 0.35 [ P < .001]; LGE and thickness of septum, r = 0.30 [ P < .001]). In the 16-segment model, the distribution of LGE was visually inhomogeneous and higher in the basal anterior, basal septal, midanterior, and midseptal regions ( P < .001). This similar distribution of LGE was observed in participants with asymmetric septal hypertrophy, those with apical HCM, participants positive for mutation and those negative for mutation, and participants with MYH7 and MYBPC3 mutations. Cox analysis indicated that both the global extent of LGE (adjusted hazard ratio = 1.68 per 10% increase in LGE; P < .001) and the regional extent of LGE (ie, basal, midventricular, and apical regions of LV when on the short-axis view; septum, anterior free wall, inferior free wall, and lateral free wall when on the long-axis view) were associated with adverse outcomes. Conclusion In hypertrophic cardiomyopathy, myocardial replacement fibrosis weakly correlated with hypertrophy, was inhomogeneous and asymmetric, and was predominantly distributed in the interventricular septal wall and anterior free wall at the basal and mid levels. Greater extent of fibrosis was associated with poor prognosis, regardless of its location in the left ventricle. © RSNA, 2021 See also the editorial by Hanneman in this issue.

Background: Heart failure with preserved ejection fraction (HFpEF) is the dominant form of heart failure (HF). We here aimed to investigate the characteristics and prognosis of HFpEF in patients with hypertrophic cardiomyopathy (HCM)., Methods: This was a prospective cohort study and patients with HCM with available NT-proBNP results were enrolled. Patients were categorized into HFpEF [defined as LVEF ≥50%, with symptoms or signs of HF, and N-terminal pro-brain natriuretic peptide ≥800 pg/mL according to American Heart Association (AHA) criteria] and without heart failure (non-HF). The outcomes of interest were all-cause death, cardiovascular death, and sudden cardiac death (SCD)., Results: Of 1178 included patients with HCM, 513 (43.5%) were identified as having HFpEF according to AHA criteria. Compared with non-HF patients, patients with HFpEF had significantly larger maximal wall thickness (P < 0.001), higher maximal left ventricular outflow tract gradient (P < 0.001), higher proportion of atrial fibrillation (P < 0.001), higher incidence of all-cause death (log-rank test, P = 0.002), and cardiovascular death (log-rank test, P = 0.005). Multivariable Cox analysis showed that patients with HFpEF had a nearly two-fold higher risk of all-cause death (adjusted HR = 1.80, 95% CI 1.11-2.90; P = 0.017) and cardiovascular death (adjusted HR =1.82, 95% CI 1.05-3.18; P = 0.033) than non-HF patients., Conclusions: Patients with HCM have a high prevalence of HFpEF and those with HFpEF present greater disease severity and higher mortality than non-HF patients, and thus may require an appropriate and more aggressive treatment for HF management. Identification of patients with HFpEF using AHA criteria can provide guidance on patient risk stratification for patients with HCM., (© 2022. The Author(s).)

Background: Deleterious rare variants in genes encoding desmosome proteins have been identified as the essential basis of arrhythmogenic cardiomyopathy (ACM) and detected in dilated cardiomyopathy, but the relationship between deleterious rare desmosomal variants and hypertrophic cardiomyopathy (HCM) remains unknown., Methods: Whole exome sequencing was performed in 1000 patients with HCM and 761 non-HCM controls to search for deleterious rare variants in genes encoding desmosomal proteins including PKP2, JUP, DSC2, DSG2, and DSP. Clinical phenotypes were assessed in patients with HCM, and patients with deleterious rare desmosomal variants underwent evaluation of ACM revised Task Force Criteria., Results: A total of 27 deleterious rare desmosomal variants were present in 24 (2.4%) patients with HCM and 5 (0.66%) controls. The variants were more prevalent in the patients with HCM than in the controls (P = 0.004). The majority of patients possessing deleterious rare desmosomal variants could not be diagnosed as ACM. Moreover, the patients with deleterious rare desmosomal variants possessed several distinctive clinical features compared with patients without such variants, including a higher incidence of nonsustained ventricular tachycardia (29.2% vs 4.5%, P < 0.001), left bundle branch block (33.3% vs 1.6%, P < 0.001), and right ventricular involvement for an HCM phenotype (29.2% vs 0.30%, P < 0.001)., Conclusions: We screened deleterious rare desmosomal variants in a large HCM case-control cohort and found deleterious rare desmosomal variants can be relevant to HCM. Moreover, our data indicated deleterious rare desmosomal variants were associated with distinctive clinical features of HCM. These findings require validation in other HCM cohorts., (Copyright © 2021 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.)

Background: The presence of variants in OBSCN was identified to be linked to hypertrophic cardiomyopathy (HCM), but whether OBSCN truncating variants were associated with HCM remained unknown., Methods: Whole-exome sequencing was performed in 986 patients with HCM and 761 non-HCM controls to search for OBSCN truncating variants, and the result was tested in a replication cohort consisting of 529 patients with HCM and 307 controls. The association of the OBSCN truncating variants with baseline characteristics and prognosis of patients with HCM were ascertained., Results: There were 28 qualifying truncating variants in the OBSCN gene detected in 26 (2.6%) patients with HCM and 6 (0.8%) controls. The OBSCN truncating variants were more prevalent in patients with HCM than controls (odds ratio, 3.4, P =0.004). This association was confirmed in the replication cohort (odds ratio, 3.8, P =0.024). The combined effects of the two cohorts estimated the odds ratio to be 3.58 ( P <0.001). Patients with or without OBSCN truncating variants shared similar demographic and echocardiographic variables at baseline. During 3.3±2.4 years (4795 patient-years) follow-up, the patients with OBSCN truncating variants were more likely to experience cardiovascular death (adjusted hazard ratio, 3.1 [95% CI, 1.40-6.70], P =0.005) and all-cause death (adjusted hazard ratio, 2.63 [95% CI, 1.21-5.71], P =0.015)., Conclusions: Our data indicated that OBSCN truncating variants contributed to the disease-onset of HCM, and increased the risk of malignant events in patients with HCM.

Objective: Elevated levels of N-terminal pro-brain natriuretic peptide (NT-proBNP) are associated with heart failure-related death in hypertrophic cardiomyopathy (HCM), but the relationship between NT-proBNP level and sudden cardiac death (SCD) in HCM remains undefined., Methods: The study prospectively enrolled 977 unrelated patients with HCM with available NT-proBNP results who were prospectively enrolled and followed for 3.0±2.1 years. The Harrell's C-statistic under the receiver operating characteristic curve was calculated to evaluate discrimination performance. A combination model was constructed by adding NT-proBNP tertiles to the HCM Risk-SCD model. The correlation between log NT-proBNP level and cardiac fibrosis as measured by late gadolinium enhancement (LGE) or Masson's staining was analysed., Results: During follow-up, 29 patients had SCD. Increased log NT-proBNP levels were associated with an increased risk of SCD events (adjusted HR 22.27, 95% CI 10.93 to 65.63, p<0.001). The C-statistic of NT-proBNP in predicting SCD events was 0.80 (p<0.001). The combined model significantly improved the predictive efficiency of the HCM Risk-SCD model from 0.72 to 0.81 (p<0.05), with a relative integrated discrimination improvement of 0.002 (p<0.001) and net reclassification improvement of 0.67 (p<0.001). Furthermore, log NT-proBNP levels were significantly correlated with cardiac fibrosis as detected either by LGE (r=0.257, p<0.001) or by Masson's trichrome staining in the myocardium (r=0.198, p<0.05)., Conclusion: NT-proBNP is an independent predictor of SCD in patients with HCM and may help with risk stratification of this disease., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2021. No commercial re-use. See rights and permissions. Published by BMJ.)

Background The FHOD3 (formin homology 2 domain-containing 3) gene has recently been identified as a causative gene of hypertrophic cardiomyopathy (HCM). However, the pathogenicity of FHOD3 variants remains to be evaluated. This study analyzed the spectrum of FHOD3 variants in a large HCM and control cohort, and explored its correlation with the disease. Methods and Results The genetic analysis of FHOD3 was performed using the whole exome sequencing data from 1000 patients with HCM and 761 controls without HCM. A total of 37 FHOD3 candidate variants were identified, including 25 missense variants and 2 truncating variants. In detail, there were 27 candidate variants detected in 33 (3.3%) patients with HCM, which was significantly higher than in the 12 controls (3.3% versus 1.6%; odds ratio, 2.13; P <0.05). On the basis of familial segregation, we identified one truncating variant (c.1286+2delT) as a causal variant in 4 patients. Furthermore, the FHOD3 candidate variant experienced significantly more risk of cardiovascular death and all-cause death (adjusted hazard ratio [HR], 3.71; 95%, 1.32-8.59; P =0.016; and adjusted HR, 3.02; 95% CI, 1.09-6.85; P= 0.035, respectively). Conclusions Our study suggests that FHOD3 is a causal gene for HCM, and that the presence of FHOD3 candidate variants is an independent risk for cardiovascular death and all-cause death in HCM.

Background: The lack of validated and effective sudden cardiac death (SCD) risk prediction methods is the biggest barrier to perform the lifesaving treatment with a prophylactic implantable cardioverter-defibrillator in Chinese patients with hypertrophic cardiomyopathy (HCM)., Objective: This study aimed to evaluate the efficacy of 3 existing SCD risk prediction methods recommended by the 2011 American College of Cardiology Foundation and American Heart Association (ACCF/AHA) guideline, the 2014 European Society of Cardiology (ESC) guideline, and the 2019 enhanced American College of Cardiology (ACC)/AHA strategy in Chinese patients with HCM., Methods: The present study consisted of 1369 consecutive adult patients with HCM without a history of SCD events. The primary end point was a composite of SCD and equivalent events, namely, resuscitation from cardiac arrest and appropriate implantable cardioverter-defibrillator shock therapy for ventricular tachycardia or fibrillation., Results: During follow-up of 3.2 ± 2.4 years, 39 patients reached SCD end points, of whom 26 (66.7%) were correctly predicted as those at a high risk of SCD by using methods recommended by the 2019 enhanced ACC/AHA strategy, 20 (51.3%) by the 2011 ACCF/AHA guideline, but only 5 (12.8%) by the 2014 ESC guideline. The 2019 enhanced ACC/AHA strategy showed a higher C-statistic (0.647) for SCD prediction than did the 2011 ACCF/AHA guideline (0.598) and 2014 ESC guideline (0.605) and resulted in the correct reclassification of SCD risk when compared with the 2011 ACCF/AHA guideline (net reclassification index 0.113; P = .074) and 2014 ESC guideline (net reclassification index 0.245; P = .038)., Conclusion: The 2019 enhanced ACC/AHA strategy showed better predictive performance for SCD risk stratification in Chinese patients with HCM, with a notably high sensitivity., (Copyright © 2020 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: Filamin C (FLNC) mutation was reported as a cause of HCM, with a high probability of sudden cardiac death. However, the mutation profile of FLNC, and its relationship with phenotypic expression in HCM, remains to be elucidated., Methods: In this study, FLNC gene was sequenced in 540 HCM patients and 307 healthy controls., Results: We found that 39 (7.2%) patients carried FLNC mutations, with a similar frequency to that of controls (4.2%, p = 0.101). Pedigree analysis showed that mutations were not well segregated with HCM. The baseline characteristics between HCM patients, with and without mutations, were comparable. FLNC mutations did not increase the risk for either all-cause mortality (HR 0.746, 95% CI 0.222-2.295, p = 0.575) or cardiac mortality (HR 0.615, 95% CI 0.153-1.947, p = 0.354) in HCM patients during a follow-up of 4.7 ± 3.2 years. Moreover, there was no significant difference in survival free from sudden cardiac arrest (HR 0.721, 95% CI 0.128-3.667, p = 0.660) and heart failure (HR 0.757, 95% CI 0.318-1.642, p = 0.447)., Conclusions: FLNC mutations were common in both HCM patients and healthy population. The pathogenicity of FLNC mutations detected in HCM patients and its association with the clinical outcomes should be cautiously interpreted., (© 2018 The Authors. Molecular Genetics & Genomic Medicine published by Wiley Periodicals, Inc.)

Background: Titin-truncating variants (TTNtv) have been detected in a variety of cardiomyopathies and represent the most common cause of dilated cardiomyopathy. However, their significance in hypertrophic cardiomyopathy (HCM) is still unclear., Methods: The titin gene (TTN) was sequenced for truncating variants in a cohort of 529 Chinese patients with HCM and 307 healthy controls. Baseline and follow-up clinical data (for 4.7 ± 3.2 years) from these patients were obtained., Results: We identified 13 and 8 TTNtv in patients with HCM (13 of 529 [2.5%]) and controls (8 of 307 [2.6%]), respectively. The prevalence of TTNtv in patients with HCM and in healthy controls was comparable (P = 0.895). There were no significant differences in baseline characteristics between patients with and those without TTNtv. However, during follow-up, patients with TTNtv (3 of 13 [23.1%]) were more likely to experience cardiovascular death compared with those without TTNtv (39 of 516 [7.6%]) [adjusted hazard ratio, 6.88; 95% confidence interval, 2.04-23.20; P = 0.002)., Conclusions: Our study suggests that TTNtv might be a genetic modifier of HCM and confer an increased risk for cardiovascular death., (Copyright © 2017 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.)