Paradigm of Sudden Death Prevention in Hypertrophic Cardiomyopathy

Candidacy and long-term outcomes of subcutaneous implantable cardioverter-defibrillators in current practice in patients with hypertrophic cardiomyopathy

BACKGROUND

In patients with Hypertrophic Cardiomyopathy (HCM) S-ICD is usually the preferred option as pacing is generally not indicated. However, limited data are available on its current practice adoption and long-term follow-up.

METHODS

Consecutive HCM patients with S-ICD implanted between 2013 and 2021 in 3 international centers were enrolled in this observational study. Baseline, procedural and follow-up data were regularly collected. Efficacy and safety were compared with a cohort of HCM patients implanted with a tv-ICD.

RESULTS

Seventy patients (64% males) were implanted with S-ICD at 41 ± 15 years, whereas 168 patients with tv-ICD at 49 ± 16 years. For S-ICD patients, mean ESC SCD risk score was 4,5 ± 1.9%: 25 (40%) at low-risk, 17 (27%) at intermediate and 20 (33%) at high-risk. Patients were followed-up for 5.1 ± 2.3 years. Two patients (0.6 per 100-person-years, vs 0.4 per 100 person-years with tv-ICD, p = 0.45) received an appropriate shock on VF, 17 (24%) were diagnosed with de-novo AF. Inappropriate shocks occurred in 4 patients (1.2 per 100-person-years, vs 0.9 per 100 person-years with tv-ICD, p = 0.74), all before Smart-Pass algorithm implementation. Four patients experienced device-related adverse events (1.2 per 100-person-years, vs 1 per 100 person-years with tv-ICD, p = 0.35%).

CONCLUSIONS

S-ICDs were often implanted in patients with an overall low-intermediate ESC SCD risk, reflecting both the inclusion of additional risk markers and a lower decision threshold. S-ICDs in HCM patients followed for over 5 years showed to be effective in conversion of VF and safe. Greater scrutiny may be required to avoid overtreatment in patients with milder risk profiles.

Unveiling Immune Infiltration Characterizing Genes in Hypertrophic Cardiomyopathy Through Transcriptomics and Bioinformatics

Background

Hypertrophic cardiomyopathy (HCM) is a dominantly inherited disease associated with sudden immune cell associations that remain unclear. The aim of this study was to comprehensively screen candidate markers associated with HCM and immune cells and explore potential pathogenic pathways.

Methods

First, download the GSE32453 dataset to identify differentially expressed genes (DEGs) and perform Gene Ontology and pathway enrichment analysis using DAVID and GSEA. Next, construct protein-protein interaction (PPI) networks using String and Cytoscape to identify hub genes. Afterward, use CIBERSORT to determine the proportion of immune cells attributed to key genes in HCM and conduct ROC analysis based on the external dataset GSE36961 to evaluate their diagnostic value. Finally, validate the expression of key genes in the hypertrophic cardiomyocyte model through qRT-PCR using data from the HPA database.

Results

Comprehensive analysis revealed that there were 254 upregulated genes and 181 downregulated genes in HCM. The enrichment study underscored pathways of inflammatory signaling, including MAPK and PI3K-Akt pathways. Pathways abundant in genes associated with HCM encompassed myocardial contraction and NADH dehydrogenase activity. Additionally, the analysis of immune infiltration revealed a notable increase in macrophages, NK cells, and monocytes in the HCM group, showing statistically significant variances in CD4 memory resting T cell infiltration when compared to the healthy control group. Within the validation dataset GSE36961, the Area Under the Curve (AUC) scores for eight crucial genes (FOS, CD86, CD68, BDNF, PIK3R1, PLEK, RAC2, CCL2) each exceeded 0.8. The HPA database revealed the positioning traits and paths of these eight crucial genes in smooth muscle cells, myocardial cells, and fibroblasts. The outcomes of the qRT-PCR were aligned with the sequencing findings.

Conclusion

Bioinformatics analysis unveiled pivotal genes, pathways, and immune involvement, illuminating the molecular underpinnings of HCM. These findings suggest promising therapeutic targets for clinical applications.

Interventions in Hypertrophic Obstructive Cardiomyopathy

Obstructive hypertrophic cardiomyopathy is the most common genetically transmitted cardiomyopathy that is associated with significant morbidity and mortality. Despite contemporary treatments and interventions, the management of patients with obstructive hypertrophic cardiomyopathy remains poorly defined compared with other branches of cardiology. In this review, we discuss established and novel therapeutic interventions in patients with obstructive hypertrophic cardiomyopathy with a focus on percutaneous and surgical strategies including surgical myectomy, mitral valve repair or replacement, percutaneous alcohol septal ablation, pacemaker and cardioverter-defibrillator implantation, septal embolization, radiofrequency endocardial catheter ablation, and percutaneous intramyocardial septal radiofrequency ablation.

Implantable cardioverter defibrillators for primary prevention in cardiomyopathies

BACKGROUND

Implantable cardioverter defibrillators (ICD) are often used as primary prevention strategy for sudden cardiac death (SCD) in young individuals. This study analyzed appropriate therapies, complications and inappropriate shocks in the real-world Indian population.

METHODS

All patients in the cardiomyopathy cohort under follow up who had ICD implanted as a primary prevention strategy were studied. The objective was to assess the incidence of appropriate ICD therapies, inappropriate therapies and complications. ICD was interrogated and stored electrograms analyzed. Underlying arrhythmia or conditions resulting in appropriate or inappropriate ICD therapy were studied. Correlation and regression studies was done to assess for the predictors of appropriate therapy.

RESULTS

Fifty patients were followed up for a mean follow-up duration of 4.4 ± 3.1 years with total follow up of 220.2 patient years. Appropriate ICD therapy was delivered in 16 out of 50 (32%) patients, with 65 appropriate therapies (median 2 per patient, range: 0-20). Inappropriate therapy delivered in 7 of the 50 (14%) patients, with 44 inappropriate therapies (median 5 per patient, range: 0-20). Complications occurred in 8 of the 50 (16%) patients. Overall, the rate of appropriate therapy was 29.5 per 100 patient years, that of inappropriate therapy was 19.9 per 100 patient years and the rate of complications was 3.6 per 100 patient years.

CONCLUSIONS

When implanted for primary prevention in patients with cardiomyopathies over a mean period of 4.4 ± 3.1 years, appropriate ICD therapy was delivered in 32% patients. However, inappropriate therapy (14% patients) and complications (16% patients) were also common.

Deficiency of Transcription Factor Sp1 Contributes to Hypertrophic Cardiomyopathy

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

The Paradigm of Sudden Death Prevention in Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is a relatively common and, often, inherited cardiac disease, once regarded as largely untreatable with ominous prognosis and, perhaps, most visibly as a common cause of sudden cardiac death (SCD) in the young. However, HCM is now more accurately considered a treatable disease with management options that significantly alter its clinical course. This is particularly true for SCD because the penetration of implantable cardioverter-defibrillators into HCM practice enables primary prevention device therapy that reliably terminates potentially lethal ventricular tachyarrhythmias (3% to 4%/year). This therapeutic advance is largely responsible for >10-fold decrease in the overall disease-related mortality to 0.5%/year, independent of patient age. A guideline-based clinical risk stratification algorithm has evolved, which included variables identifiable with cardiac magnetic resonance: ≥1 risk markers judged major within the clinical profile of an individual patient, associated with a measure of physician judgment and shared decision-making, can be sufficient to consider the recommendation of a prophylactic defibrillator implant. Implantable cardioverter-defibrillator decisions using the American College of Cardiology and the American Heart Association traditional major risk marker strategy are associated with a 95% sensitivity for identifying those patients who subsequently experience appropriate therapy, albeit often 5 to 10+ years after implant but without heart failure deterioration or death after a device intervention. A mathematical SCD risk score proposed by European Society of Cardiology is associated with a relatively low sensitivity (33%) for predicting and preventing SCD events but with potential for less device overtreatment.

The challenge of risk stratification in hypertrophic cardiomyopathy: Clinical, genetic and imaging insights from a quaternary referral centre

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is the commonest genetic cardiomyopathy and may result in sudden cardiac death (SCD). Clinical risk stratification scores are utilised to estimate SCD risk and determine potential utility of a primary prevention implantable cardioverter defibrillator (ICD).

METHODS

Patients with a confirmed diagnosis of HCM from a quaternary HCM service were defined according to clinical characteristics, genetic profiles and cardiac imaging results. European Risk-SCD score and American Heart Association / American College of Cardiology (AHA/ACC) Score were calculated. The primary outcome was cardiac arrest.

RESULTS

380 patients with HCM were followed up for a median of 6.4 years. 18 patients (4.7%) experienced cardiac arrest, with predictive factors being younger age (37.2 vs 54.4 years, p = 0.0041), unexplained syncope (33.3% vs 9.4%, p = 0.007), non-sustained ventricular tachycardia (50.0% vs 12.7%, p < 0.0001), increased septal thickness (21.5 vs 17.5 mm, p = 0.0003), and presence of a sarcomeric gene mutation (100.0% vs 65.8%, p = 0.038). The Risk-SCD and AHA/ACC scores had poor agreement (kappa coefficient 0.38). Risk-SCD score had poor sensitivity (44.4%), classifying 55.6% of patients with cardiac arrest as low-risk but was highly specific (93.7%). AHA/ACC risk score did not discriminate between groups significantly. 20 patients (5.3%) died, with most >60-year-olds having a non-cardiac cause of death (p = 0.0223).

CONCLUSION

This study highlights limited (38%) agreement between the Risk-SCD and AHA/ACC scores. Most cardiac arrests occurred in ostensibly low or medium-risk patients under both scores. Appropriate ICD selection remains challenging. Incorporating newer risk markers such as HCM genotyping and myocardial fibrosis quantification by cardiac MRI may assist future risk refinement.

Low T3 syndrome predicts more adverse events in patients with hypertrophic cardiomyopathy

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is a common cardiac genetic disorder that clinically manifests with sudden death and progressive heart failure. Moreover, thyroid dysfunction is associated with increased cardiovascular morbidity and mortality risks. Therefore, this study aimed to clarify whether thyroid hormones could serve as an independent predictor of adverse events in patients with HCM.

METHODS

The cohort consisted of 782 patients with HCM who had thyroid hormones baseline data and were admitted to the Affiliated Hospital of Jiaxing University. Patients were divided into two groups according to serum levels of free triiodothyronine (fT3): the normal fT3 and low triiodothyronine (T3) syndrome groups. Low T3 syndrome was defined as fT3 < 2.43 pmol/L with a normal thyroid-stimulating hormone (TSH) level. Patients whose TSH levels were abnormally high or abnormally low were excluded from this study. The primary endpoint was the occurrence of sudden cardiac death (SCD) events, and the secondary endpoint was a composite of worsening heart failure (WHF) events, including heart failure death, cardiac decompensation, hospitalization for heart failure, and HCM-related stroke. The Kaplan-Meier and Cox regression were performed for the survival analysis.

RESULTS

After a median follow-up of 52 months, 75 SCD events and 134 WHF events were recorded. The Kaplan-Meier survival curves showed that the cumulative incidence of SCD events and WHF events were significantly higher in patients with low T3 syndrome (log-rank p = .02 and log-rank p = .001, respectively). Furthermore, multivariate Cox regression analysis demonstrated that low T3 syndrome is a strong predictor of SCD events and WHF events (adjusted hazard ratio [HR: 1.53, 95% confidence interval [CI]: 1.13-2.24, p < .01; HR: 3.87, 95% CI: 2.91-4.98, p < .001, respectively).

CONCLUSIONS

Low T3 syndrome is highly prevalent among patients with HCM and was independently associated with an increased risk of SCD events and WHF events. The routine assessment of serum fT3 levels may provide risk stratification in this population.

High-risk imaging characteristics in left ventricular apex for the life-threatening arrhythmic events in Japanese hypertrophic cardiomyopathy patients

Left ventricular (LV) apical aneurysm is known to be associated with the life-threatening arrhythmic events in hypertrophic cardiomyopathy (HCM). However, the current 2014 ESC guideline has not included apical aneurysm as a major risk factor for sudden cardiac death and 2018 JCS guideline includes it only as a modulator, while it has been included as a new major risk marker in 2020 AHA/ACC guideline. Therefore, we sought to identify high-risk imaging characteristics in LV apex which is associated with a higher occurrence of ventricular tachycardia/fibrillation (VT/VF). In 99 consecutive Japanese HCM patients (median age, 65 years; 59 males) undergoing implantable cardioverter-defibrillator (ICD) implantation for primary prevention following cardiac magnetic resonance including late gadolinium enhancement (LGE), the occurrence of appropriate ICD interventions for VT/VF was evaluated for 6.2 (median) years after ICD implantation. Overall, appropriate ICD interventions occurred in 43% with annual rates of 7.0% for appropriate interventions. Kaplan-Meier analysis demonstrated that the presence of LV apical aneurysm was significantly associated with a higher occurrence of appropriate interventions (annual rates 18.9% vs. 6.4%, P = 0.013). Similarly, patients with high LV mid-to-apex pressure gradient (annual rates 14.9% vs. 6.2%, P = 0.022) and presence of apical LGE (annual rates 10.9% vs. 4.0%, P = 0.001) experienced appropriate interventions more frequently. An aneurysm, high-pressure gradient, and LGE in an apex are associated with VT/VF. These characteristics in apex should be kept in mind when implanting ICD in Japanese HCM patients as a primary prevention.

Subendocardial Involvement as an Underrecognized LGE Subtype Related to Adverse Outcomes in Hypertrophic Cardiomyopathy

BACKGROUND

Late gadolinium enhancement (LGE) has been established as an independent predictor for adverse outcomes in hypertrophic cardiomyopathy (HCM). However, the prevalence and clinical significance of some LGE subtypes have not been well demonstrated.

OBJECTIVES

In this study, the authors sought to investigate the prognostic value of subendocardium-involved LGE pattern and location of right ventricle insertion points (RVIPs) with LGE in HCM patients.

METHODS

In this single-center retrospective study, 497 consecutive HCM patients with LGE confirmed by cardiac magnetic resonance (CMR) were included. Subendocardium-involved LGE was defined as LGE involving subendocardium not corresponding to a coronary vascular distribution. Subjects with ischemic heart disease that would contribute to subendocardial LGE were excluded. Endpoints included a composite of heart failure-related events, arrhythmic events, and stroke.

RESULTS

Of the 497 patients, subendocardium-involved LGE and RVIP LGE were observed in 184 (37.0%) and 414 (83.3%), respectively. Extensive LGE (≥15% of left ventricular mass) was detected in 135 patients. During a median follow-up of 57.9 months, 66 patients (13.3%) experienced composite endpoints. Patients with extensive LGE had a significantly higher annual incidence of adverse events (5.1% vs 1.9% per year; P < 0.001). However, spline analysis showed that the association between LGE extent and HRs for adverse outcomes tended to be nonlinear. The risk of composite endpoint increased with percentage increase in LGE extent in patients with extensive LGE, whereas a similar trend was not observed in patients with nonextensive LGE (<15%). In patients with extensive LGE, LGE extent significantly correlated with composite endpoints (HR: 1.05; P = 0.03) after adjusting for left ventricular ejection fraction <50%, atrial fibrillation, and nonsustained ventricular tachycardia, whereas in patients with nonextensive LGE, subendocardium-involved LGE rather than LGE extent was independently associated with adverse outcomes (HR: 2.12; P = 0.03). RVIP LGE was not significantly associated with poor outcomes.

CONCLUSIONS

In HCM patients with nonextensive LGE, the presence of subendocardium-involved LGE rather than LGE extent is associated with unfavorable outcomes. Given that the prognostic value of extensive LGE has been broadly recognized, subendocardial involvement as an underrecognized LGE pattern shows the potential to improve risk stratification in HCM patients with nonextensive LGE.

Art and science of risk stratification of sudden cardiac death in hypertrophic cardiomyopathy: Current state, unknowns, and future directions

The progress in the management of hypertrophic cardiomyopathy (HCM) over the last several decades has resulted in great improvements in quality of life and overall survival for HCM patients. Yet, sudden cardiac death (SCD) due to ventricular tachyarrhythmias is among the common causes of HCM-related mortality. SCD risk stratification is a central and often challenging domain in the care of the HCM patient. Distinguishing the individuals most likely to benefit from a primary prevention implantable-cardioverter defibrillator (ICD) from those truly at a low risk of SCD in whom an ICD is not necessary is a nuanced process. Clinicians need to carefully balance the potential benefit and risks of ICDs, particularly in young patients. Because of intense investigations in diverse HCM cohorts globally, two main approaches to SCD risk stratification in HCM have emerged, one based on major SCD risk factors and one based on a mathematically derived risk score. In this overview, we discuss the current state, latest advances and remaining unknowns about established and novel markers of risk of SCD in HCM. We also review how the risk factor- and risk score-based assessments can and should be used in conjunction to enhance rather than contradict each other in facilitating informed ICD decision-making in contemporary clinical practice.

Development of the Implantable Cardioverter-Defibrillator: JACC Historical Breakthroughs in Perspective

Implantable cardioverter-defibrillators (ICDs) represent transformational technology, arguably the most significant advance in cardiovascular medicine in 50 years. The vision and determination of pioneers Mirowski and Mower was fundamental to this monumental achievement, working with limited resources and confronted by skepticism/criticism from medical establishment. The inventors were followed >35 years in which a multitude of innovative clinical scientists and engineers introduced technological advances leading to the sophisticated devices in practice today. A pivotal patient experiment with automated termination of ventricular fibrillation (1980) led to U.S. Food and Drug Administration approval. Transvenous lead systems converted ICDs from thoracotomy-based secondary prevention to primary prevention of sudden death devices in countless patients worldwide. ICD acceptance was solidified by prospective randomized controlled trials showing reduced mortality superior to antiarrhythmic drugs. ICDs eventually expanded from coronary disease to inherited arrhythmia conditions (eg, hypertrophic cardiomyopathy). The ICD breakthrough story demonstrates how significant progress is possible in medicine against all odds, given fearless imagination to pursue novel ideas that conflict with accepted wisdom.

Aloe-emodin ameliorated MI-induced cardiac remodeling in mice via inhibiting TGF-β/SMAD signaling via up-regulating SMAD7

BACKGROUND

Aloe-emodin (AE), a natural anthraquinone extract from traditional Chinese medicinal plants, has been certified to protect against acute myocardial ischemia. However, its effect on cardiac remodeling after chronic myocardial infarction (MI) and the possible mechanism remain unclear.

PURPOSE

This study investigated the effect of AE on cardiac remodeling and oxidative damage induced by myocardial infarction (MI) in vitro and explored the underlying mechanisms.

METHODS

Echocardiography and Masson staining were used to demonstrate myocardial dysfunction and fibrosis. Cell apoptosis was detected by TUNEL staining. The expressions of fibrosis-related factors such as type I collagen, α-smooth muscle actin (α-SMA) and connective tissue growth factor (CTGF) were detected by Western blot.

RESULTS

Our data demonstrated that AE treatment significantly improved cardiac function, reduced structural remodeling, and reduced cardiac apoptosis and oxidative stress in mice with myocardial infarction. In vitro, AE could protect neonatal mouse cardiomyocytes (NMCM) from angiotensin II (Ang II)-induced cardiomyocyte hypertrophy and apoptosis, and significantly inhibited (p < 0.05) Ang II-induced reactive oxygen species (ROS) increase. Furthermore, AE treatment significantly reversed the Ang ii-induced upregulation.

CONCLUSION

In summary, our work reveals for the first time that AE activates the TGF-β signaling pathway by up-regulating Smad7 expression, which in turn regulates the expression of fibrosis-related genes, ultimately improving cardiac function, inhibiting the development of cardiac fibrosis and hypertrophy in rats with chronic MI.

Refractory electrical storm in a patient with hypertrophic cardiomyopathy and an implantable cardioverter-defibrillator

A 63-year-old man with hypertrophic cardiomyopathy (HCM), mid-ventricular obstruction, and an apical aneurysm had an episode of cardiac arrest due to sustained ventricular tachycardia (VT). He was resuscitated and an implantable cardioverter-defibrillator (ICD) was implanted. In the following years, several episodes of VT and ventricular fibrillation were successfully terminated by antitachycardia pacing or ICD shocks. Three years after ICD implantation, he was re-admitted because of refractory electrical storm (ES). Since aggressive pharmacological treatments, direct current cardioversions, and deep sedation were not effective, he underwent epicardial catheter ablation which was successful to terminate ES. However, because of the recurrence of refractory ES after one year, he proceeded to surgical left ventricular myectomy with apical aneurysmectomy which provided him a relatively stable clinical course for six years. Although epicardial catheter ablation may be an acceptable option, surgical resection of apical aneurysm seems to be most efficacious for ES in patients with HCM and an apical aneurysm.

Learning objectives

In patients with hypertrophic cardiomyopathy (HCM), implantable cardioverter-defibrillators (ICDs) are the gold standard of therapy for prophylaxis against sudden death. Electrical storm (ES) caused by recurrent episodes of ventricular tachycardia can cause sudden death even in patients with ICDs. Although epicardial catheter ablation may be an acceptable option, surgical resection of apical aneurysm is most efficacious for ES in patients with HCM, mid-ventricular obstruction, and an apical aneurysm.

Apical aneurysm formation in apical hypertrophic cardiomyopathy: Pilot study with cardiac magnetic resonance

BACKGROUND

The dynamic changes and apical aneurysm formation in apical hypertrophic cardiomyopathy (HCM) have not been specifically described. This study aimed to describe these changes to better understand the progression of apical HCM.

METHODS AND RESULTS

Seventy-two patients with apical HCM who underwent at least two cardiac magnetic resonance (CMR) examinations were retrospectively included in this study. The mean interval between the first and last CMR examinations was 50.1 ± 26.8 months (ranging from 4 to 118 months). Compared with the initial values, the left atrial diameter, maximum left ventricular wall thickness and late gadolinium enhancement extent significantly increased (all P < 0.05), while the left ventricular ejection fraction significantly decreased (P < 0.05), at the latest CMR examination. More importantly, the dynamic process of apical aneurysm formation in apical HCM was observed in a subset of patients, which may follow these four stages: starting with systolic apical cavity obliteration, then broadening of the apical slit in systole, further developing into an apical outpouching, and finally forming an apical aneurysm. Eleven patients experienced adverse cardiovascular events, including new-onset or progressive atrial fibrillation (n = 7), hospitalization with heart failure (n = 3) and implantable cardioverter defibrillator intervention (n = 1), at the time of the latest CMR examination.

CONCLUSIONS

In the progression of apical HCM, cardiac structure and function will change accordingly. Apical aneurysm formation in apical HCM is a chronic and continuous dynamic process that may follow a 4-step pathway of disease progression.

A deep learning platform to assess drug proarrhythmia risk

Drug safety initiatives have endorsed human iPSC-derived cardiomyocytes (hiPSC-CMs) as an in vitro model for predicting drug-induced cardiac arrhythmia. However, the extent to which human-defined features of in vitro arrhythmia predict actual clinical risk has been much debated. Here, we trained a convolutional neural network classifier (CNN) to learn features of in vitro action potential recordings of hiPSC-CMs that are associated with lethal Torsade de Pointes arrhythmia. The CNN classifier accurately predicted the risk of drug-induced arrhythmia in people. The risk profile of the test drugs was similar across hiPSC-CMs derived from different healthy donors. In contrast, pathogenic mutations that cause arrhythmogenic cardiomyopathies in patients significantly increased the proarrhythmic propensity to certain intermediate and high-risk drugs in the hiPSC-CMs. Thus, deep learning can identify in vitro arrhythmic features that correlate with clinical arrhythmia and discern the influence of patient genetics on the risk of drug-induced arrhythmia.

Identification of circRNA-miRNA-mRNA regulatory network and its role in cardiac hypertrophy

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is a grave hazard to human health. Circular RNA (circRNAs) and micro RNA (miRNAs), which are competitive endogenous RNA, have been shown to play a critical role inHCM pathogenicity. However, to a great extent, the biological activities of ceRNA in HCM pathophysiology and prognosis remain to be investigated.

MATERIALS AND METHODS

By analyzing the expression files in the Gene Expression Comprehensive (GEO) database, differentially expressed (DE) circRNAs, miRNAs, and mRNAs in HCM were identified, and the target molecules of circRNAs and miRNAs were predicted. The intersection of the differentially expressed RNA molecules and the expected target was then calculated, and a ceRNA network was subsequently constructed using RNA molecules. Using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses, the potential etiology was elucidated. qPCR was used to validate a portion of the hub gene using Angiotensin II to generate a cell hypertrophy model.

RESULTS

Three large-scale HCM sample datasets were extracted from the GEO database. After crossing these molecules with their expected targets, the circRNA-miRNA-mRNA network had two DEcircRNAs, two DEmiRNAs, and thirty DEmRNAs, compared to normal tissues. Functional enrichment analysis of GO and KEGG demonstrated that many of the HCM pathways and mechanisms were associated with calcium channel release, which is also the primary focus of future research. The qPCR results revealed that circRNA, miRNA, and mRNA expression levels were different. They may include novel noninvasive indicators for the early screening and prognostic prediction of HCM.

CONCLUSION

In this study, we hypothesized a circRNA-miRNA-mRNA regulation network that is closely related to the progression and clinical outcomes of HCM and may contain promising biomarkers and treatment targets for HCM.

Temporal and Global Trends of the Incidence of Sudden Cardiac Death in Hypertrophic Cardiomyopathy

BACKGROUND

Since the initial clinical description of hypertrophic cardiomyopathy (HCM) over 60 years ago, sudden cardiac death (SCD) has been the most visible and feared complication of HCM.

OBJECTIVES

This study sought to characterize the temporal, geographic, and age-related trends of reported SCD rates in adult HCM patients.

METHODS

Electronic databases were systematically searched up to November 2021 for studies reporting on SCD event rates in HCM patients. Patients with SCD equivalents (appropriate implantable cardioverter-defibrillator [ICD] shocks and nonfatal cardiac arrests) were not included. A random-effects model was used to pool study estimates calculating the overall incidence rates (IR) for each time-era, geographic region, and age group. We analyzed 2 periods (before vs after 2000, following clinical implementation of ICD in HCM). Following 2000, 5-year intervals were used to demonstrate the temporal change in SCD rates.

RESULTS

A total of 98 studies (N = 70,510 patients and 431,407 patient-years) met our inclusion criteria. The overall rate of HCM SCD was 0.43%/y (95% CI: 0.37-0.50%/y; I² = 75%; SCD events: 1,938; person-years of follow-up: 408,715), with young patients (<18 years of age) demonstrating a >2-fold-risk for sudden death vs adult patients 18-60 years of age (IR: 1.09%; 95% CI: 0.69%-1.73% vs IR: 0.43%; 95% CI: 0.37%-0.50%) (P value for subgroup differences <0.01). Contemporary SCD rates from 2015 to present were 0.32%/y and significantly lower compared with 2000 or earlier (IR: 0.32%; 95% CI: 0.20%-0.52% vs IR: 0.73%; 95% CI: 0.53%-1.02%, respectively). Reported SCD rates for HCM were lowest in North America (IR: 0.28%; 95% CI: 0.18%-0.43%,) and highest in Asia (IR: 0.67%; 95% CI: 0.54%-0.84%).

CONCLUSIONS

Contemporary HCM-related SCD rates are low (0.32%/y) representing a 2-fold decrease compared with prior treatment eras. Young HCM patients are at the highest risk. The maturation of SCD risk stratification strategies and the application of primary prevention ICD to HCM are likely responsible for the notable decline over time in SCD events. In addition, worldwide geographic disparities in SCD rates were evident, underscoring the need to increase access to SCD prevention treatment for all HCM patients.

Anxiety Predicts Poor Prognosis in Patients With Hypertrophic Cardiomyopathy

Background

Hypertrophic cardiomyopathy (HCM) is the prevalent inherited cardiomyopathy and a major contributor to sudden death and heart failure in young adults. Although depression has been associated with poor prognosis in patients with cardiovascular disease, the relationship between anxiety and HCM clinical outcomes has not been addressed. We aimed to determine the prevalence of anxiety symptoms in patients with HCM and the association between anxiety and adverse prognosis in this population.

Methods

A total of 793 patients with HCM were prospectively enrolled and followed up for a mean of 4.1 years from March 2014 to January 2018. The primary endpoint was sudden cardiac death (SCD) events, and the secondary endpoint was HCM-related heart failure events. Anxiety symptoms were assessed using the Hospital Anxiety and Depression Scale (HADS) during outpatient visits or hospital stays.

Results

Elevated scores on the HADS anxiety subscale (HADS-A ≥ 8) were defined as clinically significant anxiety. SCD and HCM-related heart failure events occurred in 76 and 149 patients, respectively, during the follow-up period. Kaplan–Meier survival curves demonstrated the significant association of anxiety with SCD events (log-rank P = 0.012) and HCM-related heart failure events (log-rank P = 0.001). Multivariable Cox regression analysis showed anxiety as a predictor of SCD events and HCM-related heart failure events (adjusted hazard ratio [HR] = 1.42, 95% confidence interval [CI] = 1.12–2.04, P = 0.03; adjusted HR = 2.9,2 95% CI = 1.73–4.03, P &lt; 0.001), independent of conventional risk factors and depression. Besides, patients with comorbid anxiety and depression showed a fourfold higher risk of heart failure events and 3.5-fold higher risk of SCD versus those with neither (adjusted HR = 4.08, 95% CI = 2.76–5.91, P &lt; 0.001; adjusted HR = 3.52, 95% CI = 2.24–4.67, P &lt; 0.001, respectively).

Conclusions

Anxiety was prevalent among Chinese patients with HCM, and it was independently associated with a higher risk of SCD and HCM-related heart failure events, particularly when comorbid with depression. Psychological assessment and intervention should be considered to alleviate anxiety symptoms in this population.

Clinical Trial Registration

http://www.chictr.org.cn, identifier: ChiCTR2000040759.

Cardiac MRI of Hereditary Cardiomyopathy

Hereditary cardiomyopathy comprises a heterogeneous group of diseases of the cardiac muscle that are characterized by the presence of genetic mutations. Cardiac MRI is central to evaluation of patients with cardiomyopathy owing to its ability to allow evaluation of many different tissue properties in a single examination. For example, cine MRI is the standard of care for assessment of myocardial structure and function. It clearly shows regions of asymmetric wall thickening that are typical of hypertrophic cardiomyopathy and allows it to be differentiated from other hereditary disorders such as Fabry disease or transthyretin cardiac amyloidosis that produce concentric hypertrophy. Late gadolinium enhancement provides a different tissue property and allows these latter two causes of concentric hypertrophy to be distinguished on the basis of their enhancement appearances (Fabry disease shows midwall basal inferolateral enhancement, and amyloidosis shows global subendocardial enhancement). Native T1 mapping may similarly allow differentiation between Fabry disease and amyloidosis without the use of contrast material. T2*-weighted MRI is important in the detection and quantification of iron overload cardiomyopathy. Other hereditary entities for which comprehensive MRI has proven essential include Danon disease, familial dilated cardiomyopathy, hereditary muscular dystrophy, arrhythmogenic right ventricular cardiomyopathy, and ventricular noncompaction. As a result of the diagnostic power of cardiac MRI, cardiac MRI examinations are being requested with increasing frequency, not only in academic centers but also in community practices. The genetic background, pathophysiologic characteristics, and clinical presentation of patients with hereditary cardiomyopathy are described; the characteristic cardiac MRI features of hereditary cardiomyopathy are discussed; and the role of MRI in risk stratification, treatment, and prognostication in patients with cardiomyopathy is reviewed. ^©RSNA, 2022 Online supplemental material is available for this article.

lncRNA ADAMTS9-AS1/circFN1 Competitively Binds to miR-206 to Elevate the Expression of ACTB, Thus Inducing Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is a genetic cardiac disease and can result in substantial disability. The current study explored the potentials of long noncoding RNA- (lncRNA-) circular RNA- (circRNA-) microRNA- (miRNA-) messenger RNA (mRNA) networks in HCM. Firstly, HCM-related microarray data were procured from the GEO database, with differentially expressed genes (DEGs) obtained. HCM-related target genes were retrieved in combination with GeneCards and CTD databases, and candidate target genes were subsequently obtained by intersection screening. Further, an interaction network diagram of candidate target genes was constructed using the STRING database, and the hub genes in the network were determined according to the core degree. The “ClusterProfiler” package of the R software was adopted for GO and KEGG analyses of candidate target genes, to analyze the potential molecular pathways in HCM. Next, upstream miRNA, lncRNA, and circRNA of ACTB were predicted with RNAInter, mirDIP, TargetScan, DIANA-LncBase, and StarBase databases, followed by construction of lncRNA/circRNA-miRNA-mRNA coexpression networks. ACTB, miR-206, circFN1, and ADAMTS9-AS1 expression in peripheral blood samples from HCM patients and normal healthy controls were detected using RT-qPCR. Moreover, rat cardiomyocyte cell lines H9c2 and HEK293 cells were selected for in vitro verification of competitive endogenous RNA (ceRNA) regulation mechanism. A total of 15 candidate target genes related to HCM were screened using the online databases. Further protein-protein interaction analysis identified ACTB as the hub gene for HCM. The targeted binding relationship between miR-206, miR-145-5p, miR-1-3p, and ACTB was found. Furthermore, ADAMTS9-AS1 and circFN1 were discovered as the upstream genes of miR-206. Moreover, ADAMTS9-AS1, circFN1, and ACTB were found to be poorly expressed, and miR-206 was highly expressed in HCM. In vitro experimentation further confirmed that ADAMTS9-AS1 and circFN1 could competitively bind to miR-206, thereby augmenting ACTB expression. Taken all, ADAMTS9-AS1/circFN1-miR-206-ACTB regulatory network may involve in HCM occurrence, providing a novel theoretical basis for in-depth understanding of mechanism of HCM.

Sex and Race Disparities in Hypertrophic Cardiomyopathy: Unequal Implantable Cardioverter-Defibrillator Use During Hospitalization

OBJECTIVE

To evaluate if there are sex and race disparities in use of implantable cardioverter-defibrillator (ICD) devices for prevention of sudden cardiac death in patients with hypertrophic cardiomyopathy (HCM).

PATIENTS AND METHODS

Using the National Inpatient Sample from January 2003 through December 2014, we identified all adult admissions with a diagnosis of HCM and an ICD implantation. Race was classified as White versus non-White. Trends in ICD use, predictors of ICD implantation, device-related complications, hospitalization costs, and lengths of stay were evaluated.

RESULTS

Among a total of 23,535 adult hospitalizations for HCM, ICD implantation was performed in 3954 (16.8%) admissions. Over the study period, there was an overall increasing trend in ICD use (11.6% in 2003 to 17.0% in 2014, P<.001). Compared with admissions not receiving an ICD, those receiving an ICD had shorter median lengths of in-hospital stay but higher hospitalization costs (P<.001). Compared with men and White race, female sex (odds ratio, 0.72; 95% CI, 0.66 to 0.78; P<.001) and non-White race (odds ratio, 0.87; 95% CI, 0.79 to 0.96; P<.001) were associated with lower adjusted odds of receiving an ICD. Women and non-White hospitalizations had higher rates of device related complications, longer lengths of in-hospital stay, and higher hospitalization costs compared with men and White race, respectively (all P<.01).

CONCLUSION

Among HCM hospitalizations, ICD devices are underused in women and racial minorities independent of demographics, hospital characteristics, and comorbidities. Women and racial minorities also had higher rates of complications and greater resource use compared with men and those belonging to the White race, respectively.

Hypertrophic Cardiomyopathy: New Concepts and Therapies

Hypertrophic cardiomyopathy (HCM), a relatively common, globally distributed, and often inherited myocardial disorder, transformed over the last several years into a treatable condition with the emergence of effective management options that alter natural history at all ages. Now available are a matured risk stratification algorithm selecting patients for prophylactic implantable defibrillators that prevent arrhythmic sudden death; low-risk, high-benefit surgical myectomy to reverse progressive heart failure symptoms due to left ventricular outflow obstruction; anticoagulation prophylaxis to prevent atrial fibrillation-mediated embolic stroke; and heart transplant for refractory end-stage disease in the absence of obstruction. Those strategies have resulted in reduction of HCM-related morbidity and reduction of mortality to 0.5% per year.

The Arrhythmic Phenotype in Cardiomyopathy

In the wide phenotypic spectrum of cardiomyopathies, sudden cardiac death (SCD) has always been the most visible and devastating disease complication. The introduction of implantable cardioverter-defibrillators for SCD prevention by the late 1980s has moved the question from how to whom we should protect from SCD, leaving clinicians with a measure of uncertainty regarding the most reliable option to guide identification of the highest-risk patients. In this review, we will go through all the available evidence in the field of arrhythmic expression and arrhythmic risk stratification in the different phenotypes of cardiomyopathies to provide practical suggestions in daily clinical management.

Non-pharmaceutical Interventions for Hypertrophic Cardiomyopathy: A Mini Review

Hypertrophic cardiomyopathy is an inherited cardiovascular disease, and 70% of patients have left ventricular outflow tract obstruction. Ventricular septal myectomy has been the gold standard treatment for most patients with refractory symptoms. Due to higher mortality associated with medical facilities with less experience, alcohol septal ablation has been accepted as an alternative to conventional surgical myectomy. It offers lower all-cause in-hospital complications and mortality, which could be potentially more preferable for patients with serious comorbidities. In recent years, radiofrequency ablation, providing another option with reproducibility and a low risk of permanent atrioventricular block, has become an effective invasive treatment to relieve left ventricular outflow tract obstruction. Moreover, substantial progress has been made in gene therapy for hypertrophic cardiomyopathy. The principal objective of this review is to present recent advances in non-pharmaceutical interventions in hypertrophic cardiomyopathy.

Cardiovascular Diseases That Have Emerged From the Darkness

It is important for both the patient and physician communities to have timely access to information recognizing rapid progress in the diagnosis and treatment of familiar but relatively uncommon cardiovascular diseases. Patients with 3 cardiovascular diseases (ie, hypertrophic cardiomyopathy, pulmonary arterial hypertension, and transthyretin (TTR) cardiac amyloidosis (ATTR)]), once considered rare without effective management options and associated with malignant prognosis, have now benefited substantially from the development of a variety of innovative therapeutic strategies. In addition, in each case, enhanced diagnostic testing has expanded the patient population and allowed for more widespread administration of contemporary treatments. In hypertrophic cardiomyopathy, introduction of implantable defibrillators to prevent sudden death as well as high-benefit:low-risk septal reduction therapies to reverse heart failure have substantially reduced morbidity and disease-related mortality (to 0.5% per year). For pulmonary arterial hypertension, a disease once characterized by a particularly grim prognosis, prospective randomized drug trials with aggressive single (or combined) pharmacotherapy have measurably improved survival and quality of life for many patients. In cardiac amyloidosis, development of disease-specific drugs can for the first time reduce morbidity and mortality, prominently with breakthrough ATTR-protein-stabilizing tafamidis. In conclusion, in less common and visible cardiovascular diseases, it is crucial to recognize substantial progress and achievement, given that penetration of such information into clinical practice and the patient community can be inconsistent. Diseases such as hypertrophic cardiomyopathy, pulmonary arterial hypertension, and ATTR cardiac amyloidosis, once linked to a uniformly adverse prognosis, are now associated with the opportunity for patients to experience satisfactory quality of life and extended longevity.

Association Between Depression and Clinical Outcomes in Patients With Hypertrophic Cardiomyopathy

Background

Hypertrophic cardiomyopathy (HCM) is considered to be the most common cause of sudden death in young people and is associated with an elevated risk of mood disorders. Depression has emerged as a critical risk factor for development and progression of coronary artery disease; however, the association between depression and HCM outcomes is less clear. We sought to examine the impact of depression on clinical outcomes in patients with HCM.

Methods and Results

Between January 2014 and December 2017, 820 patients with HCM were recruited and followed for an average of 4.2 years. End points were defined as sudden cardiac death (SCD) events and HCM‐related heart failure events. A Chinese version of the Structured Clinical Interview followed the Diagnostic and Statistical Manual of Mental Disorders,Fifth Edition and was used to diagnose depression. During the follow‐up period, SCD events occurred in 75 individuals (21.8 per 1000 person‐years), and HCM‐related heart failure events developed in 149 individuals (43.3 per 1000 person‐years). Kaplan–Meier cumulative incidence curves showed a significant association of depression disorders with SCD events (log‐rank P=0.001) and HCM‐related heart failure events (log‐rank P=0.005). A multivariate Cox regression analysis indicated that depression was an independent predictor of SCD events and HCM‐related heart failure events (41.9 versus 21.7 per 1000 person‐years; adjusted hazard ratio [HR], 1.9; 95% CI, 1.6–2.3; P<0.001; and 69.9 versus 38.6 per 1000 person‐years; HR, 1.8; 95% CI, 1.6–2.1; P<0.001, respectively).

Conclusions

Depression is common among patients with HCM. The diagnosis of depression is significantly and independently associated with an increased risk of SCD events and heart failure events in patients with HCM.

Low Risk of Hypertrophic Cardiomyopathy With Contemporary Management Strategies Implemented in Non-Referral Regional Community-Based Practices

Major advances in diagnosis and treatment have emerged for hypertrophic cardiomyopathy (HCM), largely in major tertiary referral centers dedicated to this disease. Whether these therapeutic benefits are confined to patients in such highly selected cohorts, or can be implemented effectively in independent regional or community-based populations is not generally appreciated. We assessed management and clinical outcomes in a non-referral HCM center (n = 214 patients) in Eastern Pennsylvania. Over a 6.0 ± 3.2-year follow-up, the HCM-related mortality rate was 0.1% per year attributed to a single disease-related death, in a 49-year-old man with end-stage heart failure, ineligible for heart transplant. Fifteen patients (7%) with prophylactically placed implantable cardioverter-defibrillators (ICDs) experienced appropriate therapy terminating life-threatening ventricular tachyarrhythmias. In 23 other patients (11%; 5%/year), heart failure due to left ventricular outflow obstruction was reversed by surgical septal myectomy (n = 20) or percutaneous alcohol septal ablation (n = 3). This regional HCM cohort was similar to a comparison tertiary center referral population in terms of HCM-mortality: 0.1%/year vs 0.3%/year (p = 0.3) and ICD therapy (31% vs 16% of primary prevention implants), although more frequently with uncomplicated benign clinical course (62% vs 46%; p <0.01). In conclusion, effective contemporary HCM management strategies and outcomes in referral-based HCM centers can be successfully replicated in regional and/or non-referral settings. Therefore, HCM is now a highly treatable disease compatible with normal longevity when assessed in a variety of clinical venues not limited to tertiary centers.

Evolution of risk stratification and sudden death prevention in hypertrophic cardiomyopathy: Twenty years with the implantable cardioverter-defibrillator

Hypertrophic cardiomyopathy (HCM) is a relatively common inherited myocardial disorder, once regarded as largely untreatable with ominous prognosis and most visibly as a common cause of sudden death (SD) in the young. Over the last several years, HCM has been transformed into a contemporary treatable disease with management options that significantly alter clinical course. With the use of implantable cardioverter-defibrillators (ICDs) in the HCM patient population, a new paradigm has emerged, with primary prevention device therapy reliably terminating potentially lethal ventricular tachyarrhythmias (3%-4% per year) and being largely responsible for a >10-fold decrease in disease-related mortality (to 0.5% per year), independent of age. An evidenced-based and guideline directed clinical risk stratification algorithm has evolved, including variables identified with cardiac magnetic resonance. One or more risk markers judged major and relevant within a patient's clinical profile can be considered sufficient to recommend a primary prevention implant (associated with a measure of physician judgment and shared decision-making). ICD decisions using the prospective individual risk marker strategy have been associated with 95% sensitivity for identifying patients who subsequently experienced appropriate ICD therapy, (albeit often delayed substantially for >5 or >10 years after implant), but without heart failure deterioration or HCM death following device intervention. A rigid mathematically derived statistical risk model proposed by the European Society of Cardiology is associated with low sensitivity (ie, 33%) for predicting SD events. Introduction of prophylactically inserted ICDs to HCM 20 years ago has significantly altered the clinical course and landscape of this disease. SD prevention has reduced HCM mortality significantly, making preservation of life and the potential for normal longevity a reality for most patients.

Explanatory Analysis of a Machine Learning Model to Identify Hypertrophic Cardiomyopathy Patients from EHR Using Diagnostic Codes

Hypertrophic cardiomyopathy (HCM) is a genetic heart disease that is the leading cause of sudden cardiac death (SCD) in young adults. Despite the well-known risk factors and existing clinical practice guidelines, HCM patients are underdiagnosed and sub-optimally managed. Developing machine learning models on electronic health record (EHR) data can help in better diagnosis of HCM and thus improve hundreds of patient lives. Automated phenotyping using HCM billing codes has received limited attention in the literature with a small number of prior publications. In this paper, we propose a novel predictive model that helps physicians in making diagnostic decisions, by means of information learned from historical data of similar patients. We assembled a cohort of 11,562 patients with known or suspected HCM who have visited Mayo Clinic between the years 1995 to 2019. All existing billing codes of these patients were extracted from the EHR data warehouse. Target ground truth labeling for training the machine learning model was provided by confirmed HCM diagnosis using the gold standard imaging tests for HCM diagnosis echocardiography (echo), or cardiac magnetic resonance (CMR) imaging. As the result, patients were labeled into three categories of "yes definite HCM", "no HCM phenotype", and "possible HCM" after a manual review of medical records and imaging tests. In this study, a random forest was adopted to investigate the predictive performance of billing codes for the identification of HCM patients due to its practical application and expected accuracy in a wide range of use cases. Our model performed well in finding patients with "yes definite", "possible" and "no" HCM with an accuracy of 71%, weighted recall of 70%, the precision of 75%, and weighted F1 score of 72%. Furthermore, we provided visualizations based on multidimensional scaling and the principal component analysis to provide insights for clinicians' interpretation. This model can be used for the identification of HCM patients using their EHR data, and help clinicians in their diagnosis decision making.

Generation of an IPSC line from a patient with hypertrophic cardiomyopathy carrying a mutation in MYH6 gene

An induced pluripotent stem cell (iPSC) line was generated from peripheral blood mononuclear cells (PBMCs) of a 41-year-old male patient with hypertrophic cardiomyopathy who carries a G3755A heterozygote mutation in the MYH6 gene. The generated iPSC line expressed pluripotency markers, exhibited a normal karyotype, presented the specific mutation, and demonstrated differentiation potential into three germ layers in vitro.

A Novel COX10 Deletion Polymorphism as a Susceptibility Factor for Sudden Cardiac Death Risk in Chinese Populations

Identifying common genetic variations that are related to sudden cardiac death (SCD) is crucial since it can facilitate the diagnosis and risk stratification of SCD. It has been reported that COX10 mutations might be related with SCD. In this study, we performed a systematic variant screening on the COX10 to filter potential functional genetic variations. Based on the screening results, an insertion/deletion polymorphism (rs397763766) in 3'untranslated regions of COX10 was selected as the candidate variant. We conducted a case-control study to investigate the association between rs397763766 and SCD susceptibility in Chinese populations. Logistic regression analysis showed that the deletion allele of rs397763766 was associated with an increased risk for SCD (odds ratio = 1.61, 95% confidence interval = 1.25-2.07, p = 1.87 × 10^-4) susceptibility than insertion allele. Further genotype-phenotype analysis using human cardiac tissue samples suggested that COX10 expression level in genotypes containing deletion allele was higher than that in ins/ins genotype. The results were further reinforced by RNA sequencing data from 1000 Genomes Project. Luciferase activity assay indicated that COX10 expression could be regulated by rs397763766 through interfering binding with miR-15b, thus conferring risk of SCD. In conclusion, the novel rs397763766 polymorphism might be a potential marker for molecular diagnosis and genetic counseling of SCD.

Long-Term Outcome in High-Risk Patients With Hypertrophic Cardiomyopathy After Primary Prevention Defibrillator Implants

Background:

The implantable cardioverter-defibrillator (ICD) is effective for preventing sudden death in patients with hypertrophic cardiomyopathy. However, data on performance and complications of implanted ICDs over particularly long time periods to inform clinical practice is presently incomplete.

Methods:

The study cohort comprises 217 consecutive hypertrophic cardiomyopathy patients with primary prevention ICDs implanted before 2008 and followed for ≥10 years (mean 12±4; range to 31).

Results:

Patients were 38±17 years at implant and 45 (21%) experienced appropriate interventions terminating ventricular tachycardia/ventricular fibrillation. The majority of ICD discharges occurred ≥5 years after implant (29 patients; 64%), including ≥10 years in 16 patients (36%). Initial device therapy increased in frequency from 2.3% of patients at <1 year to 8.5% of patients at ≥10-years after implant ( P =0.005). Inappropriate ICD shocks in 39 patients occurred most commonly <5 years after implant (54%) and decreased in frequency with increasing time from implant (from 9.7% of patients at <5 years to 3.8% at ≥10 years, P =0.02). Other major device complications including infection and lead fractures and dislodgement occurred in 27 patients (12%) but did not increase in frequency over follow-up after implant ( P =0.47). There were no arrhythmic sudden death events among the 217 patients with ICD.

Conclusions:

In hypertrophic cardiomyopathy, after a primary prevention implant, ICD therapy often followed prolonged periods of device dormancy and increased progressively in frequency over time, including one-third of patients with initial therapy after 5 to 9 years, and an additional one-third of patients at ≥10 years. Frequency of inappropriate shocks decreased over follow-up, likely reflecting standard changes in device programming, while occurrence of device complications, such as lead fractures/infection, did not increase during follow-up.

Apical hypertrophic cardiomyopathy with left ventricular apical aneurysm: prevalence, cardiac magnetic resonance characteristics, and prognosis

Aims

Hypertrophic cardiomyopathy (HCM) with left ventricular apical aneurysm (LVAA) is associated with an increased risk of adverse cardiovascular events. However, the clinical significance of LVAA in apical HCM (ApHCM) has not been reported. This study aimed to investigate the prevalence, cardiac magnetic resonance (CMR) characteristics, and prognosis of LVAA in ApHCM patients.

Methods and results

A total of 1332 consecutive ApHCM patients confirmed by CMR in our hospital were retrospectively analysed. LVAAs were identified in 31 patients of all ApHCM patients (2.3%, 31/1332). Besides, 31 age- and gender-matched ApHCM patients without LVAA were used for comparison. Of the 31 aneurysm patients (mean age, 53.8 ± 15.1 years old), 28 (90.3%) had clinical symptoms, and 3 (9.7%) had a family history of HCM. The rate of missed diagnosis of echocardiography for detecting LVAA was 64.5% (20/31), most (90%, 18/20) of unidentified LVAAs by echocardiography were small aneurysms (&lt;20 mm). Compared with ApHCM patients without LVAA, the proportion of systolic mid-cavity obstruction and late gadolinium enhancement (LGE) presence, and the LGE extent in ApHCM patients with LVAA were significantly higher (all P&lt;0.05). The Kaplan–Meier curves showed that the event-free survival rate in ApHCM patients with LVAA was significantly lower than that in ApHCM patients without LVAA (log rank, P = 0.010).

Conclusion

ApHCM with LVAA is a very rare condition, which is often missed by echocardiography and could be reliably detected with CMR and is associated with a higher risk of adverse cardiovascular events compared with ApHCM without LVAA.

Hypertrophic Cardiomyopathy and Sudden Death Initially Identified at Autopsy

Hypertrophic cardiomyopathy (HC) is associated with a well-recognized risk for unexpected sudden death (SD). Most such reported patients have been referred to dedicated centers and/or expert cardiologists for risk stratification, with the number of SDs decreasing sharply due to penetration of the implantable cardioverter-defibrillator (ICDs) into HC practice. However, the clinical circumstances, and morphologic features of HC patients who incur SD without the opportunity to be considered for preventive intervention with ICDs are largely undefined. Using the long-standing unique Jesse Edwards Registry (St. Paul, Minnesota), we studied 86 selected heart specimens from young HC patients who died suddenly and unexpectedly without prior clinical evaluation, ages 31 ± 16 years. The patients were predominantly male (87%) with only modest phenotypic expression and maximum LV wall thickening of only 18 ± 4 mm. SD events occurred predominantly with sedentary/mild activities (66%) often in bed or asleep (32%), but also during physical activity (22%) including with organized competitive sports. This largely unappreciated sub-population of patients with HC (and SD) is characterized by mild-to-moderate degree of LV hypertrophy, representing a clinical challenge which is particularly relevant in the current ICD era for HC, with the potential for SD prevention.