Dilated cardiomyopathy

Evaluation of Modified Look-Locker Inversion Recovery and Arrhythmia-Insensitive Rapid Cardiac T1 Mapping Pulse Sequences in Cardiomyopathy Patients

OBJECTIVE

The aim of this study was to compare the performance of arrhythmia-insensitive rapid (AIR) and modified Look-Locker inversion recovery (MOLLI) T1 mapping in patients with cardiomyopathies.

METHODS

In 58 patients referred for clinical cardiac magnetic resonance imaging at 1.5 T, we compared MOLLI and AIR native and postcontrast T1 measurements. Two readers independently analyzed myocardial and blood T1 values. Agreement between techniques, interreader agreement per technique, and intrascan agreement per technique were evaluated.

RESULTS

The MOLLI and AIR T1 values were strongly correlated (r = 0.98); however, statistically significantly different T1 values were derived (bias 80 milliseconds, pooled data, P < 0.01). Both techniques demonstrated high repeatability (MOLLI, r = 1.00 and coefficient of repeatability [CR] = 72 milliseconds; AIR, r = 0.99 and CR = 184.2 milliseconds) and produced high interreader agreement (MOLLI, r = 1.00 and CR = 51.7 milliseconds; AIR, r = 0.99 and CR = 183.5 milliseconds).

CONCLUSIONS

Arrhythmia-insensitive rapid and MOLLI sequences produced significantly different T1 values in a diverse patient cohort.

Endomyocardial biopsy in differential diagnosis between arrhythmogenic right ventricular cardiomyopathy and dilated cardiomyopathy: an in vitro simulated study

Arrhythmogenic right ventricular cardiomyopathy (ARVC) and dilated cardiomyopathy (DCM), despite being two dramatically different entities, have overlapping phenotypes. As it is easy to misdiagnose between ARVC and DCM, there is a need to establish a new differential diagnostic parameter to differentiate the two. We investigated the utility of endomyocardial biopsy (EMB) for the differential diagnosis, and our study had three aims. The first was to verify the EMB high diagnostic efficacy. The second was to investigate the EMB perforation risk at the right ventricle (RV) free wall of end-stage ARVC. The third was to determine the best EMB sampling site in differential diagnosis between ARVC and DCM. Transmural tissues were sampled at six sites on the ventricular free walls and interventricular septum of recipient hearts (35 ARVCs and 35 DCMs). Participants with wall thickness <1.7 mm were included in the subgroup with high perforation risk, and the rest were included in a subgroup with low perforation risk. The best EMB sampling site was determined by the largest area under curve (AUC) among receiver operating characteristic curves. We found significant differences (P<.01) in percentages of tissue components in transmural sections between ARVC and DCM. In the subgroup with high perforation risk, there were 12 ARVCs and no DCMs, and paper-like RV walls and transmural fat replacement were their features in the cardiac enhancement computed tomography images. In the subgroup with low perforation risk, the largest AUC was on the myocardium at the ARV: AUC=0.839, cutoff=74.76%, sensitivity=73.68%, specificity=97.14%. We conclude that EMB high differential diagnostic efficacy is a meaningful fact regardless of limited sampling range, that EMB perforation risk at the RV free wall of end-stage ARVC cannot be neglected, and that the best EMB sampling site is the ARV. Among participants with low perforation risk, ARV is still recommended as an EMB sampling site with good differential diagnostic efficacy.

Splicing Factor RBM20 Regulates Transcriptional Network of Titin Associated and Calcium Handling Genes in The Heart

RNA binding motif 20 (RBM20) regulates pre-mRNA splicing of over thirty genes, among which titin is a major target. With RBM20 expression, titin expresses a larger isoform at fetal stage to a smaller isoform at adult resulting from alternative splicing, while, without RBM20, titin expresses exclusively a larger isoform throughout all ages. In addition to splicing regulation, it is unknown whether RBM20 also regulates gene expression. In this study, we employed Rbm20 knockout rats to investigate gene expression profile using Affymetrix expression array. We compared wild type to Rbm20 knockout at day1, 20 and 49. Bioinformatics analysis showed RBM20 regulates fewer genes expression at younger age and more at older age and commonly expressed genes have the same trends. GSEA indicated up-regulated genes are associated with heart failure. We examined titin binding partners. All titin direct binding partners are up-regulated and their increased expression is associated with dilated cardiomyopathy. Particularly, we found that genes involving calcium handling and muscle contraction are changed by RBM20. Intracellular calcium level measurement with individual cardiomyocytes further confirmed that changes of these proteins impact calcium handling. Selected genes from titin binding partners and calcium handling were validated with QPCR and western blotting. These data demonstrate that RBM20 regulates gene splicing as well as gene expression. Altered gene expression by RBM20 influences protein-protein interaction, calcium releasing and thus muscle contraction. Our results first reported gene expression impacted by RBM20 with heart maturation, and provided new insights into the role of RBM20 in the progression of heart failure.

Non-contrast-enhanced T1 Mapping of Dilated Cardiomyopathy: Comparison between Native T1 Values and Late Gadolinium Enhancement

PURPOSE

We sought to use non-contrast-enhanced T₁ mapping to determine the native T₁ values required to identify myocardial fibrosis in patients with dilated cardiomyopathy (DCM).

METHODS

A total of 25 patients with DCM and 15 healthy controls were enrolled. All subjects underwent T₁ mapping using modified look-locker inversion recovery, and the patients underwent late gadolinium-enhancement (LGE) imaging. Basal and mid-ventricular levels were divided into eight segments and the T₁ value was measured in each segment. The T₁ values of septal segments with LGE were compared with those of the septal segments without LGE, the minimum T₁ value of each patient, and the T₁ values of the normal septal myocardium.

RESULTS

Late gadolinium-enhancement was present in 12 septal segments (24.0%) from 10 patients (40.0%). T₁ values were significantly higher in septal segments with LGE than in those without (1373.7 vs. 1288.0 ms; P = 0.035) or in normal septal myocardium (1209.1 ms; P < 0.01). A receiver operating characteristic analysis revealed the appropriate cutoff value of 1349.4 ms for identifying LGE with a sensitivity of 75% and specificity of 92.1%. When the minimum T₁ value + 1.2 standard deviation (SD) was used as the threshold, the sensitivity was 75% and specificity was 89.5%.

CONCLUSION

Non-contrast-enhanced T₁ mapping can be used for assessment of myocardial fibrosis associated with DCM by using the appropriate threshold.

Reverse remodeling in Dilated Cardiomyopathy: Insights and future perspectives

Dilated Cardiomyopathy (DCM) has been classically considered a progressive disease of the heart muscle that inexorably progresses towards refractory heart failure, ventricular arrhythmias and heart transplant. However, the prognosis of DCM has significantly improved in the past few years, mostly as the result of successful therapy-induced reverse remodeling. Reverse remodeling is a complex process that involves not only the left ventricle, but also many other cardiac structures and it is now recognized both as a measure of therapeutic effectiveness and as an important prognostic tool. Nevertheless, several aspects of reverse remodeling remain unclear, including the best timing for its quantification, its predictors and its interaction with individual genetic backgrounds. In this review, we summarize our current understanding of reverse remodeling in patients with DCM and provide practical recommendations for the clinical management of this challenging patient population.

Increased myocardial native T1 relaxation time in patients with nonischemic dilated cardiomyopathy with complex ventricular arrhythmia

PURPOSE

To study the relationship between diffuse myocardial fibrosis and complex ventricular arrhythmias (ComVA) in patients with nonischemic dilated cardiomyopathy (NICM). We hypothesized that NICM patients with ComVA would have a higher native myocardial T1 time, suggesting more extensive myocardial diffuse fibrosis.

MATERIALS AND METHODS

We prospectively enrolled NICM patients with a history of ComVA (n = 50) and age-matched NICM patients without ComVA (n = 57). Imaging was performed at 1.5T with a protocol that included cine magnetic resonance imaging (MRI) for left ventricular (LV) function, late gadolinium enhancement (LGE) for focal scar, and native T1 mapping for diffuse fibrosis assessment.

RESULTS

Global native T1 time was significantly higher in patients with NICM with ComVA when compared to patients with NICM without ComVA (1131 ± 42 vs. 1107 ± 45 msec, P = 0.006), and this finding remained after excluding segments with scar on LGE (1124 ± 36 vs. 1102 ± 44 msec, P = 0.006). Native T1 was similar in NICM patients with and without the presence of LGE (1121 ± 39 vs. 1117 ± 48 msec, P = 0.68) and mildly correlated with LV end-diastolic volume index (r = 0.27, P = 0.005), LV end-systolic volume index (r = 0.24, P = 0.01), and LV ejection fraction (r = -0.28, P = 0.003). Native T1 value for each 10-msec increment was an independent predictor of ComVA (odds ratio 1.14, 95% confidence interval 1.03-1.25; P = 0.008) beyond LV function and LGE.

CONCLUSION

NICM patients with ComVA have higher native T1 compared to NICM without any documented ComVA. Native myocardial T1 is independently associated with ComVA, after adjusting for LV function and LGE.

LEVEL OF EVIDENCE

2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;47:779-786. In memoriam: The authors are grateful for Dr. Josephson's inspiring guidance and contributions to this study.

GDF-15 is a better complimentary marker for risk stratification of arrhythmic death in non-ischaemic, dilated cardiomyopathy than soluble ST2

Growth differentiation factor (GDF)-15 and soluble ST2 (sST2) are established prognostic markers in acute and chronic heart failure. Assessment of these biomarkers might improve arrhythmic risk stratification of patients with non-ischaemic, dilated cardiomyopathy (DCM) based on left ventricular ejection fraction (LVEF). We studied the prognostic value of GDF-15 and sST2 for prediction of arrhythmic death (AD) and all-cause mortality in patients with DCM. We prospectively enrolled 52 patients with DCM and LVEF ≤ 50%. Primary end-points were time to AD or resuscitated cardiac arrest (RCA), and secondary end-point was all-cause mortality. The median follow-up time was 7 years. A cardiac death was observed in 20 patients, where 10 patients had an AD and 2 patients had a RCA. One patient died a non-cardiac death. GDF-15, but not sST2, was associated with increased risk of the AD/RCA with a hazard ratio (HR) of 2.1 (95% CI = 1.1-4.3; P = .031). GDF-15 remained an independent predictor of AD/RCA after adjustment for LVEF with adjusted HR of 2.2 (95% CI = 1.1-4.5; P = .028). Both GDF-15 and sST2 were independent predictors of all-cause mortality (adjusted HR = 2.4; 95% CI = 1.4-4.2; P = .003 vs HR = 1.6; 95% CI = 1.05-2.7; P = .030). In a model including GDF-15, sST2, LVEF and NYHA functional class, only GDF-15 was significantly associated with the secondary end-point (adjusted HR = 2.2; 95% CI = 1.05-5.2; P = .038). GDF-15 is superior to sST2 in prediction of fatal arrhythmic events and all-cause mortality in DCM. Assessment of GDF-15 could provide additional information on top of LVEF and help identifying patients at risk of arrhythmic death.

Magnetic Resonance Imaging Correlates of Left Bundle Branch Disease in Patients With Nonischemic Cardiomyopathy

The pathologic correlates of intraventricular conduction delays in patients with nonischemic cardiomyopathy (NIC) have been scarcely investigated. We assessed left ventricular (LV) structural, functional, and tissue abnormalities associated with intraventricular conduction left bundle disease (LBD), including left anterior hemiblock or complete left bundle branch block, in a cohort of patients with NIC submitted to cardiovascular magnetic resonance. Twelve-lead electrocardiogram and cardiovascular magnetic resonance were performed in 196 consecutive patients with NIC. The presence and extent of myocardial fibrosis was evaluated with late gadolinium enhancement (LGE) technique. Compared with normal intraventricular conduction patients, those with LBD were older (66 vs 59 years, p = 0.001), had greater LV volumes (p = 0.035 for end-diastolic and p = 0.009 for end-systolic volume) and mass (p = 0.034), and showed lower LV ejection fraction (33% vs 40%, p = 0.008). LGE was observed more commonly in LBD than in normal intraventricular conduction patients and was more often located in the ventricular septum (p < 0.001). On multivariate analysis, septal LGE was independently associated with a higher likelihood of LBD (odds ratio 6.1, 95% confidence interval 2.9 to 12.7, p < 0.001), even after correction for LV volumes, mass, and ejection fraction. In conclusion, in NIC, the presence of LBD is associated with worse LV remodeling and dysfunction than normal intraventricular conduction. Septal fibrosis yielded a 6-fold greater likelihood of LBD, independently of the degree of LV dilatation and systolic dysfunction.

Cardiac Rehabilitation Improves Cardiometabolic Health in Young Patients with Nonischemic Dilated Cardiomyopathy

Nonischemic dilated cardiomyopathy is deadly and costly, and treatment options are limited. Cardiac rehabilitation has proved safe and beneficial for adults with various types of heart failure. Therefore, we retrospectively evaluated the hypothesis that rehabilitation is safe and improves cardiometabolic health in young patients with nonischemic dilated cardiomypathy. From 2011 through 2015, 8 patients (4 males) (mean age, 20.6 ± 6.6 yr; range, 10-31 yr) underwent rehabilitation at our institution. They were in American Heart Association class C or D heart failure and were on maximal medical therapy. Their mean left ventricular ejection fraction at baseline was 0.26 ± 0.15. Two patients had a left ventricular assist device, and 2 were inpatients. To evaluate safety, we documented adverse events during rehabilitation sessions. Clinical endpoints were measured at baseline, immediately after completing rehabilitation, and after one year. Patients attended 120 of 141 possible sessions (85%), with no adverse events. There were no marked changes in mean left ventricular ejection fraction or body mass index. The patients' mean waist circumference decreased by 1.37 ± 0.6 in (n=5; 95% CI, -2.1 to -0.63). Their 6-minute walk distance increased by a mean of 111 ± 75 m (n=5; 95% CI, 18-205). In our small sample of young patients with nonischemic dilated cardiomyopathy, cardiac rehabilitation was feasible and was associated with minimal risk. Our findings suggest that prospective studies in this population are warranted.

Long-term prognostic value of combined free triiodothyronine and late gadolinium enhancement in nonischemic dilated cardiomyopathy

BACKGROUND

Thyroid dysfunction and myocardial fibrosis are both associated with cardiovascular events in patients with dilated cardiomyopathy (DCM).

HYPOTHESIS

The combination of thyroid hormone (TH) and myocardial fibrosis (detected by late gadolinium enhancement [LGE]) is an independent and incremental predictor of adverse events in DCM.

METHODS

We consecutively enrolled 220 idiopathic DCM patients with thyroid function and LGE assessment at Fuwai Hospital (China) from January 2010 to October 2011 and followed up through December 2015. Patients were divided into 4 groups according to the presence or absence of LGE and FT3 value (median level of 2.79 pg/mL): LGE-positive + FT3 < 2.79 pg/mL, LGE-positive + FT3 ≥ 2.79 pg/mL, LGE-negative + FT3 < 2.79 pg/mL, and LGE-negative + FT3 ≥ 2.79 pg/mL.

RESULTS

During a median follow-up of 61 months, 56 patients (25.5%) died, with 27/56 (48.2%), 8/45 (17.8%), 12/54 (22.2%), and 9/65 (13.8%) among 4 groups (P = 0.009), respectively. Multivariable Cox regression analysis identified LGE-positive and FT3 < 2.79 pg/mL as a significant independent predictor of all-cause mortality (hazard ratio: 2.893, 95% confidence interval: 1.323-6.326, P = 0.008). Combining the predictive value of FT3 and LGE status significantly improved risk reclassification for all-cause mortality, as indicated by the net reclassification improvement (0.28; P = 0.005) and integrated discrimination improvement (0.058; P = 0.001).

CONCLUSIONS

The findings suggest that the combination of FT3 and LGE yielded a more accurate predictive value for long-term prognosis in patients with DCM, which may improve patient selection for intensive interventions.

Fatty Images of the Heart: Spectrum of Normal and Pathological Findings by Computed Tomography and Cardiac Magnetic Resonance Imaging

Ectopic cardiac fatty images are not rarely detected incidentally by computed tomography and cardiac magnetic resonance, or by exams focused on the heart as in general thoracic imaging evaluations. A correct interpretation of these findings is essential in order to recognize their normal or pathological meaning, focusing on the eventually associated clinical implications. The development of techniques such as computed tomography and cardiac magnetic resonance allowed a detailed detection and evaluation of adipose tissue within the heart. This pictorial review illustrates the most common characteristics of cardiac fatty images by computed tomography and cardiac magnetic resonance, in a spectrum of normal and pathological conditions ranging from physiological adipose images to diseases presenting with cardiac fatty foci. Physiologic intramyocardial adipose tissue may normally be present in healthy adults, being not related to cardiac affections and without any clinical consequence. However cardiac fatty images may also be the expression of various diseases, comprehending arrhythmogenic right ventricular dysplasia, postmyocardial infarction lipomatous metaplasia, dilated cardiomyopathy, and lipomatous hypertrophy of the interatrial septum. Fatty neoplasms of the heart as lipoma and liposarcoma are also described.

Putative functional genes in idiopathic dilated cardiomyopathy

Idiopathic dilated cardiomyopathy (DCM) is a complex disorder with a genetic and an environmental component involving multiple genes, many of which are yet to be discovered. We integrate genetic, epigenetic, transcriptomic, phenotypic, and evolutionary features into a method - Hridaya, to infer putative functional genes underlying DCM in a genome-wide fashion, using 213 human heart genomes and transcriptomes. Many genes identified by Hridaya are experimentally shown to cause cardiac complications. We validate the top predicted genes, via five different genome-wide analyses: First, the predicted genes are associated with cardiovascular functions. Second, their knockdowns in mice induce cardiac abnormalities. Third, their inhibition by drugs cause cardiac side effects in human. Fourth, they tend to have differential exon usage between DCM and normal samples. Fifth, analyzing 213 individual genotypes, we show that regulatory polymorphisms of the predicted genes are associated with elevated risk of cardiomyopathy. The stratification of DCM patients based on cardiac expression of the functional genes reveals two subgroups differing in key cardiac phenotypes. Integrating predicted functional genes with cardiomyocyte drug treatment experiments reveals novel potential drug targets. We provide a list of investigational drugs that target the newly identified functional genes that may lead to cardiac side effects.

Chronic Chagas cardiomyopathy: a therapeutic challenge and future strategies

Infectious diseases are the main cause of acquired dilated cardiomyopathy. This group of disorders shares in common inflammatory cell infiltrate and myocardial remodeling. As part of its pathophysiology, there is coronary microvascular dysfunction, distinct from that observed in coronary artery disease. Chagas cardiomyopathy presents several vascular characteristics that are similar to those presented in other acquired cardiomyopathies. There is convincing evidence of the microvascular involvement and the inflammatory processes that lead to endothelial activation and ischemic damage. Current therapy for the Chagas disease is limited, and it is proposed to combine it with other pharmacological strategies that modify critical physiopathological aspects beneficial for the clinical course of the Chagas cardiomyopathy.

Heart failure in dilated cardiomyopathy mimicking asthma triggered by pneumonia

Heart failure is a rare cause of wheezing and may develop into a critical condition in children. Few cases report patients with heart failure, secondary to dilated cardiomyopathy, with high fever. A 23-month-old girl visited the emergency department with high fever, cough, first wheezing episode, chest retraction and tachycardia. The chest X-ray revealed consolidation on the left lower lung field; the cardiothoracic ratio was 60%. She was diagnosed with bronchial asthma triggered by pneumonia, which remained unchanged during four visits. Subsequently, she was diagnosed with heart failure in idiopathic dilated cardiomyopathy and discharged without sequelae. During the first wheezing episode in children with abnormal vital signs, heart failure should be considered in the differential diagnosis, and a chest X-ray should be performed. Additionally, when the cardiothoracic ratio is greater than 50%, 12-lead ECG and echocardiography should be performed. Moreover, cognitive bias should be considered in all emergency care unit situations.

Intercalated disc in failing hearts from patients with dilated cardiomyopathy: Its role in the depressed left ventricular function

Alterations in myocardial structure and reduced cardiomyocyte adhesions have been previously described in dilated cardiomyopathy (DCM). We studied the transcriptome of cell adhesion molecules in these patients and their relationships with left ventricular (LV) function decay. We also visualized the intercalated disc (ID) structure and organization. The transcriptomic profile of 23 explanted LV samples was analyzed using RNA-sequencing (13 DCM, 10 control [CNT]), focusing on cell adhesion genes. Electron microscopy analysis to visualize ID structural differences and immunohistochemistry experiments of ID proteins was also performed. RT-qPCR and western blot experiments were carried out on ID components. We found 29 differentially expressed genes, most of all, constituents of the ID structure. We found that the expression of GJA3, DSP and CTNNA3 was directly associated with LV ejection fraction (r = 0.741, P = 0.004; r = 0.674, P = 0.011 and r = 0.565, P = 0.044, respectively), LV systolic (P = 0.003, P = 0.003, P = 0.028, respectively) and diastolic dimensions (P = 0.006, P = 0.001, P = 0.025, respectively). Electron microscopy micrographs showed a reduced ID convolution index and immunogold labeling of connexin 46 (GJA gene), desmoplakin (DSP gene) and catenin α-3 (CTNNA3 gene) proteins in DCM patients. Moreover, we observed that protein and mRNA levels analyzed by RT-qPCR of these ID components were diminished in DCM group. In conclusion, we report significant gene and protein expression changes and found that the ID components GJA3, DSP and CTNNA3 were highly related to LV function. Microscopic observations indicated that ID is structurally compromised in these patients. These findings give new data for understanding the ventricular depression that characterizes DCM, opening new therapeutic perspectives for these critically diseased patients.

Urinary Proteomics in Predicting Heart Transplantation Outcomes (uPROPHET)-Rationale and database description

OBJECTIVES

Urinary Proteomics in Predicting Heart Transplantation Outcomes (uPROPHET; NCT03152422) aims: (i) to construct new multidimensional urinary proteomic (UP) classifiers that after heart transplantation (HTx) help in detecting graft vasculopathy, monitoring immune system activity and graft performance, and in adjusting immunosuppression; (ii) to sequence UP peptide fragments and to identify key proteins mediating HTx-related complications; (iii) to validate UP classifiers by demonstrating analogy between UP profiles and tissue proteomic signatures (TP) in diseased explanted hearts, to be compared with normal donor hearts; (iv) and to identify new drug targets. This article describes the uPROPHET database construction, follow-up strategies and baseline characteristics of the HTx patients.

METHODS

HTx patients enrolled at the University Hospital Gasthuisberg (Leuven) collected mid-morning urine samples. Cardiac biopsies were obtained at HTx. UP and TP methods and the statistical work flow in pursuit of the research objectives are described in detail in the Data supplement.

RESULTS

Of 352 participants in the UP study (24.4% women), 38.9%, 40.3%, 5.7% and 15.1% had ischemic, dilated, hypertrophic or other cardiomyopathy. The median interval between HTx and first UP assessment (baseline) was 7.8 years. At baseline, mean values were 56.5 years for age, 25.2 kg/m2 for body mass index, 142.3/84.8 mm Hg and 124.2/79.8 mm Hg for office and 24-h ambulatory systolic/diastolic pressure, and 58.6 mL/min/1.73 m2 for the estimated glomerular filtration rate. Of all patients, 37.2% and 6.5% had a history of mild (grade = 1B) or severe (grade ≥ 2) cellular rejection. Anti-body mediated rejection had occurred in 6.2% patients. The number of follow-up urine samples available for future analyses totals over 950. The TP study currently includes biopsies from 7 healthy donors and 15, 14, and 3 patients with ischemic, dilated, and hypertrophic cardiomyopathy.

CONCLUSIONS

uPROPHET constitutes a solid resources for UP and TP research in the field of HTx and has the ambition to lay the foundation for the clinical application of UP in risk stratification in HTx patients.

Genetic Mutations and Multifactorial Inheritance: Dilated Cardiomyopathy

The following fictional case is intended as a learning tool within the Pathology Competencies for Medical Education (PCME), a set of national standards for teaching pathology. These are divided into three basic competencies: Disease Mechanisms and Processes, Organ System Pathology, and Diagnostic Medicine and Therapeutic Pathology. For additional information, and a full list of learning objectives for all three competencies, see http://journals.sagepub.com/doi/10.1177/2374289517715040.

Sudden cardiac death: focus on the genetics of channelopathies and cardiomyopathies

Sudden cardiac death (SCD) describes a natural and unexpected death from cardiac causes occurring within a short period of time (generally within 1 h of symptom onset) in the absence of any other potentially lethal condition. Most SCD-related diseases have a genetic basis; in particular congenital cardiac channelopathies and cardiomyopathies have been described as leading causes of SCD. Congenital cardiac channelopathies are primary electric disorders caused by mutations affecting genes encoding cardiac ion channels or associated proteins, whereas cardiomyopathies are related to mutations in genes encoding several categories of proteins, including those of sarcomeres, desmosomes, the cytoskeleton, and the nuclear envelope. The purpose of this review is to provide a general overview of the main genetic variants that have been linked to the major congenital cardiac channelopathies and cardiomyopathies. Functional alterations of the related proteins are also described.

Prevalence and Spectrum of NKX2-5 Mutations Associated With Sporadic Adult-Onset Dilated Cardiomyopathy

Dilated cardiomyopathy (DCM), the most common form of primary myocardial disease, is a leading cause of congestive heart failure and the most common indication for heart transplantation. Recently, NKX2-5 mutations have been involved in the pathogenesis of familial DCM. However, the prevalence and spectrum of NKX2-5 mutations associated with sporadic DCM remain to be evaluated. In this study, the coding regions and flanking introns of the NKX2-5 gene, which encodes a cardiac transcription factor pivotal for cardiac development and structural remodeling, were sequenced in 210 unrelated patients with sporadic adult-onset DCM. A total of 300 unrelated healthy individuals used as controls were also genotyped for NKX2-5. The functional effect of the mutant NKX2-5 was investigated using a dual-luciferase reporter assay system. As a result, two novel heterozygous NKX2-5 mutations, p.R139W and p.E167X, were identified in 2 unrelated patients with sporadic adult-onset DCM, with a mutational prevalence of approximately 0.95%. The mutations were absent in 600 referential chromosomes and the altered amino acids were completely conserved evolutionarily across species. Functional assays revealed that the NKX2-5 mutants were associated with significantly reduced transcriptional activity. Furthermore, the mutations abrogated the synergistic activation between NKX2-5 and GATA4 as well as TBX20, two other cardiac key transcription factors that have been causally linked to adult-onset DCM. This study is the first to associate NKX2-5 loss-of-function mutations with enhanced susceptibility to sporadic DCM, which provides novel insight into the molecular etiology underpinning DCM, and suggests the potential implications for the genetic counseling and personalized treatment of the DCM patients.

Role of implantable cardioverter defibrillator in non-ischemic cardiomyopathy: a systematic review and meta-analysis of prospective randomized clinical trials

INTRODUCTION

A mortality benefit in patients with implantable cardioverter defibrillator (ICD) in ischemic cardiomyopathy is well established. However, the benefit of ICD implantation in non-ischemic cardiomyopathy (NICM) on total mortality remains uncertain. We performed a systematic review and meta-analysis of randomized controlled trials (RCT) evaluating the role of primary prevention ICD in NICM patients.

METHODS

We performed a systematic review on PubMed, The Cochrane Library, EMBASE, EBSCO, Web of Science, and CINAHL databases from the inception through February 2017 to identify RCT evaluating the role of ICD in NICM patients. Mantel-Haenszel risk ratio (RR) fixed effects model was used to summarize data across treatment arms. If heterogeneity (I ²) ≥25, random effects model was used instead.

RESULTS

We analyzed a total of 2573 patients from five RCTs comparing ICD with medical therapy in patients with NICM. The mean follow up for the trials was 48 ± 22 months. There was a significant reduction in (a) all-cause mortality (RR 0.84, 95% CI 0.71-0.99, p = 0.03) and (b) sudden cardiac death (RR 0.47, 95% CI 0.30-0.73, p < 0.001) in ICD group versus medical therapy.

CONCLUSION

Our analysis demonstrates that the use of ICD for primary prevention is associated with a reduction in all-cause mortality and SCD in patients with NICM.

Troponins, intrinsic disorder, and cardiomyopathy

Cardiac troponin is a dynamic complex of troponin C, troponin I, and troponin T (TnC, TnI, and TnT, respectively) found in the myocyte thin filament where it plays an essential role in cardiac muscle contraction. Mutations in troponin subunits are found in inherited cardiomyopathies, such as hypertrophic cardiomyopathy (HCM) and dilated cardiomyopathy (DCM). The highly dynamic nature of human cardiac troponin and presence of numerous flexible linkers in its subunits suggest that understanding of structural and functional properties of this important complex can benefit from the consideration of the protein intrinsic disorder phenomenon. We show here that mutations causing decrease in the disorder score in TnI and TnT are significantly more abundant in HCM and DCM than mutations leading to the increase in the disorder score. Identification and annotation of intrinsically disordered regions in each of the troponin subunits conducted in this study can help in better understanding of the roles of intrinsic disorder in regulation of interactomes and posttranslational modifications of these proteins. These observations suggest that disease-causing mutations leading to a decrease in the local flexibility of troponins can trigger a whole plethora of functional changes in the heart.

Evaluation of left ventricular strain in patients with dilated cardiomyopathy

Objective Dilated cardiomyopathy (DCM) can cause structural and functional changes in the left ventricle (LV). In this study, we evaluated whether cardiac magnetic resonance tissue-tracking (MR-TT) can be applied to the detection of LV abnormalities in patients with DCM. Methods We used MR-TT to analyze the global peak radial strain (GPRS), global peak circumferential strain (GPCS), and global peak longitudinal strain (GPLS) in every segment of the LV in 23 patients with DCM and 25 controls. The LV ejection fraction was also measured as a function indicator. Results Compared with the controls, the GPRS, GPCS, and GPLS were significantly reduced in patients with DCM, indicating global LV function impairment in all directions. We also identified a significant linear correlation between the GPRS, GPCS, and GPLS and the LV ejection fraction, indicating that LV function relies on coordinated wall motion from all directions. Moreover, we found that patients with DCM had a significantly reduced magnitude of the PRS, PCS, and PLS in most segments at different levels, indicating impaired myocardial function in most LV regions. Conclusions Our results demonstrate that LV myocardial strain in patients with DCM can be sensitively detected by MR-TT (not only the global LV function changes but also the segmental strain), which can help to identify the injured segment at an early stage and guide clinical treatment.

Extracellular vesicles do not contribute to higher circulating levels of soluble LRP1 in idiopathic dilated cardiomyopathy

Idiopathic dilated cardiomyopathy (IDCM) is a frequent cause of heart transplantation. Potentially valuable blood markers are being sought, and low‐density lipoprotein receptor‐related protein 1 (LRP1) has been linked to the underlying molecular basis of the disease. This study compared circulating levels of soluble LRP1 (sLRP1) in IDCM patients and healthy controls and elucidated whether sLRP1 is exported out of the myocardium through extracellular vesicles (EVs) to gain a better understanding of the pathogenesis of the disease. LRP1 α chain expression was analysed in samples collected from the left ventricles of explanted hearts using immunohistochemistry. sLRP1 concentrations were determined in platelet‐free plasma by enzyme‐linked immunosorbent assay. Plasma‐derived EVs were extracted by size‐exclusion chromatography (SEC) and characterized by nanoparticle tracking analysis and cryo‐transmission electron microscopy. The distributions of vesicular (CD9, CD81) and myocardial (caveolin‐3) proteins and LRP1 α chain were assessed in SEC fractions by flow cytometry. LRP1 α chain was preferably localized to blood vessels in IDCM compared to control myocardium. Circulating sLRP1 was increased in IDCM patients. CD9‐ and CD81‐positive fractions enriched with membrane vesicles with the expected size and morphology were isolated from both groups. The LRP1 α chain was not present in these SEC fractions, which were also positive for caveolin‐3. The increase in circulating sLRP1 in IDCM patients may be clinically valuable. Although EVs do not contribute to higher sLRP1 levels in IDCM, a comprehensive analysis of EV content would provide further insights into the search for novel blood markers.

Associations between Interleukin-31 Gene Polymorphisms and Dilated Cardiomyopathy in a Chinese Population

To explore the role of Interkeulin-31 (IL-31) in dilated cardiomyopathy (DCM), in our study, two SNPs of IL-31, rs4758680 (C/A) and rs7977932 (C/G), were analyzed in 331 DCM patients and 493 controls in a Chinese Han population. The frequencies of C allele and CC genotype of rs4758680 were significantly increased in DCM patients (P = 0.005, P = 0.001, resp.). Compared to CC genotype of rs4758680, the A carriers (CA/AA genotypes) were the protect factors in DCM susceptibility while the frequencies of CA/AA genotypes were decreased in the dominant model for DCM group (P < 0.001, OR = 0.56, 95%CI = 0.39–0.79). Moreover, IL-31 mRNA expression level of white blood cells was increased in DCM patients (0.072 (0.044–0.144) versus 0.036 (0.020–0.052), P < 0.001). In survival analysis of 159 DCM patients, Kaplan-Meier curve revealed the correlation between CC homozygote of rs4758680 and worse prognosis for DCM group (P = 0.005). Compared to CC genotype, the CA/AA genotypes were the independent factors in both univariate (HR = 0.530, 95%CI = 0.337–0.834, P = 0.006) and multivariate analyses after age, gender, left ventricular end-diastolic diameter, and left ventricular ejection fraction adjusted (HR = 0.548, 95%CI = 0.345–0.869, P = 0.011). Thus, we concluded that IL-31 gene polymorphisms were tightly associated with DCM susceptibility and contributed to worse prognosis in DCM patients.

Cardiac vagal control in a knock-in mouse model of dilated cardiomyopathy with a troponin mutation

The aim of this study was to evaluate cardiac vagal nerve activity and identify the abnormality of cardiac vagal control in heart failure caused by dilated cardiomyopathy (DCM) using a knock-in mouse model with a ΔK210 mutation in the cardiac troponin T gene. The effects of electrical stimulation of the cervical vagal nerve at 5 and 10Hz (peripheral vagal control) and α₂-adrennoceptor stimulation by intravenous medetomidine at 0.1mg/kg (central vagal control) were examined in wild-type (WT) mice and DCM mice. Microdialysis technique was applied to the left ventricular myocardium of anesthetized mice and myocardial interstitial acetylcholine (ACh) levels were measured by HPLC as an index of ACh release from cardiac vagal nerve endings. Electrical vagal nerve stimulation increased cardiac interval and myocardial interstitial ACh level in both WT and DCM mice, and these responses did not differ between WT and DCM mice. In contrast, intravenous medetomidine increased cardiac interval and myocardial interstitial ACh level in both WT and DCM mice, but the responses of cardiac interval and myocardial interstitial ACh level were significantly suppressed in DCM mice compared to WT mice. Medetomidine did not affect the myocardial interstitial ACh response induced by vagal nerve stimulation in WT mice. In this mouse model of DCM, peripheral vagal control including ACh release from vagal nerve endings and the postsynaptic response of pacemaker cells was preserved, but central vagal control through α₂-adrenoceptors was impaired.

Clinical significance of cathepsin L and cathepsin B in dilated cardiomyopathy

Dysregulated expression of lysosomal cysteine cathepsins is associated with adverse cardiac remodeling, a characteristic of several cardiovascular diseases. However, the information regarding the role of cysteine cathepsin L (CTSL) and cathepsin B (CTSB) in dilated cardiomyopathy (DCM) is limited. The present study was aimed to investigate the expression of CTSL and CTSB in animal model of doxorubicin (doxo)-induced cardiomyopathy as well as in peripheral blood samples of DCM patients. Cardiac tissue sections from doxo-treated and control rats were used to study the expression of CTSL and CTSB by enzyme assay and immunohistochemistry (IHC). Peripheral blood mononuclear cells (PBMCs) isolated from DCM patients (n = 29) along with age-matched healthy controls (n = 28) were used to assay enzymatic activity of these cathepsins. Activities of these proteases were further correlated with echocardiographic parameters of DCM patients. A significant increase in CTSL activity and protein expression was observed with no changes in CTSB levels in doxo-treated rats as compared to controls. We also observed a drastic increase in the functional activity of cathepsin L+cathepsin B (CTSL+B), CTSL, and CTSB in DCM patients compared to controls (p ≤ 0.001). Increased levels of these proteases exhibited a statistically significant correlation with reduced left ventricular ejection fraction (LVEF) in DCM patients (ρ = -0.58, p = 0.01). For the first time, this study demonstrates a correlation between increased expression of CTSL and CTSB in PBMCs with severity of left ventricular dysfunction in DCM patients. Thus, these proteases may serve as blood-based biomarker of DCM and prove useful in its management.

Comparison between brain natriuretic peptide and calcitonin gene-related peptide in children with dilated cardiomyopathy and controls

Background

Dilated cardiomyopathy (DCM) is revealed with the left ventricular dilatation and systolic dysfunction.

Objective

This study was performed to determine the level of calcitonin gene-related peptide (CGRP) and brain natriuretic peptide (BNP) in children with DCM and controls and comparison of these two biomarkers in patients.

Materials and Methods

This study was performed from April 2014 to March 2015 on patients with DCM. The levels of BNP and CGRP were measured by ELISA, and final amounts of biomarkers were compared with the echocardiographic finding.

Results

In this study, the mean age was 10.567 ± 5.50 and 12.135 ± 4.626 years for controls and cases, respectively (P = 0.321). The majority of echocardiographic indices in the left and right heart had different means in cases and controls (P < 0.05). Means of BNP were 213.814 ± 309.601 and 2.76 ± 1.013 for case and control, respectively (P < 0.001). Means of CGRP were 2.278 ± 1.586 and 1.488 ± 0.501 for cases and controls, respectively, (P = 0.001). In the patients group, however, no significant relationship was observed between CGRP level and Ross classification but observed a direct relationship of Ross classification with BNP (χ² = 15.845, P < 0.05).

Conclusions

The present research was performed on DCM patients and showed that most echocardiographic parameters, mean of CGRP and mean of BNP increased in patients compared to healthy children. The severity of illness based on the Ross classification showed significant and positive correlation with BNP level but not with CGRP. Probably, it could be concluded that BNP would be a better biomarker in DCM patients.

Novel Genetic Variants in BAG3 and TNNT2 in a Swedish Family with a History of Dilated Cardiomyopathy and Sudden Cardiac Death

Familial dilated cardiomyopathy is a rare cause of dilated cardiomyopathy (DCM), especially in childhood. Our aim was to describe the clinical course and the genetic variants in a family where the proband was a four-month-old infant presenting with respiratory problems due to DCM. In the family, there was a strong family history of DCM and sudden cardiac death in four generations. DNA was analyzed initially from the deceased girl using next-generation sequencing including 50 genes involved in cardiomyopathy. A cascade family screening was performed in the family after identification of the TNNT2 and the BAG3 variants in the proband. The first-degree relatives underwent clinical examination including biochemistry panel, cardiac ultrasound, Holter ECG, exercise stress test, and targeted genetic testing. The index patient presented with advanced DCM. After a severe clinical course, the baby had external left ventricular assist as a bridge to heart transplantation. 1.5 months after transplantation, the baby suffered sudden cardiac death (SCD) despite maximal treatment in the pediatric intensive care unit. The patient was shown to carry two heterozygous genetic variants in the TNNT2 gene [TNNT2 c.518G>A(p.Arg173Gln)] and BAG3 [BAG3 c.785C>T(p.Ala262Val)]. Two of the screened individuals (two females) appeared to carry both the familial variants. All the individuals carrying the TNNT2 variant presented with DCM, the two adult patients had mild or moderate symptoms of heart failure and reported palpitations but no syncope or presyncopal attacks prior to the genetic diagnosis. The female carriers of TNNT2 and BAG3 variants had more advanced DCM. In the family history, there were three additional cases of SCD due to DCM, diagnosed by autopsy, but no genetic analysis was possible in these cases. Our findings suggest that the variants in TNNT2 and BAG3 are associated with a high propensity to life-threatening cardiomyopathy presenting from childhood and young adulthood.

Murine Electrophysiological Models of Cardiac Arrhythmogenesis

Cardiac arrhythmias can follow disruption of the normal cellular electrophysiological processes underlying excitable activity and their tissue propagation as coherent wavefronts from the primary sinoatrial node pacemaker, through the atria, conducting structures and ventricular myocardium. These physiological events are driven by interacting, voltage-dependent, processes of activation, inactivation, and recovery in the ion channels present in cardiomyocyte membranes. Generation and conduction of these events are further modulated by intracellular Ca2+ homeostasis, and metabolic and structural change. This review describes experimental studies on murine models for known clinical arrhythmic conditions in which these mechanisms were modified by genetic, physiological, or pharmacological manipulation. These exemplars yielded molecular, physiological, and structural phenotypes often directly translatable to their corresponding clinical conditions, which could be investigated at the molecular, cellular, tissue, organ, and whole animal levels. Arrhythmogenesis could be explored during normal pacing activity, regular stimulation, following imposed extra-stimuli, or during progressively incremented steady pacing frequencies. Arrhythmic substrate was identified with temporal and spatial functional heterogeneities predisposing to reentrant excitation phenomena. These could arise from abnormalities in cardiac pacing function, tissue electrical connectivity, and cellular excitation and recovery. Triggering events during or following recovery from action potential excitation could thereby lead to sustained arrhythmia. These surface membrane processes were modified by alterations in cellular Ca2+ homeostasis and energetics, as well as cellular and tissue structural change. Study of murine systems thus offers major insights into both our understanding of normal cardiac activity and its propagation, and their relationship to mechanisms generating clinical arrhythmias.

Association of LIM Domain 7 Gene Polymorphisms and Plasma Levels of LIM Domain 7 with Dilated Cardiomyopathy in a Chinese Population

The aim of our study was to investigate the potential association of mRNA expression and plasma levels of the LIM domain 7 (LMO7) gene with the pathogenesis of dilated cardiomyopathy (DCM). Two SNPs of the LMO7 gene were genotyped in 310 patients with DCM and 415 controls. Our results showed that SNP rs7986131 (p = 0.002, OR = 1.38, 95% CI = 1.12-1.71), but not SNP rs4884021, was associated with DCM in the Han Chinese population. Haplotype analysis showed that the haplotype GT was associated with increased DCM susceptibility while AC was a protective haplotype. The Cox multivariate survival analysis indicated that the rs7986131 TT genotype (HR 1.659, 95% CI = 1.122-2.454, p = 0.011) was an independent multivariate predictor for shorter overall survival in patients with DCM. LMO7 mRNA expression and plasma LMO7 levels were significantly decreased in DCM (p < 0.0001). Spearman correlation test revealed that the plasma LMO7 level was negatively associated with left ventricular end-diastolic diameter (r = -0.384, p = 0.01), left ventricular end-diastolic volume (r = -0.375, p = 0.012), and brain natriuretic peptide (r = -0.482, p = 0.001). Our study suggested that the LMO7 gene may play an important role in the pathogenesis of DCM in the Han Chinese population.

Temporal change of myocardial tissue character is associated with left ventricular reverse remodeling in patients with dilated cardiomyopathy: A cardiovascular magnetic resonance study

BACKGROUND

Prognostic significance of temporal change in myocardial tissue characterization by cardiovascular magnetic resonance (CMR) has not been elucidated in patients with non-ischemic dilated cardiomyopathy (DCM).

METHODS AND RESULTS

Sixty-eight patients with newly-diagnosed DCM who underwent CMR including late gadolinium enhancement (LGE) both at baseline and during follow-up period were enrolled. LGE score was defined by a signal intensity of ≥5 standard deviations above the remote reference myocardium mean. Left ventricular reverse remodeling (LVRR) defined as a LV ejection fraction increase of ≥10% and a decrease in indexed LV end-diastolic diameter of ≥10% compared to those at baseline was detected in 38% of the patients. There was no significant difference in LGE score between baseline and follow-up (5.8% vs. 7.3%; p=0.38). The change in LGE area (delta-LGE) was significantly lower in patients with LVRR than those without (-0.5%±3.4% vs. 3.0±7.4%; p=0.02). On the other hand, T2 ratio during the follow-up significantly reduced (1.95±0.48 vs. 1.67±0.56; p<0.01); however, there was no significant difference in the change in T2 ratio between patients with LVRR and those without (-0.29±0.73 vs. -0.27±0.66; p=0.88). Multivariate logistic analysis indicated that baseline LGE score [odds ratio; 0.78; 95% confidence interval (CI) 0.66 to 0.90; p<0.01] together with delta-LGE (odds ratio; 0.77; 95% CI 0.61 to 0.92; p=0.01) were independently associated with subsequent LVRR (p<0.01).

CONCLUSIONS

The temporal change of LGE-CMR score during the clinical course was significantly correlated with following LVRR.

Identification of the molecular mechanisms underlying dilated cardiomyopathy via bioinformatic analysis of gene expression profiles

In the present study, gene expression profiles of patients with dilated cardiomyopathy (DCM) were re-analyzed with bioinformatics tools to investigate the molecular mechanisms underlying DCM. Gene expression dataset GSE3585 was downloaded from Gene Expression Omnibus, which included seven heart biopsy samples obtained from patients with DCM and five healthy controls. Differential analysis was performed using a Limma package in R to screen for differentially expressed genes (DEGs). Functional enrichment analysis was subsequently conducted for DEGs using the Database for Annotation, Visualization and Integration Discovery. A protein-protein interaction (PPI) network was constructed using information from Search Tool for the Retrieval of Interacting Genes software. A total of 89 DEGs were identified in the patients with DCM, including 67 upregulated and 22 downregulated genes. Functional enrichment analysis demonstrated that the downregulated genes predominantly encoded chromosomal proteins and transport-related proteins, which were significantly associated with the biological processes of ‘nucleosome assembly’, ‘chromatin assembly’, ‘protein-DNA complex assembly’, ‘nucleosome organization’ and ‘DNA packaging’ (H1 histone family member 0, histone cluster 1 H1c, histone cluster 1 H2bd and H2A histone family member Z). The upregulated genes detected in the present study encoded secreted proteins or phosphotransferase, which were associated with biological processes including ‘cell adhesion’ [connective tissue growth factor (CTGF)], ‘skeletal system development’ [CTGF and insulin-like growth factor binding protein 3 (IGFBP3)], ‘muscle organ development’ (SMAD7) and ‘regulation of cell migration’ [SMAD7, IGFBP3 and insulin receptor (INSR)]. Notably, signal transducer and activator of transcription 3, SMAD7, INSR, CTGF, exportin 1, IGFBP3 and phosphatidylinositol-4,5-bisphosphate 3-kinase, catalytic subunit alpha were hub nodes with the higher degree in the PPI network. Therefore, the results of the present study suggested that DEGs may alter the biological processes of ‘nucleosome formation’, ‘cell adhesion’, ‘skeletal system development’, ‘muscle organ development’ and ‘regulation of cell migration’ in the development of DCM.

Expression of Bcl-2 and microRNAs in cardiac tissues of patients with dilated cardiomyopathy

Dilated cardiomyopathy (DCM) is associated with sudden cardiac death and heart failure, resulting in a significant medical burden. The mechanisms underlying the pathogenesis of DCM remain elusive. In the present study, human cardiac tissues from patients with DCM and healthy donors were collected and their pathology was examined. The expression levels of apoptosis regulator Bcl-2 and fibrosis-associated microRNAs were also evaluated. Extensive myocardial fibrosis and apoptosis in DCM cardiac tissues was observed. As demonstrated by western blotting, reverse transcription-quantitative polymerase chain reaction and immunohistochemistry, the expression of Bcl‑2 was significantly increased in the apex, and the left and right ventricle of the heart in patients with DCM. In the specified locations, it was identified that miR‑21 was upregulated, while members of miR‑29 family (miR‑29a, miR‑29b and miR‑29c) and miR‑133 family (miR-133a and miR-133b) were downregulated. The present study suggested that Bcl‑2 and specific microRNAs may be involved in DCM pathogenesis, with a potential implication as therapeutic targets.

Diagnostic and prognostic roles of echocardiography and cardiac magnetic resonance

Accurate prediction of sudden cardiac death due to ventricular arrhythmia remains challenging. Left ventricular ejection fraction has shown an association with increased risk of ventricular arrhythmias and is included in the recommendations for implantable cardioverter defibrillator as primary prevention. However, left ventricular ejection fraction may be normal in a large number of patients who are at risk of ventricular arrhythmias. Echocardiography remains the imaging technique of first choice to rule out the presence of structural heart disease and assess left and right ventricular function. Advances in strain echocardiography and cardiac magnetic resonance have provided important insights into the mechanisms of ventricular arrhythmias, and will be summarized in this review.

Childhood Cardiomyopathies: A Study in Tertiary Care Hospital in Upper Egypt

Introduction

Cardiomyopathy (CMP) is defined by the World Health Organization (WHO) as a disease of the myocardium associated with cardiac dysfunction. An understanding of CMP is very important, as it is a common cause of heart failure in children, and the most common indication for heart transplantation in children older than one year, but data on CMP in Egypt are scarce. The aim of this study was to determine the number, risk factors, clinical presentation, complications and outcome of different types of childhood cardiomyopathies in Sohag University Hospital.

Methods

This cross-sectional hospital based study enrolled fifty children with Cardiomyopathy in Pediatric Departments, Neonatal Care Units, and Cardiac Outpatient Clinics in Sohag University Hospital from March 01, 2014 to February 28, 2015.

Results

Cases with Dilated Cardiomyopathy (DCMP) were 38 (76%), and those who had Hypertrophic Cardiomyopathy (HCMP) were 12 (24%). Dyspnea was the most common presenting complaint in 71% of cases. In cases with DCMP, the mean EF was 33.8, and FS was 17.11, while in cases with HCMP, the mean EF was 70.75, FS was 37. Fifty percent of cases were found to have moderate to severe PHT. Serum CK-MB was elevated in 3 (6%) cases, while serum Troponin I was elevated in 2 (4.2%) cases who diagnosed as having myocarditis. Viral myocarditis was the most common identified etiological agent responsible for 14 (37%) cases with DCMP.

Conclusions

CMP represents a considerable percentage of children with cardiac disorders. DCMP is the most common type, usually presented with congestive heart failure, and the most common cause is myocarditis. L-Carnitine profile was normal in all cases, despite its routine use. Pediatricians need to raise their clinical suspicion to CMPs, as atypical presentations are not uncommon. To do screening for other family members, cardiac enzymes (CK-MB, Troponin I) have to be done in all newly diagnosed CMP cases, along with a revision of the routine prescription of L-Carnitine.

Anti-calreticulin antibodies and calreticulin in sera of patients diagnosed with dilated or hypertrophic cardiomyopathy

Distinct cellular level of the Ca²⁺-binding chaperone calreticulin (CRT) is essential for correct embryonal cardiac development and postnatal function. However, CRT is also a potential autoantigen eliciting formation of antibodies (Ab), whose role is not yet clarified. Immunization with CRT leads to cardiac injury, while overexpression of CRT in cardiomyocytes induces dilated cardiomyopathy (DCM) in animals. Hence, we analysed levels of anti-CRT Ab and calreticulin in the sera of patients with idiopatic DCM and hypertrophic cardiomyopathy (HCM). ELISA and immunoblot using human recombinant CRT and Pepscan with synthetic, overlapping decapeptides of CRT were used to detect anti-CRT Ab. Serum CRT concentration was tested by ELISA. Significantly increased levels of anti-CRT Ab of isotypes IgA (p < 0.001) and IgG (p < 0.05) were found in patients with both DCM (12/34 seropositive for IgA, 7/34 for IgG) and HCM (13/38 seropositive for IgA, 11/38 for IgG) against healthy controls (2/79 for IgA, 1/79 for IgG). Titration analysis in seropositive DCM and HCM patients documented anti-CRT Ab detected at 1/1600 dilution for IgG and 1/800 for IgA (and IgA1) and at least at 1/200 dilution for IgA2, IgG1, IgG2 and IgG3. Pepscan identified immunogenic CRT epitopes recognized by IgA and IgG Ab of these patients. Significantly increased levels of CRT relative to healthy controls were found in sera of patients with HCM (p < 0.01, 5/19). These data extend the knowledge of seroprevalence of anti-CRT Ab and CRT, and suggest possible involvement of autoimmune mechanisms directed to CRT in some forms of cardiomyopathies, which are clinically heterogeneous.

Higher hemoglobin A1c levels are associated with impaired left ventricular diastolic function and higher incidence of adverse cardiac events in patients with nonischemic dilated cardiomyopathy

We aimed to elucidate the relationship between glycated hemoglobin (HbA1c), cardiac systolic/diastolic function, and heart failure (HF) prognosis during guideline-directed medical therapy in patients with nonischemic dilated cardiomyopathy (NIDCM). We evaluated 283 hospitalized NIDCM patients, who were grouped according to baseline (BL) and 1-year (1Y) levels of HbA1c (<6.0, 6.0-6.9, and ≥7.0 %). The primary endpoint was defined as either readmission for HF worsening or cardiac death. Approximately half of the patients had BL- or 1Y-HbA1c ≥6.0 % (31 % at BL, 34 % at 1Y had 6.0-6.9 %; 12 % at BL, 12 % at 1Y had ≥7.0 %). The absolute value of left ventricular ejection fraction (LVEF) and its improvement during 1 year showed no significant difference among the 1Y-HbA1c groups (p = 0.273), whereas a lower absolute value and a more significant reduction in the early diastolic velocity of the mitral annulus (E _a) were seen in the group with 1Y-HbA1c ≥7.0 % (both p < 0.001). In multiple regression analysis, higher 1Y-plasma B-type natriuretic peptide and lower 1Y-Ea were independently associated with higher 1Y-HbA1c (both adjusted p < 0.05). The cumulative incidence of the primary endpoint was highest in the group with 1Y-HbA1c ≥7.0 % (log-rank p = 0.001). Multivariate analysis demonstrated that higher 1Y-HbA1c was independently associated with a higher incidence of the primary endpoint (adjusted p = 0.005). In conclusion, hyperglycemia during clinical follow-up is a risk factor for progression of concomitant LV abnormal relaxation, leading to poor HF prognosis in patients with NIDCM.

Circulating miR-185 might be a novel biomarker for clinical outcome in patients with dilated cardiomyopathy

B cells contribute to the development of dilated cardiomyopathy (DCM) by inducing myocyte injuries and myocardial fibrosis. Our recent research indicated that microRNA (miR) -185 participated in human B-cell activation. Thus, this study was aimed to explore the relationship between miR-185 and DCM progression. Forty-one healthy volunteers and fifty newly diagnosed DCM patients were enrolled. The levels of plasma miR-185, TNF-α secreting B cells, and anti-heart autoantibody were detected. We found that the mean levels of plasma miR-185 in DCM patients were significantly higher than those in healthy controls. Furthermore, these DCM patients could be divided into miR-185^high and miR-185^low groups according to the cluster distribution. During one-year follow-up period, the miR-185^high group showed apparent improvements in left ventricular ejection fraction, left ventricular end diastolic diameter, and NT-proBNP, accompanied by significant declines in both cardiovascular mortality and total admissions for heart failure re-hospitalizations. In addition, the levels of anti-β1-AR antibody and TNF-α secreting B cells were also reduced in miR-185^high group. These findings suggested that high miR-185 levels might be associated with a favorable prognosis by repressing B cell function in DCM. The findings of this study need to be confirmed with larger sample size and longer duration of observation.

Analyses of more than 60,000 exomes questions the role of numerous genes previously associated with dilated cardiomyopathy

Background

Hundreds of genetic variants have been described as disease causing in dilated cardiomyopathy (DCM). Some of these associations are now being questioned. We aimed to identify the prevalence of previously DCM associated variants in the Exome Aggregation Consortium (ExAC), in order to identify potentially false‐positive DCM variants.

Methods

Variants listed as DCM disease‐causing variants in the Human Gene Mutation Database were extracted from ExAC. Pathogenicity predictions for these variants were mined from dbNSFP v 2.9 database.

Results

Of the 473 DCM variants listed in HGMD, 148 (31%) were found in ExAC. The expected number of individuals with DCM in ExAC is 25 based on the prevalence in the general population. Yet, 35 variants were found in more than 25 individuals. In 13 genes, we identified all variants previously associated with DCM; four genes contained variants above our estimated cut‐off. Prediction tools found ExAC variants to be significantly more tolerated when compared to variants not found in ExAC (P = 0.004).

Conclusion

In ExAC, we identified a higher genotype prevalence of variants considered disease‐causing than expected. More importantly, we found 13 genes in which all variants previously associated with DCM were identified in ExAC, questioning the association of these genes with the monogenic form of DCM.

FLNC Gene Splice Mutations Cause Dilated Cardiomyopathy

A genetic etiology has been identified in 30% to 40% of dilated cardiomyopathy (DCM) patients, yet only 50% of these cases are associated with a known causative gene variant. Thus, in order to understand the pathophysiology of DCM, it is necessary to identify and characterize additional genes. In this study, whole exome sequencing in combination with segregation analysis was used to identify mutations in a novel gene, filamin C (FLNC), resulting in a cardiac-restricted DCM pathology. Here we provide functional data via zebrafish studies and protein analysis to support a model implicating FLNC haploinsufficiency as a mechanism of DCM.

•

Deoxyribonucleic acid obtained from 2 large DCM families was studied using whole-exome sequencing and cosegregation analysis resulting in the identification of a novel disease gene, FLNC. The 2 families, from the same Italian region, harbored the same FLNC splice-site mutation (FLNC c.7251+1G>A).

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A third U.S. family was then identified with a novel FLNC splice-site mutation (FLNC c.5669-1delG) that leads to haploinsufficiency as shown by the FLNC Western blot analysis of the heart muscle.

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The FLNC ortholog flncb morpholino was injected into zebrafish embryos, and when flncb was knocked down caused a cardiac dysfunction phenotype.

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On electron microscopy, the flncb morpholino knockdown zebrafish heart showed defects within the Z-discs and sarcomere disorganization.

Proteomic identification of putative biomarkers for early detection of sudden cardiac death in a family with a LMNA gene mutation causing dilated cardiomyopathy

Dilated cardiomyopathy (DCM) is a severe heart disease characterized by progressive ventricular dilation and impaired systolic function of the left ventricle. We recently identified a novel pathogenic mutation in the LMNA gene in a family affected by DCM showing sudden death background. We now aimed to identify potential biomarkers of disease status, as well as sudden death predictors, in members of this family. We analysed plasma samples from 14 family members carrying the mutation, four of which (with relevant clinical symptoms) were chosen for the proteomic analysis. Plasma samples from these four patients and from four sex- and age-matched healthy controls were processed for their enrichment in low- and medium-abundance proteins (ProteoMiner™) prior to proteomic analysis by 2D-DIGE and MS. 111 spots were found to be differentially regulated between mutation carriers and control groups, 83 of which were successfully identified by MS, corresponding to 41 different ORFs. Some proteins of interest were validated either by turbidimetry or western blot in family members and healthy controls. Actin, alpha-1-antytripsin, clusterin, vitamin-D binding protein and antithrombin-III showed increased levels in plasma from the diseased group. We suggest following these proteins as putative biomarkers for the evaluation of DCM status in LMNA mutation carriers.

BIOLOGICAL SIGNIFICANCE

We developed a proteomic analysis of plasma samples from a family showing history of dilated cardiomyopathy caused by a LMNA mutation, which may lead to premature death or cardiac transplant. We identified a number of proteins augmented in mutation carriers that could be followed as potential biomarkers for dilated cardiomyopathy on these patients.

Methylome analysis reveals alterations in DNA methylation in the regulatory regions of left ventricle development genes in human dilated cardiomyopathy

Dilated cardiomyopathy (DCM) is one of the main causes of heart failure (called cardiomyopathies) in adults. Alterations in epigenetic regulation (i.e., DNA methylation) have been implicated in the development of DCM. Here, we identified a total of 1828 differentially methylated probes (DMPs) using the Infinium 450K HumanMethylation Bead chip by comparing the methylomes between 18 left ventricles and 9 right ventricles. Alterations in DNA methylation levels were observed mainly in lowly methylated regions corresponding to promoter-proximal regions, which become hypermethylated in severely affected left ventricles. Subsequent mRNA microarray analysis showed that the effect of DNA methylation on gene expression regulation is not unidirectional but is controlled by the functional sub-network context. DMPs were significantly enriched in the transcription factor binding sites (TFBSs) we tested. Alterations in DNA methylation were specifically enriched in the cis-regulatory regions of cardiac development genes, the majority of which are involved in ventricular development (e.g., TBX5 and HAND1).

Pattern of late gadolinium enhancement predicts arrhythmic events in patients with non-ischemic cardiomyopathy

BACKGROUND

Left ventricular late gadolinium enhancement (LV-LGE) by cardiac magnetic resonance (CMR) imaging has been associated with adverse clinical outcomes in patients with non-ischemic cardiomyopathy (NICM). However, an association between the characteristics of the LGE and arrhythmic risk has not been demonstrated consistently. This study evaluated the impact of the LV-LGE characteristics on the arrhythmia risk in patients with NICM.

METHODS

This study enrolled 365 consecutive patients (54±15years) with NICM who underwent CMR imaging. All patients were monitored for the following outcomes: major arrhythmic events (MA), including sustained ventricular tachycardia, an appropriate implantable cardioverter-defibrillator intervention, ventricular fibrillation and sudden cardiac death.

RESULTS

During 44.3±36.4months of follow-up, 44 (12.1%) patients experienced MA. LV-LGE was observed in 40 (90.9%) and 221 (68.8%) patients with and without MA, respectively. LV-LGE was more frequently observed in the MA group (p=0.002). The age- and sex-adjusted hazard ratio (HR) of MA was increased in patients with LGE extent≥8% (HR 8.45, 95% confidence interval (CI) 2.91-24.6), and those with subendocardial (HR 6.98, 95% CI 1.74-28.0) and subepicardial LGE patterns (HR 7.2, 95% CI 1.61-35.6). In multivariable models adjusted for other clinical variables, only the subepicardial LGE pattern had 7.2 (95% CI, 1.61-32.6, p=0.01) time increase in the MA risk.

CONCLUSIONS

LV-LGE in patients with NICM is not uncommon. The subepicardial pattern of the LV-LGE was an independent predictor of MA, suggesting that specific patterns of the LV-LGE are closely related to the severity of arrhythmic events.

Association between polymorphisms of the HSPB7 gene and Cheyne-Stokes respiration with central sleep apnea in patients with dilated cardiomyopathy and congestive heart failure

BACKGROUND

CSR-CSA is frequent in patients with CHF. Dilated cardiomyopathy (DCM) is a structural heart disease with strong genetic background, yet one of the leading etiological causes of CHF. Studies have showed that the HSPB7 gene is associated with DCM.

OBJECTIVES

We aimed to explore the prevalence of polymorphisms of the HSPB7 gene in the Chinese Han population with CSR-CSA and CHF caused by DCM.

METHODS

A total of 503 unrelated subjects of the Chinese Han population, including 283 CHF patients caused by DCM and 220 healthy controls, were involved in the study. The CHF patients were classified as the CSA-CHF group and the non-CSA-CHF group according to the PSG parameters. The rs1739843 polymorphisms of the HSPB7 gene were identified by real-time quantitative polymerase chain reaction.

RESULTS

In the present study, 35.8% of CHF patients caused by DCM had CSR-CSA. Comparison demonstrated that the CSA-CHF group had significantly higher TT genotype and T allele frequencies in the rs1739843 single nucleotide polymorphism (SNP) of the HSPB7 gene. There were no significant differences among the CC genotype distribution of the CSA-CHF group and the non-CSA-CHF group or the control group.

CONCLUSIONS

The rs1739843 polymorphism of the HSPB7 gene might be involved in the pathogenesis of CSR-CSA and CHF subjects caused by DCM in the Chinese Han population. This finding was from a genetic search for the role of the HSPB7 gene in CSR-CSA of CHF patients caused by DCM.

Familial Dilated Cardiomyopathy Caused by a Novel Frameshift in the BAG3 Gene

BACKGROUND

Dilated cardiomyopathy, a major cause of chronic heart failure and cardiac transplantation, is characterized by left ventricular or biventricular heart dilatation. In nearly 50% of cases the pathology is inherited, and more than 60 genes have been reported as disease-causing. However, in 30% of familial cases the mutation remains unidentified even after comprehensive genetic analysis. This study clinically and genetically assessed a large Spanish family affected by dilated cardiomyopathy to search for novel variations.

METHODS AND RESULTS

Our study included a total of 100 family members. Clinical assessment was performed in alive, and genetic analysis was also performed in alive and 1 deceased relative. Genetic screening included resequencing of 55 genes associated with sudden cardiac death, and Sanger sequencing of main disease-associated genes. Genetic analysis identified a frame-shift variation in BAG3 (p.H243Tfr*64) in 32 patients. Genotype-phenotype correlation identified substantial heterogeneity in disease expression. Of 32 genetic carriers (one deceased), 21 relatives were clinically affected, and 10 were asymptomatic. Seventeen of the symptomatic genetic carriers exhibited proto-diastolic septal knock by echocardiographic assessment.

CONCLUSIONS

We report p.H243Tfr*64_BAG3 as a novel pathogenic variation responsible for familial dilated cardiomyopathy. This variation correlates with a more severe phenotype of the disease, mainly in younger individuals. Genetic analysis in families, even asymptomatic individuals, enables early identification of individuals at risk and allows implementation of preventive measures.

Natural History of Dilated Cardiomyopathy in Children

Background

The long‐term progression of idiopathic dilated cardiomyopathy (DCM) in pediatric patients compared with adult patients has not been previously characterized. In this study, we compared outcome and long‐term progression of pediatric and adult DCM populations.

Methods and Results

Between 1988 and 2014, 927 DCM patients were consecutively enrolled. The pediatric population (aged <18 years at enrollment) included 47 participants (5.1%). At presentation, the pediatric population compared with adult patients had a significantly increased occurrence of familial forms (P=0.03), shorter duration of heart failure (P=0.04), lower systolic blood pressure (P=0.01), decreased presence of left bundle‐branch block (P=0.001), and increased left ventricular ejection fraction (P=0.03). Despite these baseline differences, long‐term longitudinal trends of New York Heart Association class III to IV, left ventricular dimensions, left ventricular ejection fraction, and restrictive filling pattern were similar between the 2 populations. Regarding survival analysis, because of the size difference between the 2 populations, we compared the pediatric population with a sample of adult patients randomly matched using the above‐mentioned baseline differences in a 3:1 ratio (141 adult versus 47 pediatric patients). During a median follow‐up of 110 months, survival free from heart transplantation was significantly lower among pediatric patients compared with adults (P<0.001). Furthermore, pediatric age (ie, <18 years) was found to be associated with an increasing risk of both death from pump failure and life‐threatening arrhythmias.

Conclusions

Despite the pediatric DCM population having higher baseline left ventricular ejection fraction and similar long‐term echocardiographic progression compared with the adult DCM population, the pediatric DCM patients had worse cardiovascular prognosis.

Determined to Fail--the Role of Genetic Mechanisms in Heart Failure

Genetic variants contribute to several steps during heart failure pathophysiology. The mechanisms include frequent polymorphisms that increase the susceptibility to heart failure in the general population and rare variants as causes of an underlying cardiomyopathy. In this review, we highlight recent discoveries made by genetic approaches and provide an outlook onto the role of epigenetic modifiers of heart failure.

Next-Generation Sequencing in Post-mortem Genetic Testing of Young Sudden Cardiac Death Cases

Sudden cardiac death (SCD) in the young (<40 years) occurs in the setting of a variety of rare inherited cardiac disorders and is a disastrous event for family members. Establishing the cause of SCD is important as it permits the pre-symptomatic identification of relatives at risk of SCD. Sudden arrhythmic death syndrome (SADS) is defined as SCD in the setting of negative autopsy findings and toxicological analysis. In such cases, reaching a diagnosis is even more challenging and post-mortem genetic testing can crucially contribute to the identification of the underlying cause of death. In this review, we will discuss the current achievements of “the molecular autopsy” in young SADS cases and provide an overview of key challenges in assessing pathogenicity (i.e., causality) of genetic variants identified through next-generation sequencing.