Dilated Cardiomyopathy Patients Research Articles

Abstract 15319: Left Ventricular Assistant Device (lvad) Support Did Not Alter Mirna Expression in Heart Failure Patients

Introduction: Micro RNAs (miRNA) are crucial regulators of various biological processes including the pathogenesis of heart failure (HF). In this study, miRNA profiling was compared with pre and post LVAD and non-failing (NF) control heart patients. Our goal was to identify miRNAs involved in HF and responses to LVAD therapy. Methods: Myocardial RNAs were isolated from non-ischemic dilated cardiomyopathy patients (n=22) who went through LVAD placement (pre LVAD) and later transplant (post LVAD) along with 6 normal hearts as controls. NanoString technology was used to quantify miRNA expressions. NanoString miRNAs raw count data were preprocessed and normalized using solver 4.0 Analysis Software. Ingenuity Pathway Analysis (IPA) was done by differentially expressed miRNA to understand the biological pathways involved. Results: Our sample population exhibited 80% male and 95% Caucasian with an average age of 57 and ejection fraction was less than 25% at the time of LVAD placement. The average LVAD duration of patients was 525 days. One ninety-five miRNAs in pre and 120 miRNAs in post LVAD patients were differentially expressed compared to control using cutoff of for the FDR adjusted p-value 0.05 and at least 2-fold changes. There was no significant change in miRNA expression when post LVAD was compared with pre LVAD patients. IPA analysis revealed that there are 15 up-regulated miRNA that promote apoptosis with a net Z score of 2.155 in post LVAD versus control. There are 27 miRNAs with a net of apoptotic with a Z score 0f 0.766 in pre LVAD versus control. It was also noticed from IPA analysis that expression of 8 identical miRNAs in both pre and post LVAD patients were involved in heart fibrosis. LVAD therapy did not change the miRNA expression Conclusions: Our results identify many miRNAs that are associated with apoptosis and fibrosis in end stage heart failure. Molecular mechanisms of heart disease will be identified by miRNA profiling and function as potential biomarkers or therapeutic targets in future. LVAD therapy does not substantially reverse these epigenetic changes in this population.

Abstract 14006: Circulating microRNAs Predict Recovery in Pediatric Dilated Cardiomyopathy Patients

Introduction: microRNAs (miRs) are small single stranded RNAs capable of targeting expression of several genes. Circulating miRs are stable and can be important biomarkers of disease progression and diagnosis. Hypothesis: We hypothesized circulating miRs could be a reliable prognostic biomarker of recovery for pediatric dilated cardiomyopathy (DCM). Methods: TaqMan Open Array miR panel (ThermoFisher Scientific) was used to investigate expression of 381 circulating miRs. Samples originated from the Pediatric Cardiomyopathy Registry (PCMR) and were collected within 3 months of a new diagnosis of DCM. Inclusion criteria included <18 years of age at diagnosis of idiopathic or familial DCM (EF<50% or left ventricular end-diastolic dimension [LVEDd] z-score ≥+2). Patients with DCM secondary to musculoskeletal diseases or anthracycline toxicity were excluded. Primary outcomes, occurring within 1 year of enrollment, were defined as: [1] Death, transplant (tx) listing or initiation of mechanical circulatory support; [2] Recovered- normalization of ventricular size and function (EF≥50% and LVEDd z-score <+2) or [3] Stable- persistent DCM with EF<50% or LVEDd z-score ≥+2. Statistical analysis included random forest, hierarchical clustering and area under the receiver operator curve (AUC). Results: N=10 subjects were included in Group 1, of which 70% were female, 6 were white, 2 Hispanic and 3 of other/unknown races, median age 9.5y. N=5 samples were included in Group 2, of which 60% were female, 3 were white, 1 black and 1 native American, median age 1.9y. N=20 samples were included in Group 3, of which 40% were female, 10 were white, 5 black, 1 Pacific islander, 2 Hispanic and 4 of other/unknown races, median age 2.1y. The top 3 miRs differentiating Group 2 (Recovered) from Group 1 (Death/Tx) (AUC of 0.92) were hsa-miR-655, -410 and -636. The top 3 miRs differentiating Group 2 (Recovered) from Group 3 (Stable) were hsa-miR-17, -410 and -345 (AUC of 0.76). Conclusions: These results indicate circulating miRs can predict recovery in the pediatric DCM population. A unique biomarker signature of miRs specific to patients who have the potential to recover would improve risk stratification of this population.

A novel likely pathogenic variant in the FBXO32 gene associated with dilated cardiomyopathy according to whole‑exome sequencing

BackgroundFamilial dilated cardiomyopathy (DCM) is a genetic heart disorder characterized by progressive heart failure and sudden cardiac death. Over 250 genes have been reported in association with DCM; nonetheless, the genetic cause of most DCM patients has been unknown. The goal of the present study was to determine the genetic etiology of familial DCM in an Iranian family.MethodsWhole-exome sequencing was performed to identify the underlying variants in an Iranian consanguineous family with DCM. The presence of the candidate variant was confirmed and screened in available relatives by PCR and Sanger sequencing. The pathogenic effect of the candidate variant was assessed by bioinformatics analysis, homology modeling, and docking.ResultsOne novel likely pathogenic deletion, c.884_886del: p.Lys295del, in F-box only protein 32 (muscle-specific ubiquitin-E3 ligase protein; FBXO32) was identified. Based on bioinformatics and modeling analysis, c.884_886del was the most probable cause of DCM in the studied family.ConclusionsOur findings indicate that variants in FBXO32 play a role in recessive DCM. Variants in FBXO32 may disturb the degradation of target proteins in the ubiquitin–proteasome system and lead to severe DCM. We suggest considering this gene variants in patients with recessively inherited DCM.

Leukocyte Nuclear Morphology Alterations in Dilated Cardiomyopathy Caused by a Lamin AC Truncating Mutation (LMNA/Ser431*) Are Modified by the Presence of a LAP2 Missense Polymorphism (TMPO/Arg690Cys).

The clinical phenotype of LMNA-associated dilated cardiomyopathy (DCM) varies even among individuals who share the same mutation. LMNA encodes lamin AC, which interacts with the lamin-associated protein 2 alpha (LAP2α) encoded by the TMPO gene. The LAP2α/Arg690Cys polymorphism is frequent in Latin America and was previously found to disrupt LAP2α-Lamin AC interactions in vitro. We identified a DCM patient heterozygous for both a lamin AC truncating mutation (Ser431*) and the LAP2α/Arg690Cys polymorphism. We performed protein modeling and docking experiments, and used confocal microscopy to compare leukocyte nuclear morphology among family members with different genotype combinations (wild type, LAP2α Arg690Cys heterozygous, lamin AC/Ser431* heterozygous, and LAP2α Arg690Cys/lamin AC Ser431* double heterozygous). Protein modeling predicted that 690Cys destabilizes the LAP2α homodimer and impairs lamin AC-LAP2α docking. Lamin AC-deficient nuclei (Ser431* heterozygous) showed characteristic blebs and invaginations, significantly decreased nuclear area, and increased elongation, while LAP2α/Arg690Cys heterozygous nuclei showed a lower perimeter and higher circularity than wild-type nuclei. LAP2α Arg690Cys apparently attenuated the effect of LMNA Ser431* on the nuclear area and fully compensated for its effect on nuclear circularity. Altogether, the data suggest that LAP2α/Arg690Cys may be one of the many factors contributing to phenotype variation of LMNA-associated DCM.

NIMA-related kinase 9 regulates the phosphorylation of the essential myosin light chain in the heart

To adapt to changing hemodynamic demands, regulatory mechanisms modulate actin-myosin-kinetics by calcium-dependent and -independent mechanisms. We investigate the posttranslational modification of human essential myosin light chain (ELC) and identify NIMA-related kinase 9 (NEK9) to interact with ELC. NEK9 is highly expressed in the heart and the interaction with ELC is calcium-dependent. Silencing of NEK9 results in blunting of calcium-dependent ELC-phosphorylation. CRISPR/Cas9-mediated disruption of NEK9 leads to cardiomyopathy in zebrafish. Binding to ELC is mediated via the protein kinase domain of NEK9. A causal relationship between NEK9 activity and ELC-phosphorylation is demonstrated by genetic sensitizing in-vivo. Finally, we observe significantly upregulated ELC-phosphorylation in dilated cardiomyopathy patients and provide a unique map of human ELC-phosphorylation-sites. In summary, NEK9-mediated ELC-phosphorylation is a calcium-dependent regulatory system mediating cardiac contraction and inotropy.

The Dysfunctional Right Ventricle in Dilated Cardiomyopathies: Looking from the Right Point of View

Dilated cardiomyopathies (DCMs) are a heterogenous group of primary myocardial diseases, representing one of the leading causes of heart failure, and the main indication for heart transplantation. While the degree of left ventricular dilation and dysfunction are two key determinants of adverse outcomes in DCM patients, right ventricular (RV) remodeling and dysfunction further negatively influence patient prognosis. Consequently, RV functional assessment and diagnosing RV involvement by using an integrative approach based on multimodality imaging is of paramount importance in the evaluation of DCM patients and provides incremental prognostic and therapeutic information. Transthoracic echocardiography remains the first-line imaging modality used for the assessment of the RV, and newer techniques such as speckle-tracking and three-dimensional echocardiography significantly improve its diagnostic and prognostic accuracy. Nonetheless, cardiac magnetic resonance (CMR) is considered the gold standard imaging modality for the evaluation of RV size and function, and all DCM patients should be evaluated by CMR at least once. Accordingly, this review provides a comprehensive overview of the anatomy and function of the RV, and the pathophysiology, diagnosis, and prognostic value of RV dysfunction in DCM patients, based on traditional and novel imaging techniques.

Generation of two induced pluripotent stem cell lines from dilated cardiomyopathy patients caused by heterozygous mutations in the HCN4 gene

Dilated cardiomyopathy (DCM) is a progressive heart muscle disease that can culminate with heart failure and death. Mutations in several genes can cause DCM, including hyperpolarization-activated cyclic nucleotide-gated channel (HCN4), which has a critical function in the autonomic control of the heart rate. Here, we generated two human induced pluripotent stem cell (iPSC) lines generated from two DCM patients carrying variants in the HCN4 gene (c.2587G > T and c.2846G > A). Both lines display normal karyotype, typical morphology of pluripotent stem cells, and differentiate into all three germ layers in vitro. These lines are valuable resources for studying the pathological mechanisms of DCM.

Impact of Cardiac Resynchronization Therapy (CRT) on the Severity of Mitral Regurgitation in Dilated Cardiomyopathy Patients

Abstract Aim Functional Mitral regurge in advanced Heart failure dilated cardiomyopathy patients is a strong predictor to mortality, this arouses studying the impact of Cardiac resynchronization therapy on functional MR in DCM. Methods and results This is a prospective observational study of Twenty-five patients with advanced heart failure DCM with sinus rhythm LBBB wide QRS≥ 130 ms with at least moderate MR, subjected to CRT implantation at Alexandria main university Hospital and followed up by Echocardiography after CRT by 1 week and 10 weeks and comparing between improved MR (Group 1) and stable MR group patients (Group 2). FMR improvement was observed in 15 patients (60%) ‘Group 1’ (p value <0.001) vs 10 patients (40%) show stable MR ‘Group 2’. Evidence of early response to CRT was observered in 9 patients (36%). MR improvement among responders to CRT was observed in 7 patients (77.8%) and was higher among early echocardiographic responders (48%) than among early clinical responders (40%). MR improvement was significantly associated with percent of reduction in QRS width in surface ECG. (P value: 0.026). Conclusions CRT improves the degree of severity of functional MR among DCM patients. Improvement of MR severity is significantly associated with baseline QRS width and percent of reduction in QRS width. Additional Content An author video to accompany this abstract is available on https://academic.oup.com/eurheartjsupp. Please click on the arrow next to ‘More Content’ and then click on ‘Author videos’.

Early detection of myocardial fibrosis in cardiomyopathy in the absence of late enhancement: role of T1 mapping and extracellular volume analysis.

To analyze myocardial fibrosis in dilated cardiomyopathy (DCM) patients with no late gadolinium enhancement (LGE) on cardiac magnetic resonance (CMR) using T1 mapping and extracellular volume (ECV) and investigate the potential correlation with left ventricular (LV) dilation and dysfunction. The study included 41 DCM patients without LGE and 79 healthy controls. T1 and ECV were compared between the two groups using multivariable logistic regression analysis. The correlations between histological and functional parameters were evaluated using Pearson's correlation. Mean native myocardial T1 and ECV were significantly higher in the DCM group compared to controls (p ≤ 0.001, respectively). Multivariable logistic regression revealed that ECV (mean, minimum), LV ejection fraction (LVEF), and LV end-diastolic diameter (LVEDD) were independent discriminators for LGE-negative DCM; the area under the curve (AUC) of LVEF, LVEDD, ECV mean, and ECV minimum were 0.97, 0.96, 0.88, and 0.68, respectively. In the DCM group, LVEDD and LVEF were positively and negatively correlated with ECV, respectively. LVEDV index and LV end-systolic volume (LVESV) index were positively correlated with native-T1 and ECV, and the absolute value of LV global strain had a negative correlation with ECV. Early myocardial fibrosis in DCM could be detected by prolonged native T1 and elevated ECV despite the absence of LGE on CMR. Moreover, the change of histological characteristics of myocardium in DCM was correlated with LV dilation and dysfunction. • At an early stage, patients with DCM may have myocardial fibrosis despite the absence of LGE. • T1 mapping and ECV are efficient methods for early detection of potential myocardial fibrosis. • Increased native T1 and ECV are correlated with left ventricular dilation and dysfunction in LGE-negative DCM patients.

The Impact of Hypertension on Left Ventricular Function and Remodeling in Non-Ischemic Dilated Cardiomyopathy Patients: A 3.0 T MRI Study.

Hypertension (HTN) is highly prevalent in non-ischemic dilated cardiomyopathy (NIDCM) patients, but little is known about its impact on left ventricular (LV) function and remodeling. To evaluate the effect of hypertension on LV function and remodeling in NIDCM patients. Retrospective. Two-hundred and twelve NIDCM (HTN-) patients, 91 NIDCM (HTN+) patients, and 74 normal controls. 3.0 T/bSSFP and phase-sensitive inversion recovery sequence. The LV geometry, myocardial strain, remodeling index (calculated as LVM/LVEDV), and LGE were measured and compared between groups. Determinants of LV strain and remodeling in NIDCM were investigated. Student's t-test, Mann-Whitney U test, one-way analysis of variance, Kruskal-Wallis test, univariable and multivariable linear regression. A P value <0.05 was considered statistically significant. Compared with normal controls, NIDCM patients had significantly higher LVEDV and significantly impaired LV strains, including LV global peak strain (PS) and peak systolic and diastolic strain rates in the radial, circumferential, and longitudinal directions. The NIDCM (HTN+) group had significantly decreased LV global longitudinal PS and peak diastolic strain rate (PDSR), and significantly increased LV mass index and remodeling index compared to the NIDCM (HTN-) group, despite there being no significant difference in ejection fraction (P=0.241). The prevalence of LV LGE was significantly higher in the NIDCM (HTN+) group than in the NIDCM (HTN-) group. In multivariable regression models adjusted for potential confounders, hypertension was independently associated with LV global longitudinal PS and PDSR. Male sex, resting heart rate, and log(NT-proBNP) level were independent determinants of LV strains. Moreover, male sex, systolic and diastolic blood pressure, and presence of LGE were independent determinants of LV remodeling index. These findings suggest that coexistence of hypertension may further exacerbate the reduction in LV global strain and the aggravation of LV remodeling in NIDCM patients. 3 TECHNICAL EFFICACY: Stage 3.

Generation of two induced pluripotent stem cell lines from dilated cardiomyopathy patients carrying TTN mutations

Dilated cardiomyopathy (DCM) is a common heart disease that can lead to heart failure and sudden cardiac death. Mutations in the TTN gene are the most frequent cause of DCM. Here, we generated two human induced pluripotent stem cell (iPSC) lines from the peripheral blood mononuclear cells (PBMCs) of two DCM patients carrying c.94816C>T and c.104188A>G mutations in TTN, respectively. The two lines exhibited a normal morphology, full expression of pluripotency markers, a normal karyotype and the ability of trilineage differentiation. The two lines can serve as useful tools for drug screening and mechanism studies on DCM.

Scleraxis and fibrosis in the pressure-overloaded heart.

In response to pro-fibrotic signals, scleraxis regulates cardiac fibroblast activation in vitro via transcriptional control of key fibrosis genes such as collagen and fibronectin; however, its role in vivo is unknown. The present study assessed the impact of scleraxis loss on fibroblast activation, cardiac fibrosis, and dysfunction in pressure overload-induced heart failure. Scleraxis expression was upregulated in the hearts of non-ischemic dilated cardiomyopathy patients, and in mice subjected to pressure overload by transverse aortic constriction (TAC). Tamoxifen-inducible fibroblast-specific scleraxis knockout (Scx-fKO) completely attenuated cardiac fibrosis, and significantly improved cardiac systolic function and ventricular remodelling, following TAC compared to Scx+/+ TAC mice, concomitant with attenuation of fibroblast activation. Scleraxis deletion, after the establishment of cardiac fibrosis, attenuated the further functional decline observed in Scx+/+ mice, with a reduction in cardiac myofibroblasts. Notably, scleraxis knockout reduced pressure overload-induced mortality from 33% to zero, without affecting the degree of cardiac hypertrophy. Scleraxis directly regulated transcription of the myofibroblast marker periostin, and cardiac fibroblasts lacking scleraxis failed to upregulate periostin synthesis and secretion in response to pro-fibrotic transforming growth factor β. Scleraxis governs fibroblast activation in pressure overload-induced heart failure, and scleraxis knockout attenuated fibrosis and improved cardiac function and survival. These findings identify scleraxis as a viable target for the development of novel anti-fibrotic treatments.

I536T variant of RBM20 affects splicing of cardiac structural proteins that are causative for developing dilated cardiomyopathy

RBM20 is one of the genes predisposing to dilated cardiomyopathy (DCM). Variants in the RS domain have been reported in many DCM patients, but the pathogenicity of variants within the RNA-recognition motif remains unknown. Two human patients with the I536T-RBM20 variant without an apparent DCM phenotype were identified in sudden death cohorts. A splicing reporter assay was performed, and an I538T knock-in mouse model (Rbm20I538T) was generated to determine the significance of this variant. The reporter assay demonstrated that the human I536T variant affected the TTN splicing pattern compared to wild-type. In the mouse experiments, Rbm20I538T mice showed different splicing patterns in Ttn, Ldb3, Camk2d, and Ryr2. The expressions of Casq1, Mybpc2, and Myot were upregulated in Rbm20I538T mice, but Rbm20I538T mice showed neither DCM nor cardiac dysfunction on histopathological examination and ultrasound echocardiography. The I536T-RBM20 (I538T-Rbm20) variant changes gene splicing and affects gene expression, but the splicing and expression changes in Ttn and Ca handling genes such as Casq1, Camk2d, and Ryr2 do not cause DCM morphology in the mouse model.Key messages• Two human patients with the I536T-RBM20 variant without a DCM phenotype were identified.• A splicing reporter assay demonstrated that the variant affected the TTN splicing.• Rbm20I538T mice showed neither DCM nor cardiac dysfunction.• Rbm20I538T mice showed different splicing patterns and the gene expressions.

The case against premature treatment of heart failure patients with implantable cardioverter-defibrillators: results from an institutional registry

Abstract Introduction Implantable cardioverter-defibrillators (ICD) are gold-standard therapy for primary prevention (PP) of sudden cardiac death (SCD) in patients with heart failure with reduced ejection fraction (HFrEF). According to relevant guidelines, ICDs should be implanted only after patients have been treated with revascularization procedures and/or optimal medical therapy (OMT) [1]. Due to perceived high risk of SCD and low chance of improvement some patients receive ICDs “too early” in the course of the disease [2]. Purpose To investigate adherence to guidelines in our institution with emphasis on premature ICD implantation and early ICD activation. Methods We analysed all ICDs newly implanted for PP in patients with HFrEF in our institution between 2011 and 2017. Follow-up data was collected from hospital medical records. Results Total number of 307 ICDs were implanted during the analysed interval, 147 (47.9%) in ischemic cardiomyopathy (ICM) and 160 (52.1%) in non-ischemic dilated cardiomyopathy (DCM) patients. Only 57.8% of ICM patients have been treated with OMT at least 3 months before implantation. The proportion was similar in DCM patients (60.0%). However, DCM patients were more commonly implanted at the time of diagnosis (13.8% vs. 0.7% in ICM). It is worth noting that OMT was up-titrated after implantation in 35.2% of patients. In 9 cases patients were treated with ICDs less than 3 months after revascularization procedures or less than 6 weeks after STEMI (6 and 3 cases respectively). Follow-up data revealed that among all the patients who prematurely received an ICD, a device activated to deliver appropriate therapy within 3 months of implantation only in 1 ICM patient (0.7% of ICM patients). That patient had established ICM and was suffering from recurrent unexplained syncopes. One DCM patient with prematurely implanted ICD had early inappropriate ICD activation that was due to supraventricular tachycardia. Early ICD activations were generally uncommon even among patients who were treated according to guidelines (1 ICM and 1 DCM patient). Conclusion Results from our institutional ICD registry show that a significant number of patients with HFrEF received premature ICD implants before being treated with OMT. This is even more common in patients newly diagnosed with DCM. Our follow-up data suggests that early ICD activation is extremely rare in all comers and hardly ever happens in patients who received ICD immediately after diagnosis, revascularization or without 3 months of OMT. This data can help improve our future practice and encourage clinicians to follow relevant guidelines when faced with these important decisions. Funding Acknowledgement Type of funding sources: None.

Golgi Apparatus fragmentation in dilated cardiomyopathy and its relationship with the alteration of vesicular transport

Abstract Background The Golgi Apparatus (GA) is an important membrane-bound organelle implied in many physiological events, as trafficking, processing and sorting of newly membrane and secretory proteins and lipids. Nevertheless, these functions can be dysregulated in a diversity of pathologies due to the alteration of the GA morphology, such as cardiovascular diseases. Previously, we described in dilated cardiomyopathy (DCM) alterations in shape and size of the secretion vesicles of GA that was related to a worse functional situation. The patients had smaller, more ellipsoidal and more numerous vesicles with a higher content of natriuretic peptides (1). This situation can be related with Golgi fragmentation, a status characterized by the presence of a dispersed GA both in physiological and pathophysiological conditions (2). However, a greater understanding of Golgi fragmentation in DCM is necessary. Purpose We attempted to analyse the components of the vesicular Golgi transport and the Golgi fragmentation in cardiac tissue samples from DCM patients, paying special attention to GM130, as one of the main molecules related with the Golgi fragmentation. Methods We analysed vesicular Golgi transport genes in human hearts by RNA-sequencing in 13 samples from DCM patients and 10 control hearts (CNT), and the miRNAs that regulate their expression by ncRNA sequencing (DCM, n=20; and CNT, n=8). Finally, we investigated changes in the protein levels of GM130 and its phosphorylated state (pGM130) by western blot with 22 DCM and 6 CNT samples in total. Results We found 134 differentially expressed genes related to the GA, and 15 of them were involved in the secretion of Golgi vesicles. Among these molecules, VAMP4, a v-SNARE related with the Golgi fragmentation, is found to be downregulated (−1.27-Fold; P&amp;lt;0.05). Moreover, we have observed a downregulation in the expression of GOLGA2, the gene that encodes GM130 (−1.24; P&amp;lt;0.05). Furthermore, its regulator, hsa-miR-17-5p (−1.42; P&amp;lt;0.01) was also downregulated. In this sense, we have found no changes in GM130 protein levels between DCM patients and CNT group. In contrast, pGM130, molecule that it has been used as a biomarker of Golgi fragmentation, was overexpressed in DCM patients (1.19; P&amp;lt;0.05). Conclusion We found a deregulation of genes related to the vesicle secretion in the GA, which together with the changes in vesicular morphology previously observed, suggests an alteration in the rate of secretion in response to the needs of the DCM patients. In addition, the increase in the phosphorylated protein GM130 suggests the presence of fragmentation in DCM patients that could be related to the alteration in vesicular transport. Funding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): National Institute of Health Carlos III European Regional Development Fund (ERDF)

Prognostic value of left ventricular contractile reserve and heart rate reserve in dilated cardiomyopathy

Abstract Background Stress echocardiography (SE) allows to assess simultaneously left ventricular contractile reserve (LVCR) and heart rate reserve (HRR) in dilated cardiomyopathy (DCM). Aim To assess the prognostic value of LVCR and HRR in DCM patients Methods We prospectively enrolled 395 DCM patients with ejection fraction ≤40% (age 62±27 years, 270 males, 68%; ejection fraction 35±9%) referred from 9 certified laboratories, 264 with nonischemic DCM (67%) and 131 (33%) with ischemic DCM. All patients underwent clinically indicated SE. The employed stress modality was exercise (n=63), or pharmacological stress (n=332, with vasodilator, n=232; or dobutamine, n=100). LVCR was present with a rest-stress decrease ≥0.20 in wall motion score index. HRR was normal with a peak-rest value ≥1.80 with exercise or dobutamine and ≥1.22 with dipyridamole or adenosine stress. Results New regional wall motion abnormality was present in 46 (12%), LVCR in 131 (33%) and abnormal HRR in 275 (70%) DCM patients. During a median follow-up of 950 days (interquartile range: 360–1187 days) 71 deaths occurred. Annual mortality was 10.5%/year in DCM patients with abnormal HRR (HRR−) and absence of LVCR (LVCR−), 5.4%/year in patients with either abnormal HRR or absent LVCR, and 2.5%/year in patients with normal HRR and presence of LVCR (Figure 1). At multivariable analysis, only abnormal HRR (HR: 2.952, 95% CI: 1.547–5.630, p=0.001) but not absence of LVCR (HR: 1.545, 95% CI: 0.929–2.568, p=0.094), was independent predictors of survival. Conclusion Abnormal HRR predicts adverse prognosis in DCM patients, in addition to the presence of LV CR. Funding Acknowledgement Type of funding sources: None.

The prognostic significance of the echocardiographic evaluation of left ventricular myocardial deformation indices at peak cardiopulmonary exercise in patients with severe dilated cardiomyopathy

Abstract Background Cardiopulmonary exercise testing (CPET) integrally estimates exercise capacity (peak VO2) and cardiovascular (CV) prognosis (VE/VCO2 slope) in patients with dilated cardiomyopathy (DCM). Myocardial deformation indices (MDI), measured by speckle tracking imaging (STI), allow reliable measurements of left ventricular (LV) function. Little is known about the exercise-induced changes of the multidimensional mechanical properties of the heart and their impact in patient's survival. We aimed to investigate the predictive role regarding 3-year survival of LV MDI (at rest and peak exercise) as well as the main CPET parameters (peak VO2, VE/VCO2 slope) in DCM patients with reduced ejection fraction (EF) using as primary combined end-point the heart transplantation and all cause death. Patients and methods We evaluated LV function using STI at rest and at peak exercise during the same CPET session in 53 DCM patients (54±12 years, 76% males, ejection fraction 33±9%).We measured global longitudinal strain (GLS), longitudinal strain rate at systole (LSRS) and diastole (LSRD) at baseline and at peak CPET along with CPET parameters. After a period of 38±15 months, all DCM patients were evaluated by a telephone interview. Results From the whole population, totally 7 patients (13%) reached the primary end-point (Group A) as 2 patients were submitted to heart transplantation and 5 patients died (60±13 years, 86% males, EF = 28±9%) while 46 patients remained alive at 3-year follow-up (Group B, 53±12 years, 74% males, EF = 33±9%). We found that Group A patients had similar age, sex and EF but reduced peak VO2 (p=0.04) and increased VE/VCO2 slope (p=0.004), impaired GLS at baseline and peak exercise (p=0.02 and p=0.04, respectively) as well as LSRS at peak exercise (p=0.05) compared to Group B patients. Conclusions The evaluation of GLS (rest and peak exercise) and LSRS (peak exercise) as systolic indices of LV myocardial deformation adds valuable information regarding CV prognosis in patients with severe idiopathic DCM. A combined baseline work-up protocol consisted of MDI evaluation at rest and exercise plus the CPET indices may characterize the true severity of heart failure in a DCM population. Funding Acknowledgement Type of funding sources: None.

Aberrant interaction between TEAD1 and Lamin A/C causes cardiomyopathy

Abstract Background Mutations in the LMNA gene encoding Lamin A/C, a major component of the nuclear lamina, cause laminopathies including dilated cardiomyopathy (DCM). DCM patients with LMNA mutations have particularly severe clinical courses such as heart transplantation and death due to heart failure. However, underlying mechanisms of LMNA-induced DCM remains elusive. Methods and results We identified LMNA Q353R mutation in a DCM family with severe heart failure. We generated Q353R heterozygous knock-in mice, which showed sarcomere dysplasia and perinatal lethality. Integrative single-cell analyses of the fetal murine hearts and patient-specific induced pluripotent stem cell-derived cardiomyocytes (iPSCMs) revealed that transcriptional regulation of cardiomyocyte maturation/development genes governed by TEAD1 was impaired in LMNA mutant cardiomyocytes. Protein array and immunostaining uncovered increased binding of TEAD1 to mutant Lamin A/C protein and abnormal localization of TEAD1 at the nuclear periphery. Furthermore, TT-10, a Hippo pathway inhibitor, rescued the dysregulation of cardiac developmental genes in LMNA mutant cardiomyocytes. Single-cell RNA-seq of cardiac tissues from DCM patients with the LMNA Q353R mutation confirmed the dysregulated expression of TEAD1 and its target genes. These results demonstrated abnormal interaction between TEAD1 and mutant Lamin A/C impairs structural maturation of cardiomyocytes and suggests that LMNA Q353R-related DCM can be treated through intervention in the Hippo pathway. Conclusion TEAD1 trapped by mutant Lamin A/C protein at the nuclear membrane perturbs transcriptional maturation in LMNA Q353R-related DCM. Funding Acknowledgement Type of funding sources: None.

Myocardial inflammation in ischaemic and non-ischaemic heart failure relates to impaired mitochondria

Abstract Background Mitochondrial dysfunction is a driving factor in the development of heart failure (HF) and relates to poor cardiac function. Through elevated oxidative stress it is linked to myocardial inflammation. Both mechanisms promote the development of cardiac fibrosis, a key contributor to adverse outcomes in ischaemic and non-ischaemic HF. Differences in myocardial mitochondrial function and inflammation between patients with ischaemic and non-ischaemic HF have been indicated. While immunosuppression in non-ischaemic HF with myocardial inflammation has improved long-term results, little is known about possible benefits in ischaemic HF. Purpose We hypothesised that: 1. Myocardial lymphocytic inflammation and fibrosis differ in patients with HF due to ischaemic cardiomyopathy (ICM) compared to patients with dilated cardiomyopathy (DCM). 2. Inflammation and fibrosis are associated with markers of mitochondrial dysfunction. Methods Myocardial tissue specimens were obtained from the left ventricular (LV) apex of 65 patients (n[ICM] = 33, n[DCM] = 32) with HF requiring an LV assist device or heart transplantation. We assessed oxidative phosphorylation capacity (OXPHOS) via high resolution respirometry in saponine-permeabilised myocardial fibres (OROBOROS Oxygraph-2k). Reactive oxygen species (ROS) production was measured fluoroscopically via the Amplex Red method. Immunohistochemistry staining for CD3 was performed on snap-frozen tissue and digitally analysed. Azan staining was used for quantification of fibrotic area. Statistical analysis was conducted with GraphPad Prism v9.0 and IBM SPSS v27.0. Results ICM and DCM patients did not differ significantly regarding age (60.9±5.4 vs. 55.8±12.4 years, p=0.11), sex (91% vs. 90% male, p=0.93), BMI (27.6±5.1 vs. 26.5±6.0 kg/m2, p=0.82), or diabetic status (31% vs. 20% Type 2 Diabetes mellitus, p=0.31). Tissue specimens of ICM patients displayed about three times larger fibrotic areas compared to DCM (20.9±21.2 vs. 7.2±5.6%, p=0.001). Cellular inflammation (&amp;gt;14 CD3+ cells/mm2) was significantly more common in ICM than DCM patients. (27 vs. 6%, p=0.024). Inflammation and fibrosis did not correlate significantly (r=0.09, p=0.46). Fibrosis was not associated with OXPHOS capacity (r=−0.129, p=0.33). In patients with inflammation, OXPHOS capacity was lower compared to patients without inflammation (92.3±40.1 vs. 131.6±55.6 pmol/(s*mg), p=0.031) and inflammation was associated with lower OXPHOS capacity (r=−0.296, p=0.019). There was a trend towards lower electron transfer capacity in patients with inflammation (98.6±43.1 vs. 129.7±48.3 pmol/(s*mg), p=0.053). ROS production was not significantly different between tissue specimens with or without inflammation (0.51±0.21 vs. 0.67±0.33 pmol/(s*ml), p=0.17). Conclusions Myocardial cellular inflammation is prominent in ICM patients and relates to impaired mitochondria. Future studies may evaluate possible benefits from immunosuppression in ICM patients. Funding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): German Research Foundation (DFG)

CMR derived left ventricular intraventricular pressure gradients identify different patterns associated with prognosis in patients with dilated cardiomyopathy

Abstract Introduction The direction of blood flow in the left ventricle (LV) is determined by intraventricular pressure gradients (IVPGs) between apex and base, which are altered when cardiac function declines. New cardiac magnetic resonance (CMR) post-processing software enables estimating LV-IVPGs. To date, the prognostic value of CMR derived IVPGs in patients with dilated cardiomyopathy (DCM) remains unknown. Methods DCM patients from the Maastricht Cardiomyopathy Registry, who underwent a CMR, were included. The software estimates the LV-IVPGs (between apex and base) by using the myocardial movement and velocity of a reconstructed 3D-LV model (derived from feature-tracking strain analysis of 2-, 3- and 4-chamber cine images). The primary outcome was a combined endpoint of heart failure (HF) hospitalisations, life-threatening arrhythmias and (sudden) cardiac death. Results In total, 447 DCM patients were included (age 55 interquartile range [46–63] years; 60% male). During a median follow-up of 6 [4–9] years, 66 patients (15%) reached the primary endpoint. In 168 patients (38%), a temporary pressure reversal from base-apex to apex-base during the systolic-diastolic transition was observed (figure). After correction for covariates that were univariably associated with outcome (p&amp;lt;0.100, age, NYHA-class≥3, and left atrial (LA) conduit strain), flow reversal from base-apex to apex-base in the diastole was independently associated with outcome in the total cohort (HR 2.91, 95%-Confidence interval (95%-CI) [1.16–7.32], p=0.023; Table). In patients without pressure reversal (N=279) in the systolic-diastolic transition, IVPG during the total cardiac cycle (HR 0.88 [0.81–0.96], p=0.003), the systolic ejection force (HR 0.92 [0.87–0.97], p=0.003), and the E-wave decelerative force “C” (passive diastolic filling, HR 0.85 [0.74–0.97], p=0.013) were predictors of outcome, independent of other covariates (age, sex, NYHA class ≥3, LV ejection fraction, late gadolinium enhancement, LV longitudinal strain, LA volume index and LA conduit strain, table). Conclusion CMR-derived LV-IVPG analysis showed pressure reversal in the systolic-diastolic transition in one-third of DCM patients, and flow reversal was an independent predictor of worse outcome in these patients. In patients without this pressure reversal, LV-IVPG during the total cardiac cyle, the systolic ejection force, and the E-wave decelerative force were predictors of outcome, independent of all evauluated clinical and imaging parameters. Funding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Netherlands Cardiovascular Research Initiative (initiative with support of the Dutch Heart Foundation) and CVON (She-PREDICTS, grant 2017-21 &amp; CVON-DCVA Double Dosis 2021)