Texture analysis of SPECT myocardial perfusion provides prognostic value for dilated cardiomyopathy.

BACKGROUND: Texture analysis (TA) has demonstrated clinical values in extracting information, quantifying inhomogeneity, evaluating treatment outcomes, and predicting long-term prognosis for cardiac diseases. The aim of this study was to explore whether TA of SPECT myocardial perfusion could contribute to improving the prognosis of dilated cardiomyopathy (DCM) patients. METHODS: Eighty-eight patients were recruited in our study between 2009 and 2020 who were diagnosed with DCM and underwent single-photon emission tomography myocardial perfusion imaging (SPECT MPI). Forty TA features were obtained from quantitative analysis of SPECT imaging in subjects with myocardial perfusion at rest. All patients were divided into two groups: the all-cause death group and the survival group. The prognostic value of texture parameters was assessed by Cox regression and Kaplan-Meier analysis. RESULTS: Twenty-five all-cause deaths (28.4%) were observed during the follow-up (39.2±28.7 months). Compared with the survival group, NT-proBNP and total perfusion deficit (TPD) were higher and left ventricular ejection fraction (LVEF) was lower in the all-cause death group. In addition, 26 out of 40 texture parameters were significantly different between the two groups. Univariate Cox regression analysis revealed that NT-proBNP, LVEF, and 25 texture parameters were significantly associated with all-cause death. The multivariate Cox regression analysis showed that low gray-level emphasis (LGLE) (P = 0.010, HR = 4.698, 95% CI 1.457-15.145) and long-run low gray-level emphasis (LRLGE) (P =0.002, HR = 6.085, 95% CI 1.906-19.422) were independent predictors of the survival outcome. When added to clinical parameters, LVEF, TPD, and TA parameters, including LGLE and LRLGE, were incrementally associated with all-cause death (global chi-square statistic of 26.246 vs. 33.521; P = 0.028, global chi-square statistic of 26.246 vs. 34.711; P = 0.004). CONCLUSION: TA based on gated SPECT MPI could discover independent prognostic predictors of all-cause death in medically treated patients with DCM. Moreover, TA parameters, including LGLE and LRLGE, independent of the total perfusion deficit of the cardiac myocardium, appeared to provide incremental prognostic value for DCM patients.

Predictive values of left ventricular mechanical dyssynchrony for CRT response in heart failure patients with different pathophysiology.

BACKGROUND: Cardiac resynchronization therapy (CRT) patients with different pathophysiology may influence mechanical dyssynchrony and get different ventricular resynchronization and clinical outcomes. METHODS: Ninety-two dilated cardiomyopathy (DCM) and fifty ischemic cardiomyopathy (ICM) patients with gated single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) were included in this retrospective study. Patients were classified based on the concordance between the left ventricular (LV) lead and the latest contraction or relaxation position. If the LV lead was located on or adjacent to both the latest contraction and relaxation position, the patient was categorized into the both match group; if the LV lead was located on or adjacent to the latest contraction or relaxation position, the patient was classified into the one match group; if the LV lead was located on or adjacent to neither the latest contraction nor relaxation position, the patient was categorized to the neither group. CRT response was defined as [Formula: see text] improvement of LV ejection fraction at the 6-month follow-up. Variables with P < .05 in the univariate analysis were included in the stepwise multivariate model. RESULTS: During the follow-up period, 58.7% (54 of 92) for DCM patients and 54% (27 of 50) for ICM patients were CRT responders. The univariate analysis and stepwise multivariate analysis showed that QRS duration, systolic phase bandwidth (PBW), diastolic PBW, diastolic phase histogram standard deviation (PSD), and left ventricular mechanical dyssynchrony (LVMD) concordance were independent predictors of CRT response in DCM patients; diabetes mellitus and left ventricular end-systolic volume were significantly associated with CRT response in ICM patients. The intra-group comparison revealed that the CRT response rate was significantly different in the both match group of DCM (N = 18, 94%) and ICM (N = 24, 62%) patients (P = .016). However, there was no significant difference between DCM and ICM in the one match and neither group. For the inter-group comparison, Kruskal-Wallis H-test revealed that CRT response was significantly different in all the groups of DCM patients (P < .001), but not in ICM patients (P = .383). CONCLUSIONS: Compared with ICM patients, systolic PBW, diastolic PBW and PSD have better predictive and prognostic values for the CRT response in DCM patients. Placing the LV lead in or adjacent to the latest contraction and relaxation position can improve the clinical outcomes of DCM patients, but it does not apply to ICM patients.

A novel mutation in KCNH2 yields loss-of-function of hERG potassium channel in long QT syndrome 2.

Mutations in hERG (human ether-à-go-go-related gene) potassium channel are closely associated with long QT syndromes. By direct Sanger sequencing, we identified a novel KCNH2 mutation W410R in the patient with long QT syndrome 2 (LQT2). However, the electrophysiological functions of this mutation remain unknown. In comparison to hERGWT channels, hERGW410R channels have markedly decreased total and surface expressions. W410R mutation dramatically reduces hERG channel currents (IKr) and shifts its steady-state activation curve to depolarization. Moreover, hERGW410R channels make dominant-negative effects on hERGWT channels. Significantly, we find hERG channel blocker E-4031 could partially rescue the function of hERGW410R channels by increasing the membrane expression. By using in silico model, we reveal that hERGW410R channels obviously elongate the repolarization of human ventricular myocyte action potentials. Collectively, W410R mutation decreases the currents of hERG channel, because of diminished membrane expression of mutant channels, that subsequently leads to elongated repolarization of cardiomyocyte, which might induce the pathogenesis of LQT2. Furthermore, E-4031 could partially rescue the decreased activity of hERGW410R channels. Thus, our work identifies a novel loss-of-function mutation in KCNH2 gene, which might provide a rational basis for the management of LQT2.

Carbon Monoxide Inhibits the Expression of Proteins Associated with Intestinal Mucosal Pyroptosis in a Rat Model of Sepsis Induced by Cecal Ligation and Puncture.

BACKGROUND Carbon monoxide (CO) has anti-inflammatory effects and protects the intestinal mucosal barrier in sepsis. Pyroptosis, or cell death associated with sepsis, is mediated by caspase-1 activation. This study aimed to investigate the role of CO on the expression of proteins associated with intestinal mucosal pyroptosis in a rat model of sepsis induced by cecal ligation and puncture (CLP). MATERIAL AND METHODS The rat model of sepsis was developed using CLP. Male Sprague-Dawley rats (n=120) were divided into six study groups: the sham group (n=20); the CLP group (n=20); the hemin group (treated with ferric chloride and heme) (n=20); the zinc protoporphyrin IX (ZnPPIX) group (n=20); the CO-releasing molecule 2 (CORM-2) group (n=20); and the inactive CORM-2 (iCORM-2) group (n=20). Hemin and CORM-2 were CO donors, and ZnPPIX was a CO inhibitor. In the six groups, the seven-day survival curves, the fluorescein isothiocyanate (FITC)-labeled dextran 4000 Da (FD-4) permeability assay, levels of intestinal pyroptosis proteins caspase-1, caspase-11, and gasdermin D (GSDMD) were measured by confocal fluorescence microscopy. Proinflammatory cytokines interleukin (IL)-18, IL-1ß, and high mobility group box protein 1 (HMGB1) were measured by Western blot and enzyme-linked immunosorbent assay (ELISA). RESULTS CO reduced the mortality rate in rats with sepsis and reduced intestinal mucosal permeability and mucosal damage. CO also reduced the expression levels of IL-18, IL-1ß, and HMGB1, and reduced pyroptosis by preventing the cleavage of caspase-1 and caspase-11. CONCLUSIONS In a rat model of sepsis induced by CLP, CO had a protective role by inhibiting intestinal mucosal pyroptosis.

Ibrutinib Contributes to Atrial Arrhythmia through the Autophagic Degradation of Connexins by Inhibiting the PI3K-AKT-mTOR Signaling Pathway.

BACKGROUND: Ibrutinib could increase the risk of atrial fibrillation (AF) in chronic lymphocytic leukemia (CLL) patients. However, the precise mechanism underlying ibrutinib-induced AF remains incompletely elucidated. METHODS: We investigated the proportion of ibrutinib-treated CLL patients with new-onset AF. Optical mapping was conducted to reveal the proarrhythmic effect of ibrutinib on HL-1 cells. Fluorescence staining and western blot were used to compare connexins 43 and 40 expression in ibrutinib-treated and control groups. To identify autophagy phenotypes, we used western blot to detect autophagy-related proteins, transmission electron microscopy to picture autophagosomes, and transfected mCherry-GFP-LC3 virus to label autophagosomes and lysosomes. Hydroxychloroquine as an autophagy inhibitor was administered to rescue ibrutinib-induced Cx43 and Cx40 degradation. RESULTS: About 2.67% of patients developed atrial arrhythmias after ibrutinib administration. HL-1 cells treated with ibrutinib exhibited diminished conduction velocity and a higher incidence of reentry-like arrhythmias compared to controls. Cx43 and Cx40 expression reduced along with autophagy markers increased in HL-1 cells treated with ibrutinib. Inhibiting autophagy upregulated Cx43 and Cx40. CONCLUSIONS: The off-target effect of ibrutinib on the PI3K-AKT-mTOR signaling pathway caused connexin degradation and atrial arrhythmia via promoting autophagy. CLINICAL TRIAL REGISTRATION: ChiCTR2100046062, https://clin.larvol.com/trial-detail/ChiCTR2100046062.

Cardiac-specific overexpression of CREM-IbΔC-X via CRISPR/Cas9 in mice presents a new model of atrial cardiomyopathy with spontaneous atrial fibrillation.

Atrial cardiomyopathy (ACM) forms the substrate for atrial fibrillation (AF) and underlies the potential for atrial thrombus formation and subsequent stroke. However, generating stable animal models that accurately replicate the entire progression of atrial lesions, particularly the onset of AF, presents significant challenges. In the present study, we found that the isoform of CRE-binding protein modulator (CREM-IbΔC-X), which is involved in the regulation of cardiac development and atrial rhythm, was highly expressed in atrial biopsies from patients with AF. Building upon this finding, we employed CRISPR/Cas9 technology to create a mouse model with cardiac-specific overexpression of CREM-IbΔC-X (referred to as CS-CREM mice). This animal model effectively illustrated the development of ACM through electrophysiological and structural remodelings over time. Proteomics and Chip-qPCR analysis of atrial samples revealed significant upregulation of cell-matrix adhesion and extracellular matrix structural components, alongside significant downregulation of genes related to atrial functions in the CS-CREM mice. Furthermore, the corresponding responses to anti-arrhythmia drugs, i.e., amiodarone and propafenone, suggested that CS-CREM mice could serve as an ideal in vivo model for drug testing. Our study introduced a novel ACM model with spontaneous AF by cardiac-specifically overexpressing CREM-IbΔC-X in mice, providing valuable insights into the mechanisms and therapeutic targets of ACM.

Febuxostat Increases Ventricular Arrhythmogenesis Through Calcium Handling Dysregulation in Human-Induced Pluripotent Stem Cell-Derived Cardiomyocytes.

Febuxostat is a xanthine oxidase inhibitor used to reduce the formation of uric acid and prevent gout attacks. Previous studies have suggested that febuxostat was associated with a higher risk of cardiovascular events, including atrial fibrillation, compared with allopurinol, another anti-hyperuricemia drug. Whereas in our clinical practice, we identified 2 cases of febuxostat-associated ventricular tachycardia (VT) events. The proarrhythmogenic effects of febuxostat on human cardiomyocytes and underlined mechanisms remain poorly understood. In this study, we employed real-time cell analysis and calcium transient to investigate the effects of febuxostat on the cytotoxicity and electrophysiology properties of human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). Up to 10 µM febuxostat treatment did not show toxicity to cell viability. However, 48-h febuxostat exposure generated dose-dependent increased irregular calcium transients and decreased calcium transient amplitude. Furthermore, RNA-seq analysis indicated that the MAPK signaling pathway was enriched in the febuxostat-treated group, especially the protein kinases c-Jun N-terminal kinase (JNK). Western blotting of 3 main protein kinases demonstrated that JNK activation is related to febuxostat-induced arrhythmia rather than extracellular signal regulated kinases (ERK) or p38. The dysfunctional calcium dynamics of febuxostat-treated hiPSC-CMs could be ameliorated by SP600125, the inhibitor of JNK. In conclusion, our study demonstrated that febuxostat increases the predisposition to ventricular arrhythmia by dysregulating calcium dynamics.

Unsupervised machine learning reveals epicardial adipose tissue subtypes with distinct atrial fibrosis profiles in patients with persistent atrial fibrillation: A prospective 2-center cohort study.

BACKGROUND: Epicardial adipose tissue (EAT) accumulation is associated with the progression of atrial fibrillation. However, the histological features of EATs are poorly defined and their correlation with atrial fibrosis is unclear. OBJECTIVE: The purpose of this study was to identify and characterize EAT subgroups in the persistent atrial fibrillation (PeAF) cohorts. METHODS: EATs and the corresponding left atrial appendage samples were obtained from patients with PeAF via surgical intervention. Adipocyte markers, that is, Uncoupling Protein 1, Transcription Factor 21, and CD137, were examined. On the basis of expression of adipocyte markers, patients with PeAF were categorized into subgroups by using unsupervised clustering analysis. Clinical characteristics, histological analyses, and outcomes were subsequently compared across the clusters. External validation was performed in a validation cohort. RESULTS: The ranking of feature importance revealed that the 3 adipocyte markers were the most relevant factors for atrial fibrosis compared with other clinical indicators. On the k-medoids analysis, patients with PeAF could be categorized into 3 clusters in the discovery cohort. The histological studies revealed that patients in cluster 1 exhibited statistically larger size of adipocytes in EATs and severe atrial fibrosis in left atrial appendages. Findings were replicated in the validation cohort, where severe atrial fibrosis was noted in cluster 1. Moreover, in the validation cohort, there was a high degree of overlap between the supervised classification results and the unsupervised cluster results from the k-medoids method. CONCLUSION: Machine learning-based cluster analysis could identify subtypes of patients with PeAF having distinct atrial fibrosis profiles. Additionally, EAT whitening (increased proportion of white adipocytes) may be involved in the process of atrial fibrosis.

Epicardial Adipose Tissue Measured From Computed Tomography Predicts Cardiac Resynchronization Therapy Response in Patients With Non-ischemic Systolic Heart Failure.

Background: Epicardial adipose tissue (EAT) has been linked with the pathogenesis of heart failure (HF). Limited data have been reported about the clinical value of EAT for cardiac resynchronization therapy (CRT) in non-ischemic systolic HF. We aimed to explore the values of EAT measured from CT to predict the response to CRT in patients with non-ischemic systolic HF. Methods: Forty-one patients with CRT were consecutively recruited for our study. All patients received both gated resting Single Photon Emission CT (SPECT) myocardial perfusion imaging (MPI) and dual-source multi-detector row CT scans. EAT thickness was assessed on both the parasternal short and horizontal long-axis views. The area of EAT was calculated at the left main coronary artery level. Left ventricular systolic mechanical dyssynchrony (LVMD) was measured by phase standard deviation (PSD) and phase histogram bandwidth (PBW). The definition of CRT response was an improvement of 5% in left ventricular ejection fraction (LVEF) at 6 months after CRT implantation. Results: After 6 months of follow-up, 58.5% (24 of 41) of patients responded to CRT. A greater total perfusion deficit (TPD) was observed in the left ventricle, and a narrower QRS complex was observed in the nonresponse group than in the response group (p < 0.05). Meanwhile, the systolic PSD and systolic PBW were statistically greater in the CRT group with no response than in the response group (p < 0.05). Meanwhile, the baseline QRS duration, TPD, systolic PSD, systolic PBW, EAT thicknesses of the left ventricular (LV) apex, right atrioventricular (AV) groove, and left AV groove were all significantly related to the CRT response in the univariate logistic regression analysis. Furthermore, the QRS duration and EAT thicknesses of the right AV groove and left AV groove were independent predictors of CRT response in the multivariate logistic regression analysis. Conclusions: The EAT thickness of the left AV groove in patients with non-ischemic systolic HF is associated with the TPD of LV and LV systolic dyssynchrony. The EAT thickness of the AV groove has a good predictive value for the CRT response in patients with non-ischemic systolic HF.

Pathogenesis and drug response of iPSC-derived cardiomyocytes from two Brugada syndrome patients with different Na v1.5-subunit mutations.

Brugada syndrome (BrS) is a complex genetic cardiac ion channel disease that causes a high predisposition to sudden cardiac death. Considering that its heterogeneity in clinical manifestations may result from genetic background, the application of patient-specific induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) may help to reveal cell phenotype characteristics underlying different genetic variations. Here, to verify and compare the pathogenicity of mutations (SCN5A c.4213G>A andSCN1B c.590C>T) identified from two BrS patients, we generated two novel BrS iPS cell lines that carried missense mutations inSCN5A or SCN1B, compared their structures and electrophysiology, and evaluated the safety of quinidine in patient-specific iPSC-derived CMs. Compared to the control group, BrS-CMs showed a significant reduction in sodium current, prolonged action potential duration, and varying degrees of decreased Vmax, but no structural difference. After applying different concentrations of quinidine, drug-induced cardiotoxicity was not observed within 3-fold unbound effective therapeutic plasma concentration (ETPC). The data presented proved that iPSC-CMs with variants in SCN5A c.4213G>A orSCN1B c.590C>T are able to recapitulate single-cell phenotype features of BrS and respond appropriately to quinidine without increasing incidence of arrhythmic events.

Anxiety is associated with increased risk for atrial cardiopathy.

Anxiety is common in patients with atrial fibrillation (AF). The mutual causal effect between anxiety and AF is expected with limited evidence. Atrial cardiopathy is a term to describe structural or electrophysiological atrium abnormality that precedes the onset of AF. This study aimed to investigate the association of anxiety with atrial cardiopathy, giving a clue to the causal relationship of this mind-heart link. This cross-sectional study analyzed 532 patients who were free of AF, atrial flutter, stroke, acute coronary syndrome and valvular heart disease. Atrial cardiopathy was defined as P-wave terminal force in lead V1 > 5000 µV·ms on electrocardiogram or severe left atrial enlargement on echocardiogram. Generalized anxiety disorder was ascertained by a score of > 17/56 on Hamilton anxiety rating scale. Multivariable logistic regression was used to explore the association of anxiety with atrial cardiopathy. A total of 65(12.2%) patients had atrial cardiopathy and 53(10.0%) had generalized anxiety disorder, respectively. Those with atrial cardiopathy were older (74.0 vs 67.0, P < 0.001), had a bigger left ventricular posterior wall thickness (10.1 vs 9.7 mm, P = 0.030), and had a higher prevalence of hypertension (83.1% vs 65.5%, P = 0.005), premature complexes (20.0% vs 6.2%, P < 0.001), and generalized anxiety disorder (20.0% vs 8.6%, P = 0.004), respectively. Multivariable logistic regression showed the significant association of anxiety with atrial cardiopathy (OR 2.788; 95% CI 1.304-5.960, P = 0.008), independent of confounding factors. Anxiety is independently associated with atrial cardiopathy. This association indicates the triggering effect of anxiety on atrial remodeling.

Association between advanced interatrial block and small vessel diseases in the brain.

BACKGROUND: The latest evidence shows the association of atrial cardiopathy with embolic strokes of undetermined source. Advanced interatrial block (aIAB) is an electrophysiological mark of atrial cardiopathy. This study investigated the relationship between aIAB and the burden of silent cerebral small vessel diseases (SVD) on magnetic resonance imaging in the absence of atrial fibrillation (AF) and atrial flutter. METHODS: This cross-sectional study included 499 patients with normal left ventricular ejection fraction (LVEF), who were free of AF, atrial flutter, stroke, and acute coronary syndrome in our hospital. aIAB was ascertained by digital electrocardiograms. Left atrial diameter, LVEF, and left ventricular posterior wall thickness (LVPWT) were measured on echocardiograms. Based on the presence of 4 manifestations of SVD, including white matter hyperintensity (WMH), lacunes, microbleeds, and enlarged perivascular spaces (EPVS) on magnetic resonance imaging, an ordinal SVD score (range, 0-4) was devised to reflect the total burden of cerebral SVD. The ordinal regression model was used to explore the association of aIAB with SVD burden after adjusting for confounding factors. RESULTS: The mean age was 67.7 years, and 327 (65.5%) were male. A total of 23 (4.6%) patients had aIAB. The number of patients with cerebral SVD scores of 0, 1, 2, 3, and 4 was 92 (18.4%), 122 (24.4%), 190 (38.1%), 83 (16.6%), and 12 (2.4%), respectively. After adjusting for age, sex, hypertension, diabetes, hyperlipidemia, left atrial diameter, LVEF, and LVPWT, the regression model showed a significant association of aIAB with cerebral SVD score (OR =2.408, 95% CI, 1.082-5.366). CONCLUSIONS: Atrial cardiopathy indexed by aIAB was independently associated with a high burden of SVD in the brain.