Myocardial Fibrosis Quantified by Extracellular Volume Is Associated With Subsequent Hospitalization for Heart Failure, Death, or Both Across the Spectrum of Ejection Fraction and Heart Failure Stage

P2 purinergic receptors at the heart of pathological left ventricular remodeling following acute myocardial infarction

Pathological left ventricular remodeling is a complex process following an acute myocardial infarction, leading to architectural disorganization of the cardiac tissue. This phenomenon is characterized by sterile inflammation and the exaggerated development of fibrotic tissue, which is noncontractile and poorly conductive, responsible for organ dysfunction and heart failure. At present, specific therapies are lacking for both prevention and treatment of this condition, and no biomarkers are currently validated to identify at-risk patients. Physiopathological understanding of this process is limited, probably due to the combination of the multicellular responses involved that are initially necessary for tissue healing but may be detrimental in the longer term. Current research focuses on understanding and modulating the inflammatory response, a key aspect of the tissue healing process. Inflammation is triggered by the release of inflammatory mediators from cardiomyocytes undergoing cell death in the context of ischemia-reperfusion injury. Among them, extracellular ATP is a strong mediator of inflammation through the activation of P2 purinergic receptors, regulating the behavior of all the cellular actors of the postmyocardial infarction response and impacting organ function and recovery. Rather than considering each cellular protagonist independently, this review provides an integrated overview of the inflammatory and tissue response to myocardial infarction by members of the P2 receptor family. Finally, it explores the possibility of reducing pathological left ventricular remodeling through the modulation of these receptors and their associated signaling pathways.

Prognostic Value of Myocardial T1 Mapping for Predicting Adverse Events in Hypertrophic Cardiomyopathy

BACKGROUND

In patients with hypertrophic cardiomyopathy, the prognostic value of myocardial T1 and extracellular volume fraction for adverse cardiovascular events has not been well defined.

METHODS

A total of 663 consecutive participants with hypertrophic cardiomyopathy who underwent 3T cardiovascular magnetic resonance were recruited. The follow-up end points included heart failure (HF)-related death, HF hospitalization, and sudden cardiac death or aborted sudden cardiac death.

RESULTS

On Cox proportional hazards regression multivariable analyses, global native T1 excluding late gadolinium enhancement areas (hazard ratio [HR], 1.04 [95% CI, 0.99-1.09]; P=0.094) and global extracellular volume fraction excluding late gadolinium enhancement (HR, 1.02 [95% CI, 0.95-1.10]; P=0.565) were not associated with sudden cardiac death. Conversely, global native T1 (HR, 1.08 per 10 ms increase [95% CI, 1.02-1.16], P=0.014; HR, 1.05 per 10 ms increase [95% CI, 1.01-1.09]; P=0.009) and global extracellular volume fraction (HR, 1.23 per 1% increase [95% CI, 1.11-1.36], P<0.001; HR, 1.10 per 1% increase [95% CI, 1.04-1.16]; P<0.001) were independently associated with HF-related death and the composite end point of HF-related death or HF hospitalization in multivariable Cox models, respectively.

CONCLUSIONS

In this study of patients with hypertrophic cardiomyopathy, we found global native T1 and global extracellular volume fraction (excluding late gadolinium enhancement) to be both independently associated with HF-related events, but not sudden cardiac death in multivariable analysis. These findings are hypothesis-generating and will require external validation in larger cohorts.

REGISTRATION

URL: https://www.chictr.org.cn; Unique identifier: ChiCTR1900024094.

Shaping cardiac diagnostics: The role of myocardial tissue mapping in unraveling ring-like fibrosis

BACKGROUND

Patients with non-ischemic cardiomyopathy exhibit a range of myocardial fibrosis (MF) patterns on cardiovascular magnetic resonance (CMR) late gadolinium enhancement (LGE) imaging. Data suggests that ring-like MF is associated with worse prognosis. In the present study it was sought to analyze the prevalence of parametric mapping abnormalities in ring-like MF and their prognostic value for arrhythmic events.

METHODS

Patients undergoing clinical CMR at 1.5T/3T were evaluated for ring-like MF defined as midwall/subepicardial fibrosis involving ≥ 3 contiguous left ventricular segments. CMR protocol included cine imaging, T1 and T2 mapping, and LGE. Mean native T1, ECV, and T2 values and a number of mid short axis segments with elevated values were calculated. LGE extent was assessed segmentally. Arrhythmic outcomes were defined as appropriate device shock, premature ventricular contractions ≥ 10%, non-sustained/sustained ventricular tachycardia, or ventricular fibrillation.

RESULTS

In total 49 patients (53 ± 17 years, 26.5% female) were analyzed. Many patients had elevated global/segmental mapping values: 45%/76% in native T1, 57%/57% in T2, and 57%/78% in ECV. During median follow-up of 12 months, arrhythmic events occurred in 65% of patients. There was no association between native T1/T2 elevation or number of LGE segments and arrhythmic outcomes. There was a significant association between ECV and arrhythmic outcomes, both septal ECV (p = 0.036) and any segmental ECV elevation (p = 0.03).

CONCLUSION

T1 and T2 myocardial tissue abnormalities are common in patients with ring-like MF. ECV elevation was associated with arrhythmic events in this cohort. Further studies are needed to establish the diagnostic and prognostic value of parametric mapping in patients with ring-like MF.

Extracellular volume fraction and native T1 mapping in diabetic cardiomyopathy: a comprehensive meta-analysis

BACKGROUND

Type 2 diabetes mellitus (T2DM) is associated with myocardial fibrosis (MF), a major contributor to adverse cardiovascular outcomes. Cardiovascular magnetic resonance (CMR), specifically extracellular volume fraction (ECV) and native T1 mapping, offers a non-invasive approach to quantify MF. This study aims to evaluate the utility of ECV and native T1 mapping as biomarkers for cardiac fibrosis and to assess their relationship with diabetes severity, measured by hemoglobin A1C (HbA1C), in patients with T2DM.

METHODS

A systematic review and meta-analysis were conducted following PRISMA guidelines. Comprehensive searches identified 19 eligible studies comprising 4,117 participants. Weighted mean differences (WMDs) were calculated for ECV and native T1 values between diabetic and non-diabetic groups. Meta-regression assessed the correlation between ECV and HbA1C. Sensitivity and subgroup analyses were performed to explore heterogeneity.

RESULTS

Diabetic patients exhibited significantly higher ECV values than controls (WMD: 2.17; 95% CI: 1.32-3.02), consistent across subgroups excluding cardiac comorbidities (WMD: 2.02; 95% CI: 0.74-3.31). HbA1C levels were also significantly elevated in diabetics (WMD: 1.78; 95% CI: 1.37-2.19). However, no significant difference in native T1 values was observed (WMD: 13.40; 95% CI: -13.98-40.79). Meta-regression revealed no significant correlation between ECV and HbA1C, potentially due to limited data and high heterogeneity (I²: 93.37%).

CONCLUSIONS

ECV is a promising marker for quantifying MF in T2DM, demonstrating significant differences between diabetics and controls. The lack of correlation between ECV and HbA1C underscores the complexity of MF in diabetes and highlights the need for further research. Future studies with standardized protocols are essential to validate these findings and refine the use of CMR in diabetic cardiomyopathy.

Advancing Cardiovascular Diagnostics: The Expanding Role of CMR in Heart Failure and Cardiomyopathies

Cardiovascular magnetic resonance (CMR) imaging has become a cornerstone in the diagnosis, risk stratification, and management of cardiovascular disease (CVD), particularly heart failure (HF) and cardiomyopathies. Renowned as the gold standard for non-invasive quantification of ventricular volumes and ejection fraction, CMR delivers superior spatial and temporal resolution with excellent tissue-blood contrast. Recent advancements, including T1, T2, and T2* mapping, extracellular volume quantification, and late gadolinium enhancement, enable precise tissue characterization, allowing early detection of myocardial changes such as fibrosis, edema, and infiltration. These features provide critical insights into the pathophysiological mechanisms underlying HF phenotypes and diverse cardiomyopathies, enhancing diagnostic accuracy and guiding therapeutic decisions. This review explores the expanding role of CMR in CV disease, highlighting its diagnostic value in HF and in several cardiomyopathies, as well as its contribution to improving patient outcomes through detailed tissue characterization and prognosis.

Insight of immune checkpoint inhibitor related myocarditis

As the understanding of immune-related mechanisms in the development and progression of cancer advances, immunotherapies, notably Immune Checkpoint Inhibitors (ICIs), have become integral in comprehensive cancer treatment strategies. ICIs reactivate T-cell cytotoxicity against tumors by blocking immune suppressive signals on T cells, such as Programmed Death-1 (PD-1) and Cytotoxic T-lymphocyte Antigen-4 (CTLA-4). Despite their beneficial effects, ICIs are associated with immune-related adverse events (irAEs), manifesting as autoimmune side effects across various organ systems. A particularly alarming irAE is life-threatening myocarditis. This rare but severe side effect of ICIs leads to significant long-term cardiac complications, including arrhythmias and heart failure, and has been observed to have a mortality rate of up to 50% in affected patients. This greatly limits the clinical application of ICI-based immunotherapy. In this review, we provide a comprehensive summary of the current knowledge regarding the diagnosis and management of ICI-related myocarditis. We also discuss the utility of preclinical mouse models in understanding and addressing this critical challenge.

Immune Profile and MRI-Detected Cardiac Fibrosis and Edema in Hypertensive and Non-Hypertensive Patients with COVID-19

Cardiac involvement in 2019 coronavirus disease (COVID-19) survivors has been reported frequently. An exacerbated immune response may be the main mechanism of myocardial injury and late cardiac sequelae in this population. Background/Objectives: We investigated the immune profile in hypertensive and non-hypertensive patients with COVID-19 who developed late cardiac fibrosis and edema, as detected by magnetic resonance imaging (MRI). Methods: We evaluated associations of cytokine and immune-cell subset levels during hospitalization for COVID-19 with the presence of myocardial interstitial fibrosis [represented by the extracellular volume (ECV)] or edema (represented by the T2), detected by cardiac MRI examination after discharge, in hypertensive and non-hypertensive patients. Results: Patients with hypertension had reduced B-cell percentages, increased natural killer cell percentages, and higher interleukin (IL)-4, IL-5, IL-13, IL-17A, and tumor necrosis factor-β levels compared to patients without hypertension. Larger percentages of human leukocyte antigen DR isotope+ blood cells, reflecting CD8+ T-cell activation, correlated with increased T2 and ECV in hypertensive patients. The HLA-DR mean fluorescence intensity was associated with ECV in non-hypertensive patients. Conclusions: Our findings reveal cytokine and immune-cell dysregulation in both hypertensive and non-hypertensive patients with COVID-19, along with moderate correlations between CD8+ T-cell activation and increased cardiac MRI markers of myocardial interstitial fibrosis and edema. These results contribute to a deeper understanding of immune dysfunction mechanisms involved in myocardial remodeling.

Distinguishing hypertensive cardiomyopathy from cardiac amyloidosis in hypertensive patients with heart failure: a CMR study with histological confirmation

PURPOSE

Differentiation of the cause of left ventricular hypertrophy (LVH) is challenging in cases with co-existing hypertension. CMR offers assessment of diffuse myocardial abnormalities via T1 mapping with extracellular volume fraction (ECV) and macroscopic fibrosis via late gadolinium enhancement imaging (LGE). The goal of the study was to understand if CMR parameters can differentiate hypertensive cardiomyopathy (HC) from cardiac amyloidosis (CA) in patients with hypertension and heart failure, using endomyocardial biopsy (EMB) as the gold standard.

METHODS

We retrospectively analyzed patients with hypertension, LVH, and heart failure undergoing EMB due to uncertain diagnosis. CMR parameters including cine, LGE characteristics, T1 mapping, and ECV were analyzed.

RESULTS

A total of 34 patients were included (mean age 66.5 ± 10.7 years, 79.4% male). The final EMB-based diagnosis was HC (10, 29%), light chain (AL) CA (7, 21%), and transthyretin (ATTR) CA (17, 50%). There was a significant difference in subendocardial LGE (p = 0.03) and number of AHA segments with subendocardial LGE (p = 0.005). The subendocardial LGE pattern was most common in AL-CA (85.7%) and African American with HC (80%). ECV elevation (≥ 29%) was present in all patients with CA (AL-CA: 57.6 ± 5.2%, ATTR-CA: 59.1 ± 15.3%) and HC (37.3 ± 4.5%).

CONCLUSIONS

Extensive subendocardial LGE pattern is not pathognomonic for CA but might also be present in African American patients with longstanding or poorly controlled HTN. The ECV elevation in HC with HF might be more significant than previously reported with an overlap of ECV values in HC and CA, particularly in younger African American patients.

Extracellular Volume and Fibrosis Volume of Left Ventricular Myocardium Assessed by Cardiac Magnetic Resonance in Vaccinated and Unvaccinated Patients with a History of SARS-CoV-2 Infection

Cardiac magnetic resonance (CMR) enables the assessment of tissue characteristics of the myocardium. Changes in the extracellular volume (ECV) and fibrosis volume (FV) of the myocardium are sensitive and early pathogenetic markers and have prognostic significance. The aim of the study was to assess ECV and FV of left ventricular myocardium in T1 mapping sequence in patients with a history of SARS-CoV-2 infection, considering vaccination status against COVID-19. The study group consisted of 97 patients (52.54 ± 8.31 years, 53% women and 47% men). The participants were divided into three subgroups: A) patients with a history of symptomatic SARS-CoV-2 infection, unvaccinated against COVID-19 (n = 39), B) patients with a history of symptomatic SARS-CoV-2 infection, with a full vaccination schedule against COVID-19 (n = 22), and C) persons without a history of SARS-CoV-2 infection constituting the control subgroup (C, n = 36). All patients underwent 1.5 T cardiac magnetic resonance. In subgroup A compared to subgroups B and C, both the ECV whole myocardium and ECV segments 2, 5-6, 8, and 10-11 were statistically significantly higher. In addition, the ECV segment 16 was statistically significantly higher in subgroup A than in subgroup C. Also, the FV whole myocardium was statistically significantly higher in subgroup A in comparison to subgroups B and C. There were no significant differences in ECV and FV between subgroups B and C. In summary, unvaccinated against COVID-19 patients with a history of symptomatic SARS-CoV-2 infection have higher myocardial ECV and FV values in the T1 mapping sequence, compared to those without COVID-19 and those suffering from COVID-19, previously vaccinated with the full vaccination schedule.

Incremental Prognostic Value of Cardiac MRI Feature Tracking and T1 Mapping in Arrhythmogenic Right Ventricular Cardiomyopathy

Purpose To explore the role of cardiac MRI feature tracking (FT) and T1 mapping in predicting sustained ventricular arrhythmias (VA) in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) and to investigate their possible incremental value beyond ARVC risk score. Materials and Methods The retrospective study analyzed 91 patients with ARVC (median age, 36 years [IQR, 27-50 years]; 60 male, 31 female) who underwent cardiac MRI examinations between November 2010 and March 2022. The primary end point was the first occurrence of sustained VA after cardiac MRI to first VA, with censoring of patients who were alive without VA at last follow-up. Cox regression analysis was performed to assess the association between variables and time to sustained VA. Time-dependent receiver operating characteristic (ROC) analysis was performed to determine the incremental value of cardiac MRI FT and T1 mapping. Results During a median follow-up of 55.0 months (IQR, 37.0-76.0 months), 36 of 91 (40%) patients experienced sustained VA. A 1% worsening in left ventricular global longitudinal peak strain (GLS), 1% worsening in right ventricular GLS, and a 1% increase in extracellular volume fraction (ECV) were associated with increased risk of sustained VA, with hazard ratios of 1.14 (95% CI: 1.06, 1.23; P = .001), 1.09 (95% CI: 1.02, 1.16; P = .02), and 1.13 (95% CI: 1.08, 1.18; P < .001), respectively, after adjustment for ARVC risk score. Adding both biventricular GLS and ECV to ARVC risk score showed significant incremental value for predicting sustained VA (area under the ROC curve: 0.73 vs 0.65; P < .001). Conclusion Cardiac MRI-derived biventricular GLS and ECV provided independent and incremental value for predicting sustained VA beyond ARVC risk score alone in patients with ARVC. Keywords: Cardiovascular MRI, Feature Tracking, T1 Mapping, Arrhythmogenic Right Ventricular Cardiomyopathy, Sustained Ventricular Arrhythmias Supplemental material is available for this article Published under a CC BY 4.0 license.

Transplanting network pharmacology technology into food science research: A comprehensive review on uncovering food-sourced functional factors and their health benefits

Network pharmacology is an emerging interdisciplinary research method. The application of network pharmacology to reveal the nutritional effects and mechanisms of active ingredients in food is of great significance in promoting the development of functional food, facilitating personalized nutrition, and exploring the mechanisms of food health effects. This article systematically reviews the application of network pharmacology in the field of food science using a literature review method. The application progress of network pharmacology in food science is discussed, and the mechanisms of functional factors in food on the basis of network pharmacology are explored. Additionally, the limitations and challenges of network pharmacology are discussed, and future directions and application prospects are proposed. Network pharmacology serves as an important tool to reveal the mechanisms of action and health benefits of functional factors in food. It helps to conduct in-depth research on the biological activities of individual ingredients, composite foods, and compounds in food, and assessment of the potential health effects of food components. Moreover, it can help to control and enhance their functionality through relevant information during the production and processing of samples to guarantee food safety. The application of network pharmacology in exploring the mechanisms of functional factors in food is further analyzed and summarized. Combining machine learning, artificial intelligence, clinical experiments, and in vitro validation, the achievement transformation of functional factor in food driven by network pharmacology is of great significance for the future development of network pharmacology research.

HIV, HIV-Specific Factors, and Myocardial Disease in Women

BACKGROUND

People with human immunodeficiency virus (HIV) (PWH) have an increased risk of cardiovascular disease (CVD). Cardiac magnetic resonance (CMR) has documented higher myocardial fibrosis, inflammation, and steatosis in PWH, but studies have mostly relied on healthy volunteers as comparators and focused on men.

METHODS

We investigated the associations of HIV and HIV-specific factors with CMR phenotypes in female participants enrolled in the Women's Interagency HIV Study's New York and San Francisco sites. Primary phenotypes included myocardial native (n) T1 (fibro-inflammation), extracellular volume fraction (fibrosis), and triglyceride content (steatosis). Associations were evaluated with multivariable linear regression, and results pooled or meta-analyzed across centers.

RESULTS

Among 261 women with HIV (WWH, N = 362), 76.2% had undetectable viremia at CMR. For the 82.8% receiving continuous antiretroviral therapy (ART) in the preceding 5 years, adherence was 51.7%, and 69.4% failed to achieve persistent viral suppression (40.7% with peak viral load <200 cp/mL). Overall, WWH showed higher nT1 than women without HIV after full adjustment. This higher nT1 was more pronounced in those with antecedent or current viremia or nadir CD4+ count <200 cells/μL, with the latter also associated with higher extracellular volume fraction. WWH and current CD4+ count <200 cells/μL had less cardiomyocyte steatosis. Cumulative exposure to specific ART showed no associations.

CONCLUSIONS

Compared with sociodemographically similar women without HIV, WWH on ART exhibit higher myocardial fibro-inflammation, which is more prominent with unsuppressed viremia or CD4+ lymphopenia. These findings support the importance of improved ART adherence strategies, along with better understanding of latent infection, to mitigate cardiac end-organ damage in this population.

Precision Phenotyping of Heart Failure in People with HIV: Early Insights and Challenges

PURPOSE OF REVIEW

People with HIV have an elevated risk of developing heart failure even with optimally controlled disease. In this review, we outline the various mechanisms through which HIV infection may directly and indirectly contribute to heart failure pathology and highlight the emerging relationship between HIV, chronic inflammation, and cardiometabolic disease.

RECENT FINDINGS

HIV infection leads to chronic inflammation, immune dysregulation, and metabolic imbalances even in those with well controlled disease. These dysregulations occur through several diverse mechanisms which may lead to manifestations of different phenotypes of heart failure in people with HIV. While it has long been known that people with HIV are at risk of developing heart failure, recent studies have suggested numerous complex mechanisms involving chronic inflammation, immune dysregulation, and metabolic derangement through which this may be mediated. Further comprehensive studies are needed to elucidate the precise relationship between these mechanisms and the development of different subtypes of heart failure in people with HIV.

Cellular and molecular mechanisms driving cardiac tissue fibrosis: On the precipice of personalized and precision medicine

Cardiac fibrosis is a significant contributor to heart failure, a condition that continues to affect a growing number of patients worldwide. Various cardiovascular comorbidities can exacerbate cardiac fibrosis. While fibroblasts are believed to be the primary cell type underlying fibrosis, recent and emerging data suggest that other cell types can also potentiate or expedite fibrotic processes. Over the past few decades, clinicians have developed therapeutics that can blunt the development and progression of cardiac fibrosis. While these strategies have yielded positive results, overall clinical outcomes for patients suffering from heart failure continue to be dire. Herein, we overview the molecular and cellular mechanisms underlying cardiac tissue fibrosis. To do so, we establish the known mechanisms that drive fibrosis in the heart, outline the diagnostic tools available, and summarize the treatment options used in contemporary clinical practice. Finally, we underscore the critical role the immune microenvironment plays in the pathogenesis of cardiac fibrosis.

Utility of native T1 mapping and myocardial extracellular volume fraction in patients with nonischemic dilated cardiomyopathy: A systematic review and meta-analysis

Background

Cardiac magnetic resonance imaging (CMR) based T1 mapping and extracellular volume fraction (ECV) are powerful tools for identifying myocardial fibrosis. This systematic review and meta-analysis aims to characterize the utility of native T1 mapping and ECV in patients with non-ischemic cardiomyopathy (NICM) and to clarify the prognostic significance of elevated values.

Methods

A literature search was conducted for studies reporting on use of CMR-based native T1 mapping and ECV measurement in NICM patients and their association with major adverse cardiac events (MACE), ventricular arrhythmias (VAs), and left ventricular reverse remodeling (LVRR). Databases searched included: Ovid MEDLINE, EMBASE, Web of Science, and Google Scholar. The search was not restricted to time or publication status.

Results

Native T1 and ECV were significantly higher in NICM patients compared to controls (MD 78.80, 95 % CI 50.00, 107.59; p < 0.01; MD 5.86, 95 % CI 4.55, 7.16; p < 0.01). NICM patients who experienced MACE had higher native T1 and ECV (MD 52.87, 95 % CI 26.59, 79.15; p < 0.01; MD 6.03, 95 % CI 3.79, 8.26; p < 0.01). There was a non-statistically significant trend toward higher native T1 time in NICM patients who experienced VAs. NICM patients who were poor treatment responders had higher baseline native T1 and ECV (MD 40.58, 95 % CI 12.90, 68.25; p < 0.01; MD 3.29, 95 % CI 2.25, 4.33; p < 0.01).

Conclusions

CMR-based native T1 and ECV quantification may be useful tools for risk stratification of patients with NICM. They may provide additional diagnostic utility in combination with LGE, which poorly characterizes fibrosis in patients with diffuse myocardial involvement.

No adverse association between exercise exposure and diffuse myocardial fibrosis in male endurance athletes

The potential association between endurance exercise and myocardial fibrosis is controversial. Data on exercise exposure and diffuse myocardial fibrosis in endurance athletes are scarce and conflicting. We aimed to investigate the association between exercise exposure and markers of diffuse myocardial fibrosis by cardiovascular magnetic resonance imaging (CMR) in endurance athletes. We examined 27 healthy adult male competitive endurance athletes aged 41 ± 9 years and 16 healthy controls in a cross sectional study using 3 Tesla CMR including late gadolinium enhancement and T1 mapping. Athletes reported detailed exercise history from 12 years of age. Left ventricular total mass, cellular mass and extracellular mass were higher in athletes than controls (86 vs. 58 g/m2, 67 vs. 44 g/m2 and 19 vs. 13 g/m2, all p < 0.01). Extracellular volume (ECV) was lower (21.5% vs. 23.8%, p = 0.03) and native T1 time was shorter (1214 ms vs. 1268 ms, p < 0.01) in the athletes. Increasing exercise dose was independently associated with shorter native T1 time (regression coefficient - 24.1, p < 0.05), but expressed no association with ECV. Our results indicate that diffuse myocardial fibrosis has a low prevalence in healthy male endurance athletes and do not indicate an adverse dose-response relationship between exercise and diffuse myocardial fibrosis in healthy athletes.

Identification of diagnostic model in heart failure with myocardial fibrosis and conduction block by integrated gene co-expression network analysis

BACKGROUND

Despite the advancements in heart failure(HF) research, the early diagnosis of HF continues to be a challenging issue in clinical practice. This study aims to investigate the genes related to myocardial fibrosis and conduction block, with the goal of developing a diagnostic model for early treatment of HF in patients.

METHOD

The gene expression profiles of GSE57345, GSE16499, and GSE9128 were obtained from the Gene Expression Omnibus (GEO) database. After merging the expression profile data and adjusting for batch effects, differentially expressed genes (DEGs) associated with conduction block and myocardial fibrosis were identified. Gene Ontology (GO) resources, Kyoto Encyclopedia of Genes and Genomes (KEGG) resources, and gene set enrichment analysis (GSEA) were utilized for functional enrichment analysis. A protein-protein interaction network (PPI) was constructed using a string database. Potential key genes were selected based on the bioinformatics information mentioned above. SVM and LASSO were employed to identify hub genes and construct the module associated with HF. The mRNA levels of TAC mice and external datasets (GSE141910 and GSE59867) are utilized for validating the diagnostic model. Additionally, the study explores the relationship between the diagnostic model and immune cell infiltration.

RESULTS

A total of 395 genes exhibiting differential expression were identified. Functional enrichment analysis revealed that these specific genes primarily participate in biological processes and pathways associated with the constituents of the extracellular matrix (ECM), immune system processes, and inflammatory responses. We identified a diagnostic model consisting of 16 hub genes, and its predictive performance was validated using external data sets and a transverse aortic coarctation (TAC) mouse model. In addition, we observed significant differences in mRNA expression of 7 genes in the TAC mouse model. Interestingly, our study also unveiled a correlation between these model genes and immune cell infiltration.

CONCLUSIONS

We identified sixteen key genes associated with myocardial fibrosis and conduction block, as well as diagnostic models for heart failure. Our findings have significant implications for the intensive management of individuals with potential genetic variants associated with heart failure, especially in the context of advancing cell-targeted therapy for myocardial fibrosis.

Quantitating myocardial fibrosis using extracellular extravascular volume determined from computed tomography myocardial perfusion imaging

PURPOSE

Both of extracellular extravascular volume (EEV) and extracellular volume fraction (ECV) were proposed to quantify enlargement of myocardial interstitial space due to myocardium loss or fibrosis. The study aimed to investigate the feasibility of using EEV derived from myocardial computed tomography (CT) perfusion imaging (VPCT) and extracellular volume quantification with single-energy subtraction CT (ECV- SECT) for quantifying myocardial fibrosis.

METHODS

In this study, 17 patients with suspected and known coronary artery disease underwent examination using a dual-source CT scanner. The EEV- VPCT was derived from dynamic whole-heart myocardial perfusion imaging, and the ECV_SECT was calculated from late-enhanced images 5 min after bolus contrast injection by subtracting the noncontrast baseline. The late gadolinium enhancement (LGE) on cardiac magnetic resonance (CMR) imaging was used as a reference.

RESULTS

In total, 11 patients and 73 segments exhibited positivity for LGE on CMR imaging. These were classified into three groups according to the segments: fibrotic segments (group I, n = 73), nonfibrotic segments in LGE-positive patients (group II, n = 103), and segments in LGE-negative patients (group III, n = 80). ECV- SECT, EEV- VPCT, myocardial blood flow (MBF), and myocardial blood volume (MBV) significantly differed among these groups (all P < 0.05). ECV- SECT was significantly higher and EEV- VPCT, MBF, and MBV were significantly lower in fibrotic myocardial segments than in nonfibrotic ones (all P < 0.01). ECV- SECT and EEV- VPCT independently affected myocardial fibrosis. There was no significant correlation between ECV- SECT and EEV- VPCT. The capability of EEV- VPCT to diagnose myocardial fibrosis was equivalent to that of ECV- SECT (area under the curve: 0.798 vs. 0.806, P = 0.844). ECV- SECT of > 41.2% and EEV- VPCT of < 10.3% indicated myocardial fibrosis.

CONCLUSIONS

EEV- VPCT is actually first-pass distribution volume that can feasibly be used to quantify myocardial fibrosis. Furthermore, the diagnostic efficacy of EEV- VPCT is comparable to that of ECV- SECT.

Review of the Protective Mechanism of Curcumin on Cardiovascular Disease

Cardiovascular diseases (CVDs) are the most common cause of death worldwide and has been the focus of research in the medical community. Curcumin is a polyphenolic compound extracted from the root of turmeric. Curcumin has been shown to have a variety of pharmacological properties over the past decades. Curcumin can significantly protect cardiomyocyte injury after ischemia and hypoxia, inhibit myocardial hypertrophy and fibrosis, improve ventricular remodeling, reduce drug-induced myocardial injury, improve diabetic cardiomyopathy(DCM), alleviate vascular endothelial dysfunction, inhibit foam cell formation, and reduce vascular smooth muscle cells(VSMCs) proliferation. Clinical studies have shown that curcumin has a protective effect on blood vessels. Toxicological studies have shown that curcumin is safe. But high doses of curcumin also have some side effects, such as liver damage and defects in embryonic heart development. This article reviews the mechanism of curcumin intervention on CVDs in recent years, in order to provide reference for the development of new drugs in the future.

Cardiovascular magnetic resonance imaging for sequential assessment of cardiac fibrosis in mice: technical advancements and reverse translation

Cardiovascular magnetic resonance (CMR) imaging has become an essential technique for the assessment of cardiac function and morphology, and is now routinely used to monitor disease progression and intervention efficacy in the clinic. Cardiac fibrosis is a common characteristic of numerous cardiovascular diseases and often precedes cardiac dysfunction and heart failure. Hence, the detection of cardiac fibrosis is important for both early diagnosis and the provision of guidance for interventions/therapies. Experimental mouse models with genetically and/or surgically induced disease have been widely used to understand mechanisms underlying cardiac fibrosis and to assess new treatment strategies. Improving the appropriate applications of CMR to mouse studies of cardiac fibrosis has the potential to generate new knowledge, and more accurately examine the safety and efficacy of antifibrotic therapies. In this review, we provide 1) a brief overview of different types of cardiac fibrosis, 2) general background on magnetic resonance imaging (MRI), 3) a summary of different CMR techniques used in mice for the assessment of cardiac fibrosis including experimental and technical considerations (contrast agents and pulse sequences), and 4) provide an overview of mouse studies that have serially monitored cardiac fibrosis during disease progression and/or therapeutic interventions. Clinically established CMR protocols have advanced mouse CMR for the detection of cardiac fibrosis, and there is hope that discovery studies in mice will identify new antifibrotic therapies for patients, highlighting the value of both reverse translation and bench-to-bedside research.

Myocarditis and Chronic Inflammatory Cardiomyopathy, from Acute Inflammation to Chronic Inflammatory Damage: An Update on Pathophysiology and Diagnosis

Acute myocarditis covers a wide spectrum of clinical presentations, from uncomplicated myocarditis to severe forms complicated by hemodynamic instability and ventricular arrhythmias; however, all these forms are characterized by acute myocardial inflammation. The term "chronic inflammatory cardiomyopathy" describes a persistent/chronic inflammatory condition with a clinical phenotype of dilated and/or hypokinetic cardiomyopathy associated with symptoms of heart failure and increased risk for arrhythmias. A continuum can be identified between these two conditions. The importance of early diagnosis has grown markedly in the contemporary era with various diagnostic tools available. While cardiac magnetic resonance (CMR) is valid for diagnosis and follow-up, endomyocardial biopsy (EMB) should be considered as a first-line diagnostic modality in all unexplained acute cardiomyopathies complicated by hemodynamic instability and ventricular arrhythmias, considering the local expertise. Genetic counseling should be recommended in those cases where a genotype-phenotype association is suspected, as this has significant implications for patients' and their family members' prognoses. Recognition of the pathophysiological pathway and clinical "red flags" and an early diagnosis may help us understand mechanisms of progression, tailor long-term preventive and therapeutic strategies for this complex disease, and ultimately improve clinical outcomes.

Risk stratification in patients with structurally normal hearts: Does fibrosis type matter?

OBJECTIVES

The study sought to assess the prognostic significance of nonischemic myocardial fibrosis (MF) on cardiovascular magnetic resonance (CMR)-both macroscopic MF assessed by late gadolinium enhancement (LGE) and diffuse microscopic MF quantified by extracellular volume fraction (ECV)-in patients with structurally normal hearts.

BACKGROUND

The clinical relevance of tissue abnormalities identified by CMR in patients with structurally normal hearts remains unclear.

METHODS

Consecutive patients undergoing CMR were screened for inclusion to identify those with LGE imaging and structurally normal hearts. ECV was calculated in patients with available T1 mapping. The associations between myocardial fibrosis and the outcomes of all-cause mortality, new-onset heart failure [HF], and an arrhythmic outcome were evaluated.

RESULTS

In total 525 patients (mean age 43.1±14.2 years; 30.5% males) were included. Over a median follow-up of 5.8 years, 13 (2.5%) patients died and 18 (3.4%) developed new-onset HF. Nonischemic midwall /subepicardial LGE was present in 278 (52.9%) patients; isolated RV insertion fibrosis was present in 80 (15.2%) patients. In 276 patients with available T1 mapping, the mean ECV was 25.5 ± 4.4%. There was no significant association between LGE and all-cause mortality (HR: 1.36, CI: 0.42-4.42, p = 0.61), or new-onset HF (HR: 0.64, CI: 0.25-1.61, p = 0.34). ECV (per 1% increase) correlated with all-cause mortality (HR: 1.19, CI: 1.04-1.36, p = 0.009), but not with new-onset HF (HR: 0.97, CI: 0.86-1.10, p = 0.66). There was no significant association between arrhythmic outcomes and LGE (p = 0.60) or ECV (p = 0.49). In a multivariable model after adjusting for covariates, ECV remained significantly associated with all-cause mortality (HR per 1% increase in ECV: 1.26, CI: 1.06-1.50, p = 0.009).

CONCLUSION

Nonischemic LGE in patients with structurally normal hearts is common and does not appear to be associated with adverse outcomes, whereas elevated ECV is associated with all-cause mortality and may be an important risk stratification tool.

Prognostic utility and characterization of left ventricular hypertrophy using global thickness

Cardiovascular magnetic resonance (CMR) can accurately measure left ventricular (LV) mass, and several measures related to LV wall thickness exist. We hypothesized that prognosis can be used to select an optimal measure of wall thickness for characterizing LV hypertrophy. Subjects having undergone CMR were studied (cardiac patients, n = 2543; healthy volunteers, n = 100). A new measure, global wall thickness (GT, GTI if indexed to body surface area) was accurately calculated from LV mass and end-diastolic volume. Among patients with follow-up (n = 1575, median follow-up 5.4 years), the most predictive measure of death or hospitalization for heart failure was LV mass index (LVMI) (hazard ratio (HR)[95% confidence interval] 1.16[1.12-1.20], p < 0.001), followed by GTI (HR 1.14[1.09-1.19], p < 0.001). Among patients with normal findings (n = 326, median follow-up 5.8 years), the most predictive measure was GT (HR 1.62[1.35-1.94], p < 0.001). GT and LVMI could characterize patients as having a normal LV mass and wall thickness, concentric remodeling, concentric hypertrophy, or eccentric hypertrophy, and the three abnormal groups had worse prognosis than the normal group (p < 0.05 for all). LV mass is highly prognostic when mass is elevated, but GT is easily and accurately calculated, and adds value and discrimination amongst those with normal LV mass (early disease).

CT for the evaluation of myocardial extracellular volume with MRI as reference: a systematic review and meta-analysis

OBJECTIVE

Myocardial extracellular volume (ECV) fraction is an important imaging biomarker in clinical decision-making. CT-ECV is a potential alternative to MRI for ECV quantification. We conducted a meta-analysis to comprehensively assess the reliability of CT for ECV quantification with MRI as a reference.

METHODS

We systematically searched PubMed, EMBASE, and the Cochrane Library for relevant articles published since the establishment of the database in July 2022. The articles comparing CT-ECV with MRI as a reference were included. Meta-analytic methods were applied to determine the pooled weighted bias, limits of agreement (LOA), and correlation coefficient (r) between CT-ECV and MRI-ECV.

RESULTS

Seventeen studies with a total of 459 patients and 2231 myocardial segments were included. The pooled mean difference (MD), LOA, and r for ECV quantification at the per-patient level was (0.07%; 95% LOA: - 0.42 to 0.55%) and 0.89 (95% CI: 0.86-0.91), respectively, while on the per-segment level was (0.44%; 95% LOA: 0.16-0.72%) and 0.84 (95% CI: 0.82-0.85), respectively. The pooled r from studies with the ECViodine method for ECV quantification was significantly higher compared to those with the ECVsub method (0.94 (95% CI: 0.91-0.96) vs. 0.84 (95% CI: 0.80-0.88), respectively, p = 0.03). The pooled r from septal segments was significantly higher than those from non-septal segments (0.88 (95% CI: 0.86-0.90) vs. 0.76 (95% CI: 0.71-0.90), respectively, p = 0.009).

CONCLUSION

CT showed a good agreement and excellent correlation with MRI for ECV quantification and is a potentially attractive alternative to MRI.

CLINICAL RELEVANCE STATEMENT

The myocardial extracellular volume fraction can be acquired using a CT scan, which is not only a viable alternative to myocardial extracellular volume fraction derived from MRI but is also less time-consuming and costly for patients.

KEY POINTS

• Noninvasive CT-ECV is a viable alternative to MRI-ECV for ECV quantification. • CT-ECV using the ECViodine method showed more accurate myocardial ECV quantification than ECVsub. • Septal myocardial segments showed lower measurement variability than non-septal segments for the ECV quantification.

Ultrasound-Induced Microbubble Cavitation for Targeted Delivery of MiR-29b Mimic to Treat Cardiac Fibrosis

OBJECTIVE

Cardiac fibrosis contributes to adverse ventricular remodeling and is associated with loss of miR-29b. Overexpression of miR-29b via plasmid or intravenous injection of microRNA mimic has blunted fibrosis, but these are inefficient and non-targeted delivery strategies. In this study, we tested the hypothesis that delivery of microRNA-29b (miR-29b) using ultrasound-targeted microbubble cavitation (UTMC) of miR-29b-loaded microbubbles would attenuate cardiac fibrosis and preserve left ventricular (LV) function.

METHODS

Lipid microbubbles were loaded with miR-29b mimic (miR-29b-MB) or negative control (NC) mimic (NC-MB), placed with cardiac fibroblasts (CFs) and treated with pulsed ultrasound. Cells were harvested to measure downstream fibrotic mediators. Mice received angiotensin II (ANG II) infusion causing afterload increase and direct ANG II-induced cardiac fibrosis. UTMC of miRNA-loaded microbubbles was administered to the heart at days 0, 3 and 7. Serial echocardiography was performed, and hearts were harvested on day 10.

RESULTS

UTMC treatment of CFs with miR-29b-MB increased miR-29b and decreased fibrotic transcripts compared with NC-MB treatment. In vivo UTMC + NC-MB led to increased LV mass, reduction in cardiac function and increase in fibrotic markers, demonstrating ANGI II-induced adverse cardiac remodeling. Mice treated with UTMC + miR-29b-MB had preservation of cardiac function, downregulation of cardiac fibrillin and trends of lower COL1A1, COL1A2 and COL3 mRNA and decreased cardiac α-smooth muscle protein.

CONCLUSION

UTMC-mediated delivery of miR-29b mimic blunts expression of fibrosis markers and preserves LV function in ANG II-induced cardiac fibrosis.

How Cardiac Fibrosis Assessed via T1 Mapping Is Associated with Liver Fibrosis in Patients with Non-Alcoholic Fatty Liver Disease

(1) Background: Nonalcoholic fatty liver disease (NAFLD) is one of the most common chronic liver diseases worldwide. Although cardiovascular and NAFLD risk factors overlap, an independent association between these conditions may exist. Hepatic and cardiac fibrosis are important markers of mortality, but the correlation between these markers in patients with NAFLD has not been well studied. Our main objective was to determine the degree of myocardial fibrosis in patients with NAFLD and its correlation with the severity of liver fibrosis. (2) Methods: In this cross-sectional study, patients with NAFLD were allocated to two groups according to the stage of liver fibrosis assessed using MRI: no or mild fibrosis (F0-F1) and significant fibrosis (F2-F4). Framingham risk scores were calculated to evaluate cardiovascular risk factors, and patients underwent multiparametric cardiac and abdominal MRIs. (3) Results: The sample comprised 44 patients (28 with no or mild liver fibrosis and 16 with significant liver fibrosis). The mean age was 57.9 ± 12 years, and 41% were men. Most patients had high cardiac risk factors and carotid disease. Relative to patients with no or mild liver fibrosis, those with significant fibrosis had a higher median calcium score (p = 0.05) and increased myocardial extracellular volume (ECV; p = 0.02). Liver fibrosis correlated with cardiac fibrosis, represented by the ECV (r = 0.49, p < 0.001). The myocardial ECV differentiated patients with and without significant liver fibrosis (AUC = 0.78). (4) Conclusion: This study showed that diffuse myocardial fibrosis is associated with liver fibrosis in patients with NAFLD.

Myocardial Recovery in Recent Onset Dilated Cardiomyopathy: Role of CDCP1 and Cardiac Fibrosis

BACKGROUND

Dilated cardiomyopathy (DCM) is a major cause of heart failure and carries a high mortality rate. Myocardial recovery in DCM-related heart failure patients is highly variable, with some patients having little or no response to standard drug therapy. A genome-wide association study may agnostically identify biomarkers and provide novel insight into the biology of myocardial recovery in DCM.

METHODS

A genome-wide association study for change in left ventricular ejection fraction was performed in 686 White subjects with recent-onset DCM who received standard pharmacotherapy. Genome-wide association study signals were subsequently functionally validated and studied in relevant cellular models to understand molecular mechanisms that may have contributed to the change in left ventricular ejection fraction.

RESULTS

The genome-wide association study identified a highly suggestive locus that mapped to the 5'-flanking region of the CDCP1 (CUB [complement C1r/C1s, Uegf, and Bmp1] domain containing protein 1) gene (rs6773435; P=7.12×10-7). The variant allele was associated with improved cardiac function and decreased CDCP1 transcription. CDCP1 expression was significantly upregulated in human cardiac fibroblasts (HCFs) in response to the PDGF (platelet-derived growth factor) signaling, and knockdown of CDCP1 significantly repressed HCF proliferation and decreased AKT (protein kinase B) phosphorylation. Transcriptomic profiling after CDCP1 knockdown in HCFs supported the conclusion that CDCP1 regulates HCF proliferation and mitosis. In addition, CDCP1 knockdown in HCFs resulted in significantly decreased expression of soluble ST2 (suppression of tumorigenicity-2), a prognostic biomarker for heart failure and inductor of cardiac fibrosis.

CONCLUSIONS

CDCP1 may play an important role in myocardial recovery in recent-onset DCM and mediates its effect primarily by attenuating cardiac fibrosis.

Multimodal Imaging of Cancer Therapy-Related Cardiac Dysfunction in Breast Cancer-A State-of-the-Art Review

BACKGROUND

This review focuses on multimodality imaging of cardiotoxicity in cancer patients, with the aim of evaluating the effectiveness of different techniques in detecting and monitoring cardiac changes associated with cancer therapy.

METHODS

Eight studies were included in the review, covering various imaging modalities such as cardiac magnetic resonance imaging, echocardiography, and multigated acquisition scanning.

RESULTS

Cardiac magnetic resonance imaging emerged as the most definitive modality, offering real-time detection, comprehensive assessment of cardiac function, the ability to detect early myocardial changes, and superior detection of cardiotoxicity when compared to the other imaging modalities. The studies also emphasize the importance of parameters such as left ventricular ejection fraction and global longitudinal strain in assessing cardiac function and predicting cardiotoxicity.

CONCLUSION

Due to the common use of HER2 agents and anthracyclines within the breast cancer population, the LVEF as a critical prognostic measurement for assessing heart health and estimating the severity of left-sided cardiac malfunction is a commonly used endpoint. CTRCD rates differed between imaging modalities, with cardiac MRI the most sensitive. The use of multimodal cardiac imaging remains a nuanced area, influenced by local availability, the clinical question at hand, body habits, and medical comorbidities. All of the imaging modalities listed have a role to play in current care; however, focus should be given to increasing the provision of cardiac MRI for breast cancer patients in the future to optimize the detection of CTRCD and patient outcomes thereafter.

The Value of Myocardial Fibrosis Parameters Derived from Cardiac Magnetic Resonance Imaging in Risk Stratification for Patients with Hypertrophic Cardiomyopathy

RATIONALE AND OBJECTIVES

The aim of the study was to determine whether myocardial fibrosis parameters of cardiac magnetic resonance imaging (MRI) has added value in the risk stratification of hypertrophic cardiomyopathy (HCM) patients.

MATERIALS AND METHODS

In this retrospective study, 108 patients with HCM (mean age ± standard deviation, 55.5 ± 13.4 years) were included from January 2019 to April 2022, and were followed up for 2 years to record sudden cardiac death (SCD) adverse events. All HCM patients underwent cardiac MRI and were divided into a training cohort (n = 81; mean age, 56.1 ± 13.0 years) and a validation cohort (n = 27; mean age, 57.8 ± 13.9 years). According to the presence of SCD risk factors defined by the 2020 AHA/ACC guidelines, HCM patients were classified into low-risk and high-risk groups. Cardiac MRI features, including late gadolinium enhancement (LGE), T1 mapping, and extracellular volume fraction (ECV), were assessed and compared between the two groups. Logistic regression analysis was used to select the optimal predictors of SCD from cardiac MRI features and HCM Risk-SCD score to construct prediction models. Receiver operating curve (ROC) analysis was used to assess the predictive performance of the constructed prediction model. Cox regression analysis was also used to determine the optimal predictors of SCD adverse events.

RESULTS

Multivariate logistic analysis showed that the global ECV was the single myocardial fibrosis parameter predictive of the risk of SCD (p < 0.001). The areas under the ROC curves (AUC) of global ECV were higher than those of LGE, global native T1, global postcontrast T1, and HCM Risk-SCD (AUC = 0.85 vs. 0.74, 0.77, 0.63, 0.78). An integrative risk stratification model combining global ECV (odds ratio, 1.36 [95% CI: 1.16-1.60]; p < 0.001) and HCM Risk-SCD score (odds ratio, 1.63 [95% CI: 1.08-2.47]; p < 0.001) achieved an AUC of 0.89 (95% CI: 0.81-0.96) in the training cohort, which was significantly higher than that of HCM Risk-SCD score alone (p = 0.03). The AUC of the integrative model was 0.93 (95% CI: 0.84-1.00) in the validation cohort. Multivariate Cox regression analysis also showed that the global ECV was an independent predictor of SCD adverse events (hazard ratio, 1.27 [95% CI: 1.10-1.47]).

CONCLUSION

The ECV derived from cardiac MRI is comparable to the HCM Risk-SCD scale in predicting the SCD risk stratification in patients with HCM.

Quantification of myocardial extracellular volume without blood sampling

Aims

Cardiac magnetic resonance (CMR) T1 relaxation time mapping is an established technique primarily used to identify diffuse interstitial fibrosis and oedema. The myocardial extracellular volume (ECV) can be calculated from pre- and post-contrast T1 relaxation times and is a reproducible parametric index of the proportion of volume occupied by non-cardiomyocyte components in myocardial tissue. The conventional calculation of the ECV requires blood sampling to measure the haematocrit (HCT). Given the high variability of the HCT, the blood collection is recommended within 24 h of the CMR scan, limiting its applicability and posing a barrier to the clinical routine use of ECV measurements. In recent years, several research groups have proposed a method to determine the ECV by CMR without blood sampling. This is based on the inverse relationship between the T1 relaxation rate (R1) of blood and the HCT. Consequently, a 'synthetic' HCT could be estimated from the native blood R1, avoiding blood sampling.

Methods and results

We performed a review and meta-analysis of published studies on synthetic ECV, as well as a secondary analysis of previously published data to examine the effect of the chosen regression modell on bias. While, overall, a good correlation and little bias between synthetic and conventional ECV were found in these studies, questions regarding its accuracy remain.

Conclusion

Synthetic HCT and ECV can provide a 'non-invasive' quantitative measurement of the myocardium's extracellular space when timely HCT measurements are not available and large alterations in ECV are expected, such as in cardiac amyloidosis. Due to the dependency of T1 relaxation times on the local setup, calculation of local formulas using linear regression is recommended, which can be easily performed using available data.

Effects of empagliflozin on cardiac structure, function and biomarkers in patients with heart failure with preserved ejection fraction: study protocol for a randomised, placebo-controlled prospective trial

INTRODUCTION

Heart failure (HF) with preserved ejection fraction (HFpEF) has become the main type of HF worldwide. Although large randomised controlled studies have demonstrated the beneficial effects of sodium-glucose cotransporter 2 inhibitors among patients with HFpEF, the mechanisms remain unclear. Basic research suggests that empagliflozin inhibits myocardial fibrosis. Myocardial extracellular volume (ECV) can be calculated using cardiac MRI (CMRI), which can reflect the degree of diffuse myocardial fibrosis. Studies show that empagliflozin can reduce ECV and left ventricular mass (LVM) assessed by CMRI in patients with diabetes with coronary heart disease and patients without diabetes with HF with reduced ejection fraction. However, whether empagliflozin reduces ECV and LVM among patients with HFpEF is unclear. This study intends to use CMRI to evaluate ECV and LVM, combined with echocardiography and an assessment of related biomarkers, to determine whether empagliflozin can improve myocardial fibrosis and left ventricular remodelling in patients with HFpEF.

METHODS AND ANALYSIS

This report describes the study design of a prospective, multicentre, randomised, double-blind, placebo-controlled and parallel-group clinical study. A total of 180 participants with HFpEF aged 40-80 years old who meet the inclusion and exclusion criteria will be randomly divided into an empagliflozin treatment group or a placebo control group. The empagliflozin treatment group will receive 10 mg of empagliflozin per day for 6 months in addition to guideline-directed medical treatment, while the control group will receive placebo oral administration with guideline-directed medical therapy for 6 months. The primary outcomes are ECV and LVM changes measured by CMRI after 6 months of treatment.

ETHICS AND DISSEMINATION

The study design is approved by the ethical committee of Beijing Hospital (2022BJYYEC-070-02). The trial is registered at the Chinese Clinical Trial Registry (http://www.chictr.org.cn). The trial results will be published in peer-reviewed journals and conferences.

TRIAL REGISTRATION NUMBER

Chinese Clinical Trial Registry (ChiCTR2200060862).

Parametric mapping by cardiovascular magnetic resonance imaging in sudden cardiac arrest survivors

Etiology of sudden cardiac arrest (SCA) is identified in less than 30% of survivors without coronary artery disease. We sought to assess the diagnostic role of myocardial parametric mapping using cardiovascular magnetic resonance (CMR) in identifying SCA etiology. Consecutive SCA survivors undergoing CMR with myocardial parametric mapping were included in the study. The determination if CMR was decisive or contributory in identifying SCA etiology was made if the diagnosis was unclear prior to CMR, and the discharge diagnosis was consistent with the CMR result. Parametric mapping was considered essential for establishing probable SCA etiology by CMR if the SCA cause could not have been determined without its utilization. If the CMR diagnosis could have been potentially based on the combination of cine and LGE imaging, parametric mapping was considered contributory. Of the 35 patients (mean age 46.9 ± 14.1 years; 57% males) included, SCA diagnosis was based on CMR in 23 (66%) patients. Of those, parametric mapping was essential for the diagnosis of myocarditis and tako-tsubo cardiomyopathy (11/48%) and contributed to the diagnosis in 10 (43%) additional cases. Inclusion of quantitative T1 and T2 parametric mapping in the SCA CMR protocol has the potential to increase diagnostic yield of CMR and further specify SCA etiology, especially myocarditis.

Half-Dose versus Single-Dose Gadobutrol for Extracellular Volume Measurements in Cardiac Magnetic Resonance

BACKGROUND

Cardiac magnetic resonance (CMR) imaging with gadolinium-based contrast agents offers unique non-invasive insights into cardiac tissue composition. Myocardial extracellular volume (ECV) has evolved as an objective and robust parameter with broad diagnostic and prognostic implications. For the gadolinium compound gadobutrol, the recommended dose for cardiac imaging, including ECV measurements, is 0.1 mmol/kg (single dose). This dose was optimized for late enhancement imaging, a measure of focal fibrosis. Whether a lower dose is sufficient for ECV measurements is unknown. We aim to evaluate the accuracy of ECV measurements using a half dose of 0.05 mmol/kg gadobutrol compared to the standard single dose of 0.1 mmol/kg.

METHODS AND RESULTS

From a contemporary trial (NCT04747366, registered 10 February 2021), a total of 25 examinations with available T1 mapping before and after 0.05 and 0.1 mmol/kg gadobutrol were analyzed. ECV values were calculated automatically from pre- and post-contrast T1 relaxation times. T1 and ECV Measurements were performed in the midventricular septum. ECV values after 0.05 and 0.1 mmol/kg gadobutrol were correlated (R2 = 0.920, p < 0.001). ECV values after 0.05 mmol/kg had a bias of +0.9% (95%-CI [0.4; 1.4], p = 0.002) compared to 0.1 mmol/kg gadobutrol, with limits of agreement from -1.5 to 3.3%.

CONCLUSIONS

CMR with a half dose of 0.05 mmol/kg gadobutrol overestimated ECV by 0.9% compared with a full dose of 0.1 mmol/kg, necessitating adjustment of normal values when using half-dose ECV imaging.

Fibrosis in Pathology of Heart and Kidney: From Deep RNA-Sequencing to Novel Molecular Targets

Diseases of the heart and the kidney, including heart failure and chronic kidney disease, can dramatically impair life expectancy and the quality of life of patients. The heart and kidney form a functional axis; therefore, functional impairment of 1 organ will inevitably affect the function of the other. Fibrosis represents the common final pathway of diseases of both organs, regardless of the disease entity. Thus, inhibition of fibrosis represents a promising therapeutic approach to treat diseases of both organs and to resolve functional impairment. However, despite the growing knowledge in this field, the exact pathomechanisms that drive fibrosis remain elusive. RNA-sequencing approaches, particularly single-cell RNA-sequencing, have revolutionized the investigation of pathomechanisms at a molecular level and facilitated the discovery of disease-associated cell types and mechanisms. In this review, we give a brief overview over the evolution of RNA-sequencing techniques, summarize most recent insights into the pathogenesis of heart and kidney fibrosis, and discuss how transcriptomic data can be used, to identify new drug targets and to develop novel therapeutic strategies.

Myocardial extracellular volume assessment at CT in hospitalized COVID-19 patients with regards to pulmonary embolism

Purpose

To evaluate myocardial status through the assessment of extracellular volume (ECV) calculated at computed tomography (CT) in patients hospitalized for novel coronavirus disease (COVID-19), with regards to the presence of pulmonary embolism (PE) as a risk factor for cardiac dysfunction.

Method

Hospitalized patients with COVID-19 who underwent contrast-enhanced CT at our institution were retrospectively included in this study and grouped with regards to the presence of PE. Unenhanced and portal venous phase scans were used to calculate ECV by placing regions of interest in the myocardial septum and left ventricular blood pool. ECV values were compared between patients with and without PE, and correlations between ECV values and clinical or technical variables were subsequently appraised.

Results

Ninety-four patients were included, 63/94 of whom males (67%), with a median age of 70 (IQR 56−76 years); 28/94 (30%) patients presented with PE. Patients with PE had a higher myocardial ECV than those without (33.5%, IQR 29.4−37.5% versus 29.8%, IQR 25.1−34.0%; p = 0.010). There were no correlations between ECV and patients’ age (p = 0.870) or sex (p = 0.122), unenhanced scan voltage (p = 0.822), portal phase scan voltage (p = 0.631), overall radiation dose (p = 0.569), portal phase scan timing (p = 0.460), and contrast agent dose (p = 0.563).

Conclusions

CT-derived ECV could help identify COVID-19 patients at higher risk of cardiac dysfunction, especially when related to PE, to potentially plan a dedicated, patient-tailored clinical approach.

Emerging molecular imaging targets and tools for myocardial fibrosis detection

Myocardial fibrosis is the heart's common healing response to injury. While initially seeking to optimize the strength of diseased tissue, fibrosis can become maladaptive, producing stiff poorly functioning and pro-arrhythmic myocardium. Different patterns of fibrosis are associated with different myocardial disease states, but the presence and quantity of fibrosis largely confer adverse prognosis. Current imaging techniques can assess the extent and pattern of myocardial scarring, but lack specificity and detect the presence of established fibrosis when the window to modify this process may have ended. For the first time, novel molecular imaging methods, including gallium-68 (68Ga)-fibroblast activation protein inhibitor positron emission tomography (68Ga-FAPI PET), may permit highly specific imaging of fibrosis activity. These approaches may facilitate earlier fibrosis detection, differentiation of active vs. end-stage disease, and assessment of both disease progression and treatment-response thereby improving patient care and clinical outcomes.

Diffuse myocardial fibrosis associates with incident ventricular arrhythmia in implantable cardioverter defibrillator recipients

Background

Diffuse myocardial fibrosis (DMF) quantified by extracellular volume (ECV) may represent a vulnerable phenotype and associate with life threatening ventricular arrhythmias more than focal myocardial fibrosis. This principle remains important because 1) risk stratification for implantable cardioverter defibrillators (ICD) remains challenging, and 2) DMF may respond to current or emerging medical therapies (reversible substrate).

Objectives

To evaluate the association between quantified by ECV in myocardium without focal fibrosis by late gadolinium enhancement (LGE) with time from ICD implantation to 1) appropriate shock, or 2) shock or anti-tachycardia pacing.

Methods

Among patients referred for cardiovascular magnetic resonance (CMR) without congenital disease, hypertrophic cardiomyopathy, or amyloidosis who received ICDs (n=215), we used Cox regression to associate ECV with incident ICD therapy.

Results

After a median of 2.9 (IQR 1.5-4.2) years, 25 surviving patients experienced ICD shock and 44 experienced shock or anti-tachycardia pacing. ECV ranged from 20.2% to 39.4%. No patient with ECV<25% experienced an ICD shock. ECV associated with both endpoints, e.g., hazard ratio 2.17 (95%CI 1.17-4.00) for every 5% increase in ECV, p=0.014 in a stepwise model for ICD shock adjusting for ICD indication, age, smoking, atrial fibrillation, and myocardial infarction, whereas focal fibrosis by LGE and global longitudinal strain (GLS) did not.

Conclusions

DMF measured by ECV associates with ventricular arrhythmias requiring ICD therapy in a dose-response fashion, even adjusting for potential confounding variables, focal fibrosis by LGE, and GLS. ECV-based risk stratification and DMF representing a therapeutic target to prevent ventricular arrhythmia warrant further investigation.

Extracellular Volume Fraction Calculated Using Contrast-Enhanced Computed Tomography as a Biomarker of Oxaliplatin-Induced Sinusoidal Obstruction Syndrome: A Preliminary Histopathological Analysis

Background

Oxaliplatin (OX)-based chemotherapy induces sinusoidal obstruction syndrome (SOS) in the nontumorous liver parenchyma, which can increase the risk of liver resection due to colorectal liver metastasis (CRLM). The extracellular volume (ECV) calculated from contrast-enhanced computed tomography (CT) has been reported to reflect the morphological change of hepatic fibrosis. The present retrospective study aimed to evaluate the ECV fraction as a predictive factor for OX-induced SOS.

Methods

Our study included 26 patients who underwent liver resection for CRLM after OX-based chemotherapy with a preoperative dynamic CT of appropriate quality. We investigated the relationship between the pathological SOS grade and the ECV fraction.

Results

Overall, 26 specimens from the patients were graded with the SOS classification of Rubbia-Brandt et al. as follows: grade 0, n = 17 (65.4%); grade 1, n = 4 (15.4%); and grade 2, n = 5 (19.2%). No specimens showed grade 3 SOS. In a univariate analysis, the ECV fraction in grade 0 SOS was significantly lower than that in grade 1 + 2 SOS (26.3 ± 3.4% vs. 30.6 ± 7.0%; P = 0.025). The cutoff value and AUC value of the ECV fraction to distinguish between grades 0 and 1 + 2 were 27.5% and 0.771, respectively.

Conclusions

Measurement of the ECV fraction was found to be a potential noninvasive diagnostic method for determining early-stage histopathological sinusoidal injury induced by OX-based chemotherapy.

Diabetes Mellitus and Heart Failure: Epidemiology, Pathophysiologic Mechanisms, and the Role of SGLT2 Inhibitors

Diabetes mellitus (DM) and heart failure (HF) are frequently encountered afflictions that are linked by a common pathophysiologic background. According to landmark studies, those conditions frequently coexist, and this interaction represents a poor prognostic indicator. Based on mechanistic studies, HF can be propagated by multiple pathophysiologic pathways, such as inflammation, oxidative stress, endothelial dysfunction, fibrosis, cardiac autonomic neuropathy, and alterations in substrate utilization. In this regard, DM may augment myocardial inflammation, fibrosis, autonomic dysfunction, and lipotoxicity. As the interaction between DM and HF appears critical, the new cornerstone in DM and HF treatment, sodium-glucose cotransporter-2 inhibitors (SGLT2i), may be able to revert the pathophysiology of those conditions and lead to beneficial HF outcomes. In this review, we aim to highlight the deleterious pathophysiologic interaction between DM and HF, as well as demonstrate the beneficial role of SGLT2i in this field.

Preclinical scenario of targeting myocardial fibrosis with chimeric antigen receptor (CAR) immunotherapy

Fibrosis is present in an important proportion of myocardial disorders. Injury activates cardiac fibroblasts, which deposit excess extracellular matrix, increasing tissue stiffness, impairing cardiac function, and leading to heart failure. Clinical therapies that directly target excessive fibrosis are limited, and more effective treatments are needed. Immunotherapy based on chimeric antigen receptor (CAR) T cells is a novel technique that redirects T lymphocytes toward specific antigens to eliminate the target cells. It is currently used in haematological cancers but has demonstrated efficacy in mouse models of hypertensive cardiac fibrosis, with activated fibroblasts as the target cells. CAR T cell therapy is associated with significant toxicities, but CAR natural killer cells can overcome efficacy and safety limitations. The use of CAR immunotherapy offers a potential alternative to current therapies for fibrosis reduction and restoration of cardiac function in patients with myocardial fibrosis.

Metabolomic Profiling of Cardiac Fibrosis and Steatosis in Women With or at Risk for HIV

BACKGROUND

Heart failure is a prevalent disorder whose prognosis remains poor despite advances in treatment. Women with or at risk for HIV may be particularly susceptible, yet the metabolic pathways that promote myocardial disease and heart failure in this context remain incompletely characterized.

METHODS

To evaluate the metabolomic signatures of cardiac magnetic resonance measured phenotypes, we used available plasma metabolomic measures from participants in the Women's Interagency HIV Study who underwent cardiac magnetic resonance imaging. Our primary outcomes were myocardial extracellular volume fraction (MECV) and intramyocardial triglyceride content (IMTG). We applied partial least squares and identified the top 10 lipid and polar metabolites associated with MECV and IMTG. We used multivariable linear regression to evaluate these metabolites' individual associations with each phenotype.

RESULTS

The mean age of participants (n = 153) was 53 ± 7, 93% were Black or Hispanic, and 74% were HIV positive. Phenylacetylglutamine, a microbial metabolite, was positively associated with MECV after full adjustment and false discovery rate correction. Three phosphatidylcholine species, N-acetylaspartic acid, and a lysophosphatidylcholine species were inversely associated with IMTG, while prolylglycine, methionine sulfoxide, sphingosine, taurine, and phosphorylcholine were positively associated with this phenotype. We found no evidence of interaction by HIV for the observed associations, but there was effect modification by hepatitis C virus of taurine's and phosphorylcholine's associations with IMTG.

CONCLUSION

Among women with or at risk for HIV, we related various lipid and polar metabolites to cardiac fibrosis or steatosis, of which phenylacetylglutamine, N-acetylaspartic acid, and prolylglycine are novel. These findings implicate plausible mechanisms that could be targetable for therapeutics.

A Preliminary Pathological Evaluation of Extracellular Volume Fraction with Contrast-enhanced Computed Tomography as a Novel Quantitative Parameter of Pancreatic Fibrosis

Objective The extracellular volume (ECV) calculated based on contrast-enhanced computed tomography (CT) has been reported as a novel imaging parameter reflecting the morphological change of fibrosis in several parenchymal organs. Our retrospective study assessed the validity of the ECV fraction for diagnosing pancreatic fibrosis and the appropriate imaging condition as the "equilibrium phase". Methods In 27 patients undergoing multiphasic CT and subsequent pancreaticoduodenectomy, we investigated pathological fibrotic changes related to the ECV fraction and conducted analyses using the value obtained by subtracting the equilibrium CT value of the portal vein from that of the abdominal aorta (Ao-PV_equilibrium) to estimate eligibility of the equilibrium phase. Results In all patients, the ECV fraction showed a weak positive correlation with the collagenous compartment ratio (r=0.388, p=0.045). All patients were divided into two groups - the high-Ao-PV_equilibrium group and low-Ao-PV_equilibrium group - based on the median value. No significant correlation was found in the high-Ao-PV_equilibrium group, whereas a significant correlation was observed in the low-Ao-PV_equilibrium group (r=0.566, p=0.035). Conclusion The ECV fraction is a possible predictive factor for histopathological pancreatic fibrosis. In its clinical application, the eligibility of the "equilibrium phase" may affect the diagnostic capability. It will be necessary to verify the imaging conditions in order to improve the accuracy of the diagnosis.

Cardiovascular magnetic resonance phenotyping of heart failure with mildly reduced ejection fraction

AIMS

The 2016 European Society of Cardiology Heart Failure Guidelines defined a new category: heart failure with mid-range ejection fraction (HFmrEF) of 40-49%. This new category was highlighted as having limited evidence and research was advocated into underlying characteristics, pathophysiology, and diagnosis. We used multi-parametric cardiovascular magnetic resonance (CMR) to define the cardiac phenotype of presumed non-ischaemic HFmrEF.

METHODS AND RESULTS

Patients (N = 300, 62.7 ± 13 years, 63% males) with a clinical diagnosis of heart failure with no angina symptoms, history of myocardial infarction, or coronary intervention were prospectively recruited. Patients underwent clinical assessment and CMR including T1 mapping, extracellular volume (ECV) mapping, late gadolinium enhancement, and measurement of myocardial blood flow at rest and maximal hyperaemia. Of 273 patients in the final analysis, 93 (34%) patients were categorized as HFmrEF, 46 (17%) as heart failure with preserved ejection fraction (HFpEF), and 134 (49%) as heart failure with reduced ejection fraction (HFrEF). Nineteen (20%) patients with HFmrEF had evidence of occult ischaemic heart disease. Diffuse fibrosis and hyperaemic myocardial blood flow were similar in HFmrEF and HFpEF, but HFmrEF showed significantly lower native T1 (1311 ± 32 vs. 1340 ± 45 ms, P < 0.001), ECV (24.6 ± 3.2 vs. 26.3 ± 3.1%, P < 0.001), and higher myocardial perfusion reserve (2.75 ± 0.84 vs. 2.28 ± 0.84, P < 0.001) compared with HFrEF.

CONCLUSION

Patients with HFmrEF share most phenotypic characteristics with HFpEF, including the degree of microvascular impairment and fibrosis, but have a high prevalence of occult ischaemic heart disease similar to HFrEF. Further work is needed to confirm how the phenotype of HFmrEF responds to medical therapy.

Cardiac Biomarkers in Sports Cardiology

Sustained physical activity induces morphological and functional changes in the cardiovascular system. While mostly physiological, they can also become a trigger for major adverse cardiovascular events, the most severe of which are sudden cardiac arrest and sudden cardiac death. Therefore, any novel method which can help more accurately estimate the cardiovascular risk should be considered for further studying and future implementation in the standard protocols. The study of biomarkers is gaining more and more ground as they have already established their utility in diagnosing ischemic cardiac disease or in evaluating cardiac dysfunction in patients with heart failure. Nowadays, they are being implemented in the screening of apparently healthy individuals for the assessment of the cardiovascular risk. The aim of this paper is to gather published data regarding the measurements of cardiac biomarkers in athletes, i.e., troponins, myoglobin, CK-MB, NT-proBNP, and D-Dimers, and their potential use in the field of sports cardiology.

Exploring the cardiac ECM during fibrosis: A new era with next-gen proteomics

Extracellular matrix (ECM) plays a critical role in maintaining elasticity in cardiac tissues. Elasticity is required in the heart for properly pumping blood to the whole body. Dysregulated ECM remodeling causes fibrosis in the cardiac tissues. Cardiac fibrosis leads to stiffness in the heart tissues, resulting in heart failure. During cardiac fibrosis, ECM proteins get excessively deposited in the cardiac tissues. In the ECM, cardiac fibroblast proliferates into myofibroblast upon various kinds of stimulations. Fibroblast activation (myofibroblast) contributes majorly toward cardiac fibrosis. Other than cardiac fibroblasts, cardiomyocytes, epithelial/endothelial cells, and immune system cells can also contribute to cardiac fibrosis. Alteration in the expression of the ECM core and ECM-modifier proteins causes different types of cardiac fibrosis. These different components of ECM culminated into different pathways inducing transdifferentiation of cardiac fibroblast into myofibroblast. In this review, we summarize the role of different ECM components during cardiac fibrosis progression leading to heart failure. Furthermore, we highlight the importance of applying mass-spectrometry-based proteomics to understand the key changes occurring in the ECM during fibrotic progression. Next-gen proteomics studies will broaden the potential to identify key targets to combat cardiac fibrosis in order to achieve precise medicine-development in the future.

An electrocardiography score predicts heart failure hospitalization or death beyond that of cardiovascular magnetic resonance imaging

The electrocardiogram (ECG) and cardiovascular magnetic resonance imaging (CMR) provide powerful prognostic information. The aim was to determine their relative prognostic value. Patients (n = 783) undergoing CMR and 12-lead ECG with a QRS duration < 120 ms were included. Prognosis scores for one-year event-free survival from hospitalization for heart failure or death were derived using continuous ECG or CMR measures, and multivariable logistic regression, and compared. Patients (median [interquartile range] age 55 [43-64] years, 44% female) had 155 events during 5.7 [4.4-6.6] years. The ECG prognosis score included (1) frontal plane QRS-T angle, and (2) heart rate corrected QT duration (QTc) (log-rank 55). The CMR prognosis score included (1) global longitudinal strain, and (2) extracellular volume fraction (log-rank 85). The combination of positive scores for both ECG and CMR yielded the highest prognostic value (log-rank 105). Multivariable analysis showed an association with outcomes for both the ECG prognosis score (log-rank 8.4, hazard ratio [95% confidence interval] 1.29 [1.09-1.54]) and the CMR prognosis score (log-rank 47, hazard ratio 1.90 [1.58-2.28]). An ECG prognosis score predicted outcomes independently of CMR. Combining the results of ECG and CMR using both prognosis scores improved the overall prognostic performance.

Improved evaluation of left ventricular hypertrophy using the spatial QRS-T angle by electrocardiography

Electrocardiographic (ECG) signs of left ventricular hypertrophy (LVH) lack sensitivity. The aim was to identify LVH based on an abnormal spatial peaks QRS-T angle, evaluate its diagnostic performance compared to conventional ECG criteria for LVH, and its prognostic performance. This was an observational study with four cohorts with a QRS duration < 120 ms. Based on healthy volunteers (n = 921), an abnormal spatial peaks QRS-T angle was defined as ≥ 40° for females and ≥ 55° for males. In other healthy volunteers (n = 461), the specificity of the QRS-T angle to detect LVH was 96% (females) and 98% (males). In patients with at least moderate LVH by cardiac imaging (n = 225), the QRS-T angle had a higher sensitivity than conventional ECG criteria (93–97% vs 13–56%, p < 0.001 for all). In clinical consecutive patients (n = 783), of those who did not have any LVH, 238/556 (43%) had an abnormal QRS-T angle. There was an association with hospitalization for heart failure or all-cause death in univariable and multivariable analysis. An abnormal QRS-T angle rarely occurred in healthy volunteers, was a mainstay of moderate or greater LVH, was common in clinical patients without LVH but with cardiac co-morbidities, and associated with outcomes.

The Dynamic Characteristics of Myocardial Contractility and Extracellular Volume in Type 2 Diabetes Mellitus Mice Investigated by 7.0T Cardiac Magnetic Resonance

Type 2 diabetes mellitus (T2DM) is associated with a high prevalence of diastolic dysfunction and congestive heart failure. A potential contributing factor is the accelerated accumulation of diffuse myocardial fibrosis and stiffness. Novel cardiac magnetic resonance (CMR) imaging techniques can identify both myocardial fibrosis and contractility quantitatively. This study aimed to investigate the dynamic characteristics of the myocardial strain and altered extracellular volume (ECV) fraction as determined by 7.0 T CMR in T2DM mice. C57Bl/6J mice were randomly divided into T2DM (fed a high-fat diet) and control (fed a normal diet) groups. They were scanned on 7.0 T MRI every 4 weeks until the end of week 24. The CMR protocol included multi-slice cine imaging to assess left ventricle strain and strain rate, and pre- and post-contrast T1 mapping images to quantify ECV. The ECV in the T2DM mice was significantly higher (p < 0.05) than that in the control group since week 12 with significantly impaired myocardial strain (p < 0.05). A significant linear correlation was established between myocardial strain and ECV (p < 0.001) and left ventricular-ejection fraction and ECV (p = 0.003). The results suggested that CMR feature tracking-derived myocardial strain analysis can assess functional abnormalities that may be associated with ECM alterations in diabetic cardiomyopathy, contributing to the study of diabetic therapy effects.

The heart under pressure: immune cells in fibrotic remodeling

The complex syndrome of heart failure (HF) is characterized by increased left ventricular pressures. Cardiomyocytes increase in size, cardiac fibroblasts transform and make extracellular matrix, and leukocytes infiltrate the cardiac tissue and alter cardiomyocyte and cardiac fibroblast function. Here we review recent advances in our understanding of the cellular composition of the heart during homeostasis and in response to cardiac pressure overload, with an emphasis on immune cell communication with cardiac fibroblasts and its consequences in cardiac remodeling.