Myocardial Injury Research Articles

Trimetazidine attenuates Ischemia/Reperfusion-Induced myocardial ferroptosis by modulating the Sirt3/Nrf2-GSH system and reducing Oxidative/Nitrative stress

Ferroptosis is a newly defined mode of cellular demise. The increasing investigation supports that ferroptosis is a crucial factor in the complex mechanisms of myocardial ischemia–reperfusion (I/R) injury. Hence, targeting ferroptosis is a novel strategy for treating myocardial injury. Although evidence suggests that trimetazidine (TMZ) is potentially efficacious against myocardial injury, the exact mechanism of this efficacy is yet to be fully elucidated. This study aimed to determine whether TMZ can act as a ferroptosis resistor and affect I/R-mediated myocardial injury. To this end, researchers have constructed in vitro and in vivo models of I/R using H9C2 cardiomyocytes, primary cardiomyocytes, and SD rats. Here, I/R mediated the onset of ferroptosis in vitro and in vivo, as reflected by excessive iron aggregation, GSH depletion, and the increase in lipid peroxidation. TMZ largely reversed this alteration and attenuated cardiomyocyte injury. Mechanistically, we found that TMZ upregulated the expression of Sirt3. Therefore, we used si-Sirt3 and 3-TYP to interfere with Sirt3 action in vitro and in vivo, respectively. Both si-Sirt3 and 3-TYP partly mitigated the inhibitory effect of TMZ on I/R-mediated ferroptosis and upregulated the expression of Nrf2 and its downstream target, GPX4-SLC7A11. These results indicate that TMZ attenuates I/R-mediated ferroptosis by activating the Sirt3-Nrf2/GPX4/SLC7A11 signaling pathway. Our study offers insights into the mechanism underlying the cardioprotective benefits of TMZ and establishes a groundwork for expanding its potential applications.

Impact of High Troponin Level on the Outcome in COVID-19 Positive Patients.

COVID-19 is a new disease caused by the recently discovered SARS-CoV-2 virus. The COVID-19 disease manifests in several ways and it may affect various systems, including the gastrointestinal, musculoskeletal, neurological, cardiovascular, and pulmonary systems. Individuals who have ad-additional health conditions, such as cardiovascular disorders, are particularly more likely to experience illness and death. This study aimed to assess the clinical effect of COVID-19 on myocardial injury, as measured by troponin elevation, and to determine if this effect has an impact on the outcome. This retrospective study was conducted at King Saud Medical City. The electronic medical records used to identify all admitted patients between March 23 and June 15, 2020, with a laboratory-confirmed positive COVID-19 diagnosis who had troponin I measured. During the study period, 768 COVID-19-positive patients were hospitalized. Of those, 187 patients were excluded because the troponin level was not measured. The remaining 581 (75.7%) had troponin I measured. Overall, 89 of 581 (15.3%) patients died. Of those, 67.8% were in the markedly elevated cTnI group, 8.5% were in the mildly elevated cTnI group, whereas no deaths were reported in the group with normal cTnI levels. Myocardial injury was observed in COVID-19-admitted patients at a significant level that warrants attention to this consequence. In older individuals with pre-existing cardiovascular comorbidities, the diagnosis of myocardial injury was linked to a higher likelihood of being admitted to the intensive care unit, experiencing a worse prognosis, and ultimately, death.

Myocardial cell mitochondria-targeted mesoporous polydopamine nanoparticles eliminate inflammatory damage in cardiovascular disease

Excess reactive oxide species (ROS) is a direct factor in myocardial injury death, thus anti-oxidant therapy is a necessary measure to prevent rapid death of cardiomyocyte cell. Cysteine (Cys) is a potent antioxidant but easily become instability because of the hyperactivity. Therefore, in order to protect the the stability of Cys, we according to the mitochondria are the main sites of ROS production, utilized the loading and ROS scavenging capacity of mesoporous polydopamine (mPDA) constructed a nanosystem targeting mitochondria with effectively ROS elimination capability by loading cysteine (Cys-mPDA@TPP). The mesoporous structure of mPDA effectively inhibited the advance reaction and hyperactivity of Cys, thus effectively improving its stability that reached the double-collaborative treatment excess ROS. In particular, Cys-mPDA@TPP achieved directly reacting with ROS in mitochondria under the targeting of triphenylphosphine (TPP), not only enhancing the elimination efficiency of ROS, but also preventing mitochondrial dysfunction of monocyte-macrophage. Furthermore, with double-collaborative ROS elimination, Cys-mPDA@TPP effectively prevent the damage of cardiomyocyte cell through inhibiting macrophage inflammatory response. Therefore, this study provides a new therapeutic strategy for myocardial inflammatory injury.

CARD9 protein SUMOylation regulates HOXB5 nuclear translocation and Parkin-mediated mitophagy in myocardial I/R injury.

Myocardial injury induced by ischemia-reperfusion (I/R) remains a difficult clinical problem. However, the exact mechanisms underlying I/R-induced have yet to be clarified. CARD9 is an important cytoplasmic-binding protein. In this study, an immunocoprecipitation assay showed that SUMOylation of the CARD9 protein promoted the binding of CARD9 to HOXB5, but hindered the O-GlcNAc glycosylation of HOXB5, a predicted transcription factor of Parkin and a key factor in mitophagy. O-GlcNAc glycosylation is an important signal for translocation of proteins from the cytoplasm to the nucleus. CARD9 protein SUMOylation is regulated by PIAS3, which is related to I/R-induced myocardial injury. Therefore, we propose that knockdown of PIAS3 inhibits SUMOylation of the CARD9 protein, facilitates the dissociation of CARD9 and HOXB5, which increases the O-GlcNAc-mediated glycosylation of HOXB5, while the resulting HOXB5 nuclear translocation promotes Parkin-induced mitophagy and alleviates myocardial I/R injury.

Salvianolic acid B alleviated myocardial ischemia-reperfusion injury via modulating SIRT3-mediated crosstalk between mitochondrial ROS and NLRP3

Salvianolic acid B alleviated myocardial ischemia-reperfusion injury via modulating SIRT3-mediated crosstalk between mitochondrial ROS and NLRP3

The effects of acetylated cordycepin derivatives on promoting vascular angiogenesis and attenuating myocardial ischemic injury

BackgroundEnhanced angiogenesis following myocardial infarction (MI) is beneficial to preserve cardiac function. The present study aimed to investigate whether acetylated derivatives of cordycepin altered its original antitumor properties and exerted cardioprotective effects by promoting angiogenesis in vitro and in vivo. MethodsCordycepin and its derivatives with single (DA), double (DAA), and triple acetyl groups (DAAA) were assessed. The cell viability of leukemia U937 cells, malignant hepatoma Huh-7 cells, and human umbilical vascular endothelial cells (HUVECs) treated with cordycepin, DA, DAA, and DAAA were determined. The expression of β-catenin in U937 cells, as well as the expression of p65, p38 and other related signal regulators in HUVECs elicited by lipopolysaccharides (LPS) were also observed. Angiogenesis was determined by tube formation in HUVECs and Matrigel plug assay in mice. Cardiac function following administration of DAAA was evaluated in mice MI model simulated by coronary artery ligation. ResultsThe inhibitory effects of cordycepin and its acetylated derivatives on U937 cells, Huh-7 cells, HUVECs, and the expression of β-catenin in U937 cells were mitigated with increasing acetylation. Intriguingly, DAAA preserved the cell viability of HUVECs compared to other acetylated derivatives. Although DAAA had a significantly diminished antitumor effect compared to cordycepin, it promoted angiogenesis in mice and tube formation in HUVECs and attenuated LPS-induced phosphorylation of p65 and p38. Additionally, administration of DAAA improved cardiac function following coronary artery ligation in mice. ConclusionDAAA could be considered a promising adjunctive therapy to prevent post-MI heart failure through promoting angiogenesis.

N6-methyladenosine modification of SPOP relieves ferroptosis and diabetic cardiomyopathy by enhancing ubiquitination of VDAC3.

Understanding the pathogenesis of diabetic cardiomyopathy (DCM), a common microvascular complication affecting the heart, is crucial for identifying new therapeutic targets and intervention strategies for DCM. Our study revealed a significant downregulation in Speckle-type POZ protein (SPOP) expression in DCM, while the overexpression of SPOP improved DCM-induced myocardial dysfunction, injury, fibrosis, hypertrophy, and ferroptosis. Mechanistically, SPOP facilitated the degradation of voltage-dependent anion channel 3 (VDAC3) by enhancing its ubiquitination. M6A demethylase AlkB homolog 5 (ALKBH5) reduced the mRNA stability of SPOP by decreasing m6A modification in its 3'UTR. The m6A reader insulin-like growth factor 2 mRNA binding protein 2 (IGF2BP2) enhanced the stability of SPOP mRNA through recognition of m6A-modified SPOP 3'UTR. Furthermore, ALKBH5 promoted ferroptosis by inhibiting SPOP-induced VDAC3 degradation, while IGF2BP2 inhibited ferroptosis via activation of SPOP-induced VDAC3 degradation in high glucose-treated neonatal mouse ventricular cardiomyocytes (NMVCs). Overall, our study has unveiled a novel role of SPOP in the pathogenesis of ferroptosis and DCM, thereby significantly advancing our understanding of the involvement of ferroptosis during the progression of DCM. Moreover, this discovery offers promising potential therapeutic interventions targeting DCM.

Targeted Delivery and ROS-Responsive Release of Lutein Nanoassemblies Inhibit Myocardial Ischemia-Reperfusion Injury by Improving Mitochondrial Function

Targeted Delivery and ROS-Responsive Release of Lutein Nanoassemblies Inhibit Myocardial Ischemia-Reperfusion Injury by Improving Mitochondrial Function

Engineered Biomimetic Nanoparticles-Mediated Targeting Delivery of Allicin Against Myocardial Ischemia-Reperfusion Injury by Inhibiting Ferroptosis.

Cardiac microvascular damage is substantially related with the onset of myocardial ischaemia-reperfusion (IR) injury. Reportedly, allicin (AL) effectively protects the cardiac microvascular system from IR injury. However, the unsatisfactory therapeutic efficacy of current drugs and insufficient drug delivery to the damaged heart are major concerns. Here, inspired by the natural interaction between neutrophils and inflamed cardiac microvascular endothelial cells (CMECs), a neutrophil membrane-camouflaged nanoparticle for non-invasive active-targeting therapy for IR injury by improving drug delivery to the injured heart is constructed. In this study, we engineered mesoporous silica nanoparticles (MSNs) coated with a neutrophil membrane to act as a drug delivery system, encapsulating AL. The potential of the nanoparticles (named AL@MSNs@NM) for specific targeting of infarcted myocardium was assessed using small animal vivo imaging system. The cardiac function of AL@MSNs@NM after treatment was evaluated by Animal Ultrasound Imaging system, HE staining, and Laser Speckle Imaging System. The therapeutic mechanism was analyzed by ELISA kits, immunofluorescence, and PCR. We discovered that AL@MSNs@NM significantly improves cardiac function index, reduced infarct size and fibrosis, increased vascular perfusion in ischemic areas, and also promoted the function of CMECs, including migration, tube formation, shear stress adaptation, and nitric oxide production. Further research revealed that AL@MSNs@NM have cardio-protective functions in IR rats by inhibiting CMEC ferroptosis and increasing platelet endothelial cell adhesion molecule-1 (PECAM-1) expression. Our results indicated that AL@MSNs@NM significantly reversed CMEC ferroptosis and increased PECAM-1 expression, enhanced cardiac function, and reduced myocardial infarction size. Therefore, this strategy demonstrates that engineered biomimetic nanotechnology effectively delivers AL for targeted therapy of myocardial infarction.

Mechanisms and Therapeutic Strategies for Myocardial Ischemia-Reperfusion Injury in Diabetic States

Mechanisms and Therapeutic Strategies for Myocardial Ischemia-Reperfusion Injury in Diabetic States

Accumulation of endogenous Muse cells in the myocardium and its pathophysiological role in patients with fulminant myocarditis.

Multi-lineage differentiating stress-enduring (Muse) cells, identified as pluripotent surface marker SSEA-3(+) cells, are stress tolerant endogenous pluripotent-like stem cells, and are involved in tissue repair. However, the significance of Muse cells in acute myocarditis has not been evaluated. In the present study, we counted Muse cells/area in biopsied myocardial tissue samples from 17 patients with fulminant myocarditis, and 6 with non-inflammatory myocardial disease as controls. Compared with controls, patients with fulminant myocarditis had significantly more Muse cells (p = 0.00042). Patients with mechanical circulatory support (p = 0.006) and myocardial degeneration (p = 0.023) had significantly more Muse cells than those without them. The Muse cell number was correlated with acute phase CK-MB level (ρ = 0.547, p = 0.029), indicating the severity of myocardial injury, and was also correlatedwith acute/recovery phase ratio of CK-MB (ρ = 0.585, p = 0.023) and cardiac troponin I (ρ = 0.498, p = 0.047) levels, indicating resilience of myocardial injury. In fulminant myocarditis, the Muse cell number was associated with the severity of clinical features in the acute phase, and also with the recovery from myocardial damage in the chronic phase. Endogenous Muse cells might be mobilized and accumulate to the myocardial tissues in fulminant myocarditis, and might participate in the repair of injured myocardium.

Synergistic Effects of Ginsenoside Rb1 and Peroxiredoxin 6 in Enhancing Myocardial Injury Treatment through Anti-Inflammatory, Anti-Oxidative, and Anti-Apoptotic Mechanisms

Synergistic Effects of Ginsenoside Rb1 and Peroxiredoxin 6 in Enhancing Myocardial Injury Treatment through Anti-Inflammatory, Anti-Oxidative, and Anti-Apoptotic Mechanisms

Dan-shen Yin attenuates myocardial fibrosis after myocardial infarction in rats: molecular mechanism insights by integrated transcriptomics and network pharmacology analysis and experimental validation

Ethnopharmacological relevanceDan-shen Yin (DSY) originated from the "Shi Fang Ge Kuo" is a Chinese formula composed of three medicines: Salvia miltiorrhiza (Dan-shen), Santalum album L. (Tan-xiang) and Amomum villosum Lour. (Sha-ren). It has many years of clinical experience in the prevention of myocardial fibrosis (MF). However, the specific mechanism of DSY in prevent MF is not clear. Aim of the studyThis study aimed to assess the efficacy of DSY in the prevention of MF and reveal its underlying mechanism in a rat model of MF after myocardial infarction (MI) induced by ligation of the left anterior descending branch (LAD) of the coronary artery. Materials and methodsThe blood-entry components of DSY were analyzed by UHPLC-Q-TOF-MS/MS. LAD-ligated rats were used to assess the efficacy of DSY in the prevention of MF. Network pharmacology and transcriptomics analysis were used to predict possible target signaling pathways of DSY in MF. Echocardiography, immunohistochemistry and ELISA methods were used to evaluate the cardiac functions and biochemical changes of the rats. The mRNA expressions of target genes were measured by RT-qPCR. The proteins expressions, including Collagen I, Collagen III, α-smooth muscle actin (α-SMA), matrix metallopeptidase 2 (MMP 2), matrix metallopeptidase 9 (MMP 9), transforming growth factor-β (TGF-β), protein kinase B (AKT), phospho-AKT, extracellular regulated protein kinases (ERK), phospho-ERK, c-Jun N-terminal kinase (JNK), phospho-JNK, mothers against decapentaplegic protein (Smad3), and phospho-Smad3 were detected and quantified by Western Blot. ResultsUHPLC-Q-TOF-MS/MS analysis disclosed that 20 components within DSY could be absorbed into blood of rats. DSY improved myocardial injury in the myocardial tissue of LAD-ligated rats, as evidenced by the elevation of left ventricular ejection fraction and left ventricular fractional shortening, and the decrease of the serum CK-MB and LDH levels. Network pharmacology and transcriptomics predicted that DSY could interfere biological processes, such as extracellular matrix organization, focal adhesion and ECM-receptor interaction, and modulate TGF-β mediated signaling pathways, including PI3K/AKT, MAPK, and Smad3. Further study confirmed that DSY reduced MF, accompanied by reduced TGF-β, Collagen I, Collagen III, α-SMA, MMP 2 and MMP 9. Moreover, DSY repressed the phosphorylation of AKT, MAPKs and Smad3. In addition, DSY reduced inflammation and suppressed the mRNA expressions of IL-1β, IL-6, TNF-α, COX2 and iNOS in MF rats. ConclusionsOur study demonstrated that DSY prevented MF in vivo, the action of which was probably via reducing extracellular matrix organization, focal adhesion ECM-receptor interaction and inflammation by regulating TGF-β mediated PI3K/AKT, MAPK and Smad signaling pathways.

Interleukin 6 blockage alters the plasma metabolome in out-of-hospital cardiac arrest

BackgroundComatose patients resuscitated from out-of-hospital cardiac arrest (OHCA) exhibit a systemic inflammatory response, as indicated by elevated interleukin-6 (IL-6) levels, which is associated with increased mortality. Tocilizumab, an IL-6 receptor antagonist that reduced C-reactive protein response and markers of myocardial injury in a phase II OHCA trial. AimTo describe the early effects of tocilizumab on circulating levels of metabolites in comatose patients resuscitated from OHCA. MethodPatients from the phase-II double-blinded randomized trial (NCT: 03863015) were included in this substudy. A total of 85 comatose patients resuscitated from OHCA were randomized at the time of arrival to the hospital to either tocilizumab 8 mg/kg or placebo, of which 80 received the intervention and did not later withdraw from the study. Plasma samples before randomization and 48 h later were analyzed by a targeted metabolomics approach quantifying 60 circulating metabolites. ResultsOf 80 enrolled patients (median age 62 years (IQR: 54–72), men 66 (83 %)), 39 were randomized to tocilizumab group and 41 to placebo. Comorbidities and cardiac arrest characteristics were overall well-balanced. At hospital arrival, levels of metabolites from the tricarboxylic acid (TCA) cycle were associated with time to return of spontaneous circulation and independently with early levels of IL-6 (all p < 0.05). The early levels of medium-chain acylcarnitines were associated with age, NT-proBNP, estimated glomerular filtration rate, and marker of neurological injury (neurofilament light chain) (all p < 0.01). At 48 h tocilizumab increased the levels of plasma amino acids especially threonine, glycine, and serine by more than a factor of 1.5 (p < 0.01). Two eicosanoids 15(S)-HETE and 12(S)-HETE were 1.9 times higher (p < 0.01). ConclusionBlocking the IL-6 receptor with tocilizumab early after OHCA impacts circulating metabolites, particularly those within the glycine, serine, and threonine pathways, highlighting the connection between acute systemic inflammation and metabolism. Further, early levels of TCA metabolites are independently associated with early inflammatory response and early medium-chain acylcarnitine with later markers of neurological injury.

L-carnitine ameliorates myocardial injury by alleviating endoplasmic reticulum stress via inhibition of PERK pathway in exertional heatstroke rats

L-carnitine ameliorates myocardial injury by alleviating endoplasmic reticulum stress via inhibition of PERK pathway in exertional heatstroke rats

CaMKII Exacerbates Doxorubicin-Induced Cardiotoxicity by Promoting Ubiquitination Through USP10 Inhibition.

Doxorubicin (DOX) is an effective anticancer drug, but it has a problem of cardiotoxicity that cannot be ignored. Ca2+/calmodulin-dependent protein kinase II (CaMKII) is tightly associated with the pathological progression of DOX-induced cardiotoxicity. Ubiquitin-specific protease 10 (USP10) plays an important role in many biological processes and cancers. However, its association with DOX-induced cardiotoxicity and CaMKII remains unclear. H9C2 cells, HL-1 cells and C57BL/6 mice were used to establish the DOX-induced cardiotoxicity model, and the CaMKII-specific inhibitor KN-93 and USP10 specific inhibitor Spautin-1 were used to observe the CaMKII and USP10 effect. In cell experiments, CCK-8 method was used to assess cell viability, LDH kit was used to assess lactate dehydrogenase expression, DCFH-DA staining was used to observe changes in active oxygen content, TUNEL staining was used to observe cell apoptosis, and Western blotting method was used to detect relevant protein markers. The expression of p-CaMKII and USP10 was assessed by immunofluorescence staining. In animal experiments, mouse echocardiograph was used were used to evaluate cardiac function, and HE staining and Masson staining were used to evaluate myocardial injury. Cardiomyocyte apoptosis was detected by TUNEL staining. Western blotting method was used to detect relevant protein markers. Our results demonstrated that activation of CaMKII and inhibition of USP10 pathway related to DOX-induced cardiotoxicity. Inhibition of CaMKII with KN-93 ameliorated DOX-induced cardiac dysfunction and cytotoxicity. In addition, CaMKII inhibition prevented DOX-induced apoptosis and ubiquitination. Furthermore, CaMKII inhibition increased USP10 expression in DOX-treated mouse hearts, H9C2 cells and HL-1 cells. At last, the USP10 inhibitor, Spautin-1, blocked the regulatory effect of CaMKII inhibition on apoptosis and ubiquitination in DOX-induced cardiotoxicity. Our findings revealed that DOX-induced myocardial apoptosis and activated CaMKII through cellular and animal levels, while providing a novel probe into the mechanism of CaMKII action: promoting ubiquitination by inhibiting USP10 aggravated apoptosis.

Exploring the mechanism of Ling-Gui-Zhu-Gan decoction in metabolic cardiomyopathy via inhibiting ferroptosis

ObjectiveThis study was to investigate the mechanism of Ling-Gui-Zhu-Gan decoction (LGZGD) in regulating lipid metabolism and thus inhibiting ferroptosis. MethodsUPLC for the determination of the main chemical composition of LGZGD. A HF-induced rat model of metabolic cardiomyopathy was established. Echocardiography was used to detect cardiac function. Serum lipid levels, myocardial injury markers, and lipid peroxidation levels were detected. Pathological changes were detected. Lipid deposition was assessed by oil red O, and the mitochondrial ultrastructure was observed by electron microscopy. Mechanistically, PLIN5, CD36, ATGL, GPX4, ACSL4, FPN1, DRP1, MFF, FIS1, and OPA1 expressions were examined. After PA-induced H9c2 cells established, apoptosis, myocardial injury markers, and lipid peroxidation levels were detected and lipid deposition levels were assessed. The expressions of PLIN5, CD36, ATGL, GPX4, ACSL4 and FPN1 were detected. H9c2 cardiomyocytes with transient knockdown of PLIN5 and overexpression of PLIN5 were constructed and treated with drug administration and modeling, and the apoptosis level was detected by flow cytometry, the levels of lipid peroxidation and ROS were detected by fluorescence, and the protein and gene expressions of ACSL4 and GPX4 were detected. Results The main active components of LGZGD were liquiritin, isoliquiritin, cinnamic acid, cinnamaldehyde, glycyrrhizic acid, and atractylenolide III. LGZGD significantly improved cardiac dysfunction, lowered lipid level and lipid deposition, reduced CK, NT-proBNP and MDA levels, restored SOD levels, and improved inflammatory cell infiltration as well as collagen fiber deposition. LGZGD decreased the expression of PLIN5, CD36, ACSL4, and increased the expression of ATGL, GPX4, and FPN1. LGZGD also decreased the gene expression of DRP1, MFF, FIS1, and increased OPA1 expression. LGZGD significantly ameliorated PA-induced apoptosis, decreased lipid deposition, lowered lipid peroxidation levels and CK level, decreased PLIN5, CD36, and ACSL4 expressions, and increased ATGL, GPX4, and FPN1 expressions. LGZGD reversed cardiomyocyte injury aggravated by transient knockdown of PLIN5, decreased apoptosis levels, lipid peroxidation levels, ROS levels, and ACSL4 expressions, and increased GPX4 expression. LGZGD enhanced cardiomyocyte protection after overexpression of PLIN5, reduced apoptosis levels, lipid peroxidation level and ROS level, decreased ACSL4 expression, and increased GPX4 expression. ConclusionPLIN5 interferes with lipid peroxidation, regulates mitochondrial function, and inhibits HF-induced ferroptosis in cardiomyocytes. LGZGD ameliorates impairment of cardiac structural function in model rats through PLIN5-mediated ferroptosis pathway, and has the effect of preventing metabolic cardiomyopathy.

Pinus massoniana pollen polysaccharides alleviate LPS-induced myocardial injury through p110β-mediated inhibition of the PI3K/AKT/NFκB pathway

Pinus massoniana pollen polysaccharides alleviate LPS-induced myocardial injury through p110β-mediated inhibition of the PI3K/AKT/NFκB pathway

A microfluidic coculture model for mapping signaling perturbations and precise drug screening against macrophage-mediated dynamic myocardial injury

A microfluidic coculture model for mapping signaling perturbations and precise drug screening against macrophage-mediated dynamic myocardial injury

Late gadolinium enhancement on cardiac MRI: A systematic review and meta-analysis of prognosis across cardiomyopathies

BackgroundLate gadolinium enhancement (LGE) on cardiac MRI has been shown to predict adverse outcomes in a range of cardiac diseases. However, no study has systematically reviewed and analyzed the literature across all cardiac pathologies including rare diseases. MethodsPubMed, EMBASE and Web of Science were searched for studies evaluating the relationship between LGE burden and cardiovascular outcomes. Outcomes included all-cause mortality, MACE, sudden cardiac death, sustained VT or VF, appropriate ICD shock, heart transplant, and heart failure hospitalization. Only studies reporting hazards ratios with LGE as a continuous variable were included. ResultsOf the initial 8928 studies, 95 studies (23,313 patients) were included across 19 clinical entities. The studies included ischemic cardiomyopathy (7182 patients, 33 studies), hypertrophic cardiomyopathy (5080 patients, 17 studies), non-ischemic cardiomyopathy not otherwise specified (2627 patients, 11 studies), and dilated cardiomyopathy (2345 patients, 14 studies). Among 42 studies that quantified LGE by percent myocardium, a 1 % increase in LGE burden was associated with life-threatening ventricular arrhythmias (LTVA) with a pooled hazard ratio of 1.04 (CI 1.02–1.05), and MACE with a pooled hazard ratio of 1.06 (CI 1.04–1.07). The risk of these events was similar across disease types, with minimal heterogeneity. ConclusionsDespite mechanistic differences myocardial injury, LGE appears to have a fairly consistent, dose-dependent effect on risk of LTVA, MACE, and mortality. This data can be applied to derive a patient's absolute risk of LTVA, and therefore can be clinically useful in informing decisions on primary prevention ICD implantation irrespective of the disease etiology.