MRI of acute myocarditis: a comprehensive approach based on various imaging sequences

Stringent monitoring can decrease mortality of immune checkpoint inhibitor induced cardiotoxicity

Background

Immune checkpoint inhibitor (ICI)-induced myocarditis is a rare immune-related adverse event (irAE) with a fatality rate of 40%-46%. However, irMyocarditis can be asymptomatic. Thus, improved monitoring, detection and therapy are needed. This study aims to generate knowledge on pathogenesis and assess outcomes in cancer centers with intensified patient management.

Methods

Patients with cardiac irAEs from the SERIO registry (www.serio-registry.org) were analyzed for demographics, ICI-related information (type of ICI, therapy line, combination with other drugs, onset of irAE, and tumor response), examination results, irAE treatment and outcome, as well as oncological endpoints. Cardiac biopsies of irMyocarditis cases (n = 12) were analyzed by Nanostring and compared to healthy heart muscle (n = 5) and longitudinal blood sampling was performed for immunophenotyping of irMyocarditis-patients (n = 4 baseline and n = 8 during irAE) in comparison to patients without toxicity under ICI-therapy (n = 4 baseline and n = 7 during ICI-therapy) using flow cytometry.

Results

A total of 51 patients with 53 cardiac irAEs induced by 4 different ICIs (anti-PD1, anti-PD-L1, anti-CTLA4) were included from 12 centers in 3 countries. Altogether, 83.0% of cardiac irAEs were graded as severe or life-threatening, and 11.3% were fatal (6/53). Thus, in centers with established consequent troponin monitoring, work-up upon the rise in troponin and consequent treatment of irMyocarditis with corticosteroids and -if required-second-line therapy mortality rate is much lower than previously reported. The median time to irMyocarditis was 36 days (range 4-1,074 days) after ICI initiation, whereas other cardiotoxicities, e.g. asystolia or myocardiopathy, occurred much later. The cytokine-mediated signaling pathway was differentially regulated in myocardial biopsies as compared to healthy heart based on enrichment Gene Ontology analysis. Additionally, longitudinal peripheral blood mononuclear cell (PBMC) samples from irMyocarditis-patients indicated ICI-driven enhanced CD4+ Treg cells and reduced CD4+ T cells. Immunophenotypes, particularly effector memory T cells of irMyocarditis-patients differed from those of ICI-treated patients without side effects. LAG3 expression on T cells and PD-L1 expression on dendritic cells could serve as predictive indicators for the development of irMyocarditis.

Conclusion

Interestingly, our cohort shows a very low mortality rate of irMyocarditis-patients. Our data indicate so far unknown local and systemic immunological patterns in cardiotoxicity.

Myocarditis: A multi-omics approach

Myocarditis, an inflammatory condition of weakened heart muscles often triggered by a variety of causes, that can result in heart failure and sudden death. Novel ways to enhance our understanding of myocarditis pathogenesis is available through newer modalities (omics). In this review, we examine the roles of various biomolecules and associated functional pathways across genomics, transcriptomics, proteomics, and metabolomics in the pathogenesis of myocarditis. Our analysis further explores the reproducibility and variability intrinsic to omics studies, underscoring the necessity and significance of employing a multi-omics approach to gain profound insights into myocarditis pathogenesis. This integrated strategy not only enhances our understanding of the disease, but also confirms the critical importance of a holistic multi-omics approach in disease analysis.

[Diagnostic and prognostic utility of cardiac magnetic resonance imaging in myocarditis]

Cardiac magnetic resonance imaging (CMR) became over the last 30 years an essential tool in the management of patients with myocarditis. Noninvasive diagnosis of acute myocarditis relies on a clinical picture compatible with myocarditis and fulfilling of the updated 2018 Lake Louise criteria. These criteria include highlights of myocardial edema by conventional T2-weighted sequences or by T2 mapping in one hand and evidence of myocardial injury using late gadolinium enhancement sequences, T1 mapping or extra-cellular volume measurement in the other hand. It is recommended to perform basal examination in the 2 or 3 weeks following acute episode and to repeat CMR during follow-up. The literature reports excellent diagnostic accuracy, between 80% and 90%, making CMR a robust and reliable noninvasive alternative to endomyocardial biopsy. Besides, beyond its diagnostic performance, CMR can also help to identify patients with unfavourable long-term outcome. For instance, medio-ventricular and septal location of late gadolinium enhancement, degree of late gadolinium enhancement extent or high T2 mapping values are independent predictive factors of major cardio-vascular events.

Patterns of cardiovascular magnetic resonance inflammation in acute myocarditis from South Asia and Middle East

Background

Cardiovascular magnetic resonance (CMR) is the test of choice for diagnosis and risk stratification of myocardial inflammation in acute viral myocarditis. The objective of this study was to assess patterns of CMR inflammation in a cohort of acute myocarditis patients from Northern Africa, Asia, and the Middle East using unsupervised machine learning.

Methods

A total of 169 racially and ethnically diverse adults (≥18 years of age) with CMR confirmed acute myocarditis were studied. The primary outcome was a combined clinical endpoint of cardiac death, arrhythmia, and dilated cardiomyopathy. Machine learning was used for exploratory analysis to identify patterns of CMR inflammation.

Results

Our cohort was diverse with 25% from Northern Africa, 33% from Southern Asia, and 28% from Western Asia/the Middle East. Twelve patients met the combined clinical endpoint – 3 had arrythmia, 8 had dilated cardiomyopathy, and 1 died. Patients who met the combined endpoint had increased anterior (p = 0.034) and septal (p = 0.042) late gadolinium enhancement (LGE). Multivariable logistic regression, adjusted for age, gender, and BMI, found that patients from Southern Asia (p = 0.041) and the Middle East (p = 0.043) were independently associated with lateral LGE. Unsupervised machine learning and factor analysis identified two distinct CMR patterns of inflammation, one with increased LGE and the other with increased myocardial T1/T2.

Conclusions

We found that anteroseptal inflammation is associated with worsened outcomes. Using machine learning, we identified two patterns of myocardial inflammation in acute myocarditis from CMR in a racially and ethnically diverse group of patients from Southern Asia, Northern Africa, and the Middle East.

Multiparametric Cardiovascular Magnetic Resonance in Acute Myocarditis: Comparison of 2009 and 2018 Lake Louise Criteria With Endomyocardial Biopsy Confirmation

Background: Cardiac magnetic resonance (CMR) has been shown to improve the diagnosis of myocarditis, but no systematic comparison of this technique is currently available. The purpose of this study was to compare the 2009 and 2018 Lake Louise Criteria (LLC) for the diagnosis of acute myocarditis using 3.0 T MRI with endomyocardial biopsy (EMB) as a reference and to provide the cutoff values for multiparametric CMR techniques.

Methods: A total of 73 patients (32 ± 14 years, 71.2% men) with clinically suspected myocarditis undergoing EMB and CMR with 3.0 T were enrolled in the study. Patients were divided into two groups according to EMB results (EMB-positive and -negative groups). The CMR protocol consisted of cine-SSFP, T2 STIR, T2 mapping, early and late gadolinium enhancement (EGE, LGE), and pre- and post-contrast T1 mapping. Their potential diagnostic ability was assessed with receiver operating characteristic curves.

Results: The myocardial T1 and T2 relaxation times were significantly higher in the EMB-positive group than in the EMB-negative group. Optimal cutoff values were 1,228 ms for T1 relaxation times and 58.5 ms for T2 relaxation times with sensitivities of 86.0 and 83.7% and specificities of 93.3 and 93.3%, respectively. The 2018 LLC had a better diagnostic performance than the 2009 LLC in terms of sensitivity, specificity, positive predictive value, and negative predictive value. T1 mapping + T2 mapping had the largest area under the curve (0.95) compared to other single or combined parameters (2018 LLC: 0.91; 2009 LLC: 0.76; T2 ratio: 0.71; EGEr: 0.67; LGE: 0.73; ). The diagnostic accuracy for the 2018 LLC was the highest (91.8%), followed by T1 mapping (89.0%) and T2 mapping (87.7%).

Conclusion: Emerging technologies such as T1/ T2 mapping have significantly improved the diagnostic performance of CMR for the diagnosis of acute myocarditis. The 2018 LLC provided the overall best diagnostic performance in acute myocarditis compared to other single standard CMR parameters or combined parameters. There was no significant gain when 2018LLC is combined with the EGE sequence.

T2-weighted short-tau-inversion-recovery imaging reflects disease activity of cardiac sarcoidosis

OBJECTIVE

We investigated the diagnostic performance of semi-quantitative hyperintensity on T2-weighted short-tau-inversion-recovery black-blood (T2W-STIR-BB) images in identifying active cardiac sarcoidosis (CS) in patients, and compared it with that of ¹⁸F-fluoro-2-deoxyglucose positron emission tomography (FDG-PET).

METHODS

This retrospective study included 40 steroid-naive patients (age 63.1±12.9 years, 20 men) diagnosed with CS who underwent both cardiac MRI and FDG-PET imaging. Active CS cases were defined as satisfying at least one of the following criteria for conventional indices: exacerbation of ventricular arrhythmia, newly identified advanced atrioventricular block, greater than 5% decrease in left ventricular ejection fraction on echocardiography, positive finding on gallium-scintigraphy or elevated levels of sarcoidosis-related serum biomarkers. T2W-STIR-BB images were semi-quantitatively analysed using a myocardium-to-spleen ratio (MSR). The diagnostic performance of T2W-STIR-BB and FDG-PET imaging for detecting active CS was investigated.

RESULTS

Thirty-three patients satisfied at least one criterion and were considered as having active CS. Thirty patients (75%) tested positive with T2W-STIR-BB imaging, and 25 patients (63%) tested positive with FDG-PET. The sensitivity, specificity, accuracy, and positive and negative predictive values for identifying active CS by semi-quantitative MSR on T2W-STIR-BB images were 79%, 43%, 73%, 87% and 30%, respectively. These results were statistically comparable to those of FDG-PET (70%, 71%, 70%, 92% and 33%, respectively).

CONCLUSIONS

When using conventional diagnostic indices for active CS as the gold standard, T2W-STIR-BB imaging demonstrated comparable diagnostic performance to that of FDG-PET. The semi-quantitative analysis of high signal intensity on T2W-STIR-BB images using MSR was useful for detection of active CS.

Bewildering ST-Elevation With Wellens' Electrocardiogram Pattern - Is Myocarditis in Your Differentials?

Myocarditis is the inflammation of the myocardium and is a challenging diagnosis owing to the heterogeneity in its etiology, pathogenesis and clinical presentations. It often presents as an acute coronary syndrome (ACS) mimic and hence may pose both diagnostic and therapeutic challenges to treating physicians to reliably differentiate between these two entities. In this case, we discuss a young male whose initial presentation of chest pain was dubious of the acute coronary syndrome but detailed history, physical examination and by careful selection of non-invasive investigations including echo and cardiac magnetic resonance imaging (MRI), led to a diagnosis of acute myocarditis. This approach not only avoided undue radiation exposure to a young individual but also eluded the unnecessary treatment with potent antiplatelet and anticoagulation therapy.

Cardiac MRI and Myocardial Injury in COVID-19: Diagnosis, Risk Stratification and Prognosis

Myocardial injury is a common complication of the COVID-19 illness and is associated with a worsened prognosis. Systemic hyperinflammation seen in the advanced stage of COVID-19 likely contributes to myocardial injury. Cardiac magnetic resonance imaging (CMR) is the preferred imaging modality for non-invasive evaluation in acute myocarditis, enabling risk stratification and prognostication. Modified scanning protocols in the pandemic setting reduce risk of exposure while providing critical data regarding cardiac tissue inflammation and fibrosis, chamber remodeling, and contractile function. The growing use of CMR in clinical practice to assess myocardial injury will improve understanding of the acute and chronic sequelae of myocardial inflammation from various pathological etiologies.

Life-saving myocarditis? A case in a young adult leading to discovery of an anomalous origin of the right coronary artery

Myocarditis and coronary artery anomalies are both potentially life-threatening aetiologies of cardiac chest pain in children. We present a case of a young man presenting with non-exertional chest pain and subsequently found to have an anomalous origin of the right coronary artery from the left coronary sinus with an interarterial course in addition to a diagnosis of myocarditis. The patient subsequently was able to undergo surgical correction of his anomalous coronary to mitigate the risk of sudden cardiac death.

Diagnostic value of 3.0 T cardiac MRI in children with suspected myocarditis: multi-parameter analysis for the evaluation of acute and chronic myocarditis

BACKGROUND

Cardiac magnetic resonance (CMR) is an established tool for detection of myocarditis. However, no comprehensive data for CMR based on the "Lake Louise" criteria in pediatric myocarditis exists to date.

PURPOSE

To evaluate the value of multi-parameter CMR in children with suspected acute (AMC) and chronic myocarditis (CMC).

MATERIAL AND METHODS

We examined 73 pediatric patients with clinically suspected AMC (n = 25) and CMC (n = 48). We compared them to 17 controls. All individuals underwent CMR, including function analyses, T2 ratio, early gadolinium enhancement ratio (EGEr), and late gadolinium enhancement (LGE).

RESULTS

In AMC, 19 (76%) patients were abnormal in any two of three parameters (T2 ratio, EGEr, and LGE). There was a significant difference between AMC and controls in LVEF (51.2% vs. 61.3%), mass (130.2 ± 14.0 vs. 120.5 ± 13.9 g), T2 ratio (1.96 ± 0.2 vs. 1.69 ± 0.13), and EGEr (4.1 ± 0.27 vs. 3.4 ± 0.39) (P < 0.05). In CMC, 26 (54.1%) patients were abnormal in any two of three parameters. There was no significant difference between CMC and controls in LVEF and mass, but there was a statistical difference in T2 ratio (1.88 ± 0.18 vs. 1.69 ± 0.13) and in EGEr (3.93 ± 0.22 vs. 3.4 ± 0.39) (P < 0.05). There was an increase in LVEF while both T2 ratio and EGEr significantly decreased (P < 0.05) during follow-up of acute fulminant myocarditis.

CONCLUSION

Comprehensive CMR may serve as a powerful tool in children with suspected AMC. CMR in assessment of CMC may be valuable, but it is not satisfactory.

Diagnostic Value of Global Cardiac Strain in Patients With Myocarditis

BACKGROUND

Cardiac strain represents an imaging biomarker of contractile dysfunction.

PURPOSE

The purpose of this study was to investigate the diagnostic value of cardiac strain obtained by feature-tracking cardiac magnetic resonance (MR) in acute myocarditis.

MATERIALS AND METHODS

Cardiac MR examinations of 46 patients with myocarditis and preserved ejection fraction at acute phase and follow-up were analyzed along with cardiac MR of 46 healthy age- and sex-matched controls. Global circumferential strain and global radial strain were calculated for each examination, along with myocardial edema and late gadolinium enhancement, and left ventricle functional parameters, through manual contouring of the myocardium. Correlations were assessed using Spearman ρ. Wilcoxon and Mann-Whitney U test were used to assess differences between data. Receiver operating characteristics curves and reproducibility were obtained to assess the diagnostic role of strain parameters.

RESULTS

Global circumferential strain was significantly lower in controls (median, -20.4%; interquartile range [IQR], -23.4% to -18.7%) than patients in acute phase (-18.4%; IQR, -21.0% to -16.1%; P = 0.001) or at follow-up (-19.2%; IQR, -21.5% to -16.1%; P = 0.020). Global radial strain was significantly higher in controls (82.4%; IQR, 62.8%-104.9%) than in patients during the acute phase (65.8%; IQR, 52.9%-79.5%; P = 0.001). Correlations were found between global circumferential strain and global radial strain in all groups (acute, ρ = -0.580, P < 0.001; follow-up, ρ = -0.399, P = 0.006; controls, ρ = -0.609, P < 0.001), and between global circumferential strain and late gadolinium enhancement only in myocarditis patients (acute, ρ = 0.035, P = 0.024; follow-up, ρ = 0.307, P = 0.038).

CONCLUSIONS

Cardiac strain could potentially have a role in detecting acute myocarditis in low-risk acute myocarditis patients where cardiac MR is the main diagnosing technique.

Right Ventricular Function in Chronic Heart Failure: From the Diagnosis to the Therapeutic Approach

There is growing attention for the study of the right ventricle in cardiovascular disease and in particular in heart failure. In this clinical setting, right ventricle dysfunction is a significant marker of poor prognosis, regardless of the degree of left ventricular dysfunction. Novel echocardiographic methods allow for obtaining a more complete evaluation of the right ventricle anatomy and function as well as of the related abnormalities in filling pressures. Specific and effective therapies for the right ventricle dysfunction are still not well defined and this represents the most difficult and important challenge. This article focuses on available diagnostic techniques for studying right ventricle dysfunction as well as on the therapies for right ventricle dysfunction.

Cardiovascular Magnetic Resonance in Nonischemic Myocardial Inflammation: Expert Recommendations

This JACC Scientific Expert Panel provides consensus recommendations for an update of the cardiovascular magnetic resonance (CMR) diagnostic criteria for myocardial inflammation in patients with suspected acute or active myocardial inflammation (Lake Louise Criteria) that include options to use parametric mapping techniques. While each parameter may indicate myocardial inflammation, the authors propose that CMR provides strong evidence for myocardial inflammation, with increasing specificity, if the CMR scan demonstrates the combination of myocardial edema with other CMR markers of inflammatory myocardial injury. This is based on at least one T2-based criterion (global or regional increase of myocardial T2 relaxation time or an increased signal intensity in T2-weighted CMR images), with at least one T1-based criterion (increased myocardial T1, extracellular volume, or late gadolinium enhancement). While having both a positive T2-based marker and a T1-based marker will increase specificity for diagnosing acute myocardial inflammation, having only one (i.e., T2-based OR T1-based) marker may still support a diagnosis of acute myocardial inflammation in an appropriate clinical scenario, albeit with less specificity. The update is expected to improve the diagnostic accuracy of CMR further in detecting myocardial inflammation.

Cardiovascular Magnetic Resonance Imaging Evidence of Edema in Chronic Chagasic Cardiomyopathy

The persistence of inflammatory processes in the myocardium in varying degrees of chronic Chagas heart disease has been poorly investigated. We hypothesized that edema could occur in patients with chronic chagasic cardiomyopathy and corresponds to the persistence of inflammatory processes in the myocardium. Eighty-two Chagas disease (CD) seropositive patients (64.6% females; age = 58.9 ± 9.9) without ischemic heart disease or conditions that cause myocardial fibrosis and dilation were considered. Late gadolinium enhancement (LGE) and T2-weighted magnetic resonance imaging of edema were obtained and represented using a 17-segment model. Patients were divided into three clinical groups according to the left ventricular (LV) ejection fraction (EF) as G1 (EF > 60%; n=37), G2 (35% > EF < 60%; n=33), and G3 (EF < 35%; n=12). Comparisons were performed by the Fisher or ANOVA tests. Bonferroni post hoc, Spearman correlation, and multiple correspondence analyses were also performed. Edema was observed in 8 (9.8%) patients; 2 (5.4%) of G1, 4 (12.1%) of G2, and 2 (16.7%) of G3. It was observed at the basal inferolateral segment in 7 (87.5%) cases. LGE was observed in 48 (58.5%) patients; 16 (43.2%) of G1, 21 (63.6%) of G2, and 11 (91.7%) of G3 (p < 0.05). It was observed in the basal inferior/inferolateral/anterolateral segments in 35 (72.9%) patients and in the apical anterior/inferior/lateral and apex segments in 21 (43.7%), with midwall (85.4%; n=41), subendocardial (56.3%; n=27), subepicardial (54.2%; n=26), transmural (31.2%; n=15), and RV (1.2%; n=1) distribution. Subendocardial lesions were observed only in patients with LVEF < 35%. There was no involvement of the mid-inferolateral/anterolateral segments with an LVEF > 35% (p < 0.05). Deteriorations of the LV and RV systolic functions were positively correlated (r _s =0.69; p < 0.05) without evidence of LGE in the RV. Edema can be found in patients with chagasic cardiomyopathy in the chronic stage. In later stages of cardiac dilation with low LVEF, the LGE pattern involves subendocardium and mid locations. Deteriorations of RV and LV are positively correlated without evidence of fibrosis in the RV.

Early Detection of Localized Immunity in Experimental Autoimmune Myocarditis Using [99mTc]Fucoidan SPECT

PURPOSE

The aim of the study was to evaluate the ability of technetium-99m-fucoidan ([^99mTc]fucoidan), a molecular imaging agent specific for selectins, in the assessment of early localized immunity in a rat model of experimental autoimmune myocarditis (EAM).

PROCEDURES

EAM was induced in Lewis rats and troponin T; brain natriuretic peptide (BNP) and anti-myosin antibodies were measured in plasma. Separately, [^99mTc]fucoidan single-photon emission computed tomography (SPECT)/x-ray computed tomography (CT) was performed in the very early phase of myocarditis at 10, 15, and 21 days after immunization. Then, hearts were collected and used for autoradiography, well counting, histology, and flow cytometry analysis.

RESULTS

The EAM acute phase is characterized by extensive myocardial necrosis, release of troponin and BNP, and pericardial effusion. [^99mTc]Fucoidan uptake was significantly increased in EAM compared with controls starting from D15. There was a close relationship between uptake of the tracer and myocardial content in CD45+, CD8+, CD11b+, and CD31+ cells.

CONCLUSIONS

[^99mTc]Fucoidan SPECT/CT accurately diagnosed the autoimmune attack in the early steps of EAM and could be used to monitor disease evolution and therapy efficiency.

Diagnostic and prognostic value of cardiac magnetic resonance in acute myocarditis: a systematic review and meta-analysis

While diagnostic criteria were elaborated for acute myocarditis using cardiac magnetic resonance (CMR) in 2009, studies have since examined the yield of traditional and novel CMR parameters to achieve greater accuracy and to predict clinical outcomes. The purpose of this systematic review and meta-analysis was to determine the diagnostic and prognostic value of CMR parameters for acute myocarditis. MEDLINE and EMBASE were systematically searched for original studies that reported CMR parameters in adult patients suspected of acute myocarditis. Each CMR parameter's binary prevalence, mean value and standard deviation were extracted. Parameters were meta-analyzed using a random-effects model to generate standardized mean differences. After screening 1492 abstracts, 53 studies were included encompassing 2823 myocarditis patients and 803 controls. Pooled standardized mean differences between myocarditis patients and controls were: T2 mapping time 2.26 (95% CI 1.50-3.02), extracellular volume 1.64 (95% CI 0.87-2.42), LGE percentage 1.30 (95% CI 0.95-1.64), T1 mapping time 1.18 (95% CI 0.35-2.01), T2 ratio 1.17 (95% CI 0.80-1.54), and EGE ratio 0.93 (95% CI 0.66-1.19). Prolonged T1 mapping time had the highest sensitivity (82%), pericardial effusion had the highest specificity (99%). Baseline LV dysfunction and the presence of LGE were predictive of major adverse cardiac events. The results support integration of parametric mapping criteria in the diagnostic criteria for myocarditis. The presence of baseline LV dysfunction and LGE predict patients at higher risk of adverse events.

STEMI mimicker in a 26-year-old man

We herein describe a case of acute myocarditis which may mimic myocardial infarction, since affected patients experience 'typical' chest pain, the ECG changes are identical to those observed in acute coronary syndromes, and serum markers are increased. This case emphasises the importance of performing appropriate cardiac MRI to help in the differential and definitive diagnosis as well as the extent of myocardial involvement. ST elevation myocardial infarction is rare in young adults and when it is encountered, it should raise the differential diagnosis of its mimickers.

Diagnostic Accuracy of Cardiovascular Magnetic Resonance in Acute Myocarditis: A Systematic Review and Meta-Analysis

OBJECTIVES

The purpose of this systematic review was to explore the diagnostic accuracy of various cardiovascular magnetic resonance (CMR) index tests for the diagnosis of acute myocarditis in adult patients.

BACKGROUND

Acute myocarditis remains one of the most challenging diagnoses in cardiology. CMR has emerged as the diagnostic tool of choice to detect acute myocardial injury and necrosis in patients with suspected myocarditis.

METHODS

We considered all diagnostic cohort and case-control studies. We searched MEDLINE, EMBASE, Cochrane Library, SCOPUS, and Web of Science up to April 21, 2017. We used the Quality Assessment of Diagnostic Accuracy Studies-2 tool to assess the quality of included studies. PROSPERO registration number CRD42017055778 was used.

RESULTS

Twenty-two studies were included in the systematic review. Because significant heterogeneity exists among the studies, we only present hierarchical receiver operator curves. The areas under the curve (AUC) for each index test were for T1 mapping 0.95 (95% confidence interval [CI]: 0.93 to 0.97), for T2 mapping 0.88 (95% CI: 0.85 to 0.91), for extracellular volume fraction (ECV) 0.81 (95% CI: 0.78 to 0.85), for increased T2 ratio/signal 0.80 (95% CI: 0.76 to 0.83), for late gadolinium enhancement (LGE) 0.87 (95% CI: 0.84 to 0.90), for early gadolinium enhancement (EGE) 0.78 (95% CI: 0.74 to 0.81), and for the Lake Louise criteria (LLC) 0.81 (95% CI: 0.77 to 0.84). Native T1 mapping had superior diagnostic accuracy across all index tests. The AUC of T2 mapping was greater than the AUC of increased T2 ratio/signal and EGE, whereas ECV showed no superiority compared with other index tests. LGE had better diagnostic accuracy compared with the classic CMR index tests, similar accuracy with T2 mapping and ECV, and only T1 mapping surpassed it.

CONCLUSIONS

Novel CMR mapping techniques provide high diagnostic accuracies for the diagnosis of acute myocarditis and constitute promising successors of the classic elements of the LLC for routine diagnostic protocols.

ST Segment Elevation Is Not Always Myocardial Infarction: A Case of Focal Myopericarditis

Protocols exist on how to manage STEMI patients, with well-established timelines. There are times when patients present with chest pain, ST segment elevation, and biomarker elevation that are not due to coronary artery disease. These conditions usually present with normal coronary angiography. We present a case that was clinically indistinguishable from STEMI and that was diagnosed with focal myopericarditis on cardiac MRI.

Cardiac Findings in Amyotrophic Lateral Sclerosis: A Magnetic Resonance Imaging Study

The objective of this study was to investigate the potential involvement of cardiac structure and function by cardiac magnetic resonance (CMR) imaging in amyotrophic lateral sclerosis (ALS) patients. Our study included 35 patients with ALS without a history of cardiac disease and an age- and gender-matched healthy control group (n = 34). All subjects received a CMR in a 1.5-T whole-body scanner. Patients were also screened with Holter monitoring, echocardiography, and a blood test of cardiac markers. Myocardial mass in ALS hearts was reduced compared to the control group, and ejection volumes in the left and right heart were severely decreased in ALS patients, as shown by echocardiography and CMR. The myocardium showed increased T1 enhancement in 77% of the patients compared to 27% of controls (p = 0.0001). A trend toward late gadolinium enhancement patterns consistent with myocardial fibrosis was observed in 23.5% of the patients (9.1% of controls). Holter monitoring was normal in all patients as well as troponin T. Cardiac involvement seems to be present in ALS patients without clinical cardiac symptoms and with a normal cardiac routine assessment. Structural myocardial defects in CMR may be due to sympathetic dysfunction and may account for reported cardiac deaths in late-stage ALS patients.

Performance of Cardiac Magnetic Resonance Imaging for Diagnosis of Myocarditis Compared with Endomyocardial Biopsy: A Meta-Analysis

Background

Cardiac magnetic resonance imaging (CMRI) is considered to be useful for the diagnosis of myocarditis, and the Lake Louise Criteria (LLC) has been proved to be of significance as the standard of diagnosis. However, the diagnostic performance of LLC-based CMRI for myocarditis compared with endomyocardial biopsy (EMB) has not been quantitatively evaluated in a meta-analysis.

Material/Methods

The databases PubMed, Cochrane’s Library, and EMBASE were searched to identify studies on LLC and its individual components for the diagnosis of myocarditis. EMB was the control reference. The sensitivity, specificity, and positive and negative diagnostic likelihood ratios were calculated with a random-effects model. The area under the receiver operating characteristic curve (AUC) was estimated to show overall effectiveness.

Results

We included 9 cohorts (614 patients) of patients with suspected MC. The combined sensitivities, specificities, and AUCs for T1-weighed global relative enhancement were 0.66, 0.73, and 0.71; for T2-weighed edema ratio they were 0.52, 0.73, and 0.72; for the late gadolinium enhancement, they were 0.70, 0.57, and 0.67; and for LLC-based CMRI they were 0.70, 0.56, and 0.70, respectively. Subgroup analysis indicated that the sensitivities, specificities, and diagnostic accuracies of LLC and its individual component-based CMRI seemed to be similar in patients with acute or chronic myocarditis. Results of the Deeks’ funnel plot asymmetry test showed no significant publication bias among the studies.

Conclusions

CMRI based on LLC or its individual components seems to have moderate accuracy in diagnosis of acute or chronic myocarditis.

Early myocardial gadolinium enhancement in patients with myocarditis: Validation of "Lake Louise consensus" criteria using a single bolus of 0.1mmol/Kg of a high relaxivity gadolinium-based contrast agent

OBJECTIVES

Global early gadolinium enhancement (EGE) is an accepted cardiac magnetic resonance (CMR) criterion for diagnosis of myocarditis. However, recommended enhancement thresholds are based specifically on standard-relaxivity Gd-chelates. We evaluated the performance of a high relaxivity MR contrast agent for detection of myocardial hyperemia in patients referred for endomyocardial biopsy (EMB).

METHODS

We retrospectively enrolled 54 patients (mean age: 44.1 years [range=18-77years]; 72% men) with suspected myocarditis who underwent CMR and EMB within four weeks of clinical onset. CMR imaging protocol included T2-weighted short tau inversion-recovery sequence, EGE and late gadolinium enhanced (LGE) imaging. For EGE imaging, free-breathing ECG-gated turbo spin echo T1-weighted (TSE T1w) sequences were acquired before and within the first three minutes after gadobenate dimeglumine (0.1mmol/Kg) administration. The ratio (EGEr) between myocardial and musculoskeletal early enhancement was calculated. Myocardial edema, EGE and late gadolinium enhancement (LGE) were correlated with EMB results. Receiver operating characteristic (ROC) curve analysis of EGE values was applied on the overall population.

RESULTS

EMB revealed myocarditis in 34/54 patients. Sensitivity, specificity and accuracy values of 0.61, 0.85 and 0.70, respectively, were obtained for a standard EGE threshold (EGEr>4.0). ROC analysis revealed an area under the curve of 0.701 for EGEr (IC95%:0.556-0.846, p=0.014) and 0.706 for absolute enhancement (IC95%:0.563-0.849, p=0.012). Sensitivity, specificity and accuracy values were 0.67, 0.80 and 0.72, respectively, for myocardial edema and 0.76, 0.75 and 0.76, respectively, for LGE.

CONCLUSIONS

High relaxivity contrast agents provide comparable results to standard-relaxivity chelates for EGE assessment in diagnosing myocarditis.

Predictive Value of Cardiac Magnetic Resonance Imaging-Derived Myocardial Strain for Poor Outcomes in Patients with Acute Myocarditis

Objective

To evaluate the utility of cardiovascular magnetic resonance (CMR)-derived myocardial strain measurement for the prediction of poor outcomes in patients with acute myocarditis.

Materials and Methods

We retrospectively analyzed data from 37 patients with acute myocarditis who underwent CMR. Left ventricular (LV) size, LV mass index, ejection fraction and presence of myocardial late gadolinium enhancement (LGE) were analyzed. LV circumferential strain (Ecc_SAX), radial strain (Err_SAX) from mid-ventricular level short-axis cine views and LV longitudinal strain (Ell_LV), radial strain (Err_Lax) measurements from 2-chamber long-axis views were obtained. In total, 31 of 37 patients (83.8%) underwent follow-up echocardiography. The primary outcome was major adverse cardiovascular event (MACE). Incomplete LV functional recovery was a secondary outcome.

Results

During an average follow-up of 41 months, 11 of 37 patients (29.7%) experienced MACE. Multivariable Cox proportional hazard regression analysis, which included LV mass index, LV ejection fraction, the presence of LGE, Ecc_SAX, Err_SAX, Ell_LV, and Err_Lax values, indicated that the presence of LGE (hazard ratio, 42.88; p = 0.014), together with ErrLax (hazard ratio, 0.77 per 1%, p = 0.004), was a significant predictor of MACE. Kaplan-Meier analysis demonstrated worse outcomes in patient with LGE and an Err_Lax value ≤ 9.48%. Multivariable backward regression analysis revealed that Err_Lax values were the only significant predictors of LV functional recovery (hazard ratio, 0.54 per 1%; p = 0.042).

Conclusion

CMR-derived Err_Lax values can predict poor outcomes, both MACE and incomplete LV functional recovery, in patients with acute myocarditis, while LGE is only a predictor of MACE.

Multimodality imaging approach in the diagnosis of chronic myocarditis with preserved left ventricular ejection fraction (MCpEF): The role of 2D speckle-tracking echocardiography

BACKGROUND

Up to one third of patients with chronic myocarditis (MC) have preserved left ventricular (LV) ejection fraction (MCpEF). The purpose of this study was to evaluate the role of adding 2D speckle-tracking echocardiography (STE) to cardiac magnetic resonance imaging (cMRI) in the diagnosis of patients with MCpEF.

METHODS AND RESULTS

We analyzed 67 patients with suspected MCpEF who underwent endomyocardial biopsy (EMB). Thirty-two patients with confirmed chronic myocardial inflammation by EMB served as study group (MCpEF) and the remaining patients (n=35) served as control group. In all patients, 2D STE and cMRI were performed within 48h before EMB. Patients with MCpEF had significantly lower LV global longitudinal systolic strain (GLS) than controls (GLS: -17.01±2.42% vs. -19.39±3.81%, p<0.001; respectively). In line, an abnormal GLS had adequate diagnostic performance to detect MCpEF (sensitivity, specificity, and accuracy of 82%, 70%, and 76%, respectively), which was superior to cMRI based on the Lake-Louise criteria (sensitivity, specificity, and accuracy 54%, 71%, and 67%, respectively). In addition, adding GLS to the Lake-Louise criteria improved significantly the diagnostic performance of cMRI to detect MCpEF (sensitivity, specificity, and accuracy 96%, 55%, and 75%, respectively).

CONCLUSION

The findings of this study suggest that GLS using 2D STE could play an important role in the diagnostic evaluation of patients with suspected chronic myocarditis with preserved LV ejection fraction (MCpEF).

Clinical applications of multi-parametric CMR in myocarditis and systemic inflammatory diseases

Cardiac magnetic resonance (CMR) has changed the management of suspected viral myocarditis by providing a ‘positive’ diagnostic test and has lead to new insights into myocardial involvement in systemic inflammatory conditions. In this review we analyse the use of CMR tissue characterisation techniques across the available studies including T2 weighted imaging, early gadolinium enhancement, late gadolinium enhancement, Lake Louise Criteria, T2 mapping, T1 mapping and extracellular volume assessment. We also discuss the use of multiparametric CMR in acute cardiac transplant rejection and a variety of inflammatory conditions such as sarcoidosis, systemic lupus erythrematous, rheumatoid arthritis and systemic sclerosis.

Is Endomyocardial Biopsy a Safe and Useful Procedure in Children with Suspected Cardiomyopathy?

Endomyocardial biopsy (EMB) is a common procedure used to aid in the diagnosis, prognosis and treatment of suspected pediatric cardiomyopathy. In suspected cardiomyopathy, no multicenter experience has previously reported on the safety and utility of EMBs. Retrospectively, adverse event (AE) and patient and procedural characteristics were obtained at seven institutions participating in the Congenital Cardiac Catheterization Outcomes Project for both a cardiomyopathy (n = 158) and a post-transplant surveillance (n = 2665) cohort. Descriptive information regarding biopsy indication, pathology and clinical management based on EMB findings were retrospectively obtained. High-severity AEs were more common in the cardiomyopathy cohort when compared to the post-transplant surveillance cohort. The cardiomyopathy cohort was younger, more hemodynamically vulnerable and required more cardiorespiratory support during the procedure. The eight high-severity AEs in the cardiomyopathy group included one myocardial perforation, two ECMO cannulations and three deaths following the EMB. Factors associated with high-severity AEs included performing another catheter-based intervention during the EMB and longer fluoroscopy time. Notably, an increased number of biopsy attempts did not increase the risk of an AE. Suspected myocarditis was the most common indication. Diagnostic EMB pathology and thus alteration to clinical management based on pathology occurred more frequently in patients with suspected myocarditis. In conclusion, there is an increased incidence of high-severity AEs in patients undergoing EMB for suspected cardiomyopathy. EMB may be more clinically useful in the management of suspected myocarditis. The increased risk of high-severity AEs when additional interventions are performed highlights the hemodynamic vulnerability in patients with suspected cardiomyopathy.

Cardiac magnetic resonance imaging abnormalities in systemic lupus erythematosus: a preliminary report

The purpose of this prospective, pilot study was to determine whether differences in myocardial T2 relaxivity can be identified among active systemic lupus erythematosus (SLE) patients with clinically suspected SLE myocarditis, other active SLE patients, inactive SLE patients and age and gender matched controls. Eleven consecutive female patients (six with active SLE and five with inactive SLE), and five age, gender and race matched healthy controls underwent imaging with echocardiography and cardiac magnetic resonance imaging (MRI). Echocardiographic measurements included left ventricular end diastolic (LVEDV) and end systolic volumes (LVESV), and mass (LVM) (all indexed to body mass); ejection fraction and cardiac output. The cardiac MRI measurement was the T2 relaxation time (an index of soft tissue signal, with higher levels suggestive of increased tissue water content). Patients with active SLE had significantly higher LVEDVand LVM than inactive SLE patients and healthy controls, and significantly larger LVESV than healthy controls. Myocardial T2 relaxation times were significantly higher in patients with active SLE compared to those with inactive SLE and to healthy controls, and remained higher even after excluding the two active SLE patients who had clinical myocarditis. The four active SLE patients who underwent repeat cardiac imaging studies after clinical improvement showed normalization of these myocardial abnormalities. The conclusion was that active SLE patients demonstrate abnormalities in myocardial structure manifested by high myocardial T2 relaxation times that normalized after clinical improvement in disease activity. These findings suggest that T2 relaxation values are a sensitive indicator of myocardial disease in patients with SLE and that myocardial T2 relaxation abnormality frequently occur in patients with active SLE, even in the absence of myocardial involvement by clinical criteria.

Myocardial biomarkers and delayed enhanced cardiac magnetic resonance relationship in clinically suspected myocarditis and insight on clinical outcome

AIMS

The relationship of cardiac magnetic resonance (CMR) late gadolinium enhancement (LGE) with myocardial biomarkers and markers of inflammation in acute viral myocarditis is not clearly defined. We assessed the relationship of LGE with myocardial and inflammatory biomarkers measured during the acute phase of myocarditis and their predictive value on clinical outcome.

METHODS

Patients with first clinical episode of acute viral myocarditis and complete CMR study, including cine and LGE images, were included. The peak values of troponin I, creatine kinase, C-reactive protein value at admission and LGE extent were reported for each case. A 29-month clinical follow-up was performed, and cardiac symptoms and adverse cardiac events (all-cause death, heart transplant, hospitalization for heart failure) were reported.

RESULTS

Forty-one patients (39 ± 15 years and 78% men) were included. Median LGE extent was 13% [interquartile range (IQR) (9%, 19%)] of left-ventricular mass and mean left-ventricular ejection fraction was 56 ± 11%. There was a significant correlation between peak troponin I and LGE extent (r = 0.51, P < 0.001), and between peak creatine kinase and LGE extent (r = 0.66, P < 0.001). There was no correlation between C-reactive protein at admission and LGE extent (r = 0.27, P = 0.09). At follow-up, eight (20%) patients had an adverse clinical event. LGE extent was significantly associated with a worse New York Heart Association status at follow-up [odds ratio (OR) 1.21, 95% confidence interval (CI) 1.07, 1.37, P = 0.002]. After adjustment for left-ventricular ejection fraction, age and clinical presentation category, LGE extent remained an independent predictor of cardiovascular events (hazard ratio 1.42; 95% CI 1.05, 1.95, P = 0.027).

CONCLUSIONS

LGE extent on CMR studies is significantly correlated to biomarkers of myocardial injury in patients with acute viral myocarditis, and is a significant independent predictor of adverse cardiovascular outcome.

[Myocarditis in the differential diagnosis of cardiomyopathies. Endomyocardial biopsy or MRI?]

Myocarditis is an inflammatory disease of the heart muscle commonly caused by viral pathogens. Dilated cardiomyopathy is a major long-term sequela of myocarditis and at least in part related to post-viral immune-mediated responses. Establishing a diagnosis of myocarditis represents a major challenge because of the variable clinical picture and the lack of readily available, non-invasive diagnostic tests. In recent years, cardiac magnetic resonance imaging (cMRI) has emerged as a promising additional diagnostic tool in patients with suspected myocarditis: cMRI not only provides important insights into structural and functional abnormalities of the heart but relevant tissue pathologies can also be visualized. The diagnostic accuracy of three tissue criteria, i.e. the edema ratio, early gadolinium enhancement ratio and late gadolinium enhancement, has been characterized in several studies. Endomyocardial biopsy (EMB) is widely considered to be the reference standard for diagnosis of myocarditis. Although limited by sampling error, EMB is the only diagnostic procedure that can be used to confirm myocarditis. Laboratory analyses of EMB may provide information about specific causes of myocarditis and are, at least in part, of prognostic relevance. In a subset of patients the results of EMB may guide therapeutic decision-making. Additional efforts are needed in cardiac imaging, molecular characterization of EMB and evaluation of serum biomarkers to improve the diagnostic work-up in patients with suspected myocarditis and to identify potential novel targets for a cause-specific therapy of myocarditis.

Myocardial tissue characterization in Chagas' heart disease by cardiovascular magnetic resonance

BACKGROUND

Chagas' heart disease is an important public health problem in South America. Several aspects of the pathogenesis are not fully understood, especially in its subclinical phases. On pathology Chagas' heart disease is characterized by chronic myocardial inflammation and extensive myocardial fibrosis. The latter has also been demonstrated by late gadolinium enhancement (LGE) by cardiovascular magnetic resonance (CMR). In three clinical phases of this disease, we sought to investigate the presence of LGE, myocardial increase in signal intensity in T2-weighted images (T2W) and in T1-weighted myocardial early gadolinium enhancement (MEGE), previously described CMR surrogates for myocardial fibrosis, myocardial edema and hyperemia, respectively.

METHODS

Fifty-four patients were analyzed. Sixteen patients with the indeterminate phase (IND), seventeen patients with the cardiac phase with no left ventricular systolic dysfunction (CPND), and twenty-one patients with the cardiac phase with left ventricular systolic dysfunction (CPD). All patients underwent 1.5 T CMR scan including LGE, T2W and MEGE image sequences to evaluate myocardial abnormalities.

RESULTS

Late gadolinium enhancement was present in 72.2 % of all patients, in 12.5 % of IND, 94.1 % of the CPND and 100 % of the CPD patients (p < 0.0001). Myocardial increase in signal intensity in T2-weighted images (T2W) was present in 77.8 % of all patients, in 31.3 % of the IND, 94.1 % of the CPND and 100 % of the CPD patients (p < 0.0001). T1-weighted myocardial early gadolinium enhancement (MEGE) was present in 73.8 % of all patients, in 25.0 % of the IND, 92.3 % of the CPND and 94.1 % of the CPD (p < 0.0001). A good correlation between LGE and T2W was observed (r = 0.72, and p < 0.001).

CONCLUSIONS

Increase in T2-weighted (T2W) myocardial signal intensity and T1-weighted myocardial early gadolinium enhancement (MEGE) can be detected by CMR in patients throughout all phases of Chagas' heart disease, including its subclinical presentation (IND). Moreover, those findings were parallel to myocardial fibrosis (LGE) in extent and location and also correlated with the degree of Chagas' heart disease clinical severity. These findings contribute to further the knowledge on pathophysiology of Chagas' heart disease, and might have therapeutic and prognostic usefulness in the future.

Lights and shadows of cardiac magnetic resonance imaging in acute myocarditis

Abstract

Cardiac magnetic resonance (CMR) is considered a primary tool for the diagnosis of acute myocarditis, due to its unique potential for non-invasive identification of the various hallmarks of the inflammatory response, with relevant impact on patient management and prognosis. Nonetheless, a marked variation in sensitivity and negative predictive value has been reported in the literature, reflecting the intrinsic drawbacks of current diagnostic criteria, which are based mainly on the use of conventional CMR pulse sequences. As a consequence, a negative exam cannot reliably exclude the diagnosis, especially in patients who do not present an infarct-like onset of disease. The introduction of new-generation mapping techniques further widened CMR potentials, allowing quantification of tissue changes and opening new avenues for non-invasive workup of patients with inflammatory myocardial disease.

Main messages

• CMR sensitivity varies in AM, reflecting its clinical polymorphism and the intrinsic drawbacks of LLc.

• Semiquantitative approaches such as EGEr or T2 ratio have limited accuracy in diffuse disease forms.

• T1 mapping allows objective quantification of inflammation, with no need to normalize measurements.

• A revised protocol including T2-STIR, T1 mapping and LGE could be hypothesized to improve sensitivity.

Incremental value of quantitative CMR including parametric mapping for the diagnosis of acute myocarditis

AIM

Cardiac magnetic resonance (CMR) can visualize inflammatory tissue changes in acute myocarditis. Several quantitative image-derived parameters have been described to enhance the diagnostic value of CMR, but no direct comparison of these techniques is available.

METHODS AND RESULTS

A total of 34 patients with suspected acute myocarditis and 50 control subjects underwent CMR. CMR protocol included quantitative assessment of T1 relaxation times using modified Look-Locker inversion recovery (MOLLI) and shortened MOLLI (ShMOLLI) acquisition schemes, extracellular volume fraction (ECV), T2 relaxation times, and longitudinal strain. Established Lake-Louise criteria (LLC) consisting of T2-weighted signal intensity ratio (T2-ratio), early gadolinium enhancement ratio (EGEr), and late gadolinium enhancement (LGE) were assessed. Receiver operating characteristics analysis was performed to compare diagnostic performance. Areas under the curve of native T1 (MOLLI: 0.95; ShMOLLI: 0.92) and T2 relaxation times (0.92) were higher compared with those of the other CMR parameters (T2-ratio: 0.71, EGEr: 0.71, LGE: 0.87, LLC: 0.90, ECV MOLLI: 0.77, ECV ShMOLLI: 0.80, longitudinal strain: 0.83). Combined with LGE, each native mapping technique outperformed the diagnostic performance of LLC (P < 0.01, respectively). A combination of native parameters (T1, T2, and longitudinal strain) significantly increased the diagnostic performance of CMR compared with LLC without need of contrast media application (0.99 vs. 0.90; P = 0.008).

CONCLUSION

In patients suspected of having acute myocarditis, diagnostic performance of CMR can be improved by implementation of quantitative CMR parameters. Especially, native mapping techniques have the potential to replace current LLC. CLINICALTRIALS.

GOV NUMBER

NCT02299856.

Characterization of Benign Myocarditis Using Quantitative Delayed-Enhancement Imaging Based on Molli T1 Mapping

Delayed contrast enhancement after injection of a gadolinium-chelate (Gd-chelate) is a reference imaging method to detect myocardial tissue changes. Its localization within the thickness of the myocardial wall allows differentiating various pathological processes such as myocardial infarction (MI), inflammatory myocarditis, and cardiomyopathies. The aim of the study was first to characterize benign myocarditis using quantitative delayed-enhancement imaging and then to investigate whether the measure of the extracellular volume fraction (ECV) can be used to discriminate between MI and myocarditis.In 6 patients with acute benign myocarditis (32.2 ± 13.8 year-old, subepicardial late gadolinium enhancement [LGE]) and 18 patients with MI (52.3 ± 10.9 year-old, subendocardial/transmural LGE), myocardial T1 was determined using the Modified Look-Locker Imaging (MOLLI) sequence at 3 Tesla before and after Gd-chelate injection. T1 values were compared in LGE and normal regions of the myocardium. The myocardial T1 values were normalized to the T1 of blood, and the ECV was calculated from T1 values of myocardium and blood pre- and post-Gd injection.In both myocarditis and MI, the T1 was lower in LGE regions than in normal regions of the left ventricle. T1 of LGE areas was significantly higher in myocarditis than in MI (446.8 ± 45.8 vs 360.5 ± 66.9 ms, P = 0.003) and ECV was lower in myocarditis than in MI (34.5 ± 3.3 vs 53.8 ± 13.0 %, P = 0.004).Both inflammatory process and chronic fibrosis induce LGE (subepicardial in myocarditis and subendocardial in MI). The present study demonstrates that the determination of T1 and ECV is able to differentiate the 2 histological patterns.Further investigation will indicate whether the severity of ECV changes might help refine the predictive risk of LGE in myocarditis.

A Case of Clozapine-Induced Myocarditis in a Young Patient with Bipolar Disorder

We present a case of drug-induced myocarditis manifesting as acute heart failure in a young patient with bipolar disorder being treated for depression. The case describes a 20-year-old man being treated in the psychiatry ward for worsening depression when he started complaining of chest pain and shortness of breath. His list of medications included clozapine, lithium, lorazepam, and haloperidol. The main findings on physical examination were tachycardia, low-grade fever, crackles in both lung bases on auscultation, and the absence of any notable edema. Abnormal labs included a troponin of 0.9, with a CK of 245 and CK-MB of 3.1. An ECG revealed sinus tachycardia and left anterior fascicular block (LAFB). An echocardiogram revealed global hypokinesis, severe left ventricular dysfunction with an ejection fraction estimated at 20%. The patient had an admitting diagnosis of acute left ventricular systolic dysfunction likely secondary to drug-induced myocarditis (suspect clozapine) versus acute coronary syndrome. He was managed conservatively and transferred to another facility for endomyocardial biopsy confirming myocarditis. This case is an example of one of the most typical presentations of suspected drug-induced acute myocarditis and will hopefully prompt the reader to think of this underdiagnosed entity in the right clinical setting.

The Role of Cardiac MRI in Patients with Troponin-Positive Chest Pain and Unobstructed Coronary Arteries

Acute coronary syndrome (ACS) still remains one of the leading causes of mortality and morbidity worldwide. Seven to fifteen percent of patients presenting with ACS have unobstructed coronary artery disease (CAD) on urgent angiography. Patients with ACS and unobstructed coronary arteries represent a clinical dilemma and their diagnosis and management is quite variable in current practice. Cardiovascular magnetic resonance imaging with its unique non-invasive myocardial tissue characterization property has the potential to identify underlying etiologies and reach a final diagnosis. These include acute and chronic myocarditis, embolic/spontaneous recanalization myocardial infarction, and Tako-Tsubo cardiomyopathy, and other conditions. Establishing a final diagnosis has a direct implication on patient's management and prognosis. In this article, we have reviewed the current evidence on the diagnostic role of cardiac magnetic resonance (CMR) in patients with ACS and unobstructed coronary arteries. We have also highlighted the potential role of CMR as a risk stratification or prognostication tool for this patient population.

Cardiac MRI: A General Overview with Emphasis on Current Use and Indications

Cardiac magnetic resonance is well-established as a robust modality of cardiovascular imaging, providing superior resolution, infinite imaging planes, and the ability to obtain multiple types of information without ionizing radiation. Limitations imposed by availability, cost effectiveness, and safety prevent universal application. Many general and specialty practitioners do not have routine exposure to Cardiac MRI (CMR). Guidelines for the use of CMR exist, but continue to adapt to advances in techniques and ongoing research. Understanding the basics of CMR acquisition techniques, categories of appropriate use, and pertinent safety information will assist with selecting the best clinical scenarios to consider CMR.

Mapping the future of cardiac MR imaging: case-based review of T1 and T2 mapping techniques

Cardiac magnetic resonance (MR) imaging has grown over the past several decades into a validated, noninvasive diagnostic imaging tool with a pivotal role in cardiac morphologic and functional assessment and tissue characterization. With traditional cardiac MR imaging sequences, assessment of various pathologic conditions ranging from ischemic and nonischemic cardiomyopathy to cardiac involvement in systemic diseases (eg, amyloidosis and sarcoidosis) is possible; however, these sequences are most useful in focal myocardial disease, and image interpretation relies on subjective qualitative analysis of signal intensity. Newer T1 and T2 myocardial mapping techniques offer a quantitative assessment of the myocardium (by using T1 and T2 relaxation times), which can be helpful in focal disease, and demonstrate special utility in the evaluation of diffuse myocardial disease (eg, edema and fibrosis). Altered T1 and T2 relaxation times in disease states can be compared with published ranges of normal relaxation times in healthy patients. In conjunction with traditional cardiac MR imaging sequences, T1 and T2 mapping can limit the interpatient and interstudy variability that are common with qualitative analysis and may provide clinical markers for long-term follow-up.

Diagnosis of myocarditis: Current state and future perspectives

Myocarditis, i.e. inflammation of the myocardium, is one of the leading causes of sudden cardiac death (SCD) and dilated cardiomyopathy (DCM) in young adults, and is an important cause of symptoms such as chest pain, dyspnea and palpitations. The pathophysiological process of disease progression leading to DCM involves an ongoing inflammation as a result of a viral-induced auto-immune response or a persisting viral infection. It is therefore crucial to detect the disease early in its course and prevent persisting inflammation that may lead to DCM and end-stage heart failure. Because of the highly variable clinical presentation, ranging from mild symptoms to severe heart failure, and the limited available diagnostic tools, the evaluation of patients with suspected myocarditis represents an important clinical dilemma in cardiology. New approaches for the diagnosis of myocarditis are needed in order to improve recognition, to help unravel its pathophysiology, and to develop new therapeutic strategies to treat the disease. In this review, we give a comprehensive overview of the current diagnostic strategies for patients with suspected myocarditis, and demonstrate several new techniques that may help to improve the diagnostic work-up.

Analysis of clinical parameters and cardiac magnetic resonance imaging as predictors of outcome in pediatric myocarditis

Myocarditis causes significant morbidity and mortality in pediatric patients, with potential adverse outcomes including heart failure, transplantation requirement, and/or death. The objective of this study was to determine predictors of early and late poor outcomes, defined as requirement for extracorporeal membrane oxygenation, ventricular assist device, transplantation, or death in pediatric myocarditis patients. A retrospective cohort study was conducted to evaluate pediatric myocarditis presenting over a 5-year period at a pediatric institution. Patients were identified using an institutional heart failure database and International Classification of Diseases, Ninth Revision, discharge diagnosis codes for myocarditis and confirmed by review of medical records. Data extraction included epidemiologic factors, the presenting ejection fraction (EF), initial and peak troponin levels, brain natriuretic peptide (BNP) level, pathogen identification, cardiac magnetic resonance imaging (MRI), and outcomes. Univariate and multivariate regression was performed to identify variables predictive of outcomes. Because published pediatric cardiac MRI data are sparse, whether late enhancement was associated with specific clinical variables or predictive of outcomes was also evaluated. Fifty-eight patients were identified. The mean age was 10.5 years, 64% were male, 62% were Caucasian, 15% were African-American, and 23% were Hispanic or Asian. Eighty-one percent presented at the institution <1 week after symptom onset. Presenting EFs were normal (>50%) or mildly decreased (40% to 50%) in 48%, moderately decreased (30% to 40%) in 9%, and severely decreased (<30%) in 42%. Thirty patients (52%) underwent viral studies; 17 of these (56%) had acute viral origins of myocarditis identified, including 8 with parvovirus (2 with influenza coinfection), 7 with enterovirus, 1 with Epstein-Barr virus, and 1 with cytomegalovirus. Twenty-eight percent had poor outcomes. Univariate analysis identified Hispanic or Asian race (odds ratio [OR] 4.5, p = 0.05), a severely decreased EF (OR 13, p = 0.002), initial BNP >10,000 pg/ml (OR 5.6, p = 0.01), and peak BNP >10,000 pg/ml (OR 13.65, p = 0.001) as risk factors for poor outcomes; initial and peak troponin >1 ng/ml were correlated significantly with good outcomes (OR 0.22, p = 0.04, and OR 0.26, p = 0.05, respectively). Multivariate analysis adjusting for severe EF, troponin, BNP, and cardiac MRI revealed peak BNP >10,000 ng/L (OR 27.71, p = 0.04), a severely decreased EF (OR 12.8, p = 0.03), and late enhancement on cardiac MRI (OR 24.51, p = 0.04) as risk factors for poor outcomes. Thirty-four patients underwent cardiac MRI (50% with abnormal and 50% with normal results). No significant differences were found between these groups with respect to gender, race, symptom duration, the EF, BNP, troponin, inflammation on cardiac biopsy, or pathogen identification. In conclusion, this study provides data from a large cohort of pediatric myocarditis patients. A presenting EF <30%, peak BNP >10,000 ng/L, and cardiac MRI late enhancement were identified as predictors of poor outcomes.

Early diagnosis of cardiac involvement in idiopathic inflammatory myopathy by cardiac magnetic resonance tomography

The aim of this study was to investigate cardiac involvement in patients with idiopathic inflammatory myopathies excluding inclusion body myositis with cardiac magnetic resonance tomography (CMR). A case series of 53 patients with polymyositis, dermatomyositis, or non-specific myositis underwent CMR including functional imaging, T1-weighted, and late gadolinium enhancement (LGE) imaging. T1-weighted and LGE images were analyzed for myocardial enhancement. Reduced left ventricular function (LVF) was found in 9 (7%) patients. Patients with reduced LVF more often presented with early and late myocardial enhancement (p = 0.014 and p = 0.001). In 33 (62.3%) patients, LGE was observed by CMR. These patients had significantly lower left ventricular ejection fractions (p < 0.001) compared to patients without LGE. LGE was mainly present in the lateral (p < 0.01) and inferior (p < 0.02) segments. No correlations of LGE presence or reduced LVF to cardiovascular risk factors were found. Myocardial inflammation is very frequent in polymyositis, dermatomyositis, and non-specific myositis. In our patient, cohort CMR demonstrated signs of myocardial inflammation in 62.3%. CMR seems to offer a measurable and quantifiable diagnostic tool for cardiac involvement of idiopathic inflammatory myopathies and can thus be used to monitor disease progress and therapeutic success in these patients.

[Contribution of cardiac MRI in the initial evaluation and follow-up of myocarditis mimicking acute coronary syndrome: a series of 43 patients]

AIMS

The diagnosis of acute myocarditis is complex, especially when the clinical presentation mimics an acute coronary syndrome. This condition may promote the progression to dilated cardiomyopathy and the occurrence of severe arrhythmias. A reassessment integrating a cardiac MRI at three months after the acute episode could help identify patients with a poor prognosis.

PATIENTS AND RESULTS

This prospective series of 43 consecutive patients hospitalised for acute myocarditis included 36 men and seven women, with a mean age of 32 years, with no indication of heart failure. All patients presented elevated levels of troponin I. Echocardiography showed moderate left ventricular dysfunction in six cases and segmental wall motion abnormalities in 22 cases. After gadolinium injection, a subepicardial late enhancement was observed in 39 cases. Three months after the acute episode, all patients were asymptomatic. The echocardiography and laboratory tests were normal. In 23 cases, the MRI showed persistence of the late enhancement without segmental wall motion abnormality. After a mean follow-up of three years, one patient was lost to follow-up and only one suffered a heart failure revealing a dilated cardiomyopathy complicated by ventricular arrhythmias.

CONCLUSION

On admission, the subepicardial localisation of late enhancement in the cardiac MRI is reliable criteria for the diagnosis of acute myocarditis, enabling to rule out an acute coronary syndrome. During follow-up, the persistence of late enhancement has no impact on prognosis. In this series, after a mean follow-up of three years, it was not associated with clinical or paraclinical abnormalities, except in one patient.

Role of cardiovascular magnetic resonance imaging (CMR) in the diagnosis of acute and chronic myocarditis

The aetiopathogenesis of acute and chronic myocarditis is rather complex as a great variety of infectious agents can induce cardiac inflammation. Moreover, many systemic and autoimmune diseases such as sarcoidosis, giant cell myocarditis and systemic lupus erythematodes, drugs and toxins have been described as non-infectious causes of inflammatory heart disorders. Myocarditis may cause sudden death and lead to dilated cardiomyopathy. The correct and timely diagnosis of myocarditis is still a difficult clinical challenge, since the clinical spectrum of myocarditis is broad and comprises (amongst others) even those patients with no symptoms or those presenting with acute cardiogenic shock. Although endomyocardial biopsy still represents the gold standard for the diagnosis of myocarditis, new non-invasive imaging techniques such as cardiovascular magnetic resonance (CMR) imaging promise the non-invasive diagnosis of myocarditis. Considering the hallmarks of acute and chronic myocarditis (accumulation of inflammatory cells; swelling, necrosis and/or apoptosis of cardiomyocytes; increase in extracellular space and water content; myocardial remodelling with fibrotic tissue replacement), an imaging modality such as CMR that enables non-invasive detection of changes in myocardial tissue composition is highly valuable and welcome. This review will focus on the 'clinical role' of CMR in the diagnosis of acute and chronic myocarditis.

Acute myocarditis: multiparametric cardiac MR imaging

PURPOSE

To evaluate the diagnostic value of cardiac magnetic resonance (MR) imaging at 3 T in patients suspected of having acute myocarditis by using a multiparametric cardiac MR imaging approach including T1 relaxation time as an additional tool for tissue characterization.

MATERIALS AND METHODS

Ethics commission approval was obtained for this prospective study, and written informed consent was obtained from all subjects. Twenty four patients with acute myocarditis (mean age ± standard deviation, 34.7 years ± 15.1; 75% men) and 42 control subjects (mean age, 38.7 years ± 10.2; 64% men) were included. Cardiac MR imaging approaches included relative T2 short tau inversion-recovery signal intensity ratio (T2 ratio), early gadolinium enhancement ratio, late gadolinium enhancement, native T1 relaxation times, and extracellular volume fraction. Receiver operating characteristic analysis was performed to compare diagnostic performance. The reference standard was the clinical evidence for acute myocarditis.

RESULTS

Native T1 relaxation times were significantly longer in patients with acute myocarditis than in control subjects (1185.3 msec ± 49.3 vs 1089.1 msec ± 44.9, respectively; P < .001). Areas under the curve of native T1 relaxation times (0.94) were higher compared with those of other cardiac MR parameters (late gadolinium enhancement, 0.90; T2 ratio, 0.79; extracellular volume fraction, 0.71; early gadolinium enhancement ratio, 0.63; P = .390, .018, .002, and < .001, respectively). Sensitivity (92%), specificity (91%), and diagnostic accuracy (91%) for native T1 relaxation times (cutoff, 1140 msec) were equivalent compared with those of the established combined Lake Louise criteria (sensitivity, 92%; specificity, 80%; diagnostic accuracy, 85%).

CONCLUSION

Diagnostic performance with native T1 mapping was superior to that with T2 ratio and early gadolinium enhancement ratio, and specificity was higher with native T1 mapping than that with Lake Louise criteria. This study underlines the potential of native T1 relaxation times to complement current cardiac MR approaches in patients suspected of having acute myocarditis.