Non-invasive imaging in the diagnosis of acute viral myocarditis

Multidisciplinary approach in cardiomyopathies: From genetics to advanced imaging

Cardiomyopathies are myocardial diseases characterized by mechanical and electrical dysfunction of the heart muscle which could lead to heart failure and life-threatening arrhythmias. Certainly, an accurate anamnesis, a meticulous physical examination, and an ECG are cornerstones in raising the diagnostic suspicion. However, cardiovascular imaging techniques are indispensable to diagnose a specific cardiomyopathy, to stratify the risk related to the disease and even to track the response to the therapy. Echocardiography is often the first exam that the patient undergoes, because of its non-invasiveness, wide availability, and cost-effectiveness. Cardiac magnetic resonance imaging allows to integrate and implement the information obtained with the echography. Furthermore, cardiomyopathies' genetic basis has been investigated over the years and the list of genetic mutations deemed potentially pathogenic is expected to grow further. The aim of this review is to show echocardiographic, cardiac magnetic resonance imaging, and genetic features of several cardiomyopathies: dilated cardiomyopathy (DMC), hypertrophic cardiomyopathy (HCM), arrhythmogenic cardiomyopathy (ACM), left ventricular noncompaction cardiomyopathy (LVNC), myocarditis, and takotsubo cardiomyopathy.

A Narrative Review of Preclinical In Vitro Studies Investigating microRNAs in Myocarditis

According to the World Health Organization's statement, myocarditis is an inflammatory myocardium disease. Although an endometrial biopsy remains the diagnostic gold standard, it is an invasive procedure, and thus, cardiac magnetic resonance imaging has become more widely used and is called a non-invasive diagnostic gold standard. Myocarditis treatment is challenging, with primarily symptomatic therapies. An increasing number of studies are searching for novel diagnostic biomarkers and potential therapeutic targets. Microribonucleic acids (miRNAs) are small, non-coding RNA molecules that decrease gene expression by inhibiting the translation or promoting the degradation of complementary mRNAs. Their role in different fields of medicine has been recently extensively studied. This review discusses all relevant preclinical in vitro studies regarding microRNAs in myocarditis. We searched the PubMed database, and after excluding unsuitable studies and clinical and preclinical in vivo trials, we included and discussed 22 preclinical in vitro studies in this narrative review. Several microRNAs presented altered levels in myocarditis patients in comparison to healthy controls. Moreover, microRNAs influenced inflammation, cell apoptosis, and viral replication. Finally, microRNAs were also found to determine the level of myocardial damage. Further studies may show the vital role of microRNAs as novel therapeutic agents or diagnostic/prognostic biomarkers in myocarditis management.

Advances in myocarditis management in the light of the latest research and recent guidelines of the European Society of Cardiology

Myocarditis remains an unknown disease with varying clinical manifestations, often leading to heart failure. The latest 2021 and 2022 guidelines of the European Society of Cardiology (ESC) are the first official European documents updating knowledge on the diagnosis and treatment of myocarditis since the 2013 ESC expert consensus statement. These guidelines and new studies allow standardization and improvements to the management of myocarditis. In this review, we discuss the most important aspects of myocarditis diagnosis, therapies and follow-up based on current knowledge.

Echocardiography in inflammatory heart disease: A comparison of giant cell myocarditis, cardiac sarcoidosis, and acute non-fulminant myocarditis

Background

Giant cell myocarditis (GCM) and cardiac sarcoidosis (CS) are, in contrast to acute non-fulminant myocarditis (ANFM), rare inflammatory diseases of the myocardium with poor prognosis. Although echocardiography is the first-line diagnostic tool in these patients, their echocardiographic appearance has so far not been systematically studied.

Methods

We assessed a total of 71 patients with endomyocardial biopsy-proven GCM (n = 21), and CS (n = 25), as well as magnetic resonance-verified ANFM (n = 25). All echocardiographic examinations, performed upon clinical presentation, were reanalysed according to current guidelines including a detailed assessment of right ventricular (RV) dysfunction.

Results

In comparison with ANFM, patients with either GCM or CS were older (mean age (±SD) 55 ± 12 or 53 ± 8 vs 25 ± 8 years), more often of female gender (52% or 24% vs 8%), had more severe clinical symptoms and higher natriuretic peptide levels. For both GCM and CS, echocardiography revealed more frequently signs of left ventricular (LV) dysfunction in form of a reduced ejection fraction (p < 0.001), decreased cardiac index (p < 0.001) and lower global longitudinal strain (p < 0.001) in contrast to ANFM. The most prominent increase in LV end-diastolic volume index was observed in CS. In addition, RV dysfunction was more frequently found in both GCM and CS than in ANFM (p = 0.042).

Conclusions

Both GCM and CS have an echocardiographic and clinical appearance that is distinct from ANFM. However, the method cannot further differentiate between the two rare entities. Consequently, echocardiography can strengthen the initial clinical suspicion of a more severe form of myocarditis, thus warranting a more rigorous clinical work-up.

Clinical and Cardiovascular Magnetic Resonance Predictors of Early and Long-Term Clinical Outcome in Acute Myocarditis

Introduction

The natural history of acute myocarditis (AM) remains partially unknown and predictors of outcome are debated. We sought to assess the impact of various cardiac magnetic resonance (CMR) parameters on early and long-term prognosis in a population of patients with AM.

Materials and Methods

In a two-center longitudinal study, we included consecutive patients with diagnosis of AM based on CMR and without hemodynamic compromise. The primary endpoint was the occurrence of an event in the acute phase (≤15 days). Secondary endpoints were the occurrence of major adverse cardiac events (MACE) and recurrence of AM during follow-up.

Results

Three hundred and eighty-eight patients were included [mean age 38.5 years, 77.3% male, mean ejection fraction (EF):56%] of which 82% (317) presented with chest pain. CMR was performed 4 ± 2 days after index presentation. Overall, 38 patients (9.8%) had an event at the acute phase, 41 (10.6%) presented at least one MACE during follow-up (median 7.5 years, 6.6–8.9) and 30 (7.7%) experienced a recurrence of AM. By multivariate analysis, the independent predictors of initial complications were absence of chest pain (OR [95%CI] = 0.35 [0.15–0.82]), presence of syncope/pre-syncope (OR [95%CI] = 3.56 [1.26–10.02]), lower EF (OR [95%CI] = 0.94 [0.91–0.98] per%), myocardial extent of late gadolinium enhancement (LGE) (OR [95%CI] = 1.05 [1.002–1.100] per%) and absence of edema (OR [95%CI] = 0.44 [0.19–0.97]). Only age (HR [95%CI] = 1.021 [1.001–1.041] per year) and an initial alteration of EF (HR [95%CI] = 0.94 [0.91–0.97] per%) were associated with MACE during follow-up. Factors independently associated with AM recurrence were myocarditis prior to the index episodes (HR [95%CI] = 5.74 [1.72–19.22]) and viral syndrome at the index episode (HR [95%CI] = 4.21 [1.91–9.28]).

Conclusion

In routine consecutive hemodynamically stable patients with diagnosis of AM based on CMR, absence of edema, reduced EF, and extent of LGE were associated with early adverse outcome. Only age and EF were associated with long-term events.

COVID-Induced Fulminant Myocarditis

Viral-induced myocarditis has different presentations, from being asymptomatic to fatal arrhythmias. It is crucial to recognize and treat this condition early to improve morbidity and mortality.

We report a case of a 56-year-old male who tested positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) three days ago and presented with syncope. The physical exam was relevant for right eyebrow laceration, tachycardia, and hypotension that responded to intravenous fluid, but two hours later, he had mental status changes, bradycardia, hypotension, and cardiac arrest. His repeated electrocardiogram (ECG) showed diffuse ST-segment elevation. Troponemia was evident in his blood work. Point-of-care ultrasound (POCUS) at the bedside showed dilated cardiomyopathy. Unfortunately, the patient re-arrested and needed advanced cardiovascular life support (ACLS).

The initial assessment of SARS-CoV-2, serial ECGs, and cardiac markers are essential for a prompt approach and therapy in COVID-19-induced myocarditis.

Spectrum of Viral Pathogens Identified in Children with Clinical Myocarditis (Pre-Coronavirus Disease-2019, 2000-2018): Etiologic Agent Versus Innocent Bystander

OBJECTIVE

To identify the etiologies of viral myocarditis in children in the pre-coronavirus disease 2019 era.

STUDY DESIGN

This was a retrospective review of all patients (age <18 years) diagnosed with myocarditis and hospitalized at Rady Children's Hospital San Diego between 2000 and 2018.

RESULTS

Twenty-nine patients met inclusion criteria. Of 28 (97%) patients who underwent testing for viruses, polymerase chain reaction was used in 24 of 28 (86% of cases), and 16 of 24 (67%) detected a virus. Pathogens were rhinovirus (6), influenza A/B (4), respiratory syncytial virus (RSV) (3), coronavirus (3), parvovirus B19 (2), adenovirus (2), and coxsackie B5 virus, enterovirus, and parainfluenza virus type 2 in one case each. Six (21%) patients had no pathogen detected but imaging and other laboratory test results were compatible with myocarditis. Age 0-2 years was associated with RSV, influenza A/B, coronavirus, and enteroviruses (P < .001). Twenty-one patients (72%) experienced full clinical recovery. Three patients (10%) required venoarterial extracorporeal membrane oxygenation (VA-ECMO), and all 3 recovered. Three others (10%) required and underwent successful cardiac transplantation without complications. Two patients (7%) died 9-10 days after hospitalization (1 had RSV and 1 had influenza A/B). Two other patients presented with complete atrioventricular block; 1 case (rhinovirus) resolved spontaneously, and 1 (coronavirus) resolved after support with VA-ECMO. Age <2 years, female sex, lower ejection fraction at admission, and greater initial and peak levels of brain natriuretic peptide were significant predictors of critical outcomes (use of VA-ECMO, listing for cardiac transplantation, and death).

CONCLUSIONS

Viral nucleic acid-based testing revealed a wider spectrum of viruses that could be associated with myocarditis in children than previously reported and traditionally anticipated. A predilection of certain pathogens in the very young patients was observed. Whether the observed range of viral agents reflects an undercurrent of change in viral etiology or viral detection methods is unclear, but the wider spectrum of viral pathogens found underscores the usefulness of polymerase chain reaction testing to explore possible viral etiologies of myocarditis in children.

A Review of the Role of Imaging Modalities in the Evaluation of Viral Myocarditis with a Special Focus on COVID-19-Related Myocarditis

Viral myocarditis is inflammation of the myocardium secondary to viral infection. The clinical presentation of viral myocarditis is very heterogeneous and can range from nonspecific symptoms of malaise and fatigue in subclinical disease to a more florid presentation, such as acute cardiogenic shock and sudden cardiac death in severe cases. The accurate and prompt diagnosis of viral myocarditis is very challenging. Endomyocardial biopsy is considered to be the gold standard test to confirm viral myocarditis; however, it is an invasive procedure, and the sensitivity is low when myocardial involvement is focal. Cardiac imaging hence plays an essential role in the noninvasive evaluation of viral myocarditis. The current coronavirus disease 2019 (COVID-19) pandemic has generated considerable interest in the use of imaging in the early detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-related myocarditis. This article reviews the role of various cardiac imaging modalities used in the diagnosis and assessment of viral myocarditis, including COVID-19-related myocarditis.

Diagnostic value of Cardiac Magnetic Resonance Imaging and Intracoronary Optical Coherence Tomography in patients with a working diagnosis of Myocardial Infarction with Non-obstructive Coronary Arteries - A Systematic review and Meta-analysis

BACKGROUND

We aimed to study the efficacy of cardiac magnetic resonance imaging (CMR) and intracoronary optical coherence tomography (OCT) in detecting the etiology of myocardial infarction with non-obstructive coronary arteries (MINOCA).

METHODS

A systematic search was conducted in PubMed, Medline, and Cochrane databases. Search terms used: Myocardial infarction, Coronary angiography, Normal coronary arteries, CMR, and OCT. Inclusion criteria was fulfilled by 18 studies. Meta-analysis was performed with 15 studies.

RESULTS

A total of 2697 patients were included. The mean age of all the patients was 51.5 and 56.4% were men. CMR established diagnosis in 74% of the patients; 29% had acute myocarditis, 18% had true myocardial infarction and 12% had takotsubo cardiomyopathy. Combining OCT with CMR was better at finding the etiology than either modality individually.

CONCLUSION

CMR is integral in identifying the etiology of MINOCA. Coupling OCT and CMR is better than either technique individually at finding the cause.

Imaging of Cardiac Infections: A Comprehensive Review and Investigation Flowchart for Diagnostic Workup

Infections of the cardiovascular system may present with nonspecific symptoms, and it is common for patients to undergo multiple investigations to arrive at the diagnosis. Echocardiography is central to the diagnosis of endocarditis and pericarditis. However, cardiac computed tomography (CT) and magnetic resonance imaging also play an additive role in these diagnoses; in fact, magnetic resonance imaging is central to the diagnosis of myocarditis. Functional imaging (fluorine-18 fluorodeoxyglucose-positron emission tomography/CT and radiolabeled white blood cell single-photon emission computed tomography/CT) is useful in the diagnosis in prosthesis-related and disseminated infection. This pictorial review will detail the most commonly encountered cardiovascular bacterial and viral infections, including coronavirus disease-2019, in clinical practice and provide an evidence basis for the selection of each imaging modality in the investigation of native tissues and common prostheses.

Diagnosis and Management of Myocarditis: An Evidence-Based Review for the Emergency Medicine Clinician

BACKGROUND

Myocarditis is a potentially fatal condition that can be misdiagnosed in the emergency department (ED) setting.

OBJECTIVE

The purpose of this narrative review article is to provide a summary of the background, pathophysiology, diagnosis, and management of myocarditis, with a focus on emergency clinicians.

DISCUSSION

Myocarditis occurs when inflammation of the heart musculature causes cardiac dysfunction. Symptoms may range from mild to severe and are often preceded by a viral prodrome. Laboratory assessment and an electrocardiogram can be helpful for the diagnosis, but echocardiography is the ideal test in the ED setting. Some patients may also require advanced imaging, though this will often occur during hospitalization or follow-up. Treatment is primarily focused on respiratory and hemodynamic support. Initial hemodynamic management includes vasopressors and inotropes, whereas more severe cases may require an intra-aortic balloon pump, extracorporeal membrane oxygenation, or a ventricular assist device. Nonsteroidal anti-inflammatory drugs should be avoided while intravenous immunoglobulin is controversial.

CONCLUSION

Myocarditis is a serious condition with the potential for significant morbidity and mortality. It is important for clinicians to be aware of the current evidence regarding the diagnosis, management, and disposition of these patients.

Focused echocardiography in COVID-19: An unusual case of acute right ventricular dysfunction

Background

During the novel coronavirus disease 2019 (COVID-19) pandemic, rapid diagnostics have been frequently sought to quickly evaluate a patient's condition. Lung ultrasound can provide an early glimpse into the disease process and its severity. The addition of focused echocardiography can be particularly helpful in the haemodynamically compromised patient to detect myocardial involvement and alternative diagnoses.

Case

We discuss here a 53-year-old patient who presented to the Emergency Department with hypoxia and hypotension. Bedside focused ultrasound revealed signs of COVID-19 pneumonia with evidence of right ventricular strain, initially thought to be due to massive pulmonary embolism. A computed tomography scan confirmed the findings on ultrasonography, but surprisingly did not demonstrate a pulmonary embolism.

Conclusion

Point-of-care ultrasound in COVID-19 aided the diagnosis of affected organs and helped categorise the type of shock in this patient; however, right ventricular dysfunction should be interpreted with caution and may not be due to a pulmonary embolism, as in this case.

Association of segmental T2 ratio and late gadolinium enhancement in patients with acute myocarditis: a feasibility study

BACKGROUND

Cardiac magnetic resonance is a valuable tool in the diagnosis of acute myocarditis, but dyspnea or chest pain often reduce patient's compliance, so definition of faster magnetic resonance protocols is of paramount importance.

METHODS

Short tau inversion recovery (STIR) and phase sensitive inversion recovery images for the assessment of late gadolinium enhancement (LGE)of 22 patients with clinical suspicion of acute myocarditis were retrospectively evaluated. Signal intensity in STIR images was measured by 2 readers by placing region of interests (ROIs) within the area of maximal signal intensity in each myocardial segment derived from the ACC/AHA segmental scheme. Segmental T2 ratio was assessed with the formula: signal intensity of myocardium/signal intensity of muscle. Receiver operating characteristic (ROC) curves were used to compare diagnostic performance of T2 Signal intensity and T2 ratio in predicting the presence of LGE in each myocardial segment. Bland-Altman analysis was used to assess inter reader agreement.

RESULTS

Signal intensity in STIR images showed an area under the curve (AUC) of 0.54 (95% CI: 0.44-0.63) for reader 1 and 0.53(95% CI: 0.44-0.63) for reader 2. Segmental T2 ratio showed an AUC of 0.8 (95% CI: 0.73-0.87) for reader 1 and 0.77 (95% CI: 0.71-0.84) for reader 2. Bland-Altman analysis showed good agreement for both T2 signal intensity (mean difference =-18.5 reader1 vs. reader 2 and 2SD=247.3) and T2 ratio (mean difference=0.03 vs. reader2 and 2SD=0.9).

CONCLUSIONS

Segmental T2 ratio showed a good diagnostic accuracy in predicting the presence of LGE in patients with clinical suspicion of acute myocarditis and might be a promising approach in reducing scan times with no reduction in diagnostic accuracy.

Recognition and Initial Management of Fulminant Myocarditis: A Scientific Statement From the American Heart Association

Fulminant myocarditis (FM) is an uncommon syndrome characterized by sudden and severe diffuse cardiac inflammation often leading to death resulting from cardiogenic shock, ventricular arrhythmias, or multiorgan system failure. Historically, FM was almost exclusively diagnosed at autopsy. By definition, all patients with FM will need some form of inotropic or mechanical circulatory support to maintain end-organ perfusion until transplantation or recovery. Specific subtypes of FM may respond to immunomodulatory therapy in addition to guideline-directed medical care. Despite the increasing availability of circulatory support, orthotopic heart transplantation, and disease-specific treatments, patients with FM experience significant morbidity and mortality as a result of a delay in diagnosis and initiation of circulatory support and lack of appropriately trained specialists to manage the condition. This scientific statement outlines the resources necessary to manage the spectrum of FM, including extracorporeal life support, percutaneous and durable ventricular assist devices, transplantation capabilities, and specialists in advanced heart failure, cardiothoracic surgery, cardiac pathology, immunology, and infectious disease. Education of frontline providers who are most likely to encounter FM first is essential to increase timely access to appropriately resourced facilities, to prevent multiorgan system failure, and to tailor disease-specific therapy as early as possible in the disease process.

Assessment of acute myocarditis by cardiac magnetic resonance imaging: Comparison of qualitative and quantitative analysis methods

BACKGROUND

To compare cardiac magnetic resonance (CMR) qualitative and quantitative analysis methods for the noninvasive assessment of myocardial inflammation in patients with suspected acute myocarditis (AM).

METHODS

A total of 61 patients with suspected AM underwent coronary angiography and CMR. Qualitative analysis was performed applying Lake-Louise Criteria (LLC), followed by quantitative analysis based on the evaluation of edema ratio (ER) and global relative enhancement (RE). Diagnostic performance was assessed for each method by measuring the area under the curves (AUC) of the receiver operating characteristic analyses. The final diagnosis of AM was based on symptoms and signs suggestive of cardiac disease, evidence of myocardial injury as defined by electrocardiogram changes, elevated troponin I, exclusion of coronary artery disease by coronary angiography, and clinical and echocardiographic follow-up at 3 months after admission to the chest pain unit.

RESULTS

In all patients, coronary angiography did not show significant coronary artery stenosis. Troponin I levels and creatine kinase were higher in patients with AM compared to those without (both P < .001). There were no significant differences among LLC, T2-weighted short inversion time inversion recovery (STIR) sequences, early (EGE), and late (LGE) gadolinium-enhancement sequences for diagnosis of AM. The AUC for qualitative (T2-weighted STIR 0.92, EGE 0.87 and LGE 0.88) and quantitative (ER 0.89 and global RE 0.80) analyses were also similar.

CONCLUSIONS

Qualitative and quantitative CMR analysis methods show similar diagnostic accuracy for the diagnosis of AM. These findings suggest that a simplified approach using a shortened CMR protocol including only T2-weighted STIR sequences might be useful to rule out AM in patients with acute coronary syndrome and normal coronary angiography.

The Diagnostic and Clinical Approach to Pediatric Myocarditis: A Review of the Current Literature

Myocarditis is an inflammatory disease of the myocardium with a broad spectrum of clinical presentations, ranging from mild symptoms to severe heart failure. The course of patients with myocarditis is heterogeneous, varying from partial or full clinical recovery in a few days to advanced low cardiac output syndrome requiring mechanical circulatory support or heart transplantation. Myocarditis is a very heterogeneous disease, especially in the pediatric age group as worldwide disease myocarditis has been defined by the World Health Organization/International Society and Federation of Cardiology as an inflammatory disease of the heart muscle diagnosed by established histological, immunologic, and immunohistological criteria. Pediatric myocarditis remains challenging from the perspectives of diagnosis and management. Multiple etiologies exist, and the majority of cases appear to be related to viral illnesses. Enteroviruses are believed to be the most common cause, although cases related to adenovirus may be more frequent than suspected. The clinical presentation is extremely varied, ranging from asymptomatic to sudden unexpected death. A high index of suspicion is crucial. There is emerging evidence to support investigations such as serum N-terminal B-type natriuretic peptide levels, as well as cardiac magnetic resonance imaging as adjuncts to the clinical diagnosis. In the future, these may reduce the necessity for invasive methods, such as endomyocardial biopsy, which remain the gold standard. Management generally includes supportive care, consisting of cardiac failure medical management, with the potential for mechanical support and cardiac transplantation. Treatments aimed at immunosuppression remain controversial. The paediatrics literature is extremely limited with no conclusive evidence to support or refute these strategies. All these summarised in this article and the listed current literature showed that there is no consensus regarding aetiology, clinical presentation, diagnosis, and management of myocarditis in pediatric patients.

The Diagnostic and Clinical Approach to Pediatric Myocarditis: A Review of the Current Literature

Myocarditis is an inflammatory disease of the myocardium with a broad spectrum of clinical presentations, ranging from mild symptoms to severe heart failure. The course of patients with myocarditis is heterogeneous, varying from partial or full clinical recovery in a few days to advanced low cardiac output syndrome requiring mechanical circulatory support or heart transplantation. Myocarditis is a very heterogeneous disease, especially in the pediatric age group as worldwide disease myocarditis has been defined by the World Health Organization/International Society and Federation of Cardiology as an inflammatory disease of the heart muscle diagnosed by established histological, immunologic, and immunohistological criteria. Pediatric myocarditis remains challenging from the perspectives of diagnosis and management. Multiple etiologies exist, and the majority of cases appear to be related to viral illnesses. Enteroviruses are believed to be the most common cause, although cases related to adenovirus may be more frequent than suspected. The clinical presentation is extremely varied, ranging from asymptomatic to sudden unexpected death. A high index of suspicion is crucial. There is emerging evidence to support investigations such as serum N-terminal B-type natriuretic peptide levels, as well as cardiac magnetic resonance imaging as adjuncts to the clinical diagnosis. In the future, these may reduce the necessity for invasive methods, such as endomyocardial biopsy, which remain the gold standard. Management generally includes supportive care, consisting of cardiac failure medical management, with the potential for mechanical support and cardiac transplantation. Treatments aimed at immunosuppression remain controversial. The paediatrics literature is extremely limited with no conclusive evidence to support or refute these strategies. All these summarised in this article and the listed current literature showed that there is no consensus regarding aetiology, clinical presentation, diagnosis, and management of myocarditis in pediatric patients.

Prognostic Value of Cardiac Magnetic Resonance Tissue Characterization in Risk Stratifying Patients With Suspected Myocarditis

BACKGROUND

Diagnosing myocarditis is challenged by nonspecific clinical signs and symptoms and low accuracy of endomyocardial biopsy. Cardiac magnetic resonance imaging (CMR) provides both cardiac anatomy and tissue characterization in this setting, but the prognostic value of this method as a primary assessment tool in patients with suspected myocarditis remains limited.

OBJECTIVES

This study sought to determine cardiac event-free survival of a consecutive cohort with suspected myocarditis with regard to CMR findings.

METHODS

Six hundred seventy patients with suspected myocarditis underwent CMR including late gadolinium enhancement (LGE) parameters between 2002 and 2015 and were included and followed. We performed multivariable model for major adverse cardiovascular events (MACE) and determined the continuous net reclassification improvement by LGE markers.

RESULTS

At a median follow-up of 4.7 years (interquartile range [IQR]: 2.3 to 7.3 years), 98 patients experienced a MACE. Two hundred ninety-four (44%) patients showed LGE presence, which was associated with a more than doubling risk of MACE (hazard ratio [HR]: 2.22; 95% confidence interval [CI]: 1.47 to 3.35; p < 0.001). Annualized MACE rates were 4.8% and 2.1% corresponding to LGE presence and absence, respectively (p < 0.001). In the multivariable model, LGE presence maintained significant association with MACE (HR: 1.72; 95% CI: 1.08 to 2.76; p = 0.023). The computed continuous net reclassification improvement was 0.39 (95% CI: 0.10 to 0.67) when LGE presence was added to the multivariable model for MACE. Regarding location and pattern, septal and midwall LGE showed strongest associations with MACE (HR: 2.55; 95% CI: 1.77 to 3.83 and HR: 2.39; 95% CI: 1.54 to 3.69, respectively; both p < 0.001). A patchy distribution portended to a near 3-fold increased hazard to MACE (HR: 2.93; 95% CI: 1.79 to 4.80; p < 0.001). LGE extent (per 10% increase) corresponded to a 79% increase in risk of MACE (HR: 1.79; 95% CI: 1.25 to 2.57; p = 0.002). A normal CMR study corresponded to low annual MACE and death rates of 0.8% and 0.3%, respectively.

CONCLUSIONS

CMR tissue characterization provides effective risk stratification in patients with suspected 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.

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.

Cardiovascular magnetic resonance predictors of clinical outcome in patients with suspected acute myocarditis

BACKGROUND

The natural history of acute myocarditis (AM) remains highly variable and predictors of outcome are largely unknown. The objectives were to determine the potential value of various cardiovascular magnetic resonance (CMR) parameters for the prediction of adverse long-term outcome in patients presenting with suspected AM.

METHODS

In a single-centre longitudinal prospective study, 203 routine consecutive patients with an initial CMR-based diagnosis of AM (typical Late Gadolinium Enhancement, LGE) were followed over a mean period of 18.9 ± 8.2 months. Various CMR parameters were evaluated as potential predictors of outcome. The primary endpoint was defined as the occurrence of at least one of the combined Major Adverse Clinical Events (MACE) (cardiac death or aborted sudden cardiac death, cardiac transplantation, sustained documented ventricular tachycardia, heart failure, recurrence of acute myocarditis, and the need for hospitalization for cardiac causes).

RESULTS

The vast majority of patients (N = 143,70 %) presented with chest pain, mild to moderate troponin elevation and ST-segment or T wave abnormalities. Various CMR parameters were evaluated on initial CMR performed 3 ± 2 days after acute clinical presentation (LV functional parameters, presence/extent of edema on T2 CMR, and extent of late gadolinium enhancement lesions). Out of the 203 patients, 22 experienced at least one major cardiovascular event (10.8 %) during follow-up for a total of 31 major cardiovascular events. Among all CMR parameters, the only independent CMR predictor of adverse clinical outcome by multivariate analysis was an initial alteration of LVEF (p = 0.04).

CONCLUSIONS

In routine consecutive patients without severe hemodynamic compromise and a CMR-based diagnosis of AM, various CMR parameters such as the presence and extent of myocardial edema and the extent of late gadolinium-enhanced LV myocardial lesions were not predictive of outcome. The only independent CMR predictor of adverse clinical outcome was an initial alteration of LVEF.

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.

Sudden cardiac death in young athletes: preparticipation screening for underlying cardiovascular abnormalities and approaches to prevention

The study of sudden cardiac death (SCD) in athletes has received more interest in the medical and lay press over the past few years. Professional athletes represent ideals of fitness and health, and the sudden death of prominent athletes can come as a shock. Underlying occult cardiovascular disorders are the most common cause of SCD in athletes. Unfortunately, because these disorders rarely present clinically, their initial manifestation is often a fatal event. Due to this, much attention has turned to both primary and secondary prevention. Primary prevention includes preparticipation screening and secondary prevention includes having automatic external defibrillators available at sporting events. This article summarizes the most common causes of athletic-related cardiac arrest and evaluates the screening methods used to screen for these conditions. The general sentiment is that we need to more effectively identify athletes who are at risk for SCD, but how to do so using an efficient screening system and in a cost-effective manner have not been determined.

The evolving approach to paediatric myocarditis: a review of the current literature

Paediatric myocarditis remains challenging from the perspectives of diagnosis and management. Multiple aetiologies exist and the majority of cases appear to be related to viral illnesses. Enteroviruses are believed to be the most common cause, although cases related to adenovirus may be more frequent than suspected. The clinical presentation is extremely varied, ranging from asymptomatic to sudden unexpected death. A high index of suspicion is crucial. There is emerging evidence to support investigations such as serum N-terminal B-type natriuretic peptide levels, as well as cardiac magnetic resonance imaging as adjuncts to the clinical diagnosis. In the future, these may reduce the necessity for invasive methods, such as endomyocardial biopsy, which remain the gold standard. Management generally includes supportive care, consisting of cardiac failure medical management, with the potential for mechanical support and cardiac transplantation. Treatments aimed at immunosuppression remain controversial. The paediatric literature is extremely limited with no conclusive evidence to support or refute these strategies. This article summarises the current literature regarding aetiology, clinical presentation, diagnosis, and management of myocarditis in paediatric patients.