Strain analysis reveals subtle systolic dysfunction in confirmed and suspected myocarditis with normal LVEF. A cardiac magnetic resonance study

Echocardiographic parameters of cardiac structure and function in the diagnosis of acute myocarditis in adult patients: A systematic review and meta-analysis

BACKGROUND

Transthoracic echocardiography (TTE) plays a key role in the initial work-up of myocarditis where the identification of pathologic structural and functional changes may assist in its diagnosis and management. The aim of this systematic review was to appraise the evidence for the utility of echocardiographic parameters of cardiac structure and function in the diagnosis of myocarditis in adult populations.

METHODS

A systematic literature search of medical databases was performed using PRISMA principles to identify all relevant studies assessing TTE parameters in adult patients with myocarditis (1995-2020; English only; PROSPERO registration CRD42021243598). Data for a range of structural and functional TTE parameters were individually extracted and those with low heterogeneity were then meta-analyzed using a random-effects model for effect size, and assessed through standardized mean difference (SMD).

RESULTS

Available data from six studies (with a pooled total of 269 myocarditis patients and 240 controls) revealed that myocarditis can be reliably differentiated from healthy controls using echocardiographic measures of left ventricular (LV) size and systolic function, in particular LV end-diastolic diameter, LV ejection fraction (LVEF) and LV global longitudinal strain (LV-GLS) (p ≤ .01 for all). LV-GLS demonstrated the highest overall effect size, followed by LVEF and LVEDD (SMD: |0.46-1.98|). Two studies also demonstrated that impairment in LV-GLS was associated with adverse cardiovascular outcomes in this population, irrespective of LVEF.

CONCLUSIONS

LV-GLS demonstrated the greatest overall effect size and therefore ability to differentiate myocarditis populations from healthy controls. GLS was also shown to be a predictor of adverse cardiovascular outcomes, in this population.

HIGHTLIGHTS

What is already known on this subject? Myocarditis is a disease process that is often a diagnosis of exclusion, as it frequently mimics other acute cardiac pathologies. Transthoracic echocardiography is traditionally the initial imaging modality used for noninvasive structural assessment in populations with myocarditis. What might this study add? This study demonstrates that left ventricular (LV) global longitudinal strain, LV ejection fraction and LV end-diastolic diameter can differentiate between myocarditis patients and healthy controls. LV-GLS demonstrated the greatest overall effect size when comparing these two populations, in comparison to the other measures. How might this impact on clinical practice? This study demonstrates that assessment of myocardial deformation indices allows for sensitive discrimination between myocarditis patients from healthy controls. Routine assessment of LV-GLS may serve as an important diagnostic tool in the acute care setting.

Cardiovascular magnetic resonance imaging in myocardial involvement of systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a chronic autoimmune disorder that primarily affects young women. Myocardial involvement in SLE frequently occurs and it is rather challenging to make the diagnosis in current clinical settings, mainly due to the extensive clinical presentation of signs and symptoms. As a noninvasive imaging reference in diagnosing cardiomyopathy and myocarditis, cardiovascular magnetic resonance (CMR) imaging can provide new insight into myocardial abnormalities including inflammation, fibrosis, and microcirculation. Therefore, the main aim of this work was to systematically review the pathology, clinical features, and diagnosis, while illustrating the clinical role of CMR on myocardial involvement of SLE.

Quantitative cardiac MRI parameters for assessment of myocarditis in children and adolescents: a systematic review and meta-analysis

AIM

To evaluate the role of quantitative cardiac magnetic resonance imaging (CMRI) parameters in myocarditis, including acute and chronic myocarditis (AM and CM), for children and adolescents.

MATERIALS AND METHODS

PRISMA principles were followed. PubMed, EMBASE, Web of Science, Cochrane Library, and grey literature were searched. The Newcastle-Ottawa Scale (NOS) and the Agency for Healthcare Research and Quality (AHRQ) checklist were utilised for quality assessment. Quantitative CMRI parameters were extracted and a meta-analysis was performed in comparison with healthy controls. The overall effect size was measured as the weighted mean difference (WMD).

RESULTS

Ten quantitative CMRI parameters of seven studies were analysed. Compared with the control group, the myocarditis group reported longer native T1 relaxation time (WMD=54.00, 95% confidence interval [CI]: 33.21,74.79, p<0.001), longer T2 relaxation time (WMD=2.13, 95% CI: 0.98, 3.28, p<0.001), increased extracellular volume (ECV; WMD=3.13, 95% CI: 1.34,4.91, p=0.001), elevated early gadolinium enhancement (EGE) ratio (WMD=1.47, 95% CI: 0.65,2.28, p<0.001), and increased T2-weighted ratio (WMD=0.43, 95% CI: 0.21,0.64, p<0.001). The AM group had longer native T1 relaxation times (WMD=72.02, 95% CI: 32.78,111.27, p<0.001), increased T2-weighted ratios (WMD=0.52, 95% CI: 0.21,0.84 p=0.001), and impaired left ventricular ejection fractions (LVEF; WMD=-5.84, 95% CI: -9.69, -1.99, p=0.003). Impaired LVEF (WMD=-2.24, 95% CI: -3.32, -1.17, p<0.001) was observed in the CM group.

CONCLUSION

Statistical differences can be observed in some CMRI parameters between patients with myocarditis and healthy controls; however, apart from native T1 mapping, there were no large differences in other parameters between two groups, which may reveal the limited benefit of CMRI in assessing myocarditis in children and adolescents.

Comparative Cardiac Magnetic Resonance-Based Feature Tracking and Deep-Learning Strain Assessment in Patients Hospitalized for Acute Myocarditis

This study sought to examine the correlation between left ventricular (LV) myocardial feature tracking (FT) and deep learning-based strain (DLS) analysis in the diagnostic (CMRd) and follow-up (CMRf) cardiac magnetic resonance imaging of patients with acute myocarditis. The retrospective study included 17 patients with acute myocarditis and 20 healthy controls. The CMRd took place within 14 days of symptom onset, while the CMRf took place at least 2 months after the event. The global-circumferential FT (FTc) and global-circumferential DLS (DLSc) were analyzed. The continuous variables were compared using paired t-tests or the Wilcoxon test, whereas Pearson's test or Spearman's test was used to evaluate the correlation between the continuous variables. The time between the CMRd and CMRf was 5 months [3-11]. The LV ejection fraction (LVEF) was 55 ± 6 and 59 ± 4%, p = 0.008, respectively, and 94.1% of the patients showed late gadolinium enhancement (LGE) and myocardial edema on the CMRd. Significantly lower FTc (-16.1 ± 2.2% vs. -18.9 ± 1.9%, p = 0.001) and DLSc (-38.1 ± 5.2% vs. -41.3 ± 4.5%, p = 0.015) were observed with respect to the controls. Significant increases in the FTc (-16.1 ± 2.2 vs. -17.5 ± 1.9%, p = 0.016) and DLSc (-38.1 ± 5.2 vs. -39.8 ± 3.9%, p = 0.049) were found between the CMRd and CMRf, which were unrelated to the LGE. The LVEF correlated well with the FTc (r = 0.840) and DLSc (r = 0.760). Both techniques had excellent reproducibility, with high intra- (FTc = 0.980, DLSc = 1.000) and inter-observer (FTc = 0.970, DLSc = 0.980) correlation. There was correlation between the LV DLSc/FTc and LVEF in the patients with acute myocarditis according to the CMRd and CMRf.

Clinical application of CMR in cardiomyopathies: evolving concepts and techniques : A position paper of myocardial and pericardial diseases and cardiac magnetic resonance working groups of Italian society of cardiology

Cardiac magnetic resonance (CMR) has become an essential tool for the evaluation of patients affected or at risk of developing cardiomyopathies (CMPs). In fact, CMR not only provides precise data on cardiac volumes, wall thickness, mass and systolic function but it also a non-invasive characterization of myocardial tissue, thus helping the early diagnosis and the precise phenotyping of the different CMPs, which is essential for early and individualized treatment of patients. Furthermore, several CMR characteristics, such as the presence of extensive LGE or abnormal mapping values, are emerging as prognostic markers, therefore helping to define patients' risk. Lastly new experimental CMR techniques are under investigation and might contribute to widen our knowledge in the field of CMPs. In this perspective, CMR appears an essential tool to be systematically applied in the diagnostic and prognostic work-up of CMPs in clinical practice. This review provides a deep overview of clinical applicability of standard and emerging CMR techniques in the management of CMPs.

Endomyocardial biopsy in the clinical context: current indications and challenging scenarios

Endomyocardial biopsy (EMB) is an invasive procedure originally developed for the monitoring of heart transplant rejection. Over the year, this procedure has gained a fundamental complementary role in the diagnostic work-up of several cardiac disorders, including cardiomyopathies, myocarditis, drug-related cardiotoxicity, amyloidosis, other infiltrative and storage disorders, and cardiac tumours. Major advances in EMB equipment and techniques for histological analysis have significantly improved diagnostic accuracy of EMB. In recent years, advanced imaging modalities such as echocardiography with three-dimensional and myocardial strain analysis, cardiac magnetic resonance and bone scintigraphy have transformed the non-invasive approach to diagnosis and prognostic stratification of several cardiac diseases. Therefore, it emerges the need to re-define the current role of EMB for diagnostic work-up and management of cardiovascular diseases. The aim of this review is to summarize current knowledge on EMB in light of the most recent evidences and to discuss current indications, including challenging scenarios encountered in clinical practice.

The prognostic value of global myocardium strain by CMR-feature tracking in immune checkpoint inhibitor-associated myocarditis

OBJECTIVES

Immune checkpoint inhibitor (ICI)-associated myocarditis is a potentially fatal complication. Sparse published researches evaluated the prognostic value of cardiovascular magnetic resonance feature tracking (CMR-FT) for ICI-associated myocarditis.

METHODS

In the single-center retrospective study, 52 patients with ICI-associated myocarditis and CMR were included from August 2018 to July 2021. The ICI-associated myocarditis was diagnosed by using the clinical criteria of the European Society of Cardiology guidelines. Major adverse cardiovascular events (MACE) were comprised of cardiovascular death, cardiogenic shock, cardiac arrest, and complete heart block.

RESULTS

During a median follow-up of 171 days, 14 (27%) patients developed MACE. For patients with MACE, the global circumferential strain (GCS), global radial strain (GRS), global longitudinal strain (GLS), and left ventricular ejection fraction (LVEF) were significantly worse and native T1 values and late gadolinium enhancement (LGE) extent were significantly increased, compared with patients without MACE (p < 0.05). The GLS remained the independent factor associated with a higher risk of MACE (hazard ratio (HR): 2.115; 95% confidence interval (CI): 1.379-3.246; p = 0.001) when adjusting for LVEF, LGE extent, age, sex, body mass index, steroid treatment, and prior cardiotoxic chemotherapy or radiation. After adjustment for LVEF, the GLS remained the independent risk factor associated with a higher rate of MACE among patients with a preserved LVEF (HR: 1.358; 95% CI: 1.007-1.830; p = 0.045).

CONCLUSIONS

GLS could provide independent prognostic value over GCS, GRS, traditional CMR features, and clinical features in patients with ICI-associated myocarditis.

KEY POINTS

• The global circumferential strain (GCS), global radial strain (GRS), and global longitudinal strain (GLS) by cardiovascular magnetic resonance feature tracking were significantly impaired in patients with an immune checkpoint inhibitor (ICI)-associated myocarditis. • GLS was still significantly impaired in patients with preserved left ventricular ejection fraction. • The worse GLS was an independent risk factor over GCS, GRS, traditional CMR features, and clinical features for predicting major adverse cardiovascular events in patients with ICI-associated myocarditis.

Global longitudinal strain by CMR improves prognostic stratification in acute myocarditis presenting with normal LVEF

BACKGROUND

Prognostic stratification of acute myocarditis (AM) presenting with normal left ventricular ejection fraction (LVEF) relies mostly on late gadolinium enhancement (LGE) characterization. Left ventricular peak global longitudinal strain (LV-GLS) measured by feature tracking analysis might improve prognostication of AM presenting with normal LVEF.

METHODS

Data of patients undergoing cardiac magnetic resonance (CMR) for clinically suspected AM in seven European Centres (2013-2020) were retrospectively analysed. Patients with AM confirmed by CMR and LVEF ≥50% were included. LGE was visually characterized: localized versus. non-localized, subepicardial versus midwall. LV-GLS was measured by dedicated software. The primary outcome was the first occurrence of an adverse cardiovascular event (ACE) including cardiac death, life-threatening arrhythmias, development of heart failure or of LVEF <50%.

RESULTS

Of 389 screened patients, 256 (66%) fulfilled inclusion criteria: median age 36 years, 71% males, median LVEF 60%, median LV-GLS -17.3%. CMR was performed at 4 days from hospitalization. At 27 months, 24 (9%) patients experienced ≥1 ACE (71% developed LVEF <50%). Compared to the others, they had lower median LV-GLS values (-13.9% vs. -17.5%, p = .001). At Kaplan-Meier analysis, impaired LV-GLS (both considered as > -20% or quartiles), non-localized and midwall LGE were associated with ACEs. Patients with LV-GLS ≤-20% did not experience ACEs. LV-GLS remained associated with ACEs after adjustment for non-localized and midwall LGE.

CONCLUSION

In AM presenting with LVEF ≥50%, LV-GLS provides independent prognostic value over LGE characterization, improving risk stratification and representing a rationale for further studies of therapy in this cohort.

Multimodality imaging in acute myocarditis

The diagnosis of acute myocarditis often involves several noninvasive techniques that can provide information regarding volumes, ejection fraction, and tissue characterization. In particular, echocardiography is extremely helpful for the evaluation of biventricular volumes, strain and ejection fraction. Cardiac magnetic resonance, beyond biventricular volumes, strain, and ejection fraction allows to characterize myocardial tissue providing information regarding edema, hyperemia, and fibrosis. Contemporary cardiac computed tomography angiography (CCTA) can not only be extremely important for the assessment of coronary arteries, pulmonary arteries and aorta but also tissue characterization using CCTA can be an additional tool that can explain chest pain with a diagnosis of myocarditis.

Emerging Role of Cardiac Magnetic Resonance Imaging in Diagnosing Myocarditis: A Blunder or The Way To Get the Problem Sorted?

Acute myocarditis is a disease affecting the myocardial tissue, which is caused by infections, rheumatic diseases, especially sarcoidosis, or certain therapies. Its diagnosis may be difficult, owing to its variable clinical presentation. In this setting, cardiac magnetic resonance plays a pivotal role in detecting myocardial inflammation through qualitative, semiquantitative, and quantitative parameters, in particular with the new quantitative techniques such as T1 and T2 mapping, combined or not with late gadolinium enhancement evaluation. This is in accordance with the revised Lake Louise criteria. In this review, the emerging role of the new cutting-edge cardiac magnetic resonance imaging techniques in diagnosing myocarditis is extensively presented.

State-of-the-art myocardial strain by CMR feature tracking: clinical applications and future perspectives

Based on conventional cine sequences of cardiac magnetic resonance (CMR), feature tracking (FT) is an emerging tissue tracking technique that evaluates myocardial motion and deformation quantitatively by strain, strain rate, torsion, and dyssynchrony. It has been widely accepted in modern literature that strain analysis can offer incremental information in addition to classic global and segmental functional analysis. Furthermore, CMR-FT facilitates measurement of all cardiac chambers, including the relatively thin-walled atria and the right ventricle, which has been a difficult measurement to obtain with the reference standard technique of myocardial tagging. CMR-FT objectively quantifies cardiovascular impairment and characterizes myocardial function in a novel way through direct assessment of myocardial fiber deformation. The purpose of this review is to discuss the current status of clinical applications of myocardial strain by CMR-FT in a variety of cardiovascular diseases. KEY POINTS: • CMR-FT is of great value for differential diagnosis and provides incremental value for evaluating the progression and severity of diseases. • CMR-FT guides the early diagnosis of various cardiovascular diseases and provides the possibility for the early detection of myocardial impairment and additional information regarding subclinical cardiac abnormalities. • Direct assessment of myocardial fiber deformation using CMR-FT has the potential to provide prognostic information incremental to common clinical and CMR risk factors.

The Arrhythmic Phenotype in Cardiomyopathy

In the wide phenotypic spectrum of cardiomyopathies, sudden cardiac death (SCD) has always been the most visible and devastating disease complication. The introduction of implantable cardioverter-defibrillators for SCD prevention by the late 1980s has moved the question from how to whom we should protect from SCD, leaving clinicians with a measure of uncertainty regarding the most reliable option to guide identification of the highest-risk patients. In this review, we will go through all the available evidence in the field of arrhythmic expression and arrhythmic risk stratification in the different phenotypes of cardiomyopathies to provide practical suggestions in daily clinical management.

Diagnostic and Prognostic Value of Cardiac Magnetic Resonance Strain in Suspected Myocarditis With Preserved LV-EF: A Comparison Between Patients With Negative and Positive Late Gadolinium Enhancement Findings

BACKGROUND

Late gadolinium enhancement (LGE) is absent in many patients with suspected myocarditis and preserved left ventricular ejection fraction (LV-EF), which poses difficulties in diagnosis and risk stratification.

PURPOSE

To investigate the diagnostic and prognostic value of ventricular myocardial strain in patients with suspected myocarditis, preserved LV-EF, and negative Lake Louis Criteria (LLC) by comparing the findings in LGE negative and LGE positive patients.

STUDY TYPE

Retrospective.

POPULATION

A total of 108 patients with clinically suspected myocarditis who did not satisfy LLC were divided into LGE negative (N = 65) and LGE positive (N = 43) groups. A control group consisted of 50 healthy volunteers.

FIELD STRENGTH/SEQUENCE

Steady-state free precession cine and phase-sensitive inversion recovery segmented gradient echo LGE sequences at 3.0 T.

ASSESSMENT

Myocardial strain of the ventricles was evaluated by feature tracking, major adverse cardiovascular events (MACE) were assessed during follow-up since the date of magnetic resonance examination.

STATISTICAL TESTS

Independent-samples t test, Mann-Whitney U test, receiver operating characteristic curve analysis, and Cox proportional hazard regression were performed. A P-value <0.05 was considered statistically significant.

RESULTS

Cardiac function and myocardial deformability were impaired in all patients relative to controls. Left ventricular-global radial (LV-GRS), circumferential (LV-GCS), and longitudinal (LV-GLS) strain had diagnostic value, even in LGE negative patients (sensitivity = 0.446, 0.523, and 0.662; specificity = 0.92, 0.80, and 0.64; AUC = 0.685, 0.675, and 0.648, respectively). After a median follow-up of 530.5 (interquartile range: 168.5-969.25) days, MACE occurred in 18 (16.67%) patients. Right ventricular GLS showed prognostic value in all patients and in LGE negative patients, both in univariable analysis (hazard ratio [HR] 1.049, 95% confidence interval [CI] 1.001-1.099 and HR 1.068, 95% CI 1.011-1.127, respectively) and in multivariable Cox survival analysis. LV-GLS was associated with MACE in LGE positive patients in multivariable Cox survival analysis.

DATA CONCLUSION

Myocardial strain provides diagnostic and prognostic value in suspected myocarditis with preserved LV-EF, even in the absence of LGE.

LEVEL OF EVIDENCE

3 TECHNICAL EFFICACY: 2.

Left ventricular myocardial strain and tissue characterization by cardiac magnetic resonance imaging in immune checkpoint inhibitor associated cardiotoxicity

Background

Immune checkpoint inhibitors (ICIs) are highly effective in treating cancer; however, cardiotoxicity can occur, including myocarditis. Cardiac magnetic resonance (CMR) imaging is useful for evaluation of myocarditis, although it has not been well studied in ICI cardiotoxicity.

Methods

We identified patients referred for CMR evaluation of ICI cardiotoxicity from September 2015 through September 2019. We assessed structural and functional parameters, feature tracking (FT) left ventricular and atrial strain, T2- weighted ratios and quantitative late gadolinium enhancement (LGE). We also applied the Updated Lake Louise Criteria for diagnosis of myocarditis.

Results

Of the 20 patients referred, the median left ventricular ejection fraction (LVEF) was 52.5% ± 19.1 and 50% had a normal LVEF (≥53%). FT strain analysis revealed an average abnormal global longitudinal strain (GLS) of −9.8%± 4.2%. In patients with a normal LVEF, the average GLS remained depressed at −12.3%± 2.4%. In all patients, GLS demonstrated a significant negative correlation with LVEF (r_s = −0.64, p 0.002). Sixteen patients (80%) had presence of LGE (14 non-ischemic pattern and 2 ischemic). Percent LGE did not correlate with any CMR parameters and notably did not correlate with LVEF (r_s = −0.29, p = 0.22) or GLS (r_s = 0.10, p = 0.67), highlighting the value of tissue characterization beyond functional assessment. Nine patients (45%) met full Updated Lake Louise Criteria and 85% met at least one criterion, suggestive of myocarditis in the correct clinical context. Thirteen patients (65%) were treated for ICI-associated myocarditis and, of these, 54% (n = 7) had recovery of LVEF to normal. There was no correlation between LVEF (p = 0.47), GLS (0.89), or % LGE (0.15) and recovery of LVEF with treatment.

Conclusion

In patients with suspected ICI cardiotoxicity, CMR is an important diagnostic tool, even in the absence of overt left ventricular dysfunction, as abnormalities in left ventricular strain, T2 signal and LGE can identifying disease.

Arrhythmic risk stratification by cardiac magnetic resonance tissue characterization: disclosing the arrhythmic substrate within the heart muscle

Sudden cardiac death (SCD) is a pivotal health problem worldwide. The identification of subjects at increased risk of SCD is crucial for the accurate selection of candidates for implantable cardioverter defibrillator (ICD) therapy. Current strategies for arrhythmic stratification largely rely on left ventricular (LV) ejection fraction (EF), mostly measured by echocardiography, and New York Heart Association functional status for heart failure with reduced EF. For specific diseases, such as hypertrophic and arrhythmogenic cardiomyopathy, some risk scores have been proposed; however, these scores take into account some parameters that are a partial reflection of the global arrhythmic risk and show a suboptimal accuracy. Thanks to a more comprehensive evaluation, cardiac magnetic resonance (CMR) provides insights into the heart muscle (the so-called tissue characterization) identifying cardiac fibrosis as an arrhythmic substrate. Combining sequences before and after administration of contrast media and mapping techniques, CMR is able to characterize the myocardial tissue composition, shedding light on both intracellular and extracellular alterations. Over time, late gadolinium enhancement (LGE) emerged as solid prognostic marker, strongly associated with major arrhythmic events regardless of LVEF, adding incremental value over current strategy in ischemic heart disease and non-ischemic cardiomyopathies. The evidence on a potential prognostic role of mapping imaging is promising. However, mapping techniques require further investigation and standardization. Disclosing the arrhythmic substrate within the myocardium, CMR should be considered as part of a multiparametric approach to personalized arrhythmic stratification.