Left ventricular endocardial longitudinal dysfunction persists after acute myocarditis with preserved ejection fraction

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.

Usefulness of Left Ventricular Myocardial Deformation in Children Hospitalized for Acute Myocarditis who Develop Arrhythmias

Cardiac arrhythmias occur in 3-40% of patients with acute myocarditis and cause significant morbidity and mortality. Myocardial injury also results in abnormal myocardial deformation. The relationship between left ventricular (LV) deformation, measured by two-dimensional speckle tracking echocardiography (2D-STE), and arrhythmia in pediatric myocarditis is unknown. We evaluated the association between 2D-STE and arrhythmias in children hospitalized with acute myocarditis. We reviewed patients ≤ 18 years hospitalized for acute myocarditis from 2008 to 2018. Arrhythmias were defined as 1) non-sustained or sustained ventricular tachycardia or ventricular fibrillation, 2) sustained supraventricular tachycardia (SVT), 3) high-grade or complete heart block, and 4) any arrhythmia treated with an antiarrhythmic medication. Systolic LV strain values (including LV global longitudinal strain (GLS), global circumferential strain (GCS), and six segments of LV regional long axis strain) were obtained from initial echocardiograms during hospitalization. Of 66 patients hospitalized, 23 (35%) had arrhythmias. SVT was the predominant arrhythmia (74%). Global and regional strain indices were reduced in the arrhythmia group: LV GLS [-8.9 (IQR -13.6, -6.1) vs. -13.7 (IQR -16.9, -9.7), p = 0.038]; basal inferior/septal [-10.7 (IQR -15.5, -7.8) vs. -16.4 (IQR -18, -11.8), p = 0.009]; basal anterior/lateral [-7.1 (IQR -12.8, -4.7) vs. -9.4 (IQR -16.7, -7.4), p = 0.025]; and mid inferior/septal segments [-9 (IQR -13, -7.7) vs. -14.1 (IQR -22.5, -10.7), p = 0.007]. After controlling for age, reductions in GLS and segmental strain in the two basal and two mid-segments were associated with increased arrhythmia occurrence (p <0.05). Our findings suggest that echocardiographic LV deformation by 2D-STE may be useful in identifying pediatric patients with acute myocarditis at risk for arrhythmias.

Long-term prognosis following hospitalization for acute myocarditis - a matched nationwide cohort study

OBJECTIVE

The aim of this study was to examine the long-term risk of heart failure (HF) and all-cause mortality, in patients discharged alive following hospitalization for myocarditis. Background. Prognosis in patients with apparently uncomplicated myocarditis is in general perceived as good, but data on long-term outcomes are sparse. Methods. From nationwide Danish registries we included patients without prior cardiac disease, discharged alive with a first-time diagnosis of myocarditis 1996-2016. Patients were matched 1:10 by age- and sex, with controls from the general population. Risk of HF hospitalization and death in cases and controls was compared by use of adjusted Cox regression analyses. Results. We identified 1557 patients with a first-time diagnosis of myocarditis, 72% men, median age 39 years. Patients with myocarditis had more hypertension, diabetes, and cancer, and received more pharmacotherapy prior to hospitalization compared to matched controls. During a mean follow-up of 8.5 years, the event rate of HF hospitalization was 8.7 vs. 2.2 per 1000 patient-years (py) in cases and controls; HR 4.59 (95% CI; 3.58-5.88) and for all-cause mortality, event rate 21.9 vs 11.2 per 1000 py; HR 2.10 (95% CI; 1.82-2.43). Among 784 patients with no events or HF medication one year after diagnosis, risk of HF hospitalization (HR 2.15; 95% CI; 1.18-3.92), and all-cause mortality (HR 1.62; 95% CI; 1.21-2.16) remained elevated compared to matched controls. Conclusion. Myocarditis in younger patients without prior cardiac disease was associated with a long-term excess risk of HF hospitalization, and death, even in patients free of events and HF medication 1 year after discharge.HighlightsMyocarditis ranges from chest discomfort to severe heart failure.In most patients, left ventricular ejection fraction recovers but the long-term adverse cardiac risk is unknown.Patients with myocarditis and no prior cardiac disease were at higher risk of death and heart failureRoutine follow-up may be warranted following an episode of acute myocarditis.

Peripheral Blood MicroRNAs as Potential Biomarkers of Myocardial Damage in Acute Viral Myocarditis

Background: microRNAs (miRs) have emerged as important modulators of cardiovascular development and disease. Our aim was to determine whether cardiac-related miRs such as miR-21-5p and miR-1-3p were differentially expressed in acute viral myocarditis and whether any of them was related with the extent of myocardial damage and left ventricular dysfunction. Methods: We enrolled 40 patients with acute viral myocarditis. Blood samples were taken on admission and miRs expression levels in peripheral blood mononuclear cells were quantified by real-time reverse transcription polymerase chain reaction. Results: miR-21-5p, miR-1-3p were significantly elevated in acute myocarditis. miR-21-5p levels showed a strong correlation with global longitudinal strain (r = 0.71, p < 0.01), while miR-1-3p had significant correlations with troponin I (r = 0.79, p < 0.01). Conclusions: The expression of miR-21-5p and miR-1-3p in peripheral blood is increased in acute viral myocarditis, and this increase is correlated with myocardial damage and indicative of left ventricular systolic dysfunction in these patients.