Structured Abstract (Word Count: 245)
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 acute myocarditis in the
adult population.
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-analysed using a random-effects model for overall effect
size, and assessed through standardized mean difference (SMD).
Results: Available data from up to six included studies
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≤0.01 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.