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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 30, No 4, July/August 2019
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Although the clinical utility of contrast echocardiography in
acute myocarditis is yet to be demonstrated and is controversial,
contrast echocardiography is used routinely to exclude LV apical
thrombus in patients with acute myocardial infarction and could
also be useful in acute myocarditis, particularly in patients with
impaired LV systolic function.
The presence of LV thrombus may be difficult to confidently
image using standard TTE and, as recommended by national
guidelines, contrast echocardiography can be useful to aid in
the diagnosis in difficult situations.
59
A LV mural thrombus
is a common complication, particularly in patients with LV
dilatation and significantly impaired contractility, so contrast
echocardiographycouldbeusedinthosepatientsinguidingfurther
management to prevent peripheral emobilisation.
38,59-61
Other
imaging modalities, including CMR or 3D echocardiography,
should be considered for confirmatory purposes.
Three-dimensional echocardiography
The real-time 3D-TTE is an advanced and important
echocardiographic imaging modality used to evaluate cardiac
patients; however its role in acute myocarditis is yet to be
elucidated as larger data on its utility are limited. Despite
this pitfall, a case was previously reported using real-time 3D
echocardiography in acute myocarditis.
35
Thuny
et al
.
35
reported
the role of both 2D and 3D echocardiography in a 43-year-old
male with acute myocarditis, where the authors demonstrated
the presence of hypokinetic and impaired LV contractility and
biventricular thromboses, which were better delineated by 3D
compared with 2D echocardiography.
35
Differentiating acute from fulminant myocarditis
Echocardiography in patients with myocarditis allows for serial
assessment of LV dysfunction and is useful to distinguish
fulminant from acute myocarditis.
61-64
Fulminant myocarditis
is characterised by the presence of a normal cavity and
hypocontractile LV with increased septal thickness, compared
with acute myocarditis. Acute myocarditis is characterised by
marked LV dilation, normal septal thickness and ventricular
dysfunction. In any form of myocarditis or inflammatory
cardiomyopathy, cardiac function should be monitored using
serial echocardiograms to demonstrate any change over time.
37,62-64
In general, LV function improves over a period of approximately
six months in fulminant myocarditis, compared with acute
myocarditis.
37,62-64
An athlete with myocarditis
Responding to increased cardiac output demanded during
exercise, both ventricles must increase stroke volume, which
imposes high stress on myocardial structures, more so on the
RV, which normally works at low pressures compared with the
LV. Previously, studies on athletes’ hearts were more focused
on the LV; however recently, due to the evolution of advanced
echocardiographic techniques and CMR, RV exercise-induced
remodelling has been demonstrated.
Echocardiography is a widely available imaging modality
that could provide useful information in sports cardiology,
particularly in areas of pre-participation screening and to
evaluate exercise-induced cardiac remodelling. Based on current
guidelines, it is recommended resuming competitive sport once
there are no biomarkers or evidence of inflammation and no
concerns regarding arrhythmias, and after the LV has assumed
normality.
65
Prior to clearance, the athlete should demonstrate
a normal work-up based on an echocardiogram, exercise
electrocardiogram and Holter monitor. If the athlete wishes to
return to competitive sporting activity, recommendations are
provided on how best to do so in a safe manner and should be
followed closely, using intermittent repeated rhythm monitors,
imaging and stress testing, depending on the sporting activity
and degree of delayed gadolinium enhancement.
Since several reports have indicated a strong prognostic role
for residual myocardial scarring after myocarditis, athletes should
be prohibited from participating in competitive sport if there is
evidence or concern regarding either ventricular arrhythmias or
progressive LV dysfunction, which could be associated with the
presence of residual myocardial scarring.
66,67
Furthermore, CMR
has added prognostic implications, as evidence of late gadolinium
enhancement was significantly associated with major adverse
cardiac events in athletes.
68,69
Despite current advancements
in imaging, including echocardiography, for young athletes
wishing to return to sport after an acute episode of myocarditis,
more data on advanced echocardiography, including STE, are
warranted.
Discussion
Even though only standard echocardiography has been used,
reports indicate that echocardiography plays some part during
the initial evaluation and subsequently in diagnosing possible
myocarditis. This limitation, compared with normal healthy
individuals, is mostly due to normal reported evaluations in those
with less severe forms of myocarditis. Despite these negatives,
multiple abnormalities have been reported, namely segmental
and global ventricular wall-motion abnormalities, and different
patterns of cardiomyopathies, such as dilated, hypertrophic
or even restrictive forms of cardiomyopathy in patients with
histology-proven myocarditis. In addition, areas of necrosis and
inflammation have been reported, which are associated with or
lead to myocardial perfusion defects on further imaging.
Despite the lack of prior larger reports, studies or broader
knowledge of myocardial contrast echocardiography in acute
myocarditis, contrast echocardiography is useful to rule out
ventricular mural thrombus. It is also useful in guiding further
management and to prevent embolisation, which could lead
to devastating outcomes, particularly in severely impaired
ventricular contractility.
58-61
Two-dimensional STE strain echocardiography is useful
in evaluating regional contractile function and assisting
with detecting subclinical myocardial dysfunction, despite
presumed normal ventricular function, based on conventional
echocardiography.
36,57
2D-STE has a favourable signal-to-noise
ratio, angle independence and the ability to differentiate active
from passive myocardial motion, compared with standard
echocardiography.
Despite limited information about the sensitivity and
specificity of some of these newer echocardiographic techniques,
their availability allows a window of opportunity to prospectively
address important questions in myocarditis. Furthermore, since