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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 30, No 4, July/August 2019
240
AFRICA
Left ventricular function
Hsiao
et al
.
36
reported septal wall thickness, left ventricular
dimensions and ejection fraction in acute myocarditis patients
compared with healthy controls, and further implemented
the role of two-dimensional speckle-tracking echocardiography
(2D-STE). Here, the authors demonstrated that 2D-STE could
be helpful when evaluating patients with acute myocarditis
during initial presentation of the disease process, compared with
2D-TTE.
Traditionally, echocardiographic findings in patients with
acute myocarditis include left ventricular (LV) regional/segmental
or global dysfunction and overall LV dilatation, however normal
LV function continues to be reported in biopsy-proven acute
myocarditis.
37
Occasionally, myocardial interstitial oedema,
which could be detected echocardiographically as increased
ventricular wall thickness, has also been reported in acute
myocarditis.
35,37,38
Additional echocardiographic measurements
suggestive of myocarditis include depressed ventricular
function, including systolic and diastolic dysfunction, and
regional wall abnormalities; however there are other non-specific
echocardiographic parameters characteristically associated with
acute myocarditis.
39-43
Right ventricular function
The LV is the most commonly assessed and reported cardiac
chamber in acute myocarditis, however echocardiographic
assessment of right ventricular (RV) function is also highly
recommended in any form of myocarditis.
44,45
Pinamonti
et al
.
44
retrospectively reviewed echocardiographic images of 42 patients
with biopsy-proven myocarditis and reported RV dysfunction to
be fairly common, as 23% of their study patients had evidence
of RV dysfunction.
44
RV dysfunction in patients with acute viral myocarditis has
been reported as the most likely cause of poorer outcomes in
terms of death and increased need for cardiac transplantation
compared with LV dysfunction.
44-47
The LV–RV interaction has
also been reported to be crucial in patients with myocarditis, as
significantly impaired LV function was reported more often in
patients with depressed RV function than in those with normal
RV function during the initial presentation.
44,45
Speckle-tracking echocardiography
STE is a new echocardiographic technology with high sensitivity
and reproducibility for detection of subclinical ventricular
systolic and diastolic dysfunction. The invention of STE strain
and strain rate indices are useful to evaluate intrinsic cardiac
deformation. STE indices provide accurate measurements of
both regional and global ventricular contractility enhanced by
angle independency and fewer pitfalls throughout the motion
plane, compared with convectional 2D echocardiography. STE
has demonstrated its superior utility compared with conventional
echocardiography in patients presenting with acute myocarditis
or any form of inflammatory cardiomyopathy.
36,48-53
The 2D-STE strain and strain rate parameters are useful
prognostic measures, even in patients presumed to have
preserved LV ejection fraction at baseline and during the follow-
up periods of the acute myocarditis process.
36
In addition,
strain parameters could be useful in predicting deterioration
and overall event-free survival after an evidenced or recovery
from acute viral myocarditis, and to differentiate myocarditis
from other conditions including coronary artery disease.
36
An
additional report indicated that STE should be recommended
in daily clinical practice to evaluate multiple cardiac conditions,
including inflammatory cardiomyopathies, as strain parameters
could detect early ventricular dysfunction compared with
conventional echocardiography, and it is also useful for long-
term prognostic purposes.
52
In the recent past, a case of acute viralmyocarditiswas reported
where significantly impaired LV longitudinal, circumferential and
radial systolic strain parameters were demonstrated.
54
The authors
also reported significantly attenuated inferior, inferolateral and
apical segmental strain values, with the inferolateral segment
demonstrating a paradoxical circumferential strain.
54
In a larger study of 28 consecutive patients with cardiac
magnetic resonance (CMR) imaging-verified diagnosis of acute
myocarditis based on the Lake Louise criteria, Løgstrup
et al
.
55
indicated that 2D-STE was useful during the initial evaluation,
as global longitudinal systolic strain added supportive
information to clinical and conventional echocardiography.
56
Furthermore the authors also reported that global longitudinal
systolic myocardial strain (including epicardial and endocardial
longitudinal systolic strain) correlated strongly with the degree
of myocardial oedema. The same study highlighted that 2D-STE
was undoubtedly useful for the diagnosis and to evaluate the
degree of myocardial dysfunction in acute myocarditis.
55
Even though three-dimensional (3D) STE is still evolving,
Caspar
et al
.
57
demonstrated significantly lower 3D global
longitudinal, circumferential, area and radial strain values in
acute viral myocarditis cohorts compared with normal healthy
controls, despite documented preserved baseline LV ejection
fraction on standard echocardiography in both groups.
Tissue Doppler imaging
Tissue Doppler imaging (TDI) indices are important and
more specific when evaluating patients with acute myocarditis.
Despite limited reports on the detection of myocarditis by novel
echocardiographicmodalities, such as tissueDoppler, studies have
demonstrated impaired longitudinal segmental myocardial strain
on Doppler echocardiography due to myocardial oedema.
55-58
Furthermore, tissue Doppler parameters and contrast-enhanced
CMR could synergistically help in confirming the diagnosis and
guide further management.
Smedema
et al
.
58
reported a case where the authors
demonstrated the importance of TDI as part of the diagnostic
work-up and management of acute myocarditis. In the same
report, the authors further highlighted TDI indices, which were
indicative of abnormalities suggestive of myocardial scarring.
56
Here the echocardiographic parameters were better suited to
characterise acute myocardial tissue changes and changes over
time in patients with acute myocarditis.
Contrast echocardiography
Generally, the clinical applications of contrast echocardiography
include LV quantification and Doppler enhancement, which are
useful during the evaluation of ventricular function, particularly
in patients with a poor echocardiographic window.
38,59-61