GUIDELINES AND STANDARDS

Recommendations for Multimodality Cardiac
Imaging in Patients with Chagas Disease: A Reportfrom the American Society of Echocardiography in
Collaboration With the InterAmerican Associationof Echocardiography (ECOSIAC) and theCardiovascular Imaging Department of theBrazilian Society of Cardiology (DIC-SBC)
Harry Acquatella, MD, FASE (Chair), Federico M. Asch, MD, FASE (Co-Chair),Marcia M. Barbosa, MD, PhD, FASE, Marcio Barros, MD, PhD, Caryn Bern, MD, MPH,
Joao L. Cavalcante, MD, FASE, Luis Eduardo Echeverria Correa, MD, Joao Lima, MD, Rachel Marcus, MD,
Jose Antonio Marin-Neto, MD, PhD, Ricardo Migliore, MD, PhD, Jose Milei, MD, PhD, Carlos A. Morillo, MD,
Maria Carmo Pereira Nunes, MD, PhD, Marcelo Luiz Campos Vieira, MD, PhD, and Rodolfo Viotti, MD*, Caracas,
Venezuela; Washington, District of Columbia; Belo Horizonte and S~
a o Paulo, Brazil; San Francisco, California; Pittsburgh,
Pennsylvania; Floridablanca, Colombia; Baltimore, Maryland; San Martin and Buenos Aires, Argentina; and Hamilton,
Ontario, Canada
In addition to the collaborating societies listed in the title, this document is endorsed by the following American
Society of Echocardiography International Alliance Partners: the Argentinian Federation of Cardiology, theArgentinian Society of Cardiology, the British Society of Echocardiography, the Chinese Society of
Echocardiography, the Echocardiography Section of the Cuban Society of Cardiology, the Echocardiography
Section of the Venezuelan Society of Cardiology, the Indian Academy of Echocardiography, the Indian
Association of Cardiovascular Thoracic Anaesthesiologists, the Iranian Society of Echocardiography, theJapanese Society of Echocardiography, the Mexican Society of Echocardiography and Cardiovascular Imaging,and the Saudi Arabian Society of Echocardiography.

Keywords: Chagas, Cardiomyopathy, Left ventricular aneurysm, Heart failure, Echocardiography, Cardiac
magnetic resonance

From Centro Medico de Caracas, San Bernardino, Caracas, Venezuela (H.A.); Medstar
Washington Hospital Center, Washington, District of Columbia (F.M.A., R.M.); Socor
de e Ecologia Humana,
Hospital, Belo Horizonte, Brazil (M.M.B.); Faculdade de Sau
Belo Horizonte, Brazil (M.B.); the University of California, San Francisco, San
Francisco, California (C.B.); the University of Pittsburgh, Pittsburgh, Pennsylvania(J.L.C.); Fundacion Cardiovascular de Colombia, Floridablanca, Colombia (L.E.E.C.);
Johns Hopkins University, Baltimore, Maryland (J.L.); the Interventional Cardiology~o Preto, University of Sa~o Paulo, Sa~o Paulo, Brazil
Unit, Medical School of Ribeira n, San Martin, Argentina (R.M., R.V.); Consejo Nacional(J.A.M.-N.); Hospital Eva Perode Investigaciones Cientificas y Tecnicas, Buenos Aires, Argentina (J.M.); McMaster
University, Population Health Research Institute, Hamilton, Ontario, Canada (C.A.M.);
the Federal University of Minas Gerais, Belo Horizonte, Brazil (M.C.P.N.); and Heart~o Paulo University Medical School, Hospital Israelita Albert Einstein, Sa~oInstitute, Sa
Paulo, Brazil (M.L.C.V.).
The following authors reported relationships with one or more commercial interests:
Caryn Bern, MD, MPH, has consulted for Chemogroup. Luis Eduardo Echeverria Correa, MD, has received a research grant from Roche. Joao Lima, MD, has received grantsupport from Toshiba Medical Systems. Rachel Marcus, MD, is a consultant for Bayer.
Carlos A. Morillo, MD, has received grants from the Canadian Institute for HealthResearch, TDR-WHO (BENEFIT trial), Merck Shape & Dohme (STOP-CHAGAS trial),
Bayer, and BMS/Pfizer; has been a speaker for Bayer and Boehringer Ingelheim; andis a member of the advisory board for Boston Scientific. The following authors reported

no actual or potential conflicts of interest in relation to this document: Harry Acquatella,
MD, FASE, Federico M. Asch, MD, FASE, Marcia M. Barbosa, MD, PhD, FASE, Marcio~o L. Cavalcante, MD, FASE, Jose Antonio Marin-Neto, MD, PhD,
Barros, MD, PhD, Joa
Ricardo Migliore, MD, PhD, Jose Milei, MD, PhD, Maria Carmo Pereira Nunes, MD,
PhD, Marcelo Luiz Campos Vieira, MD, PhD, and Rodolfo Viotti, MD.
Reprint requests: American Society of Echocardiography, 2530 Meridian Parkway,
Suite 450 Durham, NC 27713 USA (Email: ase@asecho.org).
* The American Society of Echocardiography and the writing group sadly note thepassing of Dr. Rodolfo Viotti in March 2017, while this document was being written.
It was our honor to work with Dr. Viotti on a topic that was very dear to him
throughout his long career.
Attention ASE Members:

Visit www.aseuniversity.org to earn free continuing medical education credit
through an online activity related to this article. Certificates are available for
immediate access upon successful completion of the activity. Nonmembers
will need to join the ASE to access this great member benefit!
0894-7317/$36.00
Copyright 2017 by the American Society of Echocardiography.
https://doi.org/10.1016/j.echo.2017.10.019

3

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I. INTRODUCTION

Abbreviations

2D = Two-dimensional

Chagas disease (ChD) is a significant public health problem in most
Latin American countries. Observed mainly in rural areas, in recent
decades it has spread to cities and to nonendemic countries, mostly
as a result of migration of infected people. Increasing numbers ofcases are now being identified in the United States, Spain, and othercountries, which makes its diagnosis and management of increasing
interest worldwide.
During an antimalarial campaign in Lassance (Minas Gerais,
Brazil) in 1909, Carlos Chagas identified the parasite Trypanosoma
cruzi, its vector for transmission (triatomine bugs, called differently
in each country: kissing bug, barbeiro, vinchuca, chinche, etc.), anddescribed the initial cases of the disease.1 Transmission occurs
mainly through the bite of these vectors but may also occur byblood transfusion, from mother to fetus, oral ingestion of contaminated foods, organ transplantation, and laboratory accidents.
Vector control programs have substantially diminished T. cruzi and
ChD incidence. However, about 70 million people remain at risk
for acquiring the infection.2
The diagnosis of ChD is made by epidemiologic history and by two
or more positive serologic tests. There are two clinical phases of T.
cruzi infection: acute ChD, seen early after acquiring the infection,and chronic ChD, lasting for decades. About 70% to 80% of individuals with chronic T. cruzi infection remain asymptomatic (indeterminate form), while 20% to 30% develop cardiac and/or
gastrointestinal disease.3 Patients with chronic Chagas heart disease(ChHD) are staged according to the severity of myocardial damage
and symptoms of congestive heart failure (HF; Table 1).4,5
Assessment by electrocardiography is mandatory because theearliest signs of ChHD are generally conduction system defects
and/or ventricular arrhythmias. The introduction of various cardiac
imaging modalities, such as echocardiography, nuclear medicine,computed tomography (CT), cardiac magnetic resonance (CMR),
and chest radiography, provides valuable information on cardiac
structure and function.
The purpose of this document is to provide recommendations forthe use of cardiac ultrasound and other imaging modalities in the diagnosis, classification, and risk assessment of myocardial damage fromearly to advanced forms of ChHD.

3D = Three-dimensional
ASE = American Society of Echocardiography
ChD = Chagas disease
ChHD = Chagas heart disease
CMR = Cardiac magnetic resonance
CT = Computed tomography
ECG = Electrocardiographic
HF = Heart failure
LA = Left atrial
LGE = Late gadolinium enhancement
LV = Left ventricular
LVEF = Left ventricular ejection fraction
PW Doppler = Pulsed wave Doppler
RV = Right ventricular
RVEF = Right ventricular ejection fraction
TEE = Transesophageal echocardiography
TTE = Transthoracic echocardiography
TABLE OF CONTENTS

I. Introduction 4
II. Epidemiology of ChD: Geographic Distribution Worldwide and in the
United States 4
III. Pathophysiology Related to Imaging and Clinical Presentation 5
IV. Special Features of Electrocardiography and Each Imaging Modality in
Relation to ChD 6
IV.a. Electrocardiography and Continuous Rhythm Monitoring
IV.b. Echocardiography

6

7

IV.b.i. M-mode and 2D echocardiography

7

IV.b.ii. Three-dimensional echocardiography

9IV.b.iii. Strain and speckle tracking echocardiography
IV.c. CMR and CT 12

11

II. EPIDEMIOLOGY OF ChD: GEOGRAPHIC DISTRIBUTIONWORLDWIDE AND IN THE UNITED STATES

IV.d. Nuclear Medicine
16
V. Ventricular Function 17
V.a. LV Systolic Function

17

V.b. LV Diastolic Function

18

V.c. RV Function 18
VI. Recommendations for the Use of Imaging Modalities According to theStage of the Disease: Diagnostic, Monitoring, and Prognostic Implications 19
VI.a. Acute ChD
VI.b. Chronic ChD

19
19

VI.b.i. Silent or asymptomatic Chagas disease (Stages A, B1 and B2):
Monitoring of LV function and myocardial damage 19
VI.b.ii. Symptomatic chronic Chagas heart disease (Stages C and D)
VI.b.ii.1. LV function and heart failure (HF)
VI.b.ii.2. Thromboembolism

20

VI.b.ii.3. Cardiac arrhythmias
VII. Summary and Conclusions 21

21

20

20

ChD is caused by the protozoan parasite T. cruzi, transmitted
when feces of an infected triatomine vector enters the mammalian host through the bite wound or mucous membranes.6
Infection is lifelong in the absence of treatment. Vector-borne
transmission occurs in parts of North America, Central America,and South America, with geographic distribution determinedboth by the ecology of the triatomine vectors and factors suchas housing conditions that govern contact between vectors andthe human population.7 Transmission can also occur throughtransfusion of infected blood components, organ and bonemarrow transplantation, and from mother to fetus. Outbreaks
attributed to contaminated food or drink have been reported innorthern South America.8 In addition, many T. cruzi–infected individuals have moved from endemic rural villages to Latin
American cities, and hundreds of thousands now live in theJournal of the American Society of Echocardiography
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Table 1 Stages of ChHD
Chronic Phase
Chagas Cardiomyopathy
Acute Phase

Indeterminate Form, A

B1

B2

C

D

Infected by
T. cruzi andfindingsof acute ChD

Positive serology
Normal ECG findings
No heart disease or HF

Structural
cardiomyopathy(abnormal ECG or
echocardiographic
findings) but normal LV function
No HF

LV dysfunction
No HF

LV dysfunction
HF (current or prior)

Refractory HF
despite optimal
medical therapy

Modified from Andrade et al.4 and Bern et al.5

United States, Spain, and other nonendemic countries outside
Latin America (Figures 12 and 29,10).
T. cruzi infects many mammalian species. The vector species
responsible for the majority of human infections are considered domestic because they are adapted to living in cracks in mud walls
and thatch roofs of rustic rural houses.11 Inhabitants of infested houses
are repeatedly exposed to vectors and parasites over many years. In
highly endemic villages, a high percentage of the adult population is
infected, with the prevalence rising with increasing age.12 The prevalence of cardiac morbidity also increases with age.13 An estimated
20% to 30% of T. cruzi–infected individuals eventually develop
Chagas cardiomyopathy, but in endemic or previously endemic settings, a much higher percentage of the elderly may have cardiac
signs.3
Latin America has made substantial progress in decreasing T. cruzi
transmission, largely through residual insecticide application to control domestic infestation.14 The estimated global ChD prevalence
declined from 18 million in 1991, when the first regional control initiative began, to approximately 6 million in 2010.2,6,14 The Pan
American Health Organization has certified interruption oftransmission by domestic vectors in several countries of SouthAmerica and Central America.15,16 T. cruzi serologic screening is
conducted in most blood banks in Latin America and the UnitedStates, and some countries have systematic screening for congenital
ChD. Nevertheless, ChD remains the most important parasitic
disease in the Western Hemisphere.
The southern half of the continental United States has established enzootic transmission cycles, with infected vectors andmammalian hosts such as raccoons, opossums, wood rats, and domestic dogs.7,17 Nevertheless, the majority of infected residents are
Latin American immigrants infected in their home countries, andinfected individuals are found in nearly every state. On the basisof the Latin American immigrant population and estimates ofprevalence in their home countries, an estimated 300,000 T.
cruzi–infected immigrants reside in the United States.9 Locally acquired vector-borne infection has been documented in a handfulof cases over the past 60 years and has been inferred in blood donors for whom acquisition of the infection in Latin America has
been ruled out or judged unlikely.7,18,19 Direct assessments ofprevalence in the United States are sparse and have been
restricted to small-scale surveys or case series in populations chosen because of anticipated high risk (e.g., Latin American immigrants with nonischemic heart disease).20-22 Because of low
provider awareness, cases of Chagas cardiomyopathy likely go
unrecognized, and women at risk for vertical transmission totheir infants are not screened.23,24 Thus, more work is needed

to raise awareness and improve the knowledge base of providers
in the United States. In addition, more extensive epidemiologic
studies and better diagnostic and treatment availability are
required.

Key Points
 ChD is a vector-borne zoonotic disease endemic to the Americas, which could beunderdiagnosed if aggressive screening campaigns are not pursued.
 Substantial progress has been made in decreasing vector- and blood-borne T. cruzi
transmission through residual insecticide application and housing improvement,
but there remain 6 million infected people and 70 million at risk for infection in
the Americas.
 Zoonotic transmission occurs in the southern half of the United States, but T. cruzi–infected migrants from Latin America greatly outnumber those infected locally. Patientswith ChD are found in nearly every state of the United States and in other countries
outside of the Americas.

III. PATHOPHYSIOLOGY RELATED TO IMAGING AND
CLINICAL PRESENTATION
The pathophysiology of myocardial damage in chronic ChHD is complex and multifactorial. ChHD is an acquired inflammatory cardiomyopathy caused by three key pathologic processes: inflammation, cell
death, and fibrosis. A consensus is now emerging that parasite persistence and parasite-driven adverse immune response play a pivotal
role in the pathogenesis of ChHD.25
Because of these underlying pathogenic mechanisms, a variety ofstructural and functional cardiovascular abnormalities have beenshown in patients with ChHD.26 Cardiac structural cells affected by
the inflammatory process include the myocytes, leading to myocytolysis and contraction band necrosis and irreversible lesions of thespecialized conduction system and cardiac neural cells. The progressive destruction of normal cardiac constituents leads to a marked
reparative and reactive fibrosis, characterized by a dense interstitialaccumulation of collagen that encloses fibers or groups of myocardial
fibers.27 This explains the frequent occurrence of atrioventricular andintraventricular blocks, sinus node dysfunction, malignant ventriculararrhythmias, and sudden death in patients with ChHD.28 Recent
studies in the experimental model of chronic T. cruzi infection haveshown that at early stages, the coalescence of focal areas of myocardial inflammation, necrosis, and fibrosis typically results in the appearance of left ventricular (LV) segmental wall motion abnormalities, ahallmark of ChHD.29 At later stages, these regional derangements
gradually cause progressive impairment of global myocardial contractile function. The ultimate consequence of is dilated cardiomyopathy
with biventricular dysfunction and congestive HF.28

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Derangements of the coronary microcirculation, including increased
platelet activity, microthrombi, microvascular spasm, and endothelial
dysfunction, have been reported in animal models of T. cruzi infection
and in studies of humans with ChD.30 These phenomena precedeand may be causally related to the development of segmental wall motion abnormalities. Abnormal reactivity to vasodilator and vasoconstrictor stimuli has also been reported in the epicardial coronary
arteries of patients with ChD. Overall, these derangements in the coronary microcirculation are likely to cause ischemic myocytolic necrosis
and reparative fibrosis that are clinically expressed as ischemic-like
symptoms, electrocardiographic changes, and perfusion defects
described in ChHD patients with angiographically normal coronary arteries. In the advanced stages of ChHD, ventricular aneurysms are detected mostly in watershed zones between principal coronary arterybranches, such as regions between the left anterior descending and posterior descending coronary arteries and the right coronary and left
circumflex coronary arteries, which supply the apex and the basalposterior wall of the left ventricle, respectively.31
Virtually all pathophysiologic aspects of chronic ChHD can be detected using various imaging modalities, which are discussed in thefollowing sections.

IV. SPECIAL FEATURES OF ELECTROCARDIOGRAPHY AND
EACH IMAGING MODALITY IN RELATION TO ChD
IV.a. Electrocardiography and Continuous Rhythm
Monitoring
Electrocardiographic (ECG) abnormalities are often the first indicatorof cardiac involvement in ChD. Electrocardiography remains a costeffective diagnostic test that should be performed routinely once serologic confirmation is obtained. Recent regional guidelines provide aclass I recommendation with level of evidence C for the indicationof 12-lead electrocardiography in the diagnosis and risk stratificationof patients with ChD.4
By and large, the acute presentation of ChD is usually mildly symptomatic and manifests as a flu-like event. In approximately 5% ofcases, acute myocarditis may clinically manifest with a wide rangeof ECG abnormalities. The most frequent findings are nonspecificand common to any myocarditis and include sinus tachycardia,
diffuse abnormal repolarization, low QRS voltage, and atrioventricular block. With severe myocarditis, higher degrees of atrioventricular
block and intraventricular conduction disturbances (bundle branch
and fascicular blocks) may occur.32 In a series of acute Chagas
myocarditis cases, ECG alterations were documented in 66% of thepatients. Abnormal repolarization was the most common finding(37%), and the most frequent arrhythmia was inappropriate sinus
tachycardia (9%), followed by atrial premature complexes (8%). In
this series, only 2% developed right bundle branch block.33
Abnormal ECG findings during the acute phase may have prognostic
implications, as reported by Porto34 in a classic series of patients presenting with acute Chagas myocarditis.
Electrocardiography is instrumental in classifying the stage of disease in patients in the chronic phase of ChD. The lack of ECG abnormalities stages T. cruzi carriers in the indeterminate phase of thedisease (stage A; Table 1). Normal ECG findings are rare in the presence of moderate or severe LV dysfunction, while a greater number of
ECG alterations correlates with worse LV function, especially if left
bundle branch block is present. Of note, ECG abnormalities werestrongly associated with ChHD in the Retrovirus Epidemiology
Donor Study II, with a high negative predictive value (95%) for

Figure 1 Estimated prevalence of T. cruzi infection per 100 habitants per country. (A) South America. (B) Mexico and Central
America.2
Chagas cardiomyopathy. This finding suggests that in rural areas
with very limited resources, normal ECG findings without other imaging modalities (such as echocardiography) could be sufficient
screening in asymptomatic T. cruzi–infected individuals.35
The earliest ECG abnormalities of ChHD usually involve the conduction system, manifesting most frequently as right bundle branch block
and/or left anterior fascicular block. Second- and third-degree atrioventricular block have also been strongly related with Chagas cardiomyopathy inendemic populations. Sinus node dysfunction may present as episodes ofsinoatrial block with bradycardia or ectopic atrial tachycardia (Figure 3).

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Figure 2 Estimated number of ChD cases per country and their status of vector transmission (2009). Obtained with permission fromthe World Health Organization (http://gamapserver.who.int/mapLibrary/Files/Maps/Global_Chagas_2009.png).

Complex ventricular arrhythmias such as ventricular tachycardia occur
even in patients without overt HF but tend to be associated with moreadvanced stages of ChHD and worse prognosis.36,37
Electrocardiography is also a useful tool for risk stratification. The
presence of premature ventricular contractions, increased QT-interval
dispersion, low-voltage QRS, QRS fragmentation, and prolonged
QRS duration have all been associated with a worse prognosis.38-40
Once ECG abnormalities arise, they imply disease progression (stage
B; Table 1), preceding the appearance of HF symptoms (stages C and
D). ECG abnormalities are frequent and related primarily with nonspecific repolarization alterations (30%–40%), right bundle branch blockin conjunction with left anterior fascicular block (20%–35%), premature ventricular ectopic beats (5%–10%), and atrial fibrillation (5%–10%).4,41 These findings have been recently supported by Echeverrıa
et al.,42 who by using electrocardiography for Chagas cardiomyopathy
staging predicted disease progression as determined by elevation in Nterminal pro–brain natriuretic peptide and high-sensitivity troponin.
Twenty-four-hour ambulatory ECG monitoring (Holter) is recommended in patients with symptoms suggestive of cardiac arrhythmias(palpitations, presyncope, or syncope) or the presence of certain ECG
findings, such as sinus bradyarrhythmias (heart rate < 40 beats/min
and/or prolonged sinus pauses), second-degree atrioventricular block,or frequent and/or repetitive (bursts of) ventricular extrasystoles.4,43
Holter monitoring may identify patients at risk for sudden deathand unmask early signs of cardiac autonomic dysfunction with
reduced heart rate variability.44 In asymptomatic patients or thosewith rare symptoms, Holter monitoring will have a low diagnostic

yield and is usually not routinely indicated. An implantable cardiac
monitor may be considered in patients with other markers of risksuch as depressed LV or right ventricular (RV) function, regional
wall motion abnormalities, or syncope with frequent premature ventricular complexes or palpitations.
In summary, electrocardiography should be performed in all patients
identified with positive T. cruzi serology. The rationale for this strategy isbased on the cost-effectiveness and wide availability of this diagnostic
test, in addition to high negative predictive value to rule out cardiomyopathy in T. cruzi–infected individuals. Electrocardiography serves two
purposes: staging and prediction of disease progression. The appropriate timing and frequency for performing electrocardiography duringfollow-up remains debatable and is not evidence based. It seems
reasonable that in individuals with a normal baseline ECG findings,
follow-up ECG testing may be performed at least every 5 to 10 years.
Further screening with biomarkers and cardiac imaging may be selectively performed, depending on baseline ECG findings. Patients withfrequent premature ventricular complexes, nonsustained ventriculartachycardia, and other bradytachyarrhythmias identified by Holter
monitoring should undergo further assessment of LV systolic function.
IV.b. Echocardiography
IV.b.i. M-Mode and Two-Dimensional Echocardiography.
ChHD is an inflammatory cardiomyopathy that may affect the
myocardium in a segmental or regional manner. On imaging, theheart may appear normal, have localized segmental ventricular8 Acquatella et al

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Figure 3 ECG progression of a single patient with ChHD over 23 years of follow-up. (A) At 31 years of age, sinus bradycardia, ventricular
bigeminy, narrow QRS (0.10 sec), and ST-T convex upward with inverted T wave (suggestive of apical aneurysm, subsequently demonstrated by two-dimensional echo). (B) At 44 years of age, sinus rhythm, no extrasystoles, and a new right bundle branch block with left anterior fascicular block (QRS duration increased to 0.134 sec), and precordial R-wave size decreased. (C) At 54 years of age, sinus bradycardia,
no extrasystoles, left anterior fascicular block is present without right bundle branch block (which appears on exercise), and QRS duration is0.126 sec. These changes may explain different rates of ECG findings. Corresponding 2D echocardiographic images at 54 years of age areshown in Figure 5.

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Figure 4 Dilated ChHD cardiomyopathy (stage D). Four-chamber view echocardiograms of two patients with ChHD in congestive HF
with severe global hypokinesis and low ejection fraction, similar to other dilated cardiomyopathies. A pacemaker wire is seen in theright heart chambers (arrow). (Left) The left ventricle (LV) and left atrium (LA) are severely dilated with normal size right ventricle (RV).
(Right) Biventricular and biatrial severe dilatation. RA, Right atrium.
abnormalities (wall motion, thinning, aneurysms, etc.), or manifest asa globally dilated cardiomyopathy with associated valvular heart disease (mainly functional mitral and tricuspid regurgitation). In general,
echocardiographic evaluation should be performed as suggested by
the American Society of Echocardiography (ASE) guidelines onchamber quantification,45 with a special emphasis on LV function
and morphology, RV function, and valvular disease. As previously
mentioned, the absence of ECG abnormalities mostly rules out significant cardiomyopathy. However, it is reasonable to perform at least asingle echocardiographic examination (baseline evaluation) on every
patient with positive serology for ChD and repeat during follow-up if
the ECG findings become abnormal to document disease progression (Table 1). Patients with symptomatic ChHD (HF) may present
with predominantly hypokinetic, dilated left ventricles with diminished LV ejection fraction (LVEF), or biventricular dilatation(Figure 4). Although infrequent, even asymptomatic subjects may
display subtle abnormalities by two-dimensional (2D) and threedimensional (3D) echocardiography, such as small aneurysms orwall motion abnormalities.
Global LV Function. Initial rural surveys using basic M-mode and
2D echocardiography were useful for clinical staging by estimating
anatomic and functional damage and assessing LV function.46,47
Current ASE guidelines recommend routine clinical evaluation
using 2D and 3D echocardiography to estimate LV, RV, left atrial(LA) and right atrial volumes and dimensions and for assessment of
LV and RV function.45 Global LV systolic function should be addressed on 2D echocardiography by calculation of LVEF throughthe biplane method of disks (the Simpson rule). The endocardial
border should be traced at the interface of the compacted myocardium and the LV cavity at end-systole and end-diastole in the apicalfour- and two-chamber views. Although the accuracy of LV volumes
and LVEF is higher when using 3D echocardiography (which is therefore preferred whenever available), 2D echocardiography has theadvantage of easiness and wider availability. However, the presenceof apical LV aneurysms present a challenge to the use of the methodof disks, as apical aneurysms frequently cannot be included within theultrasound field (Figure 5).
Regional Wall Motion Abnormalities. LV segmental abnormalities
are common in ChHD at any stage of the disease. These are locatedmainly at the LV apex (Figure 6, Videos 1 and 2, available at www.

onlinejase.com) and inferior and inferolateral walls (Figures 7 and 8)
but may also affect other LVor RV segments.48 Technically, it is importantto perform a comprehensive examination from multiple windows, as
wall motion abnormalities should be demonstrated in at least two
different views to avoid false-positive results. The use of ultrasoundcontrast agents for LVopacification (Figure 9) and wall motion evaluationis recommended when images are suboptimal in at least two contiguous
segments.49,50 In addition, contrast could be particularly useful for thedetection of small aneurysms and thrombus, typical of ChHD.51 In a review of 2D echocardiographic series of patients with ChHD, among 920
asymptomatic patients with mild cardiac damage, the prevalence of LV
aneurysm was 8.5%, while it increased to 55% in patients with moreadvanced cardiac disease.47 Similarly, LV apical abnormalities had alow prevalence in those with normal ECG findings but increased to
24% in those with abnormal ECG findings. Other common contractile
abnormalities involve the inferolateral or inferior walls, with prevalenceof up to 23% in symptomatic patients.
Valvular Disease. A comprehensive evaluation in patients with ChD
should include careful examination of the cardiac valves.
Two-dimensional echocardiography is used to evaluate valvular andsubvalvular structure and, together with a thorough Doppler examination, provide a good understanding of the severity and etiology
of different valvular diseases and dysfunction.52,53 Functional
incompetence of the mitral and tricuspid valves is common as
ChHD advances (Figure 10). Ventricular remodeling with progressive
dysfunction, dyssynchrony, valvular annular dilation, tethering of thesubvalvular apparatus, fibrosis, and atrial enlargement may induce
various degrees of valve dysfunction. An understanding of these alterations will help in determining the need and proper strategy for therapeutic interventions.
IV.b.ii. Three-Dimensional Echocardiography. Cardiac chambers are 3D structures with complex anatomy and variable shape.
Therefore, the accuracy of 2D echocardiography for evaluation of cardiac
structure, shape, and dimensions is limited, as it requires some degree ofreconstruction and geometric assumptions. Three-dimensional echocardiography, on the other hand, allows visualization of cardiac chambersin their entirety without geometric assumptions.45,54-56 Creation of 3D
echocardiographic images requires specialized transducers foracquisition of a volume (pyramid) of data rather than a slice (2Dechocardiography). The 3D volume could be acquired through a single

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Figure 5 Challenges in 2D echocardiographic LVEF and volume evaluation by the method of disks (Simpson rule) in patients with
ChHD with apical aneurysm. Four-chamber and two-chamber apical views (biplane method) in a 54-year-old patient with ChHD.
LV volumes are increased, and LVEF is mildly decreased. ECG follow-up is shown in Figure 3C. Notice the LV apical aneurysm, especially in mid-systole (right). As in this case, large apical aneurysms are frequently difficult to contain within the image, and therefore
adequate tracing of the cavity/endocardial interface may not be feasible.

heartbeat or by stitching together smaller volumes in consecutive beats.
Although 3D echocardiography has significant advantages over 2D
echocardiography, as mentioned above, there are limitations, related
mostly to lower temporal and spatial resolution or stitching artifact withmultibeat acquisition. Nevertheless, by direct visualization of the entire
left ventricle, 3D echocardiography avoids foreshortening of the left
ventricle from the apical windows and facilitates measurement of LV
volumes and LVEF by direct endocardial contour tracing, rather thanassumptions of LV shape from 2D apical views with the single or
biplane method of disks (Figure 11). Three-dimensional echocardiography is currently well validated compared with other 3D imaging techniques such as CMR and cardiac CT.45,54,56 This concept also applies
to visualization and volume measurements of other cardiac chambers,
such as the left atrium and right ventricle (Figure 12).57,58 As withpatients with other forms of cardiomyopathy, 3D echocardiography
should be used in patients with ChD to evaluate cardiac chamber sizeand ventricular function.45 Currently, LV volumes and LVEF can bemeasured using a variety of semiautomated software that are less timeconsuming and improve reproducibility.55 In patients with ChHD presenting with HF, it is important to have information concerning RV sizeand function, which is particularly challenging with 2D echocardiography.
The use of 3D echocardiography allows an accurate analysis of RV volumes and RV ejection fraction (RVEF; Figure 12). In addition, the useof 3D or 3D-derived 2D images (biplane, Xplane, etc.) could help in detecting small LV aneurysms that would otherwise be overlooked by 2D
echocardiography because of foreshortening.
The analysis of mitral regurgitation severity in patients with chronic
Chagas cardiomyopathy should include 3D echocardiography as part

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Figure 6 Left ventricular apical aneurysm and thrombus (stage B2). Apical four- and two-chamber views (left and right) of a 48-yearold patient with chronic ChHD who presented with a right arm embolic event. A left ventricular apical aneurysm (ANEU) shows bloodstasis with small thrombus (STA-THRB). The mid and basal segments of the left ventricle (LV) had normal contractility. LVEF was 45%.
Right ventricle (RV), left atrium (LA), and right atrium (RA) were roughly spared from disease.

of the comprehensive mitral valve evaluation to assess the structure
and morphology of the leaflets and subvalvular apparatus. Althougha dilated annulus with tethering of the leaflets from a dilated left
ventricle (functional or secondary mitral regurgitation) is the mostcommon finding in ChHD, the examination should evaluate othercoexisting valvular abnormalities.52-54 Therefore, careful attention
should be paid to valvular and subvalvular function and structure toevaluate for presence, location, and extent of prolapse, redundanttissue, clefts, rheumatic changes, annular dimensions, cusp
separation, and other abnormalities that are not specific for ChHD.
Color 3D echocardiography may be used to identify multiple ornoncircumferential jets, measure the vena contracta area, or, in
combination with continuous-wave Doppler echocardiography,
calculate regurgitant orifice area or regurgitant volume and fraction
using the proximal isovelocity surface area method. Comprehensive
analysis with information derived from 2D, 3D, and Doppler echocardiography may be useful for the prediction of success in future attempts at mitral valve repair (surgical or percutaneous), similar toother etiologies of functional mitral regurgitation.

Figure 7 Inferolateral wall fibrosis and akinesis, M-mode, andautopsy specimen. Long-axis slow sweep M-mode echocardiogram (A) and cardiac specimen (B) from a 52-year-old male patient with ChHD, HF, and arrhythmias, showing extensive
scarring and akinetic inferolateral wall (posterior wall [PW]),
extensive to apex, contrasting with relatively preserved septal(S) systolic motion and thickening. The coronary arteries werenormal at autopsy. (Reproduced with permission from Acquatella et al.46).

IV.b.iii. Strain and Speckle-Tracking Echocardiography.
Myocardial deformation imaging is a relatively new technique forquantitative assessment of myocardial contractility.59 Strain is a measure of myocardial deformation, defined as the change in length of the
myocardium relative to the original length. Strain rate is the rate ofchange in strain.60 Myocardial deformation imaging with echocardiography can be measured using Doppler tissue imaging and 2D
and 3D speckle-tracking echocardiography (Figures 13 and 14).
Tissue Doppler–derived strain has several limitations, particularly in
relation to angle dependency and noise interference. Therefore,
strain measurement based on speckle-tracking, which is not angle
dependent, has become a method of choice to assess myocardial
deformation.
Speckle-tracking echocardiography has allowed the increased recognition of subclinical myocardial dysfunction, particularly in patients with

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Figure 8 Left ventricular aneurysms in the inferior and inferolateral walls. Two patients with ChHD with segmental contractile abnormalities at the inferior-posterior-basal left ventricular walls. (Left) Two-chamber apical views in diastole and systole, respectively,
showing a ‘‘punch-type’’ localized lesion in the midsegment of the inferior wall (arrows). (Right) Two- and three-chamber apical viewsof a localized lesion in the basal segment of the inferolateral wall (arrows). AO, Aorta; LA, left atrium; LV, left ventricle.

Figure 9 Left ventricular apical aneurysm (arrows) in patients with HF. (Left) Apical four- and two-chamber views of a patient with
ChHD in stage B2 with a large left ventricular apical aneurysm (white arrows); the right ventricle (RV) has a normal size. (Right) Contrast
echocardiography for left ventricular opacification in a different patient with ChHD and biventricular damage shows a large apicalaneurysm (black arrows) with a thrombus (Th). Arrows show areas of dyskinesis. Contrast infusion defines the extension of the aneurysm and size of the thrombus. The right ventricle is more dilated than the left ventricle (LV). LA, Left atrium; RA, right atrium.
the indeterminate form of ChD.61-63 Global longitudinal strain is themost validated method for the detection of subclinical LV dysfunction
in patients with ChHD (and other types of cardiomyopathies) and ishighly correlated with the amount of myocardial fibrosis, as detectedby CMR.64 Regional strain is of particular interest in ChHD, given thefrequent segmental myocardial involvement described above (apicaland inferior or inferolateral walls).
In addition to early detection of myocardial injury in ChD, strain
has also been explored as a potential predictor of disease progression
signaled by an increase in brain natriuretic peptide and worsening diastolic dysfunction.62,63,65
Other uses of myocardial strain are currently being explored, suchas for evaluation of mechanical dispersion (Figure 14),66 as well as LA
and RV strain. However, their use is currently experimental.
In conclusion, a growing body of evidence suggests that assessment of cardiac function by echocardiographic myocardial

deformation parameters provides incremental information inclinical settings. In the context of ChD, the clinical impact of early
myocardial changes assessed by these advanced echocardiographic techniques in predicting disease progression remains tobe well defined.
IV.c. Cardiac Magnetic Resonance and Computed
Tomography
Cardiac Magnetic Resonance. The three main aspects involvedin the diagnosis, risk stratification, and management of patients with
ChD are related to the underlying cardiomyopathy and arrhythmogenic substrate including risk for sudden cardiac death and thromboembolic risk. CMR, although not widely available, has been
increasingly shown to be a versatile noninvasive imaging modality
for this entity. Given its excellent spatial resolution and uniqueJournal of the American Society of Echocardiography
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Figure 10 Mitral regurgitation (MR). A 47-year-old woman with
ChHD in HF (stage D) and severe MR. The color Doppler image
acquired from the apical four-chamber view shows a large
eccentric regurgitant color area (red arrow) with ‘‘wall-hugging’’appearance, directed to the left pulmonary veins and reaching
the roof of the left atrium (LA), allowing a qualitative visual estimation as severe MR. Regurgitant volume was >50 mL/beat.
The left ventricle (LV) is severely hypokinetic and dilated; LVEF
was 25%. It is recommended to perform a comprehensive MR
evaluation with multiple qualitative and quantitative parameters.
RA, Right atrium; RV, right ventricle.
capability of tissue characterization of myocardial edema and fibrosis,
CMR can provide good insight into the pathophysiology of thedisease.67
CMR protocols begin with cine sequences using steady-state free
precession, which allow accurate assessment of the severity andextent of biventricular involvement by accurate calculation of ejection
fraction and evaluation of wall motion abnormalities. As mentioned
previously, LV systolic dysfunction is the strongest predictor of
morbidity and mortality in ChD. Asymptomatic LV systolic dysfunction is even more prevalent than symptomatic HF. Importantly, diagnosis at a subclinical stage may help in preventing or delaying
progression of the disease by appropriate therapeutic interventions.
Regional wall motion abnormalities, including the typical apical aneurysm, can be readily recognized by this technique without the potential limitations of inadequate echocardiographic windows.
The use of noncontrast T2-weighted sequences allows the evaluation of myocardial edema, which can occur through all phases of thedisease and with good correlation with the traditional late gadolinium
enhancement (LGE).68 LGE is assessed using T1-weighted sequences,approximately 10 to 15 min after gadolinium administration. As aparamagnetic extracellular contrast agent, gadolinium will distributeinto the areas where there is expansion of the interstitium related

Acquatella et al 13

to myocardial fibrosis or necrosis. For adequate LGE imaging, thenormal or unaffected myocardium signal is nulled (black), whereas
the involved myocardial segments will have a prolonged washoutfrom decreased capillary density, causing shortening of T1 and therefore a higher or brighter signal.69
Several patterns of LGE have been described in patients with
ChHD, including subendocardial and transmural (both are difficult
to distinguish from prior myocardial infarction), midwall, or subepicardial. LGE tends to more commonly involve the basal inferolateralsegments and LV apex (Figure 15, Video 3; available at www.
onlinejase.com). Myocardial fibrosis can be found in up to 8% of patients with positive serology for ChD despite normal ECG and echocardiographic findings.70 Importantly, the presence and extent of
myocardial fibrosis correlate well with the New York Heart
Association functional class and likelihood of ventricular arrhythmias,
particularly when a transmural pattern is found extending beyond
two or more contiguous segments.71,72 In addition, myocardial
fibrosis inversely correlates with LV systolic function.5 Therefore,
assessment of fibrosis by LGE imaging has been shown to be an excellent marker of disease severity.
CMR with LGE imaging can also evaluate thromboembolic risk.
Specifically, the high spatial resolution of CMR makes it the best imaging modality to detect intracardiac thrombi related to LV aneurysms.
LV thrombus, which carries a high risk for stroke and peripheral embolism, could be missed by echocardiography in patients with limited image quality, even when using ultrasound contrast agents.73,74
Although CMR imaging is an excellent tool for the risk stratification and prognosis of patients with ChD, it is not readily available
to most patients living in rural endemic areas. In addition, CMR
studies in patients who have received prior implantable cardiac devices such as defibrillators, conventional pacemakers, and cardiac resynchronization devices, are at this time relatively contraindicated.
Cardiac CT. The literature on cardiac CT in ChD is limited to isolated case reports. Data acquisition is performed following intravenous iodine contrast injection with ECG synchronization. Different
scanning protocols are available that can be restricted to imaging
only the diastolic phase (prospective acquisition, less radiation, andcommonly used for coronary computed tomographic angiography)
or imaging the entire cardiac cycle (retrospective acquisition, more radiation), which allows quantification of cardiac function. The 3D data
set is postprocessed offline using multiplanar reconstruction for visualization of the entire cardiovascular anatomy in any given plane, withexcellent spatial resolution.
Similar to CMR image acquisition, cardiac arrhythmias such asatrial fibrillation or premature atrial or ventricular contractions can
produce image artifacts, making it difficult for study analysis andinterpretation. Technological advances with availability of a larger
number of detector rows (i.e., $256) allows volumetric coverageof the entire heart with one beat, therefore minimizing some ofthese problems.
Cardiac CT could be considered in three particular clinical scenarios for patients with ChD: (1) To exclude significant coronary artery disease in patients with low to intermediate pretest probability.
This differential diagnosis could be particularly challenging in patientswith ChHD presenting with cardiomyopathy and/or wall motion abnormalities. Coronary computed tomographic angiography has an
excellent negative predictive value to exclude coronary artery diseasein patients with low and intermediate pretest probability.75 (2) In theplanning of complex electrophysiologic procedures. Patients with
ChHD have larger epicardial compared with endocardial substrate14 Acquatella et al

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Figure 11 LVEF by 3D echocardiography. Three-dimensional four-chamber apical view of a 56-year-old man with HF in New YorkHeart Association functional class III and depressed left ventricular systolic function. Evaluation of left ventricular volumes and
LVEF was done by 3D echocardiography using an automated adaptive analytics algorithm for quantification. LV end-diastolic (ED)volume was 67 mL; LV end-systolic (ES) volume was 42 mL; LVEF was 37%; left atrial end-systolic volume was 25 mL. HR, Heartrate; LA, left atrium; LV, left ventricle; SV, stroke volume.

Figure 12 RV function by 3D echocardiography. RV 3D echocardiography in a 49-year-old patient with ChHD and HF presenting in
New York Heart Association functional class III. In addition, the results for RV longitudinal strain (RVLS) by speckle-tracking are shown(top left). RV end-diastolic volume (EDV) was 149.5 ml; RV end-systolic volume (ESV) was 104.6 ml; RVEF was 30%; RV stroke volume(SV) was 44.9 mL; septal RVLS was 9.34%; free wall RVLS was 9.55%.

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Acquatella et al 15

Figure 13 Global longitudinal strain of the left and right ventricles. (A) Abnormal LV longitudinal strain findings in a patient with ChHD withright bundle branch block, reduced LVEF, and prior symptoms of heart failure (stage C). (Top left) LV longitudinal strain in apical fourchamber view; note the delayed peak strain of the septal segments (yellow and blue tracings) typical of right bundle branch block. (Top right)
Apical two-chamber view. (Bottom left) Apical three-chamber view. (Bottom right) ‘‘Bull’s-eye’’ plot of strain values for each myocardial
segment. (B) Abnormal findings of RV longitudinal strain (global strain [GS] was 6.5%, free wall strain was 12.6%) in a patient with
ChHD (asymptomatic with abnormal ECG findings and decreased LVEF, stage B2). (Top left) Apical four-chamber view. (Bottom left)
Regional strain values. (Top right) Time-strain curves. (Bottom right) M-mode parametric colorization. 4CH, Four-chamber; A2C, apicaltwo-chamber; A4C, apical four-chamber; ANT, anterior; ANT_SEPT, anteroseptal; AVC, aortic valve closure; Avg, average; FR, frame
rate; GLPS, global longitudinal peak strain; HR, heart rate; INF, inferior; LAT, lateral; LAX, long-axis; POST, posterior; SEPT, septal.

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Figure 14 Mechanical dispersion by myocardial strain imaging. Longitudinal strain curves from apical four-chamber view displaying
six of the 18 LV segments used to calculate mechanical dispersion. (Left) Mechanical dispersion in a patient with ChHD without ventricular arrhythmias. (Right) A patient with ChHD who presented with LV dysfunction and a previous episode of sustained ventriculartachycardia. The time to maximal myocardial shortening of longitudinal strain was markedly dispersed compared to the patient
without arrhythmias. AVC, Aortic valve closure.

Key Points
 CMR is a versatile imaging modality for ChHD, allowing exquisite visualization ofheart function, anatomy, and tissue characterization.
 Presence of myocardial fibrosis by CMR with LGE imaging has been associated withincreased cardiac arrhythmias and risk for sudden cardiac death.
 Cardiac CT can provide ancillary noninvasive evaluation of coronary artery anatomy
and atherosclerosis. Coregistration of 3D data sets with electrophysiologic electricalmapping during ablations might improve procedural safety and outcomes.

IV.d. Nuclear Medicine
Various nuclear medicine imaging modalities have been used to assess
biventricular function, myocardial perfusion, innervation, and inflammation in patients with ChD. Those with proven clinical value aredescribed here.

Figure 15 CMR with LGE. Small, focal LV apical aneurysm in a
25-year-old patient with ChHD presenting with a stroke. Delayed gadolinium enhancement shows an LV aneurysm withmyocardial fibrosis (white within the apical myocardium).
Video 3 with cine noncontrast CMR shows the apical dyskinesis
and small aneurysm.
areas for ventricular arrhythmias.7 This puts patients at risk for coronary artery injury during ablation, a complication that can be avoided
by properly planning the procedure with advanced imaging.
Coregistration of cardiac computed tomographic 3D data sets withelectroanatomic mapping data allows better understanding of the
anatomic relationship of the arrhythmia-substrate areas and the coronary arteries, therefore increasing ablation safety.73 (3) To evaluate LV
function and morphology in patients with difficult echocardiographic
windows who are unable to undergo CMR because of device incompatibility. Retrospective gated acquisition following intravenous
contrast injection can provide quantification of cardiac function as
well as detection of regional wall motion abnormalities, apical aneurysms, and intracardiac thrombi.

Radionuclide Planar Gated Angiography. This method can beused for the evaluation of global biventricular function in patients forwhom echocardiography is hindered by technical problems, preventing optimal imaging or adequate quantitative evaluation.76-78 Thismethod was once considered the gold standard for themeasurement of LVEF because it allows the averaging of hundredsof cardiac cycles without resorting to any geometric assumptions in
the usually distorted LV shape exhibited by patients with ChHD
with aneurysms or other wall motion abnormalities.
Single-Photon Emission Computed Tomographic Myocardial Perfusion Scintigraphy. In patients with ChHD, perfusion
defects may be related to concomitant epicardial coronary diseaseor, more frequently, to microvascular disease in the setting of normal
results on coronary angiography. More specifically related to ChHD,
fixed perfusion defects seen during both stress and rest conditions
predominate in LV regions exhibiting advanced wall motion impairment (such as akinesis or dyskinesis) and are interpreted as representing areas of fibrosis. Reversible perfusion defects, on the other hand,denote the occurrence of myocardial ischemia due to microvascularflow disturbances. These ischemic defects have been describedeven in Chagas patients with the indeterminate form of the disease
and are topographically correlated with myocardial areas exhibiting
more significant wall motion abnormalities at later stages of the cardiomyopathy.79,80 Moreover, the increase over time in the extent

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Acquatella et al 17

V. VENTRICULAR FUNCTION

with marked wall thinning at the apex involving opposing walls
and limited by an area of normal contraction. Aneurysm size isvariable (Figures 6, 8, and 9) and is frequently difficult todistinguish from a healed transmural myocardial infarction.48
LV apical aneurysms are found in 8.5% of asymptomatic patients,
but this increases to 55% (ranging from 47% to 64%) in patientswith moderate or severe LV systolic dysfunction. RV aneurysms
are unusual, but some patients have apical aneurysms affecting
both ventricles. An autopsy study showed that 82% of aneurysms
were found at the LV apex, 9% in the right ventricle, and 9% in
both ventricles.91
Mural thrombi can be associated with aneurysms (Figure 6) and areimportant risk factors for systemic embolisms in patients with
ChHD.91-94 The prevalence of LV thrombus in clinical studies isapproximately 20%, but it may be higher in more advanced diseasestages, as suggested by autopsy studies that showed LV thrombosis
in 35% to 44% of patients with ChHD who died of congestive HFor sudden cardiac death.95,96

V.a. LV Systolic Function
Echocardiography is the imaging modality of choice to determine LV
structure and function in ChD, complementing information provided
by clinical status and electrocardiography.4,47 In selected
asymptomatic patients with normal ECG findings, further
evaluation with echocardiography may be recommended to classify
the presence and severity of myocardial damage, based mainly on
detection of subtle regional wall motion defects.4
T. cruzi–infected patients in the indeterminate form may have subtle
changes in LV segmental contractility detected either by conventional or
speckle-tracking echocardiography.61,85 Once the disease progresses toheart damage with development of ECG changes consistent with
ChHD, increased LV diameters associated with segmental wallmotion abnormalities are usually seen. In more advanced disease
with HF, diffuse hypokinesis with enlargement of all cardiac
chambers is the predominant characteristic (Figures 4 and 5).47,86
Regional LV contractility abnormalities represent a characteristic
aspect of ChD and may occur in any stage of the disease. The frequency of these abnormalities varies according to the stage of the disease. In asymptomatic patients with preserved LVEF, wall motion
abnormalities can be detected in up to 10% of patients, particularly
in inferolateral basal segments (Figures 6–9).48 As the disease progresses to a dilated cardiomyopathy, the prevalence of regional abnormalities increases to approximately 50% of patients.47,87 Althoughsegmental wall motion abnormalities are one of the most common
findings of cardiac involvement in ChD, the mechanism has notbeen defined. It has been hypothesized that microvascular
involvement leads to ischemia in distal areas of the coronary
territories.88 The diagnosis of LV segmental lesions is essential,
because it permits the identification of individuals at risk for worsening of LV function and ventricular arrhythmias.66,89,90
Apical aneurysm is a hallmark of ChHD, so the presence ofapical aneurysms may help differentiate this disease from idiopathic cardiomyopathy.37,48 The prevalence of aneurysms
varies widely, because of the heterogeneity of the population
analyzed and the accuracy of the imaging method used for its
diagnosis. Importantly, apical aneurysms may be missed if a
detailed echocardiographic examination is not performed. To
better identify apical aneurysms, multiple views, often
unconventional or foreshortened with the transducer slightly
angled to visualize the apex, may be required. An apicalaneurysm is usually defined as a well-delineated dyskinetic area

Assessment of LV Systolic Function by Echocardiography. The
quantification of LV size and function constitutes one of the earliest indications for echocardiography. The accuracy of the determination of
global and regional LV function with echocardiography has improved
dramatically over the past decade with several technological developments.97
A pioneering study using M-mode echocardiography demonstrated hypokinesis of the posterior wall with relative preservationof septal motion in patients with ChHD (Figure 7).46 In advanced
ChHD, a diffuse hypokinesis was detected with a nonspecific pattern,indistinguishable from idiopathic cardiomyopathy.98
Previous studies have used the change in the M-mode LV dimension from diastole to systole to calculate the percentage of fractional
shortening and LVEF. However, this method is no longer recommended in ASE guidelines45 and is particularly unreliable in patients with
ChD with pronounced LV dilation or in those with either marked
segmental wall motion abnormalities or aneurysms. Therefore, mostrecent studies have used 2D echocardiography for the assessmentof LV function and to quantify LVEF.
Three-dimensional echocardiography has been shown to quantify
LV volumes and function more accurately, as no geometric assumptions are required (Figure 11). Given the frequency of segmental abnormalities and aneurysms, it seems most appropriate to include fullvolume 3D echocardiography of the left and right ventricles in any
echocardiographic examination of patients with suspected ChHD.
However, there are limited data to date on the additional value of
3D echocardiography for the evaluation of the left ventricle and left
atrium in ChD.65,99
Regardless of the parameter used to estimate ventricular systolic
dysfunction, the most consistent independent risk predictor of mortality in ChD is impaired LV function.39 In a systematic review, echocardiographic or cine ventriculographic evidence of decreased
contractility, either qualitatively or quantitatively expressed, wasfound to be strongly associated with an increased risk for mortality
in the majority of the studies reviewed.100 Although LVEF has been
the most widely used prognostic variable, other echocardiographic
parameters have been reported to be useful in the risk stratificationof patients with impaired LV systolic function.101,102 Additional
information about myocardial perfusion and fibrosis from CMR or
single-photon emission computed tomographic imaging can help
assess prognosis (see specific sections in this document for moredetails).

of myocardial fibrosis, as denoted by the transformation of previously
reversible into fixed perfusion defects, correlates with a decrease in
LVEF.81
Myocardial Sympathetic Innervation Imaging. Myocardial
scintigraphy with 123I-metaiodobenzylguanidine can be used for thein vivo assessment of cardiac sympathetic innervation integrity in patients with ChHD. Regional sympathetic denervation is an early
derangement in the pathophysiology of ChHD, preceding the development of regional LV contraction disturbances. In fact, abnormal
metaiodobenzylguanidine uptake has been shown in most Chagas
patients with no apparent cardiac involvement.31,82 Impaired
regional myocardial sympathetic innervation has also been
associated with the occurrence of sustained ventricular tachycardia
in patients with ChHD.83,84

18 Acquatella et al

Key Points
 Echocardiography is the most common imaging modality used to detect
cardiac involvement in patients with ChD, even in those with normal ECG
findings.
 Segmental LV wall motion abnormalities may be found in early stages of the disease,especially at the apex and in the inferior and inferolateral walls.
 Apical aneurysms are the hallmark lesion in ChD, which is helpful in distinguishing
ChHD from other cardiomyopathies.
 Late manifestation of ChD is characterized by diffuse LV hypokinesis with enlargement of all cardiac chambers.
 LV systolic dysfunction is a powerful predictor of mortality in ChD.

V.b. LV Diastolic Function
Assessment of diastolic function includes evaluation of myocardial
relaxation, ventricular stiffness, and estimation of LV filling pressures. As in other cardiomyopathies, diastolic dysfunction usually
precedes systolic dysfunction.103,104 Therefore, it is reasonable toassume that most patients with myocardial disease also havediastolic dysfunction. As recommended by the updated ASE andEuropean Association of Cardiovascular Imaging guidelines,
evaluation of diastolic function and LV filling pressures is based
mostly on four parameters: LA volume index, peak tricuspid
regurgitation velocity, mitral annular tissue Doppler velocity (e0 ),and E/e0 ratio.105 Diastolic dysfunction is initially manifested by
impaired relaxation, an energy-dependent process that leads to a
reduction in early passive filling of the left ventricle and increasein active filling (low E and high A waves in mitral inflow, grade I
diastolic dysfunction).106 With the development of systolic
dysfunction, the increase in diastolic volume produces a rise in diastolic pressures that results in a decrease in atrial contribution toventricular filling, an increase in LA pressure, and LA dilatation(grade II). Patients with HF typically show grade II or III diastolic
dysfunction with a decrease in atrial function (high E and low A
waves).
Doppler Tissue Imaging. Peak e0 velocity obtained by pulsed
Doppler tissue imaging is decreased in patients with ChD with
ECG abnormalities, systolic dysfunction, and HF but is frequently
normal in the indeterminate form. The combined use of peak velocity of the E wave of mitral flow and e0 (E/e0 ratio) is a surrogate
for LV end-diastolic filling pressures (E/e0 < 8 reflects normalpressures, and E/e0 $ 15 reflects elevated pressures).105 E/e0 is
gradually increased from indeterminate to more advanced formsof ChHD.107-109 An elevated E/e0 ratio > 15 is a strong predictorof poor outcomes in patients with ChHD with mild to moderate
LV dysfunction,102 and it correlates with functional class, brain
natriuretic peptide level, and detection of fibrosis by gadolinium
delayed enhancement with CMR.110 However, patients with
ChHD may present with some confounding factors, including
atrial fibrillation or RV pacing, that limit the accuracy of mitralannular velocities and E/e0 ratio in the assessment of diastolic
function.
Color M-Mode Flow Velocity Propagation. Flow velocity
propagation is decreased in patients with ChD with systolic
dysfunction and HF but may be normal in patients without ECG
and regional contraction abnormalities.47 The apical contractility
abnormality may contribute to a diminished diastolic suction in patients with ChHD, showing a decreased slope of flow propagation
velocity.

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Key Points
 LV diastolic dysfunction is a common finding in early stages of Chagas cardiomyopathy because of extensive fibrotic changes in the myocardium.
 Evaluation of diastolic function by means of E/e0 and LA volume index has additional,
independent prognostic value in patients with systolic dysfunction and HF.
 The accuracy of some variables used to assess diastolic function (such as E and e0 ) is
reduced in the presence of arrhythmias and RV pacing, which is common in patientswith ChHD.

V.c. RV Function
The right ventricle is composed of three parts, inlet, main cavity, andoutlet (infundibulum), giving it a complex geometry that is difficult toanalyze in a single biplane view and making its volume calculation
impossible by the use of 2D geometric assumptions. In addition,
the thin walls, prominent trabeculations, and presence of the moderator band further contribute to the difficult task of defining the RV
endocardial borders. Thus, as opposed to the left ventricle, RVEF by
2D echocardiography is not recommended. Although 3D echocardiography seems to be a promising technique, it is still difficult to obtainadequate RV images to allow a routinely useful RVEF calculation inclinical practice. Instead, other easier to obtain parameters havebeen shown to be clinically useful and are recommended by recent
ASE guidelines.45,111,112 These parameters are tricuspid annularplane systolic excursion (obtained by M-mode echocardiography of
the tricuspid valve annulus), fractional area change (obtained by thedifference between the end-diastolic and end-systolic RV areas,
divided by the diastolic area times 100), tissue Doppler systolic velocity of the tricuspid annulus (RV s0 ), and RV myocardial performanceindex (Tei index, which expresses both RV systolic and diastolic function). Although indices such as tricuspid annular plane systolic excursion and RV s0 express basal, longitudinal contractility, they have goodcorrelation with RV global systolic function and may be useful for assessing RV systolic function in a variety of clinical scenarios. Morerecently, strain has emerged as an echocardiographic tool for the mechanical evaluation of the ventricles, allowing the detection of subclinical dysfunction, while traditional indices of systolic function, such asejection fraction, are still preserved. RV free wall strain (Figure 13B) isa novel technique for evaluating RV systolic function in ChD.113
The Right Ventricle in ChD. RV involvement is common in
ChHD and has been described even in the indeterminate form by nuclear and biopsy studies.98,114,115 However, in clinical practice, RV
dysfunction assessed by traditional methods of echocardiography isusually not seen in the absence of LV dysfunction.
RV dysfunction in ChHD seems to be multifactorial and could be
generated by the burden of chronic pulmonary hypertension secondary to LV systolic dysfunction or, most importantly, by direct damage
to the RV myocardium with chronic myocarditis with progressive
fibrosis that affects the myocardium of both ventricles. Chagas patients with RV dysfunction may have low cardiac output without clinical evidence of elevated LV filling pressures or pulmonary
congestion, so they can be surprisingly stable clinically without acute
symptoms of dyspnea. However, RV dysfunction is still related to an
ominous prognosis.116
RV Evaluation by Echocardiography in ChD. Few studies havesystematically analyzed the RV in the context of ChD. However, early
abnormalities have been described even in the indeterminate form,
such as shortening of the RV isovolumetric contraction time or low
RV s0 on Doppler tissue imaging.117,118 Moreover, RV Tei index

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provides incremental prognostic information to that of more
traditional risk factors, such as New York Heart Association
functional class and LV function.116 The value of RV strain is still unclear in ChD.61,113 Occasionally, RV apical aneurysm is the only
detectable abnormality.91
RV Evaluation by CMR. CMR in ChD has been used almost
exclusively for LV evaluation. However, the incremental value of
CMR to other traditional imaging modalities in structural and functional evaluation of the right ventricle has been recently highlighted.119 Although less commonly present, similar features tothose described for the left ventricle can be explored and describedin the right ventricle (RVEF, aneurysms, thrombus, fibrosis, andinflammation patterns).113,119 Advanced RV dysfunction isfrequently present in ChHD once severe LV dysfunction has
developed.

Key Points
 RV dysfunction is a typical feature of chronic Chagas cardiomyopathy.
 Although more frequently found in the presence of LV dysfunction, RV dysfunction
has been described in patients with the indeterminate form of ChHD.
 Because of inherent anatomic and functional peculiarities linked to the morphologyof the right ventricle, diagnosis of early RV dysfunction in ChHD is sometimes challenging using most echocardiographic approaches and is more amenable to methods
such as CMR or radionuclide angiography.

VI. RECOMMENDATIONS FOR THE USE OF IMAGING
MODALITIES ACCORDING TO THE STAGE OF THE DISEASE:DIAGNOSTIC, MONITORING, AND PROGNOSTICIMPLICATIONS
VI.a. Acute ChD
As stated previously, acute ChD is frequently unrecognized, andmost patients with chronic ChD do not remember having beenacutely ill. Therefore, reports of acute disease are very limited
and reflect the findings of patients who were particularly symptomatic and more likely to seek medical attention. Electrocardiography
has been used extensively for the detection of cardiac abnormalities in acute ChD, partly because of its low cost and portability.
In contrast, echocardiography has been incorporated only more
recently. The largest published echocardiographic series on acute
ChD included 58 subjects, with a prevalence of abnormal echocardiographic findings slightly higher than 50%.120 Pericardial effusion
was the most common abnormal finding on echocardiography(42% of cases), while decreased LVEF was present in 37%.
Apical or anterior dyskinesis was found in 21%, and only 6%
had LV dilation. Abnormal ECG findings were present in 41%.
Acute myocarditis was documented by myocardial biopsy or necropsy in half of the patients.
There have been a few reports of groups with orally transmitted Chagas infection.121,122 In these patients, beverages orfood were contaminated either by infected triatomines or theirfeces. The absence of contact with the vector and of traditional
cutaneous and Roma~na signs (eye swelling) may confuse thediagnosis of orally transmitted ChD with other more common
infections. The clinical presentation may be severe because of
the massive load of parasites. The majority of patients were
symptomatic
and59%
showedECG
abnormalities.
Echocardiographic findings were similar to those described in
the previous paragraph. Importantly, as its presentation isfrequently vague in symptoms and ECG and echocardiographic

Acquatella et al 19

findings, the likelihood of suspecting acute ChD in nonendemicareas is actually very low.
ChD reactivation could happen in the setting of immunosuppression and may present similarly to acute ChD. Sporadic casereports exist in patients with human immunodeficiency virus orwith drug-induced immunosuppression such as after transplantation.123
In summary, among the few series reported of acute ChD withechocardiographic examination, symptoms were present in 98% of
patients.120,121,124-126 The most common echocardiographic finding
was mild to moderate pericardial effusion, with some cases oftamponade requiring pericardial drainage. Signs of congestion due
to HF or cardiac tamponade were observed in 24%, diminished
LVEF in 35%, and regional wall motion abnormalities in 28%,
while ECG abnormalities were the most frequent finding.

Recommendations
 Echocardiography should be performed whenever acute ChD is suspected.
 A febrile illness accompanied by myocarditic findings on echocardiography and/or
pericardial fluid should raise suspicion for acute ChD in endemic countries and in
Latin American immigrants with immunosuppressed states living in nonendemic
countries.
 As acute myocarditis is a common cardiac presentation, assessment of ejection fraction and wall motion abnormalities is of critical importance.
 Hypotension may be a sign of hemodynamically significant pericardial effusion leading to cardiac tamponade.

VI.b. Chronic ChD
The spectrum of chronic ChD spans from the indeterminate form toovert HF (Figure 1). Stages A and B are silent or asymptomatic and
can last for many years or decades. Indeed, in most patients the disease never progresses to the more advanced symptomatic stages C
and D. The role of cardiac imaging and the frequency of examinations
is different for each of these stages.
VI.b.i. Silent or Asymptomatic ChD (Stages A, B1, and B2):
Monitoring of LV Function and Myocardial Damage.
Chronically infected individuals become an intermediate-phase reservoir of T. cruzi infection known as the indeterminate phase. This isdefined by the presence of two general criteria: (1) at least two positive serologic tests based on the detection of a specific immunoglobulin G antibody or a positive direct demonstration of the parasite inblood or tissue and (2) the absence of signs and symptoms of
ChD.127,128 More than two thirds of T. cruzi–infected individuals
remain in the clinically indeterminate phase throughout theirlives.129 However, some of these patients evolve to a chronic form
with clinically evident heart involvement. Conversion to ChHD
with new ECG abnormalities or evidence of definite cardiomyopathy
has been reported at rates of 1.8% to 5% per year.35,129 This rate ofconversion may be higher if cardiac examination is performed withmore sensitive imaging techniques for detection of early myocardialdamage, such as advanced echocardiography (strain) or CMR (forfibrosis and inflammation).4,61,70 Indeed, anatomopathologic studies
with endomyocardial biopsy have demonstrated fibrosis or
inflammatory cardiac damage in patients with ChD with nootherwise apparent cardiomyopathy.130
Electrocardiography has been the traditional modality of choice for
ChD, both because of the specificity of its findings in endemic areas
and because of the excellent prognosis associated with normal
ECG findings. Echocardiography, although more difficult to provide
in a resource-limited environment, is the most useful imaging tool

20 Acquatella et al

for the evaluation, classification, and follow-up of patients with
ChHD, including those with the indeterminate form.4 In early stagesof cardiac involvement, echocardiography may demonstratesegmental LV wall motion abnormalities (anywhere in the spectrum
from hypokinesis to dyskinesis or aneurysms) and diastolic dysfunction, even when ECG findings are normal.47,131,132 The LV areas
most commonly involved are inferior, inferolateral, and apex andfrequently do not respect the distribution of coronary artery
territories.48 These segmental abnormalities could identify individuals
at risk for ventricular function deterioration or ventricular arrhythmia
on Holter89,90 and should, in fact, reclassify the patient to the chronic
stage of ChHD (stage B1).
ChD also leads to impairment of LV diastolic function, which canoccur early in the process, including in patients without LV systolic
dysfunction. The prevalence and severity of diastolic dysfunction
gradually increase as the disease progress from the indeterminate
form (present in 10% of cases) to more advanced stages, in which it
is found in nearly all patients.65,108,110
The use of advanced imaging modalities such as CMR in the early,
subclinical stages of ChD is limited by their cost and availability.
Although there is additive value compared with electrocardiography
and echocardiography, the clinical significance of CMR-specific findings during these early stages is still unclear. In patients with the indeterminate form, the presence of myocardial fibrosis (by LGE), edema(hyperintensity in T2-weighted sequences), and hyperemia(T1-weighted myocardial early gadolinium enhancement sequences)
has been demonstrated in 12%, 31%, and 25% of cases, respectively.68 Whether early therapeutic interventions would be justified
on the basis of these findings seems to be unlikely, as patients withthe undetermined form of the disease have an excellent prognosis,
and their life expectancy is similar to individuals without ChD.129
Evaluation of LV function is of great value in determining ChD
prognosis because LV dysfunction is one of the most consistent independent predictors of death identified in most series.37 Given thewide availability, low cost, and high accuracy in cardiac function evaluation, it is recommended to consider performing echocardiography
as part of the initial evaluation of patients with positive serology andwhenever there are changes in clinical or electrocardiographic status.

Recommendations
 Electrocardiography and echocardiography should be performed as part of the initial
evaluation of all patients with newly diagnosed ChD, to exclude LV dysfunction and aneurysms as well as conduction abnormalities (right bundle branch, left anterior fascicular, and atrioventricular block) or arrhythmias.
 ECG follow-up is reasonable at least every 2 to 5 years in patients with ChD with theindeterminate form.
 Echocardiography should be performed if any changes in ECG findings or clinical condition suggesting possible HF are noted.
 The use of advanced imaging modalities to detect silent myocardial damage (such as
strain imaging or CMR) in the indeterminate stage is currently not recommended, as it
has limited clinical value.

VI.b.ii. Symptomatic Chronic ChHD (Stages C and D). Morbidity
and prognosis of patients with advanced ChHD is almost exclusively
related to three conditions: HF, thromboembolism, and cardiac arrhythmias. The goals of imaging are to identify the substrate for these conditions to occur, that is, the presence of LV dysfunction and mitral
regurgitation, LV aneurysms or mural thrombus, and myocardial fibrosis
and/or inflammation. To achieve these goals, a comprehensive echocardiographic examination should be done according to the ASE chamber
quantification and valvular regurgitation guidelines, which would include
2D, Doppler, and preferably more advanced novel techniques such as

Journal of the American Society of Echocardiography
January 2018

3D echocardiography and strain.45,53 CMR can also achieve all thesegoals and should be considered an alternative to echocardiography orin some cases as a complementary technique.
VI.b.ii.1. LV Function and HF. As previously stated, a prominent
feature of HF due to ChHD involves the inflammation with subsequent necrosis and reparative fibrosis of the myocardium in both atria
and ventricles and the specialized intracardiac conduction system. HF
in chronic Chagas myocarditis can present with regional wall motion
abnormalities or LV global systolic dysfunction (typically in moreadvanced stages of the disease).
Although in essence the clinical presentation has similar characteristics to other dilated cardiomyopathies, a worse prognosis for patients
having HF of Chagas etiology has been suggested.133
Basic Imaging Goals for Patients at Risk or Presenting with
HF:. Although echocardiography is the preferred method, CMR orother imaging modalities could achieve most or some of these goals:
 Determine the LVEF by 3D echocardiography or the method of disks andgrade as normal, mild, moderate, or severe global LV systolic dysfunction.
 Evaluate the presence, location, and grade of regional wall motion abnormalities using a 16-segment model of the left ventricle, including descriptionof aneurysms.
 Estimate LV remodeling by measuring LV dimensions and volumes.
 Evaluate RV dimensions and function by fractional area change, tricuspid
annular plane systolic excursion, and RV s0 .
 Evaluate the presence and grading of LV diastolic dysfunction by using E/A
mitral inflow ratio, mitral annular e0 , tricuspid regurgitation velocity, and LA volume index. In addition, estimate LV filling pressures by using the E/e0 ratio.105
 Estimate systolic pulmonary artery pressure by peak tricuspid regurgitation
velocity (if tricuspid regurgitation is present).
 Estimate right atrial pressure by measuring the inferior vena cava diameter
during expiration and the percentage of reduction in the inspiratory phase.
 Evaluate for the presence, severity, mechanism, and etiology of mitral andtricuspid regurgitation.
 Evaluate for the presence of thrombi in the atria and ventricles.

VI.b.ii.2. Thromboembolism. Thromboembolic events are relatively frequent in ChD and represent the third most common causeof death in this entity.92,134,135 Even early stages of the disease may
present with dyskinetic segments or ventricular aneurysms,
predisposing to thromboembolism.93 Although aneurysms are themost significant source of thrombus, advanced cardiomyopathy also
predisposes to other embolic sources such as atrial fibrillation or
venous stasis. Therefore, careful examination of the LA appendage(in patients with atrial fibrillation or flutter), pacemaker or implantablecardioverter-defibrillator leads, and so on, by transesophageal echocardiography may be warranted. Importantly, embolic events could
present both as systemic and as pulmonary embolism. Stroke is themost common clinically recognized form of embolism, followed bylimb ischemia and pulmonary embolism. Ventricular dysfunction, apical aneurysms (Figure 6), mural thrombus, LA enlargement withblood stasis, and cardiac arrhythmias are important risk factors forthrombosis in ChD that should be evaluated in patients with
ChHD presenting with thromboembolism.93
Basic Imaging Goals for Patients at Risk or Presenting with
Thromboembolism:.
 Determine the presence, location, and size of potential sources of embolism (left ventricle, right ventricle, LA appendage, cardiac devices, etc.).
This evaluation may require advanced imaging modalities such as
contrast echocardiography, transesophageal echocardiography, CMR,or cardiac CT.

Journal of the American Society of Echocardiography
Volume 31 Number 1

VI.b.ii.3. Cardiac Arrhythmias. Cardiac arrhythmias play a significant role in the natural history and prognosis of patients with Chagas
cardiomyopathy.136 Sudden cardiac death remains one the leading
causes of death in ChHD and is usually triggered by malignant ventricular arrhythmias that are almost invariably related to regional scarring and fibrosis, resulting in regional wall motion abnormalities. As
with other cardiomyopathies, 2D echocardiography is the most
readily available and cost-effective test for assessment of LV and RV
function and detection of wall motion abnormalities and LV aneurysms, all of which are important variables to determine prognosis
and disease progression.4,89,133,137 Wall motion abnormalities,
mechanical dispersion, and abnormal global longitudinal strain(Figures 13 and 14) have been associated with a higher frequency ofventricular arrhythmias even in the presence of preserved global LV
systolic function.47,66,89
CMR provides additional information that may improve predictionof malignant ventricular arrhythmias and sudden cardiac death.
ChHD is characterized by diffuse myocardial fibrosis that can be detected by delayed enhanced gadolinium techniques, defining the substrate for ventricular tachycardia.72 These malignant rhythm
disturbances may also be detected in association with irreversible
perfusion defects seen with myocardial scintigraphy or with regionsof ventricular sympathetic denervation as shown by metaiodobenzylguanidine myocardial scintigraphy.
Basic Imaging Goals for Patients at Risk for or Presenting with
Malignant Arrhythmias:.
 Two-dimensional echocardiography is recommended as the preferred imaging
tool in patients with Chagas cardiomyopathy, as it provides information on
prognostic variables such as LVEF and segmental wall motion abnormalities.
 CMR can provide detailed insight into the myocardial substrate for malignant arrhythmias by accurate assessment of LVEF, regional wall motion abnormalities, and detection of myocardial fibrosis and edema.
 Nuclear medicine methods constitute alternative ways to stratify risk for malignant arrhythmia in patients with ChHD by detection of perfusion defects,
myocardial fibrosis, and regional sympathetic denervation.

Recommendations for Imaging in SymptomaticStages of ChHD
 The overall goals of imaging are to identify the substrate for HF, thromboembolism,
and malignant arrhythmias such as the presence of LV dysfunction, LV aneurysms
or thrombus, myocardial fibrosis or inflammation, and regional sympathetic denervation.
 Although echocardiography is in general the preferred method, CMR is a valuable
alternative and could achieve most of these goals. Nuclear angiography is valuable
for evaluation of LV and RV function, while nuclear scintigraphy is helpful in detecting myocardial perfusion defects, fibrosis, or denervation.
 Monitoring of cardiac structure and function by echocardiography (and/or CMR)
should be performed at least yearly in patients at stage B or higher, as it provides
important prognostic information and could assist in making therapeutic decisions.
 In patients at stage B or higher, the imaging report should always include^ LVEF,^ Regional wall motion abnormalities and aneurysms,^ LV diastolic function,^ RV function,^ Mitral and tricuspid regurgitation,^ Pulmonary artery systolic pressure,^ Presence of intracardiac thrombus, and^ Myocardial edema or fibrosis.

VII. SUMMARY AND CONCLUSIONS
Although prevalent mostly in Latin America, ChD is nowadays present in traditionally nonendemic areas such as the United States

Acquatella et al 21

and Europe. Therefore, physicians around the globe should be awareof the presence of this disease and have a basic understanding of how
to diagnose and treat it. This document seeks to provide a deep understanding of the potential role that each cardiac imaging modality playsin the management of patients at risk and those already diagnosed
with ChD.
The diagnosis of ChHD is based on epidemiology, positive
serology, and clinical and imaging findings. Staging is based on thepresence of cardiac involvement and symptoms of HF. As an inflammatory cardiomyopathy, ChHD may affect the myocardium in a
global or focal manner. The typical findings are focal hypokinesis, aneurysms, fibrosis or mural thrombus, most commonly affecting the LV
apex. More advanced stages could be difficult to distinguish fromother dilated cardiomyopathies.
Screening for heart disease with electrocardiography (conduction
abnormalities such as right bundle branch block and arrhythmias) is
widely accepted because of its low cost and wide availability. Moreadvanced cardiac evaluation with echocardiography, CMR, CT, or
nuclear modalities has incremental value and is critical in determining
the best treatment options and in predicting prognosis. Among all current imaging options, echocardiography should be the initial imaging
modality given its low cost, safety, and availability.
SUPPLEMENTARY DATA
Supplementary data related to this article can be found at https://doi.
org/10.1016/j.echo.2017.10.019.
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