IJCS | Volume 31, Nº2, March / April 2018

181 Figure 3 – Chart A: Echocardiography of apical two-chamber view of the left ventricle shows an image suggestive of a large apical aneurysm filled with thrombus (yellow arrow). Chart B: Point Tracking Technique (Speckle tracking) supporting the analysis of RV systolic function in a patient with Chagas’ disease. EDA: end-diastole area; ESA: end-systole area; FAC: Fractional area change; GLS-endo: Global longitudinal strain in the endocardial layer. Two-dimensional echocardiographic evaluation of the right ventricle can be performed through an acquisition protocol with images dedicated to this investigation. 56 New methods for the assessment of right ventricular systolic function, such as the analysis of myocardial deformation (Figura 3, B), have already shown to correlate quite often to the quantification of RV ejection fraction by other methods, such as magnetic resonance imaging, in groups of patients with Chagas’ disease. Although three‑dimensional echocardiography presents the benefit of volumetric quantification of cavities and, as a result, of ventricular ejection fractions, its role in patients with CCC has not been adequately established yet. Nuclear Medicine: Radioisotope ventriculography (RIV), also known as radionuclear angiocardiography, can be used as an alternativemethod to echocardiography to measure the LV ejection fraction (EF), and presents the advantage of being a quantitative method free from geometric inferences, thereby granting it the role of a real gold standardmethod in this context.When simultaneous measurement of the right and left ventricular ejection fraction (RVEF, LVEF) is required, RIV has been used successfully and may detect earlier and more severe RV dysfunction, including in patients with the digestive form of Chagas' disease. 57 Myocardial perfusion scintigraphy may be required for non-invasive investigation of Chagas disease patients with precordialgia. Negative findings for myocardial ischemia virtually excludes the presence of significant coronary artery disease, indicating a high negative predictive value. However, reversible perfusion defects have been detected in 30 to 50% of patients, in the absence of atherosclerotic epicardial CAD. 58-60 These perfusion changes have been attributed to coronary microcirculation in CCC and it has been postulated that such ischemic changes can contribute to regional myocardial damage in the chronic phase of the cardiomyopathy. 37,60 Fixed perfusion defects, on the other hand, are also frequently observed in patients with CCC and, in general, represent areas of fibrosis caused by the typical pathophysiology of Chagas disease. 42 Iodine-123-labeled meta-iodobenzylguanidine myocardial scintigraphy ( 123 I-MIBG) allows the non‑invasive evaluation of the neuronal integrity of the cardiac sympathetic nervous system at a myocardial level. The use of this imaging technique allowed the identification of regional myocardial denervation in early stages of chronic Chagas' disease in patients with no apparent impairment of left ventricular function, involving mainly the basal parts of the posterolateral Simões et. al. Chagas Disease Cardiomyopathy Int J Cardiovasc Sci. 2018;31(2)173-189 Review Article