ABC | Volume 113, Nº1, July 2019

Statement Position Statement on Indications of Echocardiography in Adults – 2019 Arq Bras Cardiol. 2019; 113(1):135-181 2.3.1. Dilated Cardiomyopathy It is characterized by LV dilation associated with global systolic dysfunction, in the absence of volume or pressure overload. The prevalence of dilated cardiomyopathy (DCM) is variable, reflecting the geographical and ethnic differences, as well as the methodologies used. A prevalence of 1:250 is estimated, based on the frequency of the left ventricular dysfunction as an expression of DCM. 27 The criterion to define LV dilation is the final diastolic diameter > 2.7 cm/m 2 . With increased gradual dilatation on the short axis, the LV cavity becomes spherical, with sphericity index (long/short axis dimension) close to 1 (normal value > 1.5). 28 Wall thickness is usually normal, but the myocardial mass is increased. The degree of impairment of systolic function is variable, and systolic dysfunction is often progressive. LV volumes are calculated in a more reproducible and accurate way by using the 3D echocardiography. Abnormalities associated with diastolic function may be present, contributing to the variation in the clinical and hemodynamic presentation of DCM. The involvement of the RV can be evidenced, but it is not a criterion for the diagnosis of DCM. 29 Notably, DCM is associated with an increased risk of severe arrhythmia, indicating the pathological involvement of the cardiac conduction system. Complex remodeling of one or both ventricles contributes to the secondary features of DCM, which include functional mitral and tricuspid regurgitation, enlarged atria, intracavitary thrombi, and evidence of low cardiac output. 28 In the context of DCM, the analysis of diastolic function aims to estimate the filling pressures; and the mitral flow pattern is usually enough to identify patients with increased LA pressure. E-wave deceleration time is an important predictor of outcomes in these patients. 30 Other diastolic dysfunction parameters, including the E/e’ ratio, have good correlation with pulmonary capillary pressure and have an additional prognostic value for LVEF. 30 Echocardiography is the imaging method of choice for the evaluation of DCM patients, providing key data not only for diagnosis, risk stratification and treatment definition, but also plays a key role in the evaluation of family members. 28 Key echocardiography indications in the evaluation of DCM are displayed in table 1. Transthoracic echocardiography (TTE) is indicated in the initial evaluation of patients with heart failure and suspected DCM. TTE is recommended in first- degree relatives of DCM patients due to the high incidence (20 to 50%) of familial DCM. 28 Several echocardiographic parameters were used to assess mechanical desynchrony in patients with DCM. However, the broader role of echocardiography in the selection of patients for cardiac resynchronization therapy remains undefined. Currently, echocardiographies are limited to patients with borderline QRS duration (120 to 149 ms), whose presence of intra- or interventricular desynchrony may provide additional information. 28 The echocardiography guiding the placement of electrodes at the site of greater mechanical activation delay (evaluation by speckle tracking) showed benefit in heart failure free survival, with a more favorable impact on ischemic heart disease compared to DCM. 31 2.3.2. Chagasic Dilated Cardiomyopathy Chagasic dilated cardiomyopathy (CCM) presents similar characteristics to idiopathic DCM, but with predominance of segmental changes in contractility, especially in the basal segments of the inferior and inferolateral walls. 32 Apical aneurysm is a typical CCM finding and is useful in the differential diagnosis of dilated cardiomyopathies. 33 The morphology of aneurysms is variable and non-standard sections are often required for the identification of apical contractile changes. The presence of thrombi within the aneurysms is frequent and associated with cerebral thromboembolic events. 34 Diastolic dysfunction is universally present in patients with CCM and heart failure. 35 The main echocardiographic parameters previously studied with a prognostic value in CCM are LVEF, right ventricular function, LA volume and E/e’ ratio. 33,36 The contractile function of the LA evaluated by the negative peak of the global atrial strain was an independent predictor of clinical events in the CCM. 35 The heterogeneity of systolic contraction, quantified by mechanical dispersion to speckle tracking, was associated with ventricular arrhythmias in patients with CCM, regardless of LVEF. 37 Recommendations for performing TTE in CCM are set out in table 1. 38 2.3.3. Cardiac Resynchronization Therapy and Pacemaker Optimization Cardiac resynchronization therapy is an established treatment option for patients with heart failure with marked reduction of LVEF. The echocardiography is fundamental in the indication, estimation of success and evaluation of the results of this procedure and may also contribute to the recovery of unfavorable results. This treatment is indicated as class I in patients with heart failure (New York Heart Association (NYHA) functional class II, III or IV), with LVEF lower than 35%, optimized medication and left bundle branch block with QRS duration above 150 ms. 28 Also in class IIa and IIb indications, it is necessary to recognize the reduction of the LVEF below 35%, being contraindicated when this value is not present. Therefore, in the possibility of indication for cardiac resynchronization therapy, transthoracic echocardiography is a class I indication, level of evidence C. In this examination, it is mandatory that LVEF be obtained by the Simpson 2Dmethod, with a description, in the report, of their volumes. It is also possible to use the 3Dmethodology, of less variability, although still unproven in this clinical scenario. Approximately 30% of patients do not present clinical improvement or significant reduction in LV final systolic volume. 39 TTE can provide information that helps identify a greater probability of successful treatment response, such as the presence of mechanical, inter- and intraventricular desynchrony, the presence of myocardial reserve and determination of the last site of activation, which may be associated with higher degree of fibrosis. To this end, the use of a variety of methods is encouraged, from the visual evaluation of 2D echocardiography, M-mode, 40 tissue Doppler and, especially, the use of a technique that evaluates longitudinal 41 or radial myocardial deformation. 42,43 In the evaluation of successful response to treatment, it is expected, in regards to imaging, mainly negative remodeling to be observed, usually characterized by reduction of 15% of the 141