ABC | Volume 112, Nº3, March 2019

Updated The Brazilian Society of Cardiology and Brazilian Society of Exercise and Sports Medicine Updated Guidelines for Sports and Exercise Cardiology - 2019 Arq Bras Cardiol. 2019; 112(3):326-368 many experts recommend that this period be at least six months after the onset of clinical manifestations. However, some experts have been more “liberal”, recommending shorter periods of convalescence. These athletes may resume training and competition after: • Left ventricular function, ventricular wall motion, and cardiac dimensions return to normal values (based on stress and resting echocardiography and radionuclide imaging). • Complex or frequent forms of ventricular and supraventricular arrhythmias and clinically relevant arrhythmias are absent. • Inflammatory and heart failure markers are normalized. • Resting ECG is normalized, although the persistence of ST-segment changes alone should not impede the athlete’s return to training and competition. 4.4. Dilated Cardiomyopathy Dilated cardiomyopathy (DCM) has an estimated prevalence of 40 cases per 100,000 individuals. It is defined as a myocardial disease, characterized by LV dilation and global systolic dysfunction, and there may be overlapping segmental abnormalities with increased myocardial mass. DCM includes disorders of genetic origin, disorders due to infection, inflammation, exposure to toxic substances or metabolic diseases, and disorders of idiopathic origin (although at least 40% of disorders classified as idiopathic are, in fact, of genetic origin). Up to 40 genes have been identified, with proteins from several cellular structures being affected (sarcomere, sarcolemma and intercellular junction). 137 DCM patients vary widely in clinical presentation and hemodynamics. 138 Long-term aerobic training may lead to changes in cardiac morphology, including increased LV cavity size and mass. Increased cavity size may produce a greater systolic volume and thus, the resting ejection fraction may be at the lower limit of normal or slightly reduced. In this context, it is important to differentiate between LV increase due to systematic training and that due to DCM. 138 4.4.1. Complementary Examinations for Dilated Cardiomyopathy 4.4.1.1. Exercise Stress Testing and Cardiopulmonary Exercise Testing Although exercise performance may only be slightly reduced in young DCM patients, arrhythmias are usually present at a very early stage of the disease (including supraventricular and ventricular tachyarrhythmia, as well as conduction delays). Recommendations for exercise stress testing and CPET 38 Recommendation grade Evidence level Exercise stress testing or CPET to assess individuals with known or suspected ventricular arrhythmias during exercise, regardless of age I C Exercise stress testing to assess DCM severity IIb B CPET to assess DCM severity Ia B Exercise stress testing to identify pathophysiological mechanisms and clarify symptoms IIb B CPET to identify pathophysiological mechanisms and clarify symptoms I B CPET: cardiopulmonary exercise testing. 4.4.1.2. Echocardiogram An echocardiogram is more sensitive than ECG for diagnosing LVH and accurately quantifies LV mass. Thus, cardiac abnormalities detected by an echocardiogram have additional predictive value. 138,139 Recommendations for performing ECHO Recommendation grade Evidence level Assessment of patients with suspected DCM or heart failure I B Assessment for differential diagnosis between DCM and “athlete's heart syndrome” I B Echo: echocardiogram. 4.4.1.3. Cardiac Magnetic Resonance Imaging CMRI can clearly and effectively demonstrate and quantify anatomical and functional changes in DCM. This examination has been found useful for evaluating HF patients by accurately calculating the function of both ventricles. It also helps distinguish idiopathic DCM from other forms of ventricular dysfunction, such as ventricular dysfunction caused by coronary artery disease. 140 In addition, the method makes an important contribution to prognostic evaluation. Determining the presence and extent of fibrosis by myocardial late enhancement has good prognostic value, since it represents a substrate for arrhythmia and SD. Further research is needed to confirm the role of CMRI in the prognostic stratification of DCM, especially when defining the arrhythmic risk of these patients. 141 4.4.2. Sports and Dilated Cardiomyopathy DCM is an uncommon myocardial disease that deserves consideration because it is a potential cause of SD in athletes. 142-144 In reality, there is little information on the risk of SD during physical activity or the relative risk of physical training for athletes with DCM. Thus, it is not clear whether asymptomatic DCM patients are at risk of SD during physical activity or competitive sports, since tachyarrhythmias are much more common in patients with more advanced disease, i.e., with explicit cardiac symptoms and reduced ejection fraction. 4.4.2.1. Recommendations for Athletes Diagnosed with Dilated Cardiomyopathy Until further information is available, symptomatic DCM athletes should not participate in competitive sports except for those in class IA and selected cases. 343