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 general population, with an estimated prevalence of 1 in 5,000, although in some European countries, such as Italy and Germany, the prevalence is 1 in 2,000. 121 Diagnosis can be challenging given the need to exclude other disorders that may present with similar signs and symptoms. 122 The main clinical manifestations are palpitations, syncope, chest pain, complex ventricular arrhythmias and SD. Since highly trained athletes may have right ventricular (RV) hypertrophy, in addition to a variety of changes in depolarization, repolarization, and nerve conduction, a differential diagnosis between “athlete’s heart syndrome” and ARVD should always be performed. Since an echocardiogram may have technical limitations with respect to RV images, its structural and functional analysis may be impaired. However, akinesia, dyskinesia or RV aneurysms associated with the dilation of this chamber are among the most important criteria in the revised classification. CMRI is a noninvasive imaging technique that has become the main tool for diagnosing ARVD. Segmental or global dysfunction of the RV or a substantial increase in this cardiac chamber, associated with myocardial thinning and presence of late enhancement (fibrosis and/or edema), supports a diagnosis of ARVD. 121,123 A 12-lead resting ECG and Holter monitoring can help with diagnosis, principally by detecting arrhythmias such as branch block pattern ventricular tachycardia, inverted T-waves in the right precordial leads (V1 to V3) and epsilon waves (present in 30% of ARVD patients). Family history should always be investigated, and a confirmed case in a first degree relative is a major criterion. Thus, suspected first- degree cases or confirmed second-degree cases are minor criteria. In especially difficult cases, a biopsy of the RV can be performed. The final clinical diagnosis may not be simple. The presence of two major criteria, one major and two minor criteria (different categories) or four minor criteria (different categories) confirm the diagnosis. New evidence suggests that ECG adaptations, such as isolated right ventricular overload or T-wave inversion from V2 to V4 (associated with right axis right deviation in black athletes) are related to benign structural adaptations of the heart in competitive athletes. In these individuals careful investigation for the other criteria is necessary, and research on family history is of fundamental importance. 124 4.2.1. Diagnosis and Management of Athletes with Suspected Arrhythmogenic Right Ventricular Dysplasia 4.2.1.1. Echocardiography In athletes with a family history of ARVD or with ECG changes suggestive of ARVD. Recommendation grade: I. Evidence level: C. 4.2.1.2. Cardiac Magnetic Resonance Imaging CRMI should be used when there is a strong suspicion, despite a non-diagnostic ECG or in cases where an echocardiogram could not adequately assess the RV. Recommendation grade: I. Evidence level: C. Competitive physical activity in patients with a definite or probable diagnosis of ARVD. Recommendation grade: III. Evidence level: B. There is sufficient evidence that exercise can trigger SD in individuals with ARVD. Probable causes include: increased sympathetic tone and even greater dilation of the ventricular chambers during exercise, which, associated with myocardial fibrosis, leads to the appearance of complex arrhythmias. 125,126 Adhesion between the cells could be compromised by genetic factors, and in the meantime, mechanical stress from exercise can lead to cardiomyocyte apoptosis and worsening of the disease. 127,128 Group 1A sports can be allowed on an individual basis. More recent studies have confirmed the deleterious role of sustained vigorous physical activity (> 6 metabolic equivalents) in the occurrence of ventricular arrhythmias in ARVD patients, and reducing exercise after diagnosis is associated with a lower occurrence of severe arrhythmias. 129,130 4.3. Myocarditis Myocarditis has a heterogeneous clinical profile and, although not very prevalent, it is the probable cause of 5 to 22% of SD cases in athletes, depending on age and region. 88,131 This disease is characterized by an inflammatory process with consequent non-ischemic degeneration and necrosis of the myocardium. Generally, myocarditis is the result of an infection (viruses, bacteria, fungi, protozoa), but it may be associated with substance use or autoimmune diseases. 132 SD may occur in the acute phase (when a myocarditis patient does not abstain from sports for 6 months), or even in the chronic phase, when there is already scar tissue in the myocardium, which is a consequence of complex arrhythmias triggered by an unstable electrical substrate. In this phase, exercise may be the arrhythmogenic trigger due to increased venous return and muscle fiber stretching from physical activity. 133,134 In athletes, the main symptoms are palpitations, precordialgia, dyspnea, fatigue and syncope. ECG changes include ventricular arrhythmias, ST-T segment changes, and rhythm and conduction disorders. It may evolve with left ventricular enlargement due to the disease, hypertrophy due to physical training or a combination of both. 135,136 CMRI and myocardial biopsy (although less common in our country) may facilitate diagnosis. Due to their prevalence in Brazil, we point out that myocarditis may also be caused by the dengue and HIV viruses, as well as by Chagas’ disease. 4.3.1. Recommendations for Athletes with Myocarditis Competitive physical activity for patients with active myocarditis. Recommendation grade: III. Evidence level: B. Athletes diagnosed with myocarditis should be advised against practicing any competitive sports and should undergo a period of convalescence. Although there is no consensus, 342