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 The European Society of Cardiology reported that SD occurs three times more in athletes (2.3 per 100,000 individuals) than non-athletes (0.9 per 100,000 individuals). 76 There have been a limited number of SD cases in asymptomatic HCM patients. Five cases of premature SD have been reported in which the autopsy revealed no macroscopic HCM or mutation of the TNNT2 gene. 82 Two patients were found with ventricular fibrillation and normal hearts who subsequently developed HCM and MYH7 gene mutation. 83 In one ARVD case, a 13-year-old mutation carrier in the non-clinically affected DSP (desmo- toquine) gene suffered SD two years after the genetic study. 84 In an Italian study of 12,500 athletes, only one case of SD due to ARVD was not clinically detected. 85 In the context of dilated cardiomyopathies, a case of SD was also described in a 35-year-old female with LMNA gene (c908-909delCT) mutation in whom no structural disease or conduction disorder was detected. 86 In assessing positive genotype/negative phenotype in the early development of cardiomyopathy, it is important to remember that intense sports activity can worsen the prognosis for mutation carriers, as in ARVD and HCM. 87,88 The current recommendations are controversial, being based on expert consensus and the available few longitudinal studies. Table 7 shows general differences between U.S. and European recommendations. For example, the American Heart Association and American College of Cardiology state that patients with HCM-positive genotypes may participate in competitive sports, as long as two-dimensional echocardiogram indicates they are asymptomatic and without evidence of LVH and they have no family history of HCM-related SD (Class IIa; Evidence level C). However, athletes with clinically expressed and diagnosed HCM should not participate in most competitive sports. 89 It is our opinion that future studies should evaluate the pathogenic potential and negative effects of intense exercise on individuals with positive genotypes. Finally, we believe that disqualification should only be used as a final intervention and that adequate information and decision-making (by the family, athlete, coach, sponsor, etc.) should be sought. Table 7 – U.S. vs. European recommendations for athletes with positive genotypes Heart Disease American Heart Association/American College of Cardiology European Society of Cardiology Cardiomyopathies (HCM, DCM, ARVD) No restrictions (e.g., asymptomatic and without left ventricular hypertrophy) Competitive sports prohibited: only non-competitive sports and leisure activities permitted Long QT No restrictions (except QTL1 and swimming) Competitive sports prohibited: only non-competitive sports and leisure activities permitted Catecholaminergic tachycardia Competitive sports prohibited Competitive sports prohibited Brugada syndrome No restrictions No restrictions Marfan Syndrome Mild-to-moderate activity only (no family history of aortic dissection or SD) Competitive sports prohibited HCM: hypertrophic cardiomyopathy; DCM: dilated cardiomyopathy; ARVD: arrhythmogenic right ventricular dysplasia. 4. Individuals with Cardiomyopathies and Myocarditis 4.1. Hypertrophic Cardiomyopathy HCM is one of the major causes of sports-related SD in individuals under 35 years of age. 90,91 The U.S. National Registry of Sudden Death in Athletes evaluated the causes of SD in competitive athletes between 1980 and 2011. Of 2,406 total deaths identified in young athletes (mean age: 19 years), 842 had some cardiovascular diagnosis. HCM was the most common cause of SD, occurring in 36% of the cases. 92 However, its contribution to SD in athletes has been systematically overestimated. Recent evidence from a meta- analysis 92 indicates that HCM caused 10.3% of athlete deaths, while 27.5% had structurally normal hearts. HCM is anautosomal dominant geneticdisease characterized by myofibrillar disarray in myocytes, accompanied by hypercontractility and asymmetrical hypertrophy (with or without obstruction of the outflow tract), which are unexplained by pressure, volume overload, or another underlying systemic condition. Ventricular hypertrophy (determined by an imaging method) > 15 mm in any segment with no other apparent cause is highly suggestive of HCM. 93 For hypertrophy between 13 and 14 mm, other factors, such as family history, specific ECG changes, symptoms, another imaging method and even genetic evaluation should be considered in the differential diagnosis. 94 In first-degree relatives of a HCM patient, hypertrophy greater than 13 mm is also highly indicative of this disease. 91 Hypertrophy related to pressure overload, physical training and basal septal hypertrophy in the elderly should be considered in the differential diagnosis. HCM patients may be totally asymptomatic or present symptoms such as lipothymia, syncope, dyspnea, palpitations or angina, especially when related to increased myocardial demand or obstruction of the outflow tract, as occurs during exercise. SD in these patients occurs primarily due to ventricular arrhythmias, although other complications such as supraventricular arrhythmias (with or without pre-excitation), 338