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 Table 9 – Risk factors for sudden death in HCM patients Greater risk factors Cardiorespiratory arrest survivor Spontaneous sustained ventricular tachycardia Family history of SD in patients < 40 years Unexplained syncope or pre-syncope Interventricular septum > 30 mm Minor risk factors Abnormal blood pressure response to exercise Patients under 30 years of age Nonsustained ventricular tachycardia HCM: hypertrophic cardiomyopathy; SD: sudden death. It can be used to assess functional capacity and heart rate response to exercise in patients with an implanted defibrillator who wish to participate in low-intensity physical activity. Recommendation grade: IIa. Evidence level: C. In athletes with high risk criteria (symptomatic), it can facilitate differential diagnosis between HCM and physiological hypertrophy. Recommendation grade: III. 4.1.2.4.2. The Role of Maximal Cardiopulmonary Exercise Testing in Hypertrophic Cardiomyopathy A maximal CPET can stratify HCM patients regarding cardiovascular morbidity and mortality, helping guide treatment. In athletes who are in the “gray zone” between physiological hypertrophy and the pathological hypertrophy of HCM, measuring oxygen consumption and peak oxygen pulse with a CPET can be of great assistance. In general, highly trained athletes have values ​between 55 and 70 mL.kg -1 .min -1 . Sharma et al. 111 demonstrated that healthy athletes can actually achieve significantly higher peak oxygen consumption than athletes with HCM (66.2 mL.kg -1 .min -1 vs. 34.3 mL.kg -1 .min -1 ). Since there was no overlap between groups, the researchers postulated a cutoff of 50 mL.kg -1 .min -1 to discriminate between the pathological hypertrophy of HCM from the dynamic component of the athlete’s heart. Finally, since there are conflicting data regarding CPET and specific predictions of SD in patients with HCM based on VE/VCO 2 slope, neither VE/VCO 2 slope nor peak VO 2 are currently used in risk stratification. 112 Recommendation grade: IIa. Evidence level: B. 4.1.3. Sports and Hypertrophic Cardiomyopathy Why is there a low prevalence of HCM among high-level athletes? The response seems to be related to a natural selection process that excludes individuals with HCM- related functional and structural alterations from the high- intensity training required to become a professional. So, is being a competitive athlete with HCM synonymous with SD? The answer is no. We all know cases of athletes who were diagnosed with this disease well into their professional careers or after they had already retired. The problem is that intense exercise can trigger severe arrhythmias, increased left ventricular outflow obstruction and/or ischemic compression in small blood vessels (possible fibrosis due to repetitive ischemia) during training and competition. Based on the premise that strenuous exercise can be an important trigger for SD, athletes with a probable or unequivocal diagnosis of HCM should be excluded frommost competitive sports. However, it should be pointed out that only a minority of HCM patients have SD or cardiac arrest during exercise. 113 This recommendation is independent of age, sex, phenotype, symptoms, LV outflow tract obstruction, drug treatment, septal ablation, or pacemaker or implanted defibrillator. 89 Although criteria have been suggested 114,115 for establishing SD risk factors in HCM patients (Table 9), it should be pointed out that such criteria should be used with caution, since they do not take important HCM-related aspects into account, such as genetics and CMRI results. Individuals classified as low risk (especially those without a gradient at rest or during effort) 116 may participate in sports such as golf, billiards, bowling and shooting (group IA). Recreational sports that require high intensity or abrupt changes of intensity are not recommended. Individuals with positive genotype/negative phenotype (without clinical evidence of disease) may participate in sports, provided they are assessed periodically, since the chance of SD is directly related to the presence of hypertrophy and fibrosis. A recent study evaluated vigorous exercise in HCM patients and individuals with positive genotype/negative phenotype. Exercise was associated with higher cardiac volumes and better diastolic function, but not with a higher incidence of ventricular arrhythmias. 117 Participation in competitive sports for clinically diagnosed HCM patients. Recommendation grade: III. Evidence level: B. 4.2. Arrhythmogenic Right Ventricular Dysplasia ARVD is a cardiac muscle disease of genetic origin characterized by changes during the formation of desmosomes. It is clinically manifested by the replacement of myocardial tissue with fatty and/or fibrous tissue, generally affecting the right ventricle and with more pronounced clinical manifestations when the apical septum of the LV is affected. Mutations in non-desmosomal genes have also been identified, such as filamin C, TMEM43 and phospholambam, especially in cases involving the LV. 118,119 Among athletes from the Veneto region of Italy, ARVD is a major cause of SD: one study found a five-fold increase in SD risk for young athletes who participated in competitive sports. 120 Based on recent data, ARVD is ranked as the third most frequent cause of SD the United Kingdom. 88 ARVD is a rare condition in the 341