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 communication with emergency services who can perform advanced cardiac life support. Effective treatment for an athlete who has suffered sudden cardiorespiratory arrest depends on a sequence of interdependent actions that, when linked together, form a chain reaction that increases the victim’s chance of survival. The American Heart Association calls this a “chain of survival” that consists of the following links: rapid access, early cardiopulmonary resuscitation, early defibrillation and early advanced cardiac life support . Most sudden cardiorespiratory arrest in athletes is due to tachyarrhythmia (ventricular fibrillation), 293 and can be treated with immediate defibrillation and cardiopulmonary resuscitation (CPR). Reducing mortality among athletes who have suffered sudden cardiorespiratory arrest requires CPR training programs and AED use, as well as personnel who can recognize emergencies, activate the emergency system, provide quality CPR, and use an AED. Current guidelines for sports facilities require the installation of strategically placed defibrillators in those with more than 2,500 patrons or those that host activities for individuals in certain at-risk groups (e.g., heart disease patients or older adults). 294,295 It is a well-established fact that for each minute without CPR, the cardiorespiratory arrest victim’s chance of survival decreases from 7% to 10%. However, regarding structural diseases, ventricular arrhythmias appear to be more susceptible to minor delays in defibrillation than structurally sound hearts, 296 which might explain why the survival rate of athletes declines more significantly when AED use is delayed. This highlights the extreme importance of early defibrillation, the third link in the chain. Numerous studies have documented increased survival rates due to programs promoting public access to defibrillation, including locations such as casinos, 297 airports 298 and airplanes. 299 If resuscitation is delayed until the arrival of emergency services, survival rates are very low, around 1 to 2%. 300 The use of AED in public places has led to survival rates of up to 74% for out-of-hospital cardiac arrests. 301 However, due to the rarity of such events among athletes, little is known about this initiative’s specific impact on them. An important risk marker, PPS should be mandatory, since it can detect cardiovascular changes that predispose an athlete to SD. Despite differing international recommendations, there is consensus that the assessment of every athlete should include clinical history, a physical examination and 12-lead ECG, being complemented with other exams according to the degree of suspicion. Athletes who experience SD require immediate high- quality cardiopulmonary resuscitation to provide vital blood flow to the brain and heart. Defibrillation should be performed, ideally, 3 to 5 minutes after collapse to increase the chance of success. If, as in most cases, the post-shock rhythm cannot achieve effective perfusion, CPR should be restarted immediately. Finally, periodic medical evaluation, an effective local emergency protocol, and personnel trained in basic life support can ensure high-quality CPR and early defibrillation. This, plus quick access to centers with advanced cardiac life support are fundamental for decreasing the number of SD cases in athletes and increasing their chance of survival. 8.3. Special Aspects in Preventing Exercise/Sports-Related Sudden Death 8.3.1. Doping: Illicit Substances in Sports Some substances used for doping can have deleterious repercussions especially on the cardiovascular system, including SD. Among the most commonly used substances, we highlight anabolic steroids, ephedrine and amphetamines. Among recreational drugs, we will address the use of cocaine and 3, 4-methylenedioxymethamphetamine, also known as ecstasy. 8.3.1.1. Anabolic Steroids Anabolic steroids cause a number of side effects, including undesirable cardiovascular effects. Anabolic steroids can induce secondary hypertension and nephrosclerosis. Testosterone may increase the vascular response to norepinephrine and, as a consequence, promote fluid retention and elevated peripheral vascular resistance, leading to increased blood pressure. Tagarakis et al. 302 were the first to describe another important effect of steroids at the microscopic level: the adaptation of cardiac capillaries and myocytes to concomitant steroid use and physical training, which leads to a disproportionate increase of in myocardial mass in relation to the cardiac capillaries. The results of this study suggest that anabolic steroids could cause an imbalance between oxygen supply and consumption, especially during exercise. Recently, it has been shown that the long-term administration of nandrolone decanoate to rats affects the physiology of the cardiac autonomic system, resulting in a greater predisposition to cardiovascular risk and SD. In addition, discontinued usage did not result in an immediate return to normality. 303 In humans, anabolic steroids may be associated with a shortened QT interval, thus negatively impacting cardiac electrical activity. 304 In addition, indiscriminate use of anabolic steroids seems to be an independent risk factor for morbidity and premature death. 305 8.3.1.2. Ephedrine In general, stimulants lead to tachycardia and increased myocardial oxygen consumption, which may lead to arrhythmias and acute myocardial infarction in susceptible individuals. Ephedrine may cause symptomatic ventricular tachycardia, frequent ventricular extrasystoles, atrial fibrillation, and SD. It is important to point out that many products called “natural” or “herbal” contain ephedrine-like substances that go unmentioned in the product description. 8.3.1.3. Amphetamines Amphetamines are the prototype central nervous system stimulants. They come in a great variety of formulas and presentations, with the most commonly used being dextroamphetamine sulfate. This substance directly stimulates adrenergic receptors at the cortical level and the 356