The intriguing problem of arrhythmias in competitive athletes

09/04/05



During the evaluation of competitive athletes, a history or a documentation of cardiac arrhythmias has become particularly important because arrhythmias may be the initial expression of an underlying cardiac disease or of primary electrical disorders, sometimes early manifestations of potentially life-threatening events. Cardiac arrhythmias are among the most important causes of non-eligibility to sports activities, and some arrhythmogenic diseases are three times more frequent among athletes than among sedentary subjects of the same age.

Arrhythmias, in young competitive athletes and also the elite are usually "benign" or "paraphysiological" (duo to prolonged training). In some cases, arrhythmias may be "pathological" and also life-threatening, and can lead to major cardiac events as cardiac arrest and sudden death.

Consequently, it is mandatory to identify in each athlete with significant arrhythmias both the risk of continuing the athletic career as well the best curative and preventive treatment if necessary.

From 1974 until April 2004, we have studied and monitored a population of 2640 competitive athletes with important arrhythmias (mean age 21.5 years), and 345 (13%) of international elite level (mean age 24 years). During the follow up, 62 Cardiac Arrests (CA) were reported, of which 24 (0.9%) were Sudden Deaths (SD) while 38 (1.4%) were resuscitated from cardiac arrest (Table I). In the subset of elite athletes, the major events were 13 (22.4%), with six sudden deaths (1.7%) and seven (2.0%) cardiac arrests. (see Table 1).

The problem of arrhythmogenic effect of illicit drugs in athletes
The current management of athletes with arrhythmias is further complicated by the large use of "illicit drugs" taken, at any age, both by professional and non professional athletes. It is advisable to use the term "illicit drugs" rather than "doping"; the former encompasses both drugs taken as true "doping", or "performance enhancing drugs (PEDs)", and "masking agents", i.e. drugs taken to the aim of masking the presence of other specific drugs in tests for doping control.

Almost all illicit drugs, banned by International Olympic Committee (IOC) and since 1999 updated yearly by the World Anti-Doping Agency, may cause cardiac collateral effects, through a direct or indirect cardiac effect, and may provoke especially arrhythmogenic effects, during short, medium or long term. The risk of lethal arrhythmias is very high in subjects with pre-existing cardiac diseases, particularly latent arrhythmogenic substrate or primary arrhythmic disorders including some inherited cardiomyopaties at risk of sudden cardiac death.

The 2005 IOC list of the "Prohibited classes of substances" includes: (www.wada-ama.org - World Anti-Doping CODE Valid 1 January 2005)

A) SUBSTANCES AND METHODS PROHIBITED AT ALL TIMES (in- and out-of-competition).

PROHIBITED SUBSTANCES
S1. ANABOLIC AGENTS

    1. Anabolic Androgenic Steroids (AAS)
      a. Exogenous AAS
      b. Endogenous AAS
2. Other Anabolic Agents, including but not limited to:
clenbuterol, zeranol, zilpaterol
S2. HORMONES AND RELATED SUBSTANCES
    1. Erythropoietin (EPO);
    2. Growth Hormone (hGH), Insulin like Growth Factor (IGF-1), Mechano Growth Factors (MGFs);
    3. Gonadotrophins (LH, hCG);
    4. Insulin;
    5. Corticotrophins.

S3. BETA-2AGONISTS
S4. AGENTS WITH ANTI-ESTROGENIC ACTIVITY
S5. DIURETICS AND OTHER MASKING AGENTS

PROHIBITED METHODS
M1. Enhancement of oxygen transfer
M2. Chemical and physical manipulation
M3. Gene doping

B) SUBSTANCES AND METHODS PROHIBITED IN-COMPETITION
S6. STIMULANTS
S7. NARCOTICS (Tab. IX)
S8. CANNABINOIDS
S9. GLUCOCORTICOSTEROIDS

SUBSTANCES PROHIBITED IN PARTICULAR SPORTS
P1. Alcohol
P2. Beta-Blockers

The media continuously reports doping scandals but there is a common lack of knowledge of specific side effects of illicit drugs within sport doping, not only among common people, but also among athletes, sporting world and, moreover, among the sport physicians and cardiologists. Greater knowledge of the short and long-term pathological cardiac and, in particular, arrhythmic effects of doping is essential for trainers and especially for young athletes.

Aim of our presentation
On the basis of the available findings and data in literature and of our personal experience in a long-term study of arrhythmic competitive athletes we focused on anabolic androgenic steroids (AAS) adverse effects with particular regard to cardiac arrhythmic morbidity and mortality among athletes who are users of these specifically banned drugs.

S1. ANABOLIC ANDROGENIC STEROIDS (AAS). Anabolic steroids are derived from modified testosterone to enhance anabolic rather than androgenic action. They represent the most used illicit drugs and most frequently discovered drugs in antidoping controls, often taken by very young athletes. AAS are taken in order to increase protein synthesis, muscle mass, level of aggressiveness, and to obtain a rapid recovery after effort. Their administration is often associated with other substances, to mask the identification in anti-doping controls or in pharmacological cocktails. Until year 2000, more than one million athletes had taken these drugs (e.g. in the US). The magnitude of the problem was particularly evident in the ex German Democratic Republic (GDR) since doping was supervised and financed by the State, de facto without legal restriction against doping procedures. The massive abuse of anabolic steroids was estimated around 10 kg or 2 million tablets per year! A considerable amount of doping drugs consisted of illegal experimental substances whose side and late effects were not clarified. The IOC 2005 prohibited list of Anabolic Androgenic Steroids (Table II) is complete and up-to-date and includes the most recent pharmaceutical AAS products. It also contains drugs in phase III investigation (not on the market!) in order to provide a complete spectrum for anti-doping controls.

Various adverse events have been reported with use of AAS: serious alterations of liver function with hepatocellular alterations, hepatitis, hepatic neoplasm, modification of connective tissue structure with decreased collagen, decrease in tension of tendons with susceptibility to ruptures, insuline-resistance, sterility, gynaecomastia, testicular hypotrophy, acne; moreover immune depression, virilization in women and aggressive behaviour including sexual aberrations and crimes have been reported.

Many different arrhythmias often during physical activity may be induced by the anabolic steroids with different direct or indirect mechanisms. These drugs may present sympathomimetic effect during physical activity, changes in lipid methabolism, systemic and cardiac thromboembolic events, progressive hypertrophic cardiomyopathy associated with fibrosis, necrosis, myocarditis. Anabolic steroids are often administrated along with masking agents as diuretics, tamoxifene (to reduce gynaecomastia), human chorionic gonadotropin (which increases endogenous testosterone levels), cocaine, thyroid hormones (to raise metabolic activity), growth hormone (hGH) for its well known anabolic effect, stimulants in order to obtain quickly a better result, and often administrated together with recreational substances like marijuana and alcohol. In sports based on muscular strength the dosage of anabolic steroids may sometimes be quite impressive with peaks of dosage in body builder with levels from 10 to 100 fold the therapeutic levels! A variety of AAS are often taken in the same user (so call "stacking"). The arrhythmias most frequently reported during treatment with anabolic steroids are: atrial fibrillation, supraventricular and ventricular ectopic beats, QT prolongation (particularly in genetically predisposed subjects), sustained and not sustained ventricular tachycardia, ventricular fibrillation.

Conclusion
AAS are one of the most important illicit drugs prohibited at all times (in and out of competition) included in the IOC-WADA list, taken to "improve athletic performance" (PEDs) that may induce a wide spectrum of arrhythmias

  • focal or re-entry type, supra/ventricular, lethal or not
  • through a direct or indirect arrhythmogenic effect
  • in the short, medium or long term
  • in healthy subjects and in the presence of a latent arrhythmogenic heart disease including some inherited forms and/or related to the assumption of illicit drugs.

Source: Eurekalert & others

Last reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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