Prevention of sport-related cardiac events

Cardiovascular adverse events during strenuous exercise relates to a number of different etiologies. For younger subjects and competitive athletes, channelopathies, congenital abnormalities and cardiomyopathies are common underlying causes of sport-related cardiac arrest. For middle-aged and older subjects (≥35 years of age), coronary artery disease is the most prevalent cause (Figure 3) (5,65). This is important to keep in mind when discussing strategies for preventing sport-related cardiac events.

Figure 3: Age-dependent changes in incidents and etiology of sport-related sudden cardiac death (65). The Figure is used with the permission of the publisher.

5.6.1 Young and competitive athletes

For athletes between 12-35 years of age, it is estimated that about 0.5-2 out of 100 000 athletes die suddenly each year (5,6). Men are more susceptible than women, and the risk increases with age (5).

Current European recommendations for pre-participation evaluation of athletes include a medical history, physical examination and a 12-lead ECG (5). Inclusion of other imaging modalities do not add substantial diagnostic power (5). The evaluation has been found to have a sensitivity of 75 %, and up to 30 % of all evaluated subjects may need further testing (66). As such, mandatory pre-participation evaluation of young athletes is controversial (66).

In Italy, introduction of a pre-participation evaluation for athletes was found to decrease sport-related SCD in from 3.6 to 0.4 per 100 000 person years over a 20 year period (67). Interestingly, these findings have never been reproduced in other cohorts (5). Currently the incidence of sport-related SCD is similar in France, USA and Italy,

suggesting that the pre-participation evaluation may not have been the cause of the reduced incident of SCD in Italy (66).

The Union of European Football Association, among several other sport societies, has introduced a mandatory pre-participation evaluation of their athletes, including an echocardiogram. Malhotra et al., published data from 20 years of screening young English soccer players, including data from 11 168 athletes. They found that 0.38 % of the screened athletes had cardiac disorders that were associated with sudden cardiac death. During the follow-up period, 8 deaths due to cardiac disorders occurred, whereof 6 (75 %) had normal cardiac screening results (68). This is in line with a Norwegian study, which found that six professional soccer players (1 % of the total cohort), all of whom had a negative screening at baseline, suffered a serious cardiovascular incident over a 8 year follow-up period (69). These findings underscore the uncertainty of a pre-participation evaluation strategy.

5.6.2 Senior athletes (> 35 years of age)

For athletes > 35 years of age, the incidence of sport-related sudden cardiac death has been reported to be 1/15.000 – 1/50.000 (6).

Pre-participation evaluation has been recommended for all active subjects ≥ 35 years of age who participate or plan to commence in strenuous physical activities (≥ 6 METs) (70). In this group, CAD is the most common cause of sport-related SCD (5).

The evaluation of these athletes is similar as for younger subjects, but identification of CV risk factors is given more attention.

As for the younger athletes, there is considerable debate about the value of both a resting ECG and the maximal exercise test in subjects with no symptoms. Thus, the newer recommendations from 2017 states that for senior athletes, information should be given about the nature of cardiac prodromal symptoms, and that exercise stress testing is indicated if symptoms are present (5). Exercise stress test might also be considered in senior athletes with a high CV risk (5).

5.6.3 National practice

A required systematic pre-participation evaluation of sports participants has not been implemented in Norway. For Olympic athletes, The Norwegian Olympic Sports Center (Olympiatoppen) offers a health evaluation, which includes an ECG. They offer a repeat evaluation when the athlete is 20, 25 and 30 years of age. Also, football players at the highest level are evaluated regularly, due to requirements from the Union of European Football Associations (71).

5.6.4 Other preventive measures

Sport-related sudden cardiac arrest (SCA) is still unavoidable. Bystander cardiopulmonary resuscitation and use of publicly available automated external defibrillators (AED) are strong predictors of survival of sport-related cardiac arrests (35). As such, it is important that coaches, staff at sport events and laypersons are skilled in cardiopulmonary resuscitation and the use of AEDs. Readily access to AEDs in exercise facilities and during sport events is beneficial in preventing sport-related sudden cardiac deaths (35,72-75).

5.6.5 Future perspectives

There is consensus among both the American Heart Association and the European Society of Cardiology that “pre-participation evaluation for young competitive athletes is justifiable and compelling on ethical, legal and medical grounds” (6). Even so, there is considerable debate within the sport cardiology community about when to screen, which methods to use and how often a pre-participation evaluation should be carried out.

A majority of subjects with sport-related SCA are asymptomatic prior to the event (7,8). This knowledge, combined with the low sensitivity and specificity of a resting ECG in identifying underlying CAD are major limitations of the current strategy of pre-participation evaluation, particularly in the senior athlete population where cardiomyopathies and channelopathies are less common causes of sport-related cardiac events. As such, there is a need to identify novel methods to assess

asymptomatic recreational athletes. As this population engage in strenuous exercise

regularly, both for competitions and training, the use of these exercise sessions to evaluate physiological responses to exercise is an attractive avenue of research in this area. The use of cardiac biomarkers could potentially unmask a pathological response to exercise; however, the clinical consequences of exercise-induced cardiac

biomarker increase need to be further elucidated.