Exercise as it relates to Disease/The importance of screening in the athletic population to detect early risk of Sudden Cardiac Disease

Brief background
Sudden Cardiac Death in the athletic population is a fairly new area of study. It looks into the sudden death of athletes during or directly after a competitive event. The reason it is an area of study is because athletes have tendencies to push their bodies to the limit and to train harder than any other population. This means they are more likely to trigger sudden cardiac death or cause hypertrophy of the heart respectively. Many athletes have cardiovascular conditions without knowing which is why places such as the United States and Italy have put in place protocols for prescreening. Common conditions include hypertrophic cardiomyopathy, congenital coronary artery anomaly, myocarditis, aortic rupture, and mitral valve prolapse. Exercise is not the cause of sudden death however is considered a trigger for those with any of the above conditions that are unknown.

Incidence
An underestimation of the reported sudden death numbers has been considered highly likely. The studies viewed relied on self-reporting from organisations and the media which could mean many never made it to the researchers. Both the US and Italy have conducted major studies within this field. The major difference between the two is the level of competitiveness the athletes were at. In the Italian study the athletes were at a high level whereas in the US they were at a high-school to college level.

Gender comparison
Studies show that gender does have an effect on the prevalence of Sudden Cardiac Death. Results showed a 10:1 ration of men to women respectively however it is thought that this could be an overestimation due to the higher participation rate of men in competitive sport. Another factor that could be the cause of men having a higher risk is the fact that males are more likely to have cardiovascular diseases. More commonly men are more probable to have arrhythmic cardiac arrest, such as cardiomyopathies and premature coronary artery disease.

Causes and Triggers
Common causes of Sudden Cardiac Death are due to the unknown cardiovascular conditions some athletes have. Conditions such as hypertrophic cardiomyopathy, congenital coronary artery anomaly, myocarditis, aortic rupture, and mitral valve prolapse. The most common cause is hypertrophic cardiomyopathy accounting for more than one third of the deaths in the US study. The rate of incidence going from most common to uncommon can be found on table 1. As shown in the table exercise is not shown as a cause of Sudden Cardiac Death but instead is considered a trigger. A study showed that sudden death was more prevalent in the athletic population proving that exercise is a trigger for those individuals with underlying cardiovascular conditions.

Prescreening
Protocol put in place requires two levels of examinations. The first requires the personal and family medical history to be examined with the addition of a 12-lead ECG. If any of these report back to be positive a second examination using techniques such as echocardiography or exercise testing are required. For 95% of athletes with hypertrophic cardiomyopathy an ECG reading will show abnormalities alerting medical staff of the condition. The use of prescreening such as this can prevent events such as Sudden Cardiac Death.

Recommendations
The only way to prevent Sudden Cardiac Death in athletes is to put in place a compulsory protocol for prescreening all competitive athletes. Studies show that the most effective prescreening protocol was to have a personal and family medical history with and ECG reading examination. Without making a compulsory protocol athletes will be placing themselves in danger without the knowledge that they even have a condition. If an athlete does present with a condition then steps may be taken so they may continue in their sport safely or see to that the athlete may take on a more appropriate sport to their condition.