Chapter 501. Sports Screening for Cardiovascular Risk

Exercise increases oxygen consumption, cardiac output, heart rate, and systemic blood pressure and therefore increases cardiac work. Children are becoming heavier, and there is an increase in childhood obesity in Western cultures. There are many studies linking childhood obesity to adult coronary heart disease. For the vast majority of children, strenuous exercise would be extremely beneficial.

There are approximately 3000 to 5000 sudden-death episodes per year in children and adolescents in the United States. There are between 5 and 10 million children and adolescents participating in organized sports activities, so the percentage of athletes dying suddenly is quite small. Highly trained athletes are thought to represent the most fit and healthy members of our society, so these tragic, early, and unexpected deaths make a deep impression on us. The majority, approximately 40% to 50% of sudden deaths, are caused by hypertrophic cardiomyopathy. Between 10% and 20% will be caused by coronary abnormalities (usually the left or right coronary artery arising from the wrong sinus origin or a single-coronary artery origin). The remaining 30% will be caused by such lesions as myocarditis, dilated cardiomyopathy including noncompaction, ion channelopathies (long QT) syndrome, Brugada syndrome, catecholaminergic polymorphic ventricular tachycardia (CPVT), arrhythmogenic right ventricular dysplasia (AVRD), Wolff-Parkinson-White (WPW) syndrome, previous Kawasaki disease with undiagnosed coronary involvement, commotio cordis, and connective tissue disorders with dilated aortic roots (eg, Marfan’s). The incidence in the population of these disorders is at most 0.3%. The percentage presenting for screening would be thought to be even less, secondary to self-selection not to participate in sports.

The pediatrician often has to verify that a child can play competitive sports, and there is great concern about the occasional child who dies suddenly during or just after strenuous exercise.

There is no consensus as to what should be included in cardiovascular screening. There is no standardization of state or federal regulations, nor is there a medical entity that establishes the precise requirements of exercise testing. There is no screening regimen that would abolish the risk of cardiovascular induced death. The European Society of Cardiology recommendation of screening ECGs for all participants is based mainly on the Italian state subsidized national program. This program mandates that all individuals from age 12 to 35 years participating in organized team sports or individual sports must obtain annual medical clearance by accredited sports medicine physicians. This medical clearance is by history, physical examination, and ECG.

At present, the American Heart Association guidelines from 2007 do not include an ECG as part of the screening process. Some of the reasons listed for not requiring ECG include the financial resources, manpower, and logistics needed to implement such a program. It seems doubtful that consensus could be reached to implement a screening ECG program secondary to the conflicting interests of the various groups involved and the competition for money with other issues and priorities in public health. There is also the additional problem of borderline or false-positive ECGs. Past screening programs have included at least 10% false-positive tests, which far outnumber the true-positives. This requirement for further testing and the possibility for exclusion from sports without cause would produce both short and long-term emotional and financial burdens on families and athletes. This does not mean that ECGs should not be performed after someone has been identified by the AHA screening guidelines. The 2007 AHA guidelines are listed in Table 501-1.

A positive family history includes sudden death, syncope, chest pain, arrhythmias, or heart disease. It is particularly likely in hypertrophic cardiomyopathy, right ventricular dysplasia, mitral valve prolapse, long QT syndrome, premature atherosclerosis, and Marfan syndrome.

A positive personal history includes syncope, chest pain, arrhythmias, murmurs, Kawasaki disease or heart disease in general.

Positive signs include left ventricular enlargement or hypertrophy, specific murmurs, and Marfanoid body habitus. There are no abnormal signs with anomalous aortic origin of a coronary artery, coronary arterial aneurysms after Kawasaki syndrome, or the long QT syndrome.

At the discretion of the examiner, a positive response or finding in any one or more of the 12 items may be judged sufficient to trigger referral for cardiovascular evaluation.

Comprehensive screening evaluations should be administered every 2 years through high school. At the collegiate level, the testing should be performed upon entry and then a more selective interim history with blood pressure measurements every year. If the interim history suggests changes, then a more thorough examination and possible referral should be performed.

Many of the causes of sudden death in young athletes are congenital in origin. Structural abnormalities such as hypertrophic cardiomyopathy and arrhythmogenic right ventricular dysplasia (AVRD) are inherited, and closer evaluation and genetic testing may be warranted in primary relatives. Other structural abnormalities, such as coronary abnormalities and myocarditis, do not merit further familial investigation. For causes where no abnormalities are found, the deaths are most likely to be arrhythmogenic in nature. The ability now exists to perform postmortem genetic testing to look for ion channelopathies, such as long QT syndrome and catecholaminergic polymorphic ventricular tachycardia (CPVT). This new modality offers the ability to further identify relatives of the deceased who are at risk for sudden death, as well as to better understand the natural history of these diseases.1-9