Discussion

This study has demonstrated that we can identify and treat significant arrhythmias in young athletes and enable the majority to return to competitive sport. One point six per cent of children referred to our centre for interventional arrhythmia assessment, were elite athletes. Of these, four patients (36%) had potentially lethal arrhythmias including WPW and complete heart block. Nine of the 11 athletes had frequent persistent cardiac symptoms, which would have undoubtedly prevented them from reaching their full athletic ability. Encouragingly, 91% returned to high-level sport after arrhythmia intervention. The only significant complication was complete heart block in one patient. This patient presented in pre-excited atrial fibrillation, a potentially lethal arrhythmia, prior to the availability of cryoablation in our unit. Since the inception of cryoablation, we have had no complications of postablation heart block in more than 500 procedures.

Between 40% and 80% of trained athletes have a minor abnormality found on their ECG, for example, sinus bradycardia, first degree AV block, early repolarisation, incomplete right bundle branch block and increased QRS voltages.2 5 9 10 13 21,–,24 In the majority, these represent normal variants or physiological adaptations of the trained heart. If these ECG findings are interpreted with regard to the athlete's age, gender, race, family history of cardiovascular disease and physical findings on examination, the percentage of athletes excluded for sport on the grounds of abnormal ECG changes can be decreased.16 21 25 During high-impact training athletes' hearts undergo physiological changes and cardiac remodelling, creating ECG and echocardiographic changes. The differentiation between an athlete's heart and pathological disease is essential to avoid inappropriate disqualification from sport. One patient in our study was found to have a resting heart rate of 40/min on club screening. In view of an associated history of dizzy spells, he underwent an electrophysiological study. This was normal and he has had no further symptoms. Asymptomatic sinus bradycardia, and sinus pauses are common in young athletes due to increased vagal tone. An incorrect diagnosis of sinus node dysfunction may have excluded this patient from competitive football.18

Where athlete's careers are involved, the decision to disqualify them on the basis of cardiac disease is complex and can prove difficult to implement.19 26 Elite athletes are highly motivated and may wish to accept the risks associated with competitive sport and resist prudent recommendations to withdraw.27 A number of papers, including most recently Papadakis and Sharma13 suggest that universal screening of athletes will lead to detection of potentially lethal cardiac disorders and result in withdrawal from athletic activity. Our report suggests that detection and appropriate treatment may, in certain conditions, allow return to sport. Our study did not include any patients with disorders such as arrhythmogenic right ventricular cardiomyopathy (ARVC) where return to sport is precluded.18 However, Bauce et al28 have shown that detailed further assessment is essential to distinguish ARVC from a normal athlete's heart adaptation. In addition, we excluded from analysis all patients with significant congenital heart disease. Decision-making in this cohort requires specific assessment of prognosis and published recommendations are available.29

Anderson and Vetter7 discuss the risk-benefit ratio of restricting a young athlete from physical activity. They conclude that most cardiac conditions leading to SCD have poorly defined risk factors and children and adolescents should be encouraged to lead healthy, active lifestyles. Although practitioners should use preparticipation screening guidelines recommended by sports organisations this may lead to defensive practice and a low threshold for advice to withdraw from sport. In this setting the cost-effectiveness and socioeconomic impact of screening must be considered. This was summarised by Wren11 who calculated that in a population of 100 000 school children, approximately 30 children may be at risk of sudden death. The basic screening of each 100 000 cohort would cost approximately eight million pounds with further costs incurred from the 2500–3000 children with abnormalities detected during the screening process. In most screening studies, the most common potentially dangerous cardiac diagnoses are hypertrophic cardiomyopathy and ARVC. However, most reports do not provide age-specific diagnoses and include both adolescents and young adults. It is possible that an analysis of adolescents alone would demonstrate a different diagnostic profile. As shown in our study, these athletes are more likely to be male and we know that SCD is 5–9 times more common in males. This suggests that it may be more efficient to introduce gender-specific screening programmes. At a time when the incidence of morbidly obese children is rising, we need to be careful that fear of cardiovascular catastrophe does not deter children from exercising.30 Although this paper does not address the complex ethical, epidemiological and medical issues of child athlete screening, it does demonstrate that most child athletes who present with cardiological symptoms suggestive of a cardiac arrhythmia, have an excellent chance of undergoing effective treatment and returning to elite sport.