Author + information
- Sudhir S. Kushwaha, MD∗ ( and )
- Avishay Grupper, MD
- ↵∗Reprint requests and correspondence:
Dr. Sudhir S. Kushwaha, Division of Cardiovascular Diseases, Mayo Clinic, 200 First Street SW, Rochester, Minnesota 55905.
Sudden cardiac death (SCD) associated with exercise in young athletes is a rare and tragic event. These deaths are usually due to a variety of cardiac diseases, which may be structural, electrical, or acquired abnormalities that are unsuspected and may become manifest in the setting of strenuous exercise (1). Following a number of high-profile SCD events in professional athletes, the question of athletic screening for cardiovascular disorders with a higher risk of malignant arrhythmias has been raised. However, there are several obstacles to screening a large population of young athletes: the low prevalence of underlying cardiovascular disease in this age group; the different diagnostic criteria for each disorder; and the imperfect specificity of the current screening modalities that may lead to false-positive screening study results. In addition, there remains the question of what constitutes enough athletic activity to potentially trigger SCD in a pre-disposed individual. These issues have a substantial impact on the feasibility and cost-effectiveness of screening this population.
The most common causes of SCD in young athletes are several congenital or acquired cardiac malformations. The prevalence of these cardiovascular disorders is estimated at 0.3% of the athletic population. The single most common cause of athlete death is hypertrophic cardiomyopathy, which is responsible for approximately 40% of the cases, followed by congenital coronary artery anomalies in 17% of the cases (2). Several other cardiovascular diseases, including arrhythmogenic right ventricular cardiomyopathy (ARVC), account for approximately 5% of SCD in athletes.
In this issue of the Journal, Zaidi et al. (3) set out to examine the accuracy of diagnostic criteria for ARVC when applied to a group of young athletes and to assess the overlap between physiological and pathological findings in the different screening modalities. Their study compared 2 groups of healthy young athletes with and without physiological T-wave inversion on a 12-lead electrocardiogram (ECG) to a group of patients with an established diagnosis of ARVC using several screening modalities.
The question that arises is how the study results differ from the current guidelines for screening young athletes and how can they improve the specificity of the screening recommendations. Both the American Heart Association and the European Society of Cardiology have proposed guidelines for pre-participation screening for young athletes (1,4) that focus on a pre-participation history and physical examination. The majority of conditions that put an athlete at risk of sudden death during exercise are genetically inherited diseases, hence the importance of family history in the screening process. In addition, both guidelines highlight several symptoms that, if present, require further testing: exertional chest pain or discomfort; unexplained syncope or pre-syncope; irregular heartbeat or palpitations; and excessive exertional dyspnea or fatigue. The current study results correlate with these recommendations, as none of the athletes expressed any symptoms suggestive of underlying cardiovascular disorder or revealed a family history of cardiomyopathy or premature SCD. In contrast, most of the ARVC patients (71%) reported significant cardiovascular symptoms, and many of them had familial heart disease and a history of SCD in the family. These findings highlight the importance of complete personal and family history as a feasible and highly specific initial screening tool for young athletes.
The most significant difference between these 2 screening guidelines is that the European Society of Cardiology proposal includes a standard 12-lead ECG as a screening modality, whereas the routine use of the ECG is not recommended by the American Heart Association because of considerations as to its practicality and cost-effectiveness and because of the implications of a false-positive screening test. ECG is a screening test with a relatively low specificity, especially in the athletic population because of the high frequency of ECG alterations associated with normal physiological adaptations of the athlete’s heart.
The European Society of Cardiology criteria for a positive pre-participation screening ECG examination are based on findings that are mainly diagnostic for hypertrophic cardiomyopathy, the most prevalent cardiovascular cause of SCD, but also include specific ECG findings for ARVC using diagnostic criteria (5) that include T-wave inversion in right precordial leads. The most important result in the current study of Zaidi et al. (3) highlights the low specificity of this finding. Although most of the ARVC patients demonstrated T-wave inversion on the 12-lead ECG, their distribution also included inferior and lateral leads. In addition, when compared with healthy athletes with T-wave inversion, there was no significant difference in the distribution and depth of T waves. The new finding was a difference in the preceding ST-segment, which was convex and elevated among most of the athletes, in contrast to the isoelectric ST-segment observed in most ARVC patients. Moreover, almost all of the athletes with T-wave inversion fulfilled possible or borderline criteria for the diagnosis of ARVC mainly on the basis of the ECG parameters.
These findings highlight the low specificity of the 12-lead ECG as a pre-participation screening tool in young athletes and the need for more definite diagnostic criteria for use in this setting and to refer athletes with suspected cardiac abnormalities to more specific screening modalities in order to avoid unnecessary exercise restriction due to false-positive results, particularly on the basis of ECG findings of T-wave inversion.
↵∗ Editorials published in the Journal of the American College of Cardiology reflect the views of the authors and do not necessarily represent the views of JACC or the American College of Cardiology.
Both authors have reported that they have no relationships relevant to the contents of this paper to disclose.
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