Cardiac preparticipation screening for the young athlete: Why the routine use of ECG is not necessary

Highlights

• ECG PPE screening is not a sound strategy for SCD reduction in the United States because the prevalence of SCD is low, the risk of false positives is high, and there are no outcomes studies demonstrating SCD reduction across the young athlete population.

• There is not a sufficiently trained work force in the United States to make mandatory ECG screening a helpful intervention and the reliability of ECG interpretation among experts is not sufficient for consistent results.

• There is no uniform interpretation of what is included in the denominator (i.e. the number of persons at risk) or in the numerator (i.e. what is considered a “SCD”) to calculate a standardized SCD rate.

• Assuming an SCD incidence of 17 per million athlete-years (1 in 60,000), a 5% false positive rate and a 0% false negative rate in the athletes screened; the number needed to screen (NNS) is 58,823, the positive predictive value (PPV) is 0.00034, and number of athletes who will not suffer SCD but are subject to further testing for every true positive test is 2941.

Abstract

The addition of an electrocardiogram (ECG) to the current United States athlete preparticipation physical evaluation (PPE) as a screening tool has dominated the PPE discussion over the past decade despite the lack of demonstrable outcomes data supporting the routine use of the diagnostic study for reduction of sudden cardiac death (SCD). A good screening test should influence a disease or health outcome that has a significant impact on public health and the population screened must have a high prevalence of the disease to justify the screening intervention. While SCD is publicly remarkable and like any death, tragic, the prevalence of SCD in young athletes is very low and the potential for false positive results is high. While ECG screening appears to have made an impact on SCD in Italian athletes, the strategy has made no impact on Israeli athletes, and the overall impact of ECG screening on American athletes is unclear. Until outcomes studies show substantial SCD reduction benefit, the addition of routine ECG PPE screening in young athletes should not be instituted.

Introduction

The science, ethics, economics, and social factors that affect the routine incorporation of an electrocardiogram (ECG) screening to the current United States (US) preparticipation physical evaluation (PPE) have dominated the PPE content discussions over the past decade. This debate persists despite the lack of reliable ECG interpretation [1] or demonstrable outcomes data supporting the routine use of the diagnostic study for reduction of sudden cardiac death (SCD) across the athlete population. While it is clear that the ECG used in large groups of athletes will find cardiac abnormalities, some true and some false, it is not clear that the implementation of this potential prevention strategy will do more good than harm for young athletes in the United States. Historically, the US PPE guidelines have not endorsed routine ECG screening [2], [3], [4], nor have most other countries around the world beyond elite athletes [5]. The debate has been fueled by data from Italy showing a drop in the rate of SCD in athletes age 12–35 years old from 3.9 per 100,000 athlete years to 0.4 from 1979–81 to 2002–04, respectively, after implementing a legislatively mandated screening process that included a personal and family history, cardiac physical exam, and a 12 lead ECG [6]. Since there has been no presentation of SCD data from the years prior to 1979, it is unclear if the level of 3.9 SCD per 100,000 athlete-years was an accurate baseline or simply an elevated rate to do random variation (not elevated for a decade or more leading into the study), and it is impossible to determine if the ECG is the variable that is solely responsible for the rate reduction. The current SCD rate in Italian athletes is now half that of the unscreened non-athlete group, down approximately 4 fold from 1979–81 [6]. A similar mandated program was initiated in Israel where all athletes had personal and family history, CV related physical exam, a 12 lead ECG (annual), and a symptom limited stress testing (every 4 years from age 17 to 34) completed by physicians with certifications to perform the exam [7]. The SCD rate from the decade prior to the ECG screening program compared to the decade after initiating the program was unchanged [7].

In a study of young Italian athletes, the normal ECG had a high negative predictive value and was associated with a structurally normal heart in 95% of the cases [8]. However, the ECG is not a reliable screen as it has a high prevalence of “false positive” ECG abnormalities. In one study, only 10% of 145 athletes determined to have an abnormal screening ECG had echocardiographic evidence of structural cardiac disease or defect [8]. This study also showed poor sensitivity and specificity (51% and 61% respectively) of an abnormal ECG for the identification of cardiac abnormalities, and a very low (7%) positive predictive accuracy [8]. The ECG can identify some potentially lethal cardiac abnormalities, but the ECG will not detect any athletes with congenital coronary artery anomalies [9] nor detect all athletes with cardiomyopathies, channelopathies, or ventricular pre-excitation. In a screening of 32,652 unselected athletes, the prevalence of an abnormal ECG pattern was about 12%, with less than 5% showing decidedly abnormal patterns [10]. The accuracy and precision of ECG reading in athletes have been refined and education programs are available to improve ECG interpretation, however, a trained and skilled work force is not available in most parts of the world, including the US.