Although sudden cardiac death (SCD) in a young athlete is uncommon, it is usually highly visible and generates a significant amount of media and community attention to the death of a seemingly healthy young athlete. Medical providers, family members, coaches, and athletes wonder what more could have been done. SCD has many possible potential causes including structural or electrical cardiac causes, some of which may be identified with an electrocardiogram (ECG) and potentially managed with medical devices, medications, or activity modification. This possibility of early identification makes the use of an ECG as a possible screening tool appealing to many; however, this is a very complex and controversial area in sports medicine.
The ECG screening debate first gained ground after the Italian experience with mandatory ECG screening in their athletes demonstrated a relative risk reduction in SCD by 89% in the Veneto region of Italy from 3.6/100,000 person-years (1979 to 1980) to 0.4/100,000 person-years (2003 to 2004) (8). This dramatic reduction in SCD in athletes with the addition of an ECG to the usual screening practice seemed like a potential method to significantly reduce young athlete deaths. U.S. critics, however, noted that the addition of an ECG to screening in Italy only reduced the rate of SCD compared with the current rate of SCD in the United States, which was obtained without an ECG, and came at the cost of an overall disqualification rate of nearly 2%. Further, the most common cause of death in the homogeneous Veneto region of Italy was arrhythmogenic right ventricular cardiomyopathy (ARVC), not hypertrophic cardiomyopathy (HCM) like that in the United States (25). Additionally, the Italian data only reflect a change in exertional sudden death rate from the detection of this ARVC; there was no significant change in disqualification rates during the screening program from other potential cardiac etiologies of SCD such as HCM, Wolff-Parkinson-White syndrome (WPW), or long QT syndrome. Finally, it was unclear if data from such a homogeneous northern European population would translate to the heterogeneous, mixed population like that found in the United States.
The University of Washington group has done a great deal of work over the last several years advancing the science of sudden death in athletes while challenging the status quo of the traditional preparticipation examination (PPE) as outlined in the fourth edition of Preparticipation Physical Evaluation (PPE monograph) (1). Specifically, they have validated the role of automated external defibrillators (AED) at the field side and have significantly contributed to the literature on interpretation of the ECG in the athlete (11,19). Although their research has clearly challenged the “value added” of the standard PPE in mitigating the risk of SCD, they have suggested that the addition of an ECG is a potentially valuable adjunct. However, despite their work, much controversy still exists.
Recently, the two largest bodies of cardiologists in the United States, the American Heart Association (AHA) and the American College of Cardiology (ACC), have chosen not to endorse universal ECG screening, noting significant problems including the large false-positive rate, an increased level of anxiety to athletes secondary to screening, a lack of demonstrated outcome difference with this intervention, ethical considerations, and the prohibitive cost of a large-scale screening program (24). Further, screening is challenged because of the low prevalence of disease with the inherent risks of false-positive and false-negative results, lack of infrastructure to perform such screening, the real risks of the follow-up procedures, testing and interventions, the second- and third-order cost effects, and most importantly, the lack of outcomes data that demonstrates that the benefit of the ECG exceeds the risk. In agreement with the PPE monograph, the ACC, and the AHA, at this time, there is not enough evidence to support the addition of an ECG to the screening process to save lives of young athletes.
In order to understand the scope of the problem, accurate estimation of SCD is critical. This information is needed to implement appropriate preventive strategies and to inform policy makers how to best allocate resources. Several studies have attempted to determine the incidence of disease. A recent state-of-the-art review concluded the incidence of SCD in athletes to be 1 in 50,000 college athletes and 1 in 80,000 high school athletes (18). Additionally, it was determined that NCAA Division 1 basketball players are at higher risk of exertional sudden death at 1/5,200 athlete-years (AY) compared with all other NCAA athletes, 1/53,703 AY (17). These numbers also have been reported per 100,000 person-years and vary from 0.5 to 2.3 per 100,000 person-years (26). A further study of college athletes found that death from drugs and suicide had essentially the same incidence of SCD as athletics (1.3 per 100,000 vs 1.2 per 100,000) (26). Despite these studies, the true incidence likely remains elusive because of a variety of reasons including problems with definition, incomplete reporting, and determination of the true number of participants. However, even if we accept these rates as reported above, the incidence is still very low, especially when compared with other conditions that affect young people. So, although the relative risk of sudden death seems to be higher in young athletes, the absolute risk of SCD in young athletes is actually quite low.
Many studies of SCD in young athletes cite HCM as the most common cause of exertional death; however, recent research questions this assumption. An autopsy review of deaths in young military personnel demonstrated that most deaths were actually unexplained and not attributed to a specific cardiac etiology, and the number of deaths from coronary artery disease was higher than expected (14). This observation was further supported by Harmon et al. (17), as it now seems that the most common cause of nontraumatic exertional sudden death in young athletes is still unknown. In fact, because we are now learning that many of the SCD in young athletes and warriors lack a specific cardiac etiology, it is hard to assume that an ECG would add value in the evaluation process. Further, it is important to note that other etiologies of sudden death such as early coronary artery disease or coronary artery anomaly will not be detected with a resting ECG.
A good screening test should have the ability to influence a disease or health outcome that has a significant impact on public health during the asymptomatic period where detection is possible with demonstrated improvement in long-term outcomes improved by treatment during the asymptomatic period (35). Further, a screening test should be sufficiently sensitive, specific, and acceptable to patients. Finally, the population screened must have a high enough prevalence of disease to justify screening in the first place, and patients must be willing to comply with the additional evaluation and early treatment in order for the screening program to be successful (35).
It could be argued that the prevalence of SCD in young athletes is actually very low, which lessens its public health impact, and as such may magnify the adverse consequences of false positives on the screening process (29). In a mathematical modeling study of population risk using the Italian statistics for ECG screening when applied to a UK athlete population, it was concluded that a required ECG would be more of a harm than a benefit from a public health perspective, with a small impact on population health and a potentially great cost to the athlete (15). The end result of the modeling study found that in order to prevent one case of SCD, 38,150 athletes would need to be screened and almost 800 athletes would be inappropriately excluded from competition (15).
Several disease states, such as WPW or HCM, may be detectable with an ECG in the asymptomatic period, but it is unclear whether this early recognition actually saves lives or alters the course of disease. Although the false-positive rate has been reduced by both the Seattle (11) and refined criteria (28), the false-positive rate is still around 6% (19). Further, it must be remembered that not all causes of SCD will present with an abnormal ECG, so the false-negative rate is also an important consideration. It has been demonstrated that up to 10% of cases of HCM will have a negative ECG (30) and that 1/3 of the cases of ARVC will have a negative ECG (38). Because criteria are modified to improve the false-positive rate, biostatistics would prove that this will increase the rate of false negatives.
Further, medical care (cardiology consultation or follow-up) may not be accessible for many young athletes, especially those in the inner city urban or rural parts of America. The treatment after the abnormal ECG may result in disqualification from sports, and many young athletes will not be willing to comply with this recommendation and are going to participate in sports anyway, but in an unorganized manner in a location without resources such as medical personnel and AED. Even if specialty care is available, the delineation between benign physiological adaptations of the athlete’s heart from pathological conditions remains challenging because there is no single test to make this determination, and downstream costs for advanced testing, such as cardiac magnetic resonance (CMR) imaging, may be prohibitive, making this determination very difficult.
When reevaluated as a screening test, it is unclear that the ECG meets the demand for an appropriate screening test. The incidence of disease remains very low, which may not meet the threshold as a significant public health problem. At this time, it is unclear if treating an asymptomatic ECG abnormality early in the course of disease provides a long-term benefit. Despite efforts to improve the sensitivity of the screening, the number needed to screen to save one life may be too high for the system to support, and as sensitivity increases, the corresponding specificity decreases. Finally, there may not be an acceptable treatment in terms of compliance, cost, and accessibility to justify the ECG in a pure screening sense.
Infrastructure and Clinical Agreement
Implementation of ECG screening will further be challenged by the relative lack of infrastructure in the United States to perform screening and follow-on testing. A group of British sports cardiology experts stated, “Sudden death in the sports arena remains rare, and ECG cannot identify all conditions associated with SCD. Due to the overlap between physiological ECG changes in athlete’s heart and similar changes in pathological states, it is important that evaluation is performed by highly trained cardiologists and sports physicians with expertise and experience in dealing with athletes and the complex phenotypic expression of inherited cardiac diseases” (7).
From this, it is clear that this is a complex problem and that an infrastructure of highly trained cardiologists and sports physicians capable of differentiating between normal and abnormal in athletes is necessary. To address this, specific ECG criteria have been developed (9,11,28) and an online teaching module (3) has been created to help close this gap. Although these tools may increase baseline knowledge and make interpretation easier, it is unclear how many community-based physicians are aware of these tools. Further, even when physicians (primary care, sports medicine, or cardiologists) are equipped with interpretation guidelines, interrater agreement between specialists has demonstrated only limited reliability and validity (5,23). When screening for uncommon entities, limited interrater agreement increases both the rate of false positives and false negatives, thus limiting the reliability of the test as a screening process. So it appears that despite the efforts to simplify interpretation with specific criteria, the concordance and reliability of ECG interpretation still remain low, and this must be improved in order to support the system. Finally, the lack of infrastructure of trained and knowledgeable specialists limits screening and must be further developed before widespread implementation of ECG screening.
Risk of Follow-up Testing/Procedures
A major concern of ECG screening is that many of the ECG abnormalities found on screening require follow-up confirmatory or diagnostic procedures, which are not devoid of risk. The risks include psychological harms from being labeled with a diagnosis or being disqualified from play (2). Further, the risks from devices or therapies may actually be higher than the risk of SCD itself (33). Risks associated with diagnostic electrophysiology (EP) procedures include arterial injury, thrombus formation, or inducement of significant arrhythmia (22). Ablation procedures are associated with a 5% to 8% complication rate (21), which may then lead to implantation of a pacemaker and limitation in physical activity. Automated implanted defibrillators carry an overall complication rate of 11.5% and risk of death in 1 in 500 insertions. Although finding WPW, often cited as a condition, during ECG screening shows a successful outcome, the risk of an adverse event or fatality in the EP laboratory may be greater than the risk of the first presentation of WPW as SCD; thus, the use of EP for diagnosis or ablation in asymptomatic individuals is very controversial (6,31).
A life-saving intervention may be judged to be cost-effective if the cost is less than $50,000 per year of life saved (37). When the cost of an ECG with history and physical examination was compared with no screening at all, the cost was found to be $76,100 (34). However, in this model, the price for the ECG was set at $5, which is a rate only feasible with a large cadre of trained volunteer physicians/technicians. More typically, an ECG performed in an office setting or submitted for reimbursement would cost $19 to $40 per test, which would significantly increase the cost per life saved. Further, these cost-benefit analyses did not factor in follow-up testing such as echocardiograms or CMR imaging, which may be needed after an abnormal ECG.
It has been estimated that the United States has approximately 8.5 million young athletes, which would cost the health system about $2.5 to $3.4 billion per year. This figure was calculated using the incidence of SCD at 4 per 100,000 AY with a cost per ECG of $39 (16). With the actual incidence of SCD possibly lower and with a lower negotiated ECG rate, this figure could be lowered, but it would still be a substantial economic burden to the health care system. Opponents of this model argue that an ECG could be performed for free or at a very low cost, but it will be very hard to reach the volume of young athletes in America solely with volunteer physicians. Further, in today’s medical legal climate, many primary care physicians are likely to seek a cardiology over-read, which will drive this cost even higher.
Another cost implication is at what interval should screening be performed. HCM is inherited as an autosomal dominant genetic condition but has variable penetrance — morphological expression of HCM may not appear until late adolescence or early adulthood (12). Therefore, a one-time ECG in a high school athlete may miss a developing cardiac abnormality and would potentially require yearly or biennial screening, which would double or triple the initial cost estimate.
Finally, the long-term cost that is not often accounted for in cost-benefit analyses is the long-term cost of falsely labeling an athlete as positive and restricting them from play. In addition to the loss of enjoyment from sports activity, or the possibility of future employment in athletics, there are potentially years lost from unnecessary restrictions in physical activity.
It is clear that not all disease processes that lead to SCD can be discovered by screening and that sudden cardiac arrest (SCA) will continue to occur in athletic settings. Rich Peverly, a National Hockey League forward for the Dallas Stars, was screened with history, physical examination, and ECG before clearance to play but still experienced SCA during play — fortunately, he was defibrillated just behind the bench area and survived. So despite the best efforts to detect etiologies that could cause SCA/SCD, these events still occur, and the best chance of survival lies in having rapid access to defibrillation and an emergency action plan (EAP).
Having an AED on-site at an athletic competition saves lives. In SCA that occurred in a high school setting, 64% survived to hospital discharge if there was an AED on-site compared with only 11% if emergency medical service (EMS) was called and defibrillation was delayed (12). Further, the AHA endorses recommendations that every school that cannot achieve an EMS call to shock time less than 5 min have an AED on-site (20). This is further recommended by a multiagency task force of 15 national medical and sports medicine organizations, which reached a consensus that high school and college athletic programs should have access to an AED with a goal of less than 3 to 5 min from collapse to shock (13).
Saving lives in young athletes goes beyond an AED. Every organization that sponsors sports should have a written EAP that outlines emergency procedures and protocols. This EAP should be sports and venue specific and should be developed in coordination with local EMS, school officials, and administrators, and should be routinely reviewed with those personnel who will be on the field side (coaches, athletic trainers, physicians, etc.) (10).
The remarkable and tragic nature of a young athlete’s death leaves many wondering if something could have been done to prevent the SCD. Because sudden death is often cardiac in nature, an ECG as a screening tool seems appealing. However, before widespread implementation of ECG screening could even be considered, several questions must be answered. First, is there a link between asymptomatic screening ECG findings and improved health outcomes? What are the actual second- and third-order cost effects of ECG screening and what are the actual risks? What cost per life saved is acceptable for society? In order to determine these things, we need large-scale randomized clinical trials to measure outcomes prospectively; however, because of the very low incidence of SCD, this would require a very large sample size or a large-scale registry. Finally, what are the infrastructure resources needed to conduct ECG screening?
As we conclude this discussion on ECG screening, there are many similarities to prostate-specific antigen (PSA) and prostate cancer screening. When introduced, the PSA revolutionized prostate cancer screening. It was believed that a screening program that could identify asymptomatic men with early disease would substantially reduce morbidity and mortality, and many professional societies supported the PSA’s use for routine screening (27). These elevated PSA led to prostate biopsies, radiation therapy, and surgery to cure early stage cancers. However, the decision to fully implement PSA was done in the absence of efficacy data from randomized trials (4). The first efficacy trial, the European Randomized Study of Screening for Prostate Cancer, reported a small survival benefit after 9 years of follow-up; however, 48 people would need to undergo invasive testing and be diagnosed with prostate cancer to prevent one prostate cancer death (32). Further, there was a growing body of data showing the harms from early aggressive treatments in the asymptomatic period, including erectile dysfunction, urinary incontinence, and bowel problems, without a significant difference in survival rates or disease outcomes (36). After the outcomes results, the American Urological Association (AUA) and the United States Preventive Services Task Force changed their stance and recommended against screening based on this risk-to-benefit ratio. The AUA further changed their recommendation to using a “shared decision-making” approach for men who desired prostate cancer screening where a full discussion of risks and benefits of screening was factored into the screening decision.
There are many parallels here with the excitement and possible benefits of an ECG in the prevention of SCD. And it may hold that deciding on the use of ECG screening before there are outcomes data, despite good intentions, also may lead to more harm than benefit. Therefore, it would seem that if an ECG were to be recommended at this time, before evidence exists regarding the long-term risks and benefits of ECG screening, we would support using a similar “shared decision-making” process where athletes are given the ability to make an informed decision to “opt in” or “opt out” of the additional testing. Before widespread ECG screening can be recommended, further study is needed; in fact, we may learn once again that more is not necessarily better and that less can be more.
Dr. O’Connor works for the U.S. Army and Department of Defense. The views and opinions expressed herein are the private views of the authors and do not reflect the views of the U.S. Army or the Department of Defense.
The authors declare no disclosures or financial conflicts of interest.
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