By Dave Siebert, MD, @DaveMSiebert
When medical students learn about hypertrophic cardiomyopathy (HCM), one fact often resonates as a shocking and tragic reality: it frequently first presents as sudden death. Yet HCM is just one of a heterogeneous list of pathologic structural and electrical cardiac disorders that can cause sudden death in athletes without prior warning. This troubling fact presents many challenges to clinicians striving to protect athletes from catastrophic incidents on the field of play.
The decision to screen an asymptomatic patient for disease is not always clear cut. The scientific literature is constantly in flux, requiring those that make medical recommendations to continually re-evaluate the best available evidence. When that evidence starts to conflict with historical practices, controversy often results.
Screening athletes for silent cardiovascular disease – such as HCM, long QT syndrome (LQTS), and arrhythmogenic right ventricular cardiomyopathy to name a few – is no different. However, the evidential landscape is in the midst of a dramatic shift.
In their recent BJSM manuscript1, Drs. Jonathan Drezner, Kimberly Harmon, Irfan Asif, and Joseph Marek present a critical review of cardiovascular screening in young athletes. They discuss a number of factors to consider when deciding whether or not to add an electrocardiogram (ECG) to the standard athlete pre-participation physical exam. Those factors include: (1) the consistent, strong evidence suggesting sudden cardiac arrest and death (SCA/D) are much more common in certain athlete subgroups2,3; (2) evidence-based methods to risk stratify and manage patients found to have a cardiovascular condition, such as Wolff-Parkinson-White4, HCM5, or LQTS6 exist; and (3) when implemented by physicians experienced in athlete ECG interpretation using modern criteria, many conditions associated with a higher risk of SCA/D can be detected with a false-positive rate of less than 2.5%7,8.
The authors also address the very concept of cardiovascular screening itself: “The premise of CV screening in athletes is that early detection of cardiac disorders associated with SCD can reduce morbidity and mortality through individualized and evidence-driven disease-specific management. Without believing in the benefit of early detection, then screening by any strategy is called into question. If one believes in early detection, screening by history and physical examination alone is inadequate.”
In September 2016, the American Medical Society for Sports Medicine (AMSSM) brought widespread attention to this dilemma with the publication of its Position Statement on Cardiovascular Preparticipation Screening in Athletes9. The consensus panel concludes that “the current (Preparticipation Physical Evaluation), while pragmatic and widely practiced, is limited in its ability to identify athletes with conditions at risk for SCA/D.” Moreover, the group discusses their concern that standardized symptom and family history questionnaires demonstrate a high false positive rate, sometimes surpassing 30%. Ironically, a high false positive rate is frequently cited as a potential pitfall of ECG screening, but the numbers aren’t comparable.
Where does the most recent evidence truly lie?
In two independent studies7,8, standard pre-participation history and physical exams failed to identify each of eight college athletes found to have potentially lethal cardiac disorders detected by screening ECG. At the same time, in one of these studies8, 37.2% of athletes reported one or more positive responses on a history questionnaire, and 3.5% had abnormal physical exam findings. The false-positive rate for an abnormal ECG, on the other hand, was just 2.2%.
Said another way, standard history or physical exam data were positive in over one-third of athletes but did not yield a single meaningful cardiac diagnosis. Conversely, each diagnosis that was made was done so solely by ECG during an otherwise negative screen.
Importantly, proponents for more intensive cardiovascular screening state that national mandates for ECG screening are not appropriate1,9. Rather, they call for the development of a trained physician infrastructure to conduct more effective screening for targeted athlete populations.
One of the most important characteristics of a screening tool is its ability to detect the disease in question in its pre-clinical state. However, many of the cardiovascular conditions relevant to young athletes often first present as sudden death in an otherwise asymptomatic patient. As such, the practice of relying on a symptom questionnaire is inherently called into question.
When deciding whether or not to add an ECG to the standard history and physical exam to screen for silent, potentially lethal cardiovascular diseases, a clinician must remember to ask themselves one simple question: What am I really looking for? After all, widespread agreement about the purpose of cardiovascular screening, achieving early detection of athletes with at-risk disorders, already exists. However, the standard history and physical exam just isn’t enough.
It’s time to refocus.
1Drezner JA, Harmon KG, Asif IM, Marek JC. Why cardiovascular screening in young athletes can save lives: a critical review. Br J Sports Med. 2016 Nov;50(22):1376-1378.
2Harmon KG, Asif IM, Maleszewski JJ, Owens DS, Prutkin JM, Salerno JC, Zigman ML, Ellenbogen R, Rao AL, Ackerman MJ, Drezner JA. Incidence and etiology of sudden cardiac arrest and death in high school athletes in the United States. Mayo Clin Proc. 2016 Nov;91(11):1493-1502.
3Harmon KG, Asif IM, Maleszewski JJ, Owens DS, Prutkin JM, Salerno JC, Zigman ML, Ellenbogen R, Rao AL, Ackerman MJ, Drezner JA. Incidence, cause, and comparative frequency of sudden cardiac death in National Collegiate Athletic Association athletes: a decade in review. Circulation. 2015 Jul 7;132(1):10-9.
4Rao AL, Salerno JC, Asif IM, Drezner JA. Evaluation and management of Wolff-Parkinson-White in athletes. Sports Health. 2014 Jul;6(4):326-32.
5Maron BJ, Rowin EJ, Casey SA, Lesser JR, Garberich RF, McGriff DM, Maron MS. Hypertrophic cardiomyopathy in children, adolescents, and young adults associated with low cardiovascular mortality with contemporary management strategies. Circulation. 2016 Jan 5;133(1):62-73.
6Johnson JN, Ackerman MJ. Return to play? Athletes with congenital long QT syndrome. Br J Sports Med. 2013 Jan;47(1):28-33.
7Fuller C, Scott C, Hug-English C, Yang W, Pasternak A. Five-year experience with screening electrocardiograms in National Collegiate Athletic Association Division I athletes. Clin J Sport Med. 2016 Sep;26(5):369-75.
8Drezner JA, Prutkin JM, Harmon KG, O’Kane JW, Pelto HF, Rao AL, Hassebrock JD, Petek BJ, Teteak C, Timonen M, Zigman M, Owens DS. Cardiovascular screening in college athletes. J Am Coll Cardiol. 2015 June 2;65(21):2353-5.
9Drezner JA, O’Connor FG, Harmon KG, Fields KB, Asplund CA, Asif IM, Price DE, Dimeff RJ, Bernhardt DT, Roberts WO. AMSSM position statement on cardiovascular preparticipation screening in athletes: current evidence, knowledge gaps, recommendations and future directions. Br J Sports Med. 2016 Sep 22.