Author + information
- Received March 24, 2013
- Revision received May 16, 2013
- Accepted May 28, 2013
- Published online October 1, 2013.
- William O. Roberts, MD, MS∗ ( and )
- Steven D. Stovitz, MD, MS
- ↵∗Reprint requests and correspondence:
Dr. William O. Roberts, University of Minnesota Medical School, Family Medicine and Community Health, Phalen Village Clinic, 1414 Maryland Avenue East, St. Paul, Minnesota 55106.
Objectives This study sought to determine the incidence of sudden cardiac death (SCD) during Minnesota State High School League (MSHSL) games and practices for high school (HS) athletes (12 to 19 years of age, with most age 15 to 18 years of age) using a uniform statewide pre-participation health screening examination (PPE) form every 3 years on a defined population across 19 academic years.
Background Adding electrocardiographic screening is being considered by some to reduce cardiac death rates in athletes, but the death rates in defined groups screened by the current U.S. PPE recommendations are unknown.
Methods MSHSL participation records were surveyed to determine the number of unduplicated athletes for 1993/1994 through 2011/2012 academic years, and catastrophic insurance records were used to find cardiac deaths.
Results There were 4 SCDs (2 cross country, 1 basketball, 1 wrestling), all male, during practice or games in 1,666,509 unduplicated athletes participating in ≥1 sports. The incidence of SCD in athletes screened every 3 years with a history and physical during MSHSL activities is 0.24 per 100,000 athlete-years over 19 years and 0.11 per 100,000 athlete-years over the past decade.
Conclusions The incidence of SCD in athletes screened every 3 years with standard PPE during MSHSL activities is 0.24 per 100,000 athlete-years in 19 academic years. This incidence is much lower than that observed in studies of Division 1 National Collegiate Athletic Association and Italian athletes (ages 18 to 25 and mean age 24 years, respectively). Our data do not warrant screening HS athletes with electrocardiography to prevent SCD episodes. The decision to screen athletes with electrocardiography should consider age, training intensity, and genetic predisposition.
As summarized by the Working Group of the National Heart, Lung, and Blood Institute (1), there is an active debate in the United States over the issue of cardiovascular screening of young people, including athletes and nonathletes, to prevent sudden cardiac death (SCD). Much of the debate hinges on the rate of SCD in the population of interest. Specifically, for young athletes, if the rate in the U.S. high school (HS) athletes equaled or exceeded that reported in Italy (i.e., 3.6/100,000 athlete-years) (2), then some authorities might suggest that the benefits of electrocardiographic screening outweigh the risks. Many issues affect the decision, such as the predictive value of specific tests (e.g., electrocardiography) for SCD and the costs, financial and otherwise, to evaluate athletes who test positive. A recent study of National Collegiate Athletic Association (NCAA) athletes in the United States reported an incidence of SCD ranging from 1.05 to 3.45 per 100,000 athlete-years (Division 3 and 1 athletes, respectively), but no autopsies were performed and the cause of death was not verified (3).
The Minnesota State High School League (MSHSL) governs interscholastic activities in the state and is a member of the National Federation of High Schools. In the late 1980s, the MSHSL Sports Medicine Advisory Committee developed a standardized sports pre-participation history and physical evaluation (PPE) form for medical providers to clear HS athletes for participation. The form is reviewed and updated annually by the Sports Medicine Advisory committee. In 1992, it was revised to conform to the recommendations of the Preparticipation Physical Examination Monograph, 1st Edition (4), and the form has been updated with each monograph edition and intervening PPE literature like the American Heart Association (AHA) cardiovascular pre-participation recommendations. The current form is based on the Preparticipation Physical Evaluation Monograph (4th Edition) (5), and AHA cardiovascular PPE recommendations (6).
In 1993, the MSHSL began to record individual athlete-years, in addition to the cumulative sports season participation that is reported annually to the National Federation of High Schools. The MSHSL requires that each athlete have catastrophic incident insurance, and the policy provides payment for sports-related deaths that occur during MSHSL games and practices. Payments are an accurate reflection of deaths that occur during MSHSL activities, and the numerator and denominator are concordant with the screened population at risk.
The purpose of this study was to determine the incidence of SCD during MSHSL games and practices for HS athletes (age range 12 to 19 years with most age 15 to 18 years) screened every 3 years with a standardized statewide PPE form that currently includes all components of the 2007 AHA cardiovascular PPE recommendations (6) using actual unduplicated athlete numbers.
This was a retrospective evaluation of MSHSL records for each academic year from 1993/1994 through 2011/2012. Because many athletes participated in >1 sport, we first determined the total number of athlete-seasons and unduplicated athletes. The unduplicated athlete records did not include specifics for sex or age. The catastrophic insurance (required for all MSHSL athletes) records were used to find cardiac deaths that occurred during HS-related practice or games. All deaths that occur during MSHSL sports practices and games are reported for insurance purposes, and events not associated with MSHSL activities do not enter the reporting system. Incidence rate was calculated by dividing the number of SCDs by the number of (unduplicated) athlete-years. This study was considered de-identified data by the University of Minnesota Institutional Review Board.
Over 19 academic-years (from 1993/1994 through 2011/2012), there were 3,925,512 athlete-seasons, 2,085,366 boys and 1,739,168 girls. There were 1,666,509 unduplicated athletes participating in ≥1 sports per academic-year (2.35 sports seasons/athlete/academic-year). Four SCDs occurred during practice or games, all in males (2 cross country, 1993/1994 and 2002/2003; 1 basketball, 1995/1996; 1 wrestling, 2001/2002). Thus, there were 0.24 deaths/100,000 athlete-years (Table 1).
This study, analyzing data from MSHSL student athletes screened every 3 years with a standardized PPE form, reveals a very low incidence of SCD during HS sports competitions and practices. The incidence of SCD in the MSHSL athlete is substantially lower than that in other studies (e.g., Italy, especially in their pre-electrocardiography years ) and NCAA college-age athletes, especially those of African-American descent, who were screened with only history and physical evaluation (3). Of importance, the subjects in the Italian study (average age, 24 years; range, 12 to 35 years) and the college study (age range, 18 to 25 years) were older than HS age. As shown in Table 1, compared with the MSHSL SCD rate from our study, the Italian pre-electrocardiographic screening (1979 to 1981) rate was 15 times higher, the rate for 1982 through 2006 was 7.9 times higher, and the rate for 2001 through 2004 was 1.8 times higher. The current PPE process combined with the emergency action plan program, “Anyone Can Save a Life (MSHSL),” appears to be effective in reducing the risk of SCD in HS athletes. Our data do not support electrocardiographic screening in the HS population.
There is an active debate in the United States regarding the need to mandate electrocardiographic screening before athletic participation. Can SCD rates be lowered in a manner in which the benefits (fewer deaths) would not be outweighed by the risks, particularly the ramifications of false-positive test results in human and financial costs? Implementation of electrocardiographic screening comes at a price in human cost (unnecessary exclusion from activities, iatrogenic complications of therapy, developing “cardiac cripples,” and anxiety for the families involved) and financial cost of screening ECGs and the evaluation of inevitable false-positive ECG interpretations in a provider corps that is not specifically trained to read ECGs in HS athletes. Although there is a cost to the present-day MSHSL exam screening, it serves several other purposes beyond cardiovascular risk screening, including putting a teenage athlete with a medical provider to screen for other medical and social problems and to provide education for potentially deadly at-risk behaviors common in this age group.
The current PPE standard for the United States and used in Minnesota is modeled after the recommendations of the 2007 AHA committee (6). This calls for a cardiovascular history and physical exam, and then further case finding diagnostic testing, such as an ECG, only if warranted by a personal or family history finding or an abnormal exam finding. The MSHSL PPE form has been used statewide since the late 1980s and since 1992 has been modeled on the Preparticipation Physical Evaluation Monograph (Editions 1 through 4). The current MSHSL form gives providers a “pilot's checklist” to reduce the risk of missing important history questions and moving potentially at-risk athletes into the pool of athletes requiring further evaluation. This form seems to be effective in removing at-risk athletes from the active athlete group until cleared for sports activity. The MSHSL data do not support adding electrocardiographic screening to the current screening protocol for reducing SCD in HS athletes. Although all states require PPEs for HS athletes, several have no standardized statewide exam form, and a trial of standardized form use should be implemented across the nation before considering the addition of electrocardiographic screening in HS-age athletes.
The Italian data have been interpreted by many to suggest that electrocardiographic testing before athletic participation is warranted (7). However, there are many limitations to the Italian study design, such as the lack of an unscreened athlete control group, known limitations and biases inherent in retrospective data versus prospective data, and the fact that multiple interventions were introduced simultaneously, not only electrocardiography (2). The Italian athlete data extend to an older age group, and older than HS-age athletes may be at greater risk as implied by the NCAA data reported by Harmon et al. (3). Perhaps the Italian athletes in the HS age group could be equally protected from SCD with the use of a standardized PPE form as is done in Minnesota and thus eliminating electrocardiographic screening in the Italian HS age group of athletes might have minimal effect on SCD rates.
The strength of our study is that we were able to evaluate in a systematic manner all student athletes who participated in PPE screening every 3 years and all who died during participation over the past 19 years. Based on these data, we would not suggest adding an ECG to the HS screening evaluation in Minnesota HS athletes. Of note, a 2009 study by Maron et al. (8) also involved SCD in the state of Minnesota from 1994 to 2004 that likely includes 3 of the deaths in our database. That study included athletes 12 to 31 years of age who did not all receive PPEs using the standard form of the MSHSL and included college and professional levels with estimated athlete-years (8). So the Maron et al. study may be less useful to policymakers trying to decide whether to implement electrocardiographic screening at the HS level.
The database does not include athletes who experienced a sudden cardiac arrest during MSHSL practice or games and lived, nor does it include SCD that occurred outside the auspices of MSHSL sports activities. The MSHSL has informally tracked cardiac events in Minnesota HS students since the year 2000 to look at the effectiveness of the League-sponsored emergency action plan that shows 12 student (presumed) cardiac events, including 8 students who lived due to the use of an automatic external defibrillator or an emergency action plan. Three of the 4 deaths occurred away from school campuses, and 7 students were not involved in HS sports (e.g., graduation party, open gym, gym class, basketball spectator). Thus, there were more cardiac events in this age group than were counted by our methods, but the denominator for this informal cohort is all Minnesota HS students rather than screened athletes alone. Although the MSHSL mandates that all athletes undergo a PPE before sports participation, there is no common database to collate the exam results and outcomes, nor is there a means to determine who or why an athlete was excluded from participation. A limitation to extrapolating these data is that Minnesota has a lower proportion of African Americans than the general U.S. population, (5.4% vs. 13.1%, respectively), according to the last U.S. census statistics (9), and previous reports found that African-American athletes experience SCD at higher rates than whites (3). The data also should not be extrapolated to older age groups based on the NCAA study (3).
Our findings suggest that mandatory electrocardiographic testing would not be beneficial to preventing deaths in similar cohorts to Minnesota HS athletes. The incidence of SCD is extremely low in MSHSL athletes, and there were, in fact, no deaths in the past 9 years of the study; it would be impossible to improve on that statistic by adding an ECG. The use of a standardized, regularly updated, and statewide approach to the PPE consistent with current guidelines may well be the key to the SCD rate. The low MSHSL rate could also be, in part, due to the aggressive MSHSL program to equip all HSs with automatic external defibrillators and to implement emergency action plans in all schools (MSHSL Anyone Can Save a Life Program).
The incidence of SCD in athletes screened every 3 years with a standard PPE form during MSHSL activities is 0.24 per 100,000 athlete-years over the past 19 academic years and 0.11 per 100,000 athlete-years over the past decade. This incidence is much lower than that observed in retrospective studies of Division I NCAA and Italian athletes (ages 18 to 25 years and mean age, 24 years, respectively). Our data do not warrant screening HS athletes with electrocardiography to prevent SCD episodes. The decision to screen athletes with electrocardiography should consider age, training intensity, and genetic predisposition to avoid unnecessary false-positive test results and unintended consequences.
Both authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- Abbreviations and Acronyms
- American Heart Association
- high school
- Minnesota State High School League
- National Collegiate Athletic Association
- pre-participation health screening examination
- sudden cardiac death
- Received March 24, 2013.
- Revision received May 16, 2013.
- Accepted May 28, 2013.
- American College of Cardiology Foundation
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- ↵United States Census Bureau. Available at: http://quickfacts.census.gov/qfd/states/27000.html. Accessed March 20, 2013.