Screening, Sideline Prep and Sudden Cardiac Death
Screening, Sideline Prep and Sudden Cardiac Death
The electrocardiographic screening of young competitive athletes has prompted a robust debate as to the true incidence of sudden cardiac death (SCD) in this population, and the effectiveness of preventive screening strategies. Although the International Olympic Committee and the European Society of Cardiology advocate that all young competitive athletes be screened routinely with a 12-lead electrocardiogram (ECG) (in addition to history and physical examination), the 2007 American Heart Association (AHA) guidelines do not make this recommendation. Instead, the AHA guidelines advocate for use of the "12 AHA elements" in screening examination forms, and if cardiac disease is found, then use of the American College of Cardiology (ACC) 36th Bethesda Conference to make participation decisions. In the absence of a randomized clinical trial showing clear superiority of one method of screening over another, a small number of retrospective observational studies are available to support or refute these screening practices.
The 1998 report from the U.S. National Registry of Sudden Death in Athletes estimated the annual SCD rate in the American high school athlete to be one in 217,000 (0.44/100,000) athlete-years. This figure has been rather constant and has been widely accepted over the years as the best estimate of American athlete SCD rate. However, an independent report in 2011 from the National Collegiate Athletic Association (NCAA) challenged the accuracy of this number, suggesting that the annual SCD rate may be as high as one in 43,770 (2.28:100,000) athlete-years in the general collegiate population or even higher, one in 3,126 (31.98:100,000) athlete-years in certain subgroups (male Division one basketball players).
Given the discrepancy between the U.S. National Registry data, and the recent NCAA report, the data presented by Roberts and Stovitz are timely and relevant. For the past 19 years in Minnesota, athlete screening has consisted of standardized preparticipation evaluation (PPE), containing history and physical with AHA elements, and 36th Bethesda Conference athlete restrictions (when indicated). Electrocardiography was not performed routinely. An aggressive emergency action plan (every school equipped with automated external defibrillators) was implemented for any collapsed athlete after year 2000. This care model is consistent with what the AHA has recommended and what is endorsed by the ACC. To assess rate of SCD, authors analyzed the records of 1,666,509 unduplicated Minnesota high school athletes participating in ≥1 sports from 1993/1994 through 2011/2012. Occurrences of SCDs were determined by searching Minnesota State High School catastrophic insurance claims data for cardiac causes of death. Only SCDs occurring during games or practices were captured; successfully resuscitated SCDs (cardiac arrests) were not included.
Four SCD episodes (all male, 2 cross country, one basketball, one wrestling) occurred over the 19-year study period, and none over the most recent 9 years. Calculated SCD rate was 0.24 in 100,000 athlete-years over 19 years, and 0.11 in 100,000 for the past decade. The incidence of SCD was very low in these high school athletes compared with rates observed in Division one NCAA and Italian athletes (ages 18 to 25 and mean age, 24 years, respectively). This was attributed to a differences in study populations (age and level of sports), a preponderance of white subjects in the study cohort (the SCD rate is probably lower in white athletes compared with blacks), and methodological differences. The authors concluded there was a very low incidence of SCD among Minnesota high school athletes during sports participation (games and practices) with the use of current screening strategies and emergency plans, and that addition of screening with electrocardiography to prevent SCD episodes is not warranted in Minnesota high school athletes.
This study is illustrative of many of the issues faced in sports cardiology and has profound relevance to the ECG debate. It helps refine what we know about the epidemiology of SCD in young American athletes, demonstrates what can be achieved through meticulous application and continuous improvement of existing clinical tools (exclusive of screening 12-lead ECGs), and provides an analysis of SCDs in high school athletes that has practical application for Minnesota high school medical personnel and policymakers.
Absolutely vital to the ECG debate is the need to accurately define the true rate with which SCDs occur. This information influences the design of clinical trials and measurement of outcomes in athletic populations, affects the priority that is given to SCD events compared with other healthcare issues that affect young athletes, assists medical teams with event planning and emergency preparedness, and allows healthcare providers to counsel athlete patients on the risks of participation. In the absence of mandatory registries in well-defined populations, investigators have mined existing data repositories (intended for other purposes) for any helpful information. However, authorities have questioned the accuracy of such reports given the data sources and inaccuracies in estimating the population at risk.
As researchers become more able to identify SCD events within large populations that can be accurately sized, the true rates of SCD in specific athletic populations is becoming more evident. For example, in a recent study of long-distance runners, race medical directors calculated a cardiac arrest rate of 0.54:100,000 among marathon and half-marathon participants (n = 10.9 million); 71% of arrests were fatal (29% resuscitated). Thus, the SCD rate was 0.39:100,000. Similar precision is required in other athletic populations to answer sports-specific questions on outcomes, priorities, event preparation, and risk.
Compared with other studies in high school athletes, the study by Roberts and Stovitz is unique in its methodology and analysis. Concerning the rate calculation, only SCDs that occurred during games or practice were identified and included in the numerator, whereas only individual, unduplicated athletes were identified and included in the denominator. There was no statistical manipulation of data to estimate the population at risk. The SCD incidence of 0.24/100,000 athlete-years over the 19 years, is much lower than what was observed in the overall NCAA population (2.28:100,000), lower than the most recent Italian rates (0.43:100,000), and lower than what was recently reported by another investigator analyzing a very similar cohort (0.7:100,000). In this unusual situation, both Roberts and Stovitz and Maron independently reported on the same group of Minnesota high school athletes. Results were different by approximately 3-fold. This might be explained by differing reporting time frames (19 years vs. 26 years) and rate calculations (one data source for SCDs/unduplicated athletes vs. multiple data sources for SCDs/estimate of athletes at risk). Regardless of the different outcomes, there is encouraging information in both reports. Both investigators confirmed low SCD rates and that the rates appear to be decreasing over the most recent decade in the Minnesota high school population. Unique to the analysis of Roberts and Stovitz is its ability to link American screening strategies to cardiac outcomes on the playing field. To my knowledge, this appears to be a rare demonstration of the association between the two in any American athletic population. Returning to the ECG debate, it does not appear that an ECG would bring any added value here, as it would not be possible for Minnesota to improve on its present SCD rate of zero over the most recent 9 years in its high school athletes.
The electrocardiographic screening of young competitive athletes has prompted a robust debate as to the true incidence of sudden cardiac death (SCD) in this population, and the effectiveness of preventive screening strategies. Although the International Olympic Committee and the European Society of Cardiology advocate that all young competitive athletes be screened routinely with a 12-lead electrocardiogram (ECG) (in addition to history and physical examination), the 2007 American Heart Association (AHA) guidelines do not make this recommendation. Instead, the AHA guidelines advocate for use of the "12 AHA elements" in screening examination forms, and if cardiac disease is found, then use of the American College of Cardiology (ACC) 36th Bethesda Conference to make participation decisions. In the absence of a randomized clinical trial showing clear superiority of one method of screening over another, a small number of retrospective observational studies are available to support or refute these screening practices.
The 1998 report from the U.S. National Registry of Sudden Death in Athletes estimated the annual SCD rate in the American high school athlete to be one in 217,000 (0.44/100,000) athlete-years. This figure has been rather constant and has been widely accepted over the years as the best estimate of American athlete SCD rate. However, an independent report in 2011 from the National Collegiate Athletic Association (NCAA) challenged the accuracy of this number, suggesting that the annual SCD rate may be as high as one in 43,770 (2.28:100,000) athlete-years in the general collegiate population or even higher, one in 3,126 (31.98:100,000) athlete-years in certain subgroups (male Division one basketball players).
Given the discrepancy between the U.S. National Registry data, and the recent NCAA report, the data presented by Roberts and Stovitz are timely and relevant. For the past 19 years in Minnesota, athlete screening has consisted of standardized preparticipation evaluation (PPE), containing history and physical with AHA elements, and 36th Bethesda Conference athlete restrictions (when indicated). Electrocardiography was not performed routinely. An aggressive emergency action plan (every school equipped with automated external defibrillators) was implemented for any collapsed athlete after year 2000. This care model is consistent with what the AHA has recommended and what is endorsed by the ACC. To assess rate of SCD, authors analyzed the records of 1,666,509 unduplicated Minnesota high school athletes participating in ≥1 sports from 1993/1994 through 2011/2012. Occurrences of SCDs were determined by searching Minnesota State High School catastrophic insurance claims data for cardiac causes of death. Only SCDs occurring during games or practices were captured; successfully resuscitated SCDs (cardiac arrests) were not included.
Four SCD episodes (all male, 2 cross country, one basketball, one wrestling) occurred over the 19-year study period, and none over the most recent 9 years. Calculated SCD rate was 0.24 in 100,000 athlete-years over 19 years, and 0.11 in 100,000 for the past decade. The incidence of SCD was very low in these high school athletes compared with rates observed in Division one NCAA and Italian athletes (ages 18 to 25 and mean age, 24 years, respectively). This was attributed to a differences in study populations (age and level of sports), a preponderance of white subjects in the study cohort (the SCD rate is probably lower in white athletes compared with blacks), and methodological differences. The authors concluded there was a very low incidence of SCD among Minnesota high school athletes during sports participation (games and practices) with the use of current screening strategies and emergency plans, and that addition of screening with electrocardiography to prevent SCD episodes is not warranted in Minnesota high school athletes.
This study is illustrative of many of the issues faced in sports cardiology and has profound relevance to the ECG debate. It helps refine what we know about the epidemiology of SCD in young American athletes, demonstrates what can be achieved through meticulous application and continuous improvement of existing clinical tools (exclusive of screening 12-lead ECGs), and provides an analysis of SCDs in high school athletes that has practical application for Minnesota high school medical personnel and policymakers.
Absolutely vital to the ECG debate is the need to accurately define the true rate with which SCDs occur. This information influences the design of clinical trials and measurement of outcomes in athletic populations, affects the priority that is given to SCD events compared with other healthcare issues that affect young athletes, assists medical teams with event planning and emergency preparedness, and allows healthcare providers to counsel athlete patients on the risks of participation. In the absence of mandatory registries in well-defined populations, investigators have mined existing data repositories (intended for other purposes) for any helpful information. However, authorities have questioned the accuracy of such reports given the data sources and inaccuracies in estimating the population at risk.
As researchers become more able to identify SCD events within large populations that can be accurately sized, the true rates of SCD in specific athletic populations is becoming more evident. For example, in a recent study of long-distance runners, race medical directors calculated a cardiac arrest rate of 0.54:100,000 among marathon and half-marathon participants (n = 10.9 million); 71% of arrests were fatal (29% resuscitated). Thus, the SCD rate was 0.39:100,000. Similar precision is required in other athletic populations to answer sports-specific questions on outcomes, priorities, event preparation, and risk.
Compared with other studies in high school athletes, the study by Roberts and Stovitz is unique in its methodology and analysis. Concerning the rate calculation, only SCDs that occurred during games or practice were identified and included in the numerator, whereas only individual, unduplicated athletes were identified and included in the denominator. There was no statistical manipulation of data to estimate the population at risk. The SCD incidence of 0.24/100,000 athlete-years over the 19 years, is much lower than what was observed in the overall NCAA population (2.28:100,000), lower than the most recent Italian rates (0.43:100,000), and lower than what was recently reported by another investigator analyzing a very similar cohort (0.7:100,000). In this unusual situation, both Roberts and Stovitz and Maron independently reported on the same group of Minnesota high school athletes. Results were different by approximately 3-fold. This might be explained by differing reporting time frames (19 years vs. 26 years) and rate calculations (one data source for SCDs/unduplicated athletes vs. multiple data sources for SCDs/estimate of athletes at risk). Regardless of the different outcomes, there is encouraging information in both reports. Both investigators confirmed low SCD rates and that the rates appear to be decreasing over the most recent decade in the Minnesota high school population. Unique to the analysis of Roberts and Stovitz is its ability to link American screening strategies to cardiac outcomes on the playing field. To my knowledge, this appears to be a rare demonstration of the association between the two in any American athletic population. Returning to the ECG debate, it does not appear that an ECG would bring any added value here, as it would not be possible for Minnesota to improve on its present SCD rate of zero over the most recent 9 years in its high school athletes.
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