Sudden death in young athletes: screening for the needle in a haystack

Author: Francis G. O'Connor, Ralph G. Oriscello
Date: June, 1998

Sudden death in an athlete inevitably stirs public concern as front-page headlines question what more could have been done to identify the risk. Parents may wonder--if this could happen to a young star athlete, could it also strike their child, who participates in recreational athletics? It might also be natural to ask whether the benefits of sports and exercise are worth the apparent risk.

A sudden death is at least as devastating to the primary care/sports medicine community. Physicians are humbled when an asymptomatic athlete with an apparently normal clinical examination dies suddenly. In 1992, the then president of the American College of Sports Medicine directed a "call to action" to the sports medicine community.[1] He noted the decrease in the number of sports-related fatalities achieved by modifying rules and equipment, and by encouraging such simple interventions as including more water intake in daily football practices. The "bad news," however, was that as other deaths were diminishing, congenital cardiovascular disease was emerging as the major cause of sudden death in high school and college athletes. This article updates the incidence and etiology of sudden death in young athletes and outlines current recommendations for preparticipation screening.

Incidence

Fortunately, sudden death in an athlete, especially a young athlete, is a rare event. Estimates vary greatly depending on the age of the athlete, the source of the sampling population, the sports activity and the definition of sudden death. Sudden cardiac death has usually been defined as one that is unexpected and nontraumatic and that occurs instantaneously or within a few minutes of an abrupt change in the person's previous clinical state.[2]

Several incidence studies of large population groups have been performed (Table 1).[3-7] One study estimated the incidence of sudden death during exercise in unscreened Rhode Island men less than 30 years of age between 1975 and 1982 as one death per 280,000 men per year.[5] Another study estimated the incidence of sudden death as one per 735,000 per year among screened, exercising, U.S. Air Force recruits between 17 and 28 years of age in the years 1965 to 1985.[4]

TABLE 1 Incidence of Nontraumatic Sudden Death in AthletesPopulation group Age distributionOrganized high school/ High school/ college athletes[3] college ageU.S. Air Force recruits[4] 17 to 28 years of ageRhode Island joggers[5] <30 years of ageRhode Island joggers[6] 30 to 65 years of ageMarathon runners[7] Mean age 37Population group IncidenceOrganized high school/ 7.47:1,000,000 per year (male) college athletes[3] 1.33:1,000,000 per year (female)U.S. Air Force recruits[4] 1:735,000 per yearRhode Island joggers[5] 1:280,000 per yearRhode Island joggers[6] 1:7,620 joggers per yearMarathon runners[7] 1:50,000 race finishers

Information from references 3 through 7.

Researchers[3] from the National Center for Catastrophic Sports Injury Research identified 160 nontraumatic athlete deaths in high school and college organized sports between July 1983 and June 1993. In addition to the estimated rates of nontraumatic sports deaths in male and female high school and college athletes (Table 1), they noted the following:

1. Estimated death rates were fivefold higher in male athletes than in female athletes (7.47 versus 1.33 per million athletes per year).

2. Estimated death rates were twofold higher in male college athletes than in male high school athletes (14.5 versus 6.6 per million athletes per year).

3. Noncardiac causes of death accounted for 22 percent of the cases.

4. Most deaths occurred in male football and basketball athletes (104 and 160, respectively).

In older athletes, incidence estimates increase somewhat, but the event remains rare. It has been estimated that one exercise-related death per year occurred per 18,000 previously healthy men between the ages of 25 and 75 living in Seattle.[8] In another study,[6] the incidence of death during jogging was estimated as one death per year for every 7,620 male Rhode Island residents 30 to 64 years of age between 1975 and 1980, with one death for every 15,240 persons without known disease.

Etiology

Several series of case studies in the past 20 years have reviewed death certificates or used clinical autopsy findings to illustrate the conditions associated with sudden death. A fairly consistent theme has evolved: Sudden deaths in younger athletes were more often associated with congenital cardiovascular structural abnormalities, while sudden cardiac deaths in older athletes were more often associated with acquired atherosclerotic cardiovascular disease. The simple epidemiologic observation that the prevalence of atherosclerosis increases with age appears to begin to have its impact on sudden death etiologies around age 30 to 35. While atherosclerosis has some role before age 35, it is clearly the predominant cause after that age.

In 1980, one of the earliest clinicopathologic studies[9] in young competitive athletes identified structural cardiovascular abnormalities in 28 of 29 athletes, with hypertrophic cardiomyopathy as the most likely etiology of sudden death in 14 of the 29 cases. In 1991, another researcher[10] reviewed seven etiologic studies and found that hypertrophic cardiomyopathy led the list at 24 percent, with coronary anomalies next at 18 percent and myocarditis at 12 percent.

In 1990, an interesting autopsy study[11] identified right ventricular dysplasia as a likely etiology in six of 22 cases of sudden death in competitive young athletes in Northern Italy (ages 11 to 35). This condition was much less prevalent in other studies. Next in frequency in this study was coronary artery atherosclerotic disease; it was found in four of the 22 cases. Finally, a detailed retrospective case control review[12] of exercise-related sudden cardiac deaths in Maryland between 1981 and 1988 demonstrated a statistically strong association between hypertrophic cardiomyopathy and sudden cardiac death in exercising young adults. Table 2 lists the possible causes of sudden, exercise-related cardiac death in young athletes (under age 30) in the estimated descending order of frequency.

TABLE 2 Likely Etiologies for Sudden Cardiac Death in Young Athletes

Hypertrophic cardiomyopathy Coronary artery anomalies Atherosclerotic coronary artery disease Myocarditis Other etiologies (less common)

Right ventricular dysplasia

Marfan's syndrome

Conduction system abnormalities

Idiopathic concentric left ventricular hypertrophy

Substance abuse (e.g., cocaine, steroids)

Aortic stenosis

Mitral valve prolapse

Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy is an autosomal-dominant congenital disorder characterized by left ventricular outflow obstruction with asymmetric septal hypertrophy and marked disarray of ventricular muscle fibers. In a recent review[13] of 4,111 subjects in the Coronary Artery Risk Development in (Young) Adults (CARDIA) Study, the prevalence of echocardiographically defined hypertrophic cardiomyopathy was estimated at two per 1,000 young adults. It is thought that this condition could predispose persons to malignant ventricular arrhythmias leading to syncope or sudden death.

Hypertrophic cardiomyopathy is often clinically silent, but a personal or family history of unexplained syncope, especially effort syncope or sudden-death events, is an important clinical due. Chest radiography may show cardiomegaly, and electrocardiography may show left ventricular hypertrophy or other changes, but results of these tests may also be normal. The diagnosis is best confirmed with two-dimensional and M-mode echocardiography.

Congenital and Acquired Coronary Disease

Congenital coronary anomalies are multiple, the most common being misplaced aortic ostium, in which the left main and right coronary artery arise from the right sinus of Valsalva. These conditions are difficult to identify unless complaints of early fatigue, angina or exercise-induced syncope lead to a directed evaluation. In one review[14] of 78 cases of sudden death thought to be secondary to autopsyproven coronary anomalies, 62 percent occurred in asymptomatic persons.

Tragically, acquired premature coronary artery disease can appear in the athlete under age 30. Genetic predisposition plus other risk-factor prevalence can sometimes lead to coronary events resulting from typical atherosclerosis. Attention to risk factors and to the early symptoms of ischemia, angina and other effort-related symptoms should be just as aggressively pursued in younger athletes as in older athletes.

Myocarditis

[16.] Burke AP, Farb A, Virmani R. Causes of sudden death in athletes. Cardiol Clin 1992;10:303-17.

[17.] McKeag DB. Preparticipation screening of the potential athlete. Clin Sports Med 1989;8:373-97.

[18.] Cantwell JD, Rose FD. Cocaine and cardiovascular events. Physician Sportsmed 1986;14:77-82.

[19.] Mochizuki RM, Richter KJ. Cardiomyopathy and cerebrovascular accident associated with anabolic-androgenic steroid use. Physician Sportsmed 1988; 16:108-14.

[20.] Epstein SE, Maron BJ. Sudden death and the competitive athlete: perspectives on preparticipation screening studies. J Am Coll Cardiol 1986;7:220-30.

[21.] Huston TP, Puffer JC, Rodney WM. The athletic heart syndrome. N Engl J Med 1985;313:24-32.

[22.] Spirito P, Maron BJ, Bonow RO, Epstein SE. Prevalence and significance of an abnormal S-T segment response to exercise in a young athletic population. Am J Cardiol 1983;51:1663-6.

[23.] Fahrenbach MC, Thompson PD. The preparticipation sports examination. Cardiovascular considerations for screening. Cardiol Clin 1992;10:319-28.

[24.] Lewis JF, Maron BJ, Diggs JA, Spencer JE, Mehrotra PP, Curry CL. Preparticipation echocardiographic screening for cardiovascular disease in a large, predominantly black population of college athletes. Am J Cardiol 1989;64:1029-33.

[25.] Maron BJ, Bodison SA, Wesley YE, Tucker E, Green KJ. Results of screening a large group of intercollegiate competitive athletes for cardiovascular disease. J Am Coll Cardiol 1987; 10: 1214-21.

[26.] Weidenbener EJ, Krauss MD, Waller BF, Taliercio CP. Incorporation of screening echocardiography in the preparticipation exam. Clin J Sport Med 1995;5:86-9.

[27.] Fananapazir L, Epstein ND. Prevalence of hypertrophic cardiomyopathy and limitations of screening methods. Circulation 1995;92:700-4.

[28.] Maron BJ, Shirani J, Poliac LC, Mathenge R, Roberts WC, Mueller FO. Sudden death in young competitive athletes. Clinical, demographic, and pathological profiles. JAMA 1996;276:199-204.

[29.] Maron BJ, Thompson PD, Puffer JC, McGrew CA, Strong WB, Douglas PS, et al. Cardiovascular preparticipation screening of competitive athletes. A statement for health professionals from the Sudden Death Committee (clinical cardiology) and Congenital Cardiac Defects Committee (cardiovascular disease in the young), American Heart Association. Circulation 1996;94:850-6.

[30.] American Academy of Family Practice, American Academy of Pediatrics, American Medical Society for Sports Medicine, American Orthopedic Society for Sports Medicine, American Osteopathic Academy of Sports Medicine. Preparticipation physical evaluation. 2d ed. Minneapolis: Physician Sportsmed, 1997.

[31.] Maron BJ, Mitchell JH, eds. 26th Bethesda Conference: recommendations for determining eligibility for competition in athletes with cardiovascular abnormalities. Task Force 6: arrhythmias. J Am Col Cardiol 1994;24:892-9.

This article exemplifies the AAFP 1997-98 Annual Clinical Focus on prevention and management of cardiovascular disease.

FRANCIS G. O'CONNOR, LTC, MC, USA, is an assistant professor and director of the Primary Care Sports Medicine Fellowship at the Uniformed Services University of the Health Sciences, Bethesda, Md. After graduating from State University of New York Health Science Center at Syracuse, he completed a residency in family medicine at St. Joseph's Hospital and Health Center, also in Syracuse. He then completed a fellowship in primary care sports medicine at the Nirschl Orthopedic and Sports Medicine Center, Arlington, Va. Dr. O'Connor has a certificate of added qualification in sports medicine.

JOHN P. KUGLER, COL, MC, USA, is director of primary care and chief of the Family Medicine Residency Program at DeWitt Army Community Hospital, Fort Belvoir, Va. He is also an assistant clinical professor at the Uniformed Services University of the Health Sciences, After graduating from the UCLA School of Medicine, Dr. Kugler completed a residency in family medicine at Silas B. Hays Army Community Hospital, Fort Ord, Calif. He completed a fellowship in faculty development/research at Madigan Army Medical Center, Tacoma, Wash., and obtained a master of public health degree from the University of Washington, Seattle.

RALPH G. ORISCELLO, M.D., is director of the Department of Medicine and Critical Care Medicine at the Elizabeth General Medical Center, Elizabeth, N.J. He is also an associate professor of medicine at Seton Hall University Post-graduate School of Medicine, Newark, N.J. A graduate of the New Jersey Medical School, also in Newark, he completed training in internal medicine and cardiology at the Columbia College of Physicians and Surgeons, New York City.

Address correspondence to Francis G. O'Connor, M.D., 7305 Scarlet Oak Ct., Fairfax Station, VA 22039. Reprints are not available from the authors.

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