risk of sudden cardiac death in young athletes: which...

Pediatr Clin N Am 51 (2004) 1421–1441

Risk of sudden cardiac death in young athletes:

which screening strategies are appropriate?

Rima S. Bader, MD, PhD, Linn Goldberg, MD,David J. Sahn, MD*

Pediatric Cardiology, Oregon Health & Science University, 3181 SW Sam Jackson Park Road,

Portland, OR 97239, USA

Sudden death is an unexpected death that occurs abruptly in a person who was

previously stable and believed to be ‘‘healthy.’’ In the sporting world and in

athletics, this has been an all too familiar event. A seemingly healthy, vibrant

young athlete collapses and dies for no apparent reason. These deaths have far-

reaching effects on the family, team members, classmates, and the community

as a whole.

There is a growing interest and awareness regarding how the medical com-

munity responds to the risk of sudden cardiac death in the young athlete who

takes part in competitive sports. Sudden death can be categorized as traumatic or

nontraumatic in origin. In athletes, traumatic causes include deaths from pene-

trating trauma (eg, subdural hematoma, cervical spine fractures), such as may be

experienced in collision sports, and blunt force that results in what is believed to

be a lethal cardiac arrhythmia, commotio cordis, and instantaneous collapse [1].

Nontraumatic deaths can be subdivided into cardiovascular and noncardio-

vascular events. Leading causes of noncardiovascular death include hyperther-

mia, rhabdomyolysis, and asthma [2]. Risks for noncardiovascular causes of

sudden death often are recognized by previous obvious clinical manifestations or

mild forms of suspected symptoms. Therefore, by uncovering these and by

duplicating them by testing, it may be possible to avoid potential life-threatening

situations. In contrast, cardiovascular mechanisms of sudden death often have an

initial presentation that results in death, with a diagnosis made only at autopsy.

In 490 B.C., Pheidippides, the renowned Athenian Marathon runner, suffered a

sudden cardiac death (SCD) after running from the battlefield of Marathon to

Athens to announce the great victory of the Greeks over the invaders.

0031-3955/04/$ – see front matter D 2004 Elsevier Inc. All rights reserved.

doi:10.1016/j.pcl.2004.04.005

* Corresponding author.

E-mail address: [email protected] (D.J. Sahn).

R.S. Bader et al / Pediatr Clin N Am 51 (2004) 1421–14411422

Identifying individuals who are at risk for SCD is of paramount importance,

but is extremely difficult given the available health resources. Furthermore, the

establishment of any given test or process to identify lethal risk may be unlikely

because our society may favor performance, despite risk. This task has generated

debate regarding the most appropriate screening methods to evaluate athletes

for SCD.

Causes of sudden death

Cardiovascular abnormalities are among the most common causes of sudden

death in competitive athletes [2–15]. The precise lesions that are responsible for

athletic field catastrophes differ considerably with regard to age. For example, in

youthful athletes (younger than 35 years), most sudden deaths are due to several

congenital cardiac malformations and hypertrophic cardiomyopathy (HCM);

HCM accounts for 40% to 50% of SCD in young athletes (Fig. 1). Approxi-

mately 80% of nontraumatic sudden deaths in young athletes are due to inherited

or congenital structural and functional cardiovascular abnormalities, which pro-

vide a substrate for arrhythmias that predispose to SCD [6,9,17].

The next most frequent cause of SCD is congenital coronary anomalies,

particularly anomalous origin of the left main coronary artery from the right sinus

of Valsalva [18]. These deaths occur most commonly during team sports, such as

basketball and football, which have high levels of participation and sustained

effort or contact.

36

19

10

5 5 43 3 3 2 2

5

0

5

10

15

20

25

30

35

40

Per

cen

tag

e

HCM

CAA

ICAM

RAO

TLAD AS

MYO

C

DCMAVRD

MVP

CADot

hers

Fig. 1. Causes of sudden cardiac death in young competitive athletes (median age = 17 years) based on

systematic tracking of 158 athletes in the US, primarily from 1985 to 1995. AS, aortic stenosis;

AVRD, arrhythmogenic right ventricular dysplasia; CAA, coronary artery abnormality; CAD,

coronary artery disease; DCM, dilated cardiomyopathy; HCM, hypertrophic cardiomyopathy; ICAM,

increased cardiac mass; MVP, mitral valve prolapse; MYOC, myocarditis; RAO, ruptured aorta;

TLAD, intramural tunneling of the left anterior descending artery.

R.S. Bader et al / Pediatr Clin N Am 51 (2004) 1421–1441 1423

Hypertrophic cardiomyopathy

HCM is a complex primary cardiac disease that is diverse in its genetic, phe-

notypic, and clinical manifestations. Typically, it is acquired as an autosomal

dominant genetic disorder that is caused by one of several mutations in genes that

encode proteins of the cardiac sarcomere. The genes encode for b-myosin heavy

chain on chromosome 14, a-tropomyosin on chromosome 15, cardiac troponin T

on chromosome 1, and myosin-binding protein C on chromosome 11 [19–21].

Although there are ongoing efforts to characterize the specific genetic muta-

tions that are responsible for HCM, DNA diagnostic techniques are not available

readily for clinical practice or for screening.

Echocardiographic screening of a group of asymptomatic young adults noted

that HCM was present in 0.17% of studied patients [22]. Electrocardiogram

screening of 12,000 adults in Japan was followed by echocardiography in a

subpopulation of this group. This process resulted in the diagnosis of HCM in

0.2% of the study participants [23]. Given the similar prevalence data of these

studies, HCM is estimated to occur in approximately 1 in 500 individuals.

Despite the fact that HCM (the leading cause of SCD in young adults) occurs at

this rate, the prevalence of sudden death is only approximately 1 in 200,000; this

underscores the heterogeneity and variable presentation of the disease process.

A major reason for this is that most patients who have HCM have a

nonobstructive form [24]. Thus, the disease often is clinically silent which makes

detection difficult. Patients who have HCM may present with dyspnea on exer-

tion, chest pain, or syncope. Dyspnea on exertion is due to restricted filling of the

thickened left ventricle during exercise. Decreased diastolic filling time further

exacerbates this condition. Chest pain is believed to be secondary to subendo-

cardial ischemia, which results from the thickened myocardium and abnormal

intramural coronary arteries that limit blood supply, and, subsequently, oxygen

flow to the myocardium. Although the obstructive syncope can occur with ob-

struction of the left ventricular outflow tract and leads to a loss of cerebral blood

flow, the most common mechanism of sudden death is believed to be secondary

to malignant arrhythmias that are generated by abnormal conduction through

thickened heart muscle [25].

A diagnosis of HCM should be suspected in any athlete who has exertion-

related cardiac symptoms. Other historical clues include a family history of

sudden death or unexplained syncope. Detection of a systolic heart murmur that

increases in intensity with Valsalva maneuver or in a standing position (decreased

venous return, increased degree of outflow obstruction) is an important diagnos-

tic clue and should prompt further evaluation. Echocardiography is an important

imaging tool in the diagnosis of HCM. Although the degree of left ventricular

thickening averages 21 mm to 22 mm in patients who have HCM, this degree of

thickening can vary widely [24]. Asymptomatic patients who have ventricular

wall thickening on the order of 13 mm to 15 mm represent a ‘‘gray area,’’ because

well-trained athletes may demonstrate similar findings that are physiologic [26].

In addition, individuals who have HCM who have not reached physical maturity


may have normal left ventricular thickness on echocardiography. This should not

be interpreted as a sign that they are safe from developing pathologic hypertrophy

in the future. Consequently, routine echocardiography should be used serially

with individuals who are suspected of having HCM until they reach physical

maturation [27].

Coronary artery abnormalities

After HCM, coronary artery malformations are the next most frequent cause of

SCD in young athletes. This group of congenital vascular anomalies accounts for

approximately 12% to 20% of SCD in individuals who are younger than 35 years

of age [2,4,16]. One of the most frequently encountered coronary anomalies that

is associated with sudden death is anomalous origin of the left main coronary

from the right sinus of Valsalva [4,28]. In these individuals, the left main coro-

nary artery is forced to take an oblique route between the aorta and the pulmonary

trunk. Restricted blood flow in this anomalous coronary is most likely to occur

during exertion, as the aorta expands with greater stroke volume. Under this load

and increased aortic and pulmonary artery pressure, the coronary ostium is

believed to be compressed, with subsequent limitation in the coronary circulation.

In conjunction with the restricted blood flow is an increased oxygen demand of

the myocardium. This perfusion-demand mismatch can result in ischemia or

infarction [29]. These ischemic episodes are believed to occur periodically but

may be cumulative over time and result in patchy myocardial necrosis or fibrosis.

The injured myocardium may become a nidus for life-threatening ventricular

tachyarrhythmias [30]. A similar situation exists in which the right coronary

artery arises from the left sinus of Valsalva. This abnormality presents the same

potential consequences, with compromised flow in the right coronary artery

territory [31]. The combined prevalence of anomalous origins of the coronary

arteries in a general population was estimated at 0.17% [32].

Other less common coronary artery malformations that have been observed in

cases of sudden death include intramural tunneling of the left anterior descending

artery, hypoplasia of the right coronary or circumflex arteries, and congenital

absence of the left coronary artery [4,28].

Some individuals may experience vague chest pain, syncope, or palpitations,

which commonly are exertion related. Typically, physical examination is normal,

as are resting electrocardiograms [29]. Although echocardiography (transthoracic

and transesophageal) may be useful [32], coronary angiography—previously

believed to be the confirmatory diagnostic test of choice—is being replaced

gradually by MRI angiography [33].

Myocarditis

In 1993, the unexpected deaths of several highly recognized athletes were

attributed to myocarditis [34]. Although these cases are uncommon, myocarditis


is implicated in up to 6% of cases of SCD among young athletes [4,16]. SCD

may occur in the actively infected individual or in the so-called ‘‘healed phase

of myocarditis.’’

Usually, myocarditis is caused by a viral infection; coxsackie B virus is the most

frequently identifiable pathogen [35]. Viral myocarditis may present with symptoms

of fatigue, dyspnea on exertion, and exercise intolerance. In other cases, patientsmay

experience syncope, presyncope, or palpitations. Signs of heart failure with systolic

dysfunction may accompany these symptoms. Individuals also may remain asymp-

tomatic. In this latter group, sudden death may be the initial presentation.

SCD occurs when a fatal arrhythmia is generated in the irritated or scarred

myocardium. Echocardiography in affected individuals is likely to demonstrate

left ventricular and atrial enlargement, a decrease in left ventricular ejection frac-

tion, and may show mitral regurgitation and wall-motion defects. Recovery from

myocarditis can take months. During this healing phase, individuals continue to be

at risk for potentially lethal arrhythmias. Therefore, before returning to strenuous

physical activity, individuals must be evaluated thoroughly, supervised during

their first exercise effort, and screened and cleared, if appropriate, by a cardiolo-

gist. Guidelines for athletic participation by patients who are recovering from

myocarditis are detailed in the 26th Bethesda Conference papers regarding eli-

gibility for competition in athletes who have cardiovascular abnormalities [36].

Aortic rupture

Aortic dissection and rupture may be associated with Marfan’s syndrome, an

autosomal, dominantly inherited disease that affects the connective tissue. Spe-

cifically, affected individuals have abnormal cross-linking of collagen and elastin.

Skeletal, ophthalmologic, and cardiovascular manifestations are evident in af-

fected people. Pathologic changes in the aorta (cystic medial necrosis and de-

generation of elastic elements) lead to aortic root dilatation. Subsequent aortic

dissection and rupture is the etiologic mechanism for SCD [4,6].

Screening of athletes is recommended for men who are taller than 60 and

women who are taller than 501000 who have two or more physical manifestations

or a family history of Marfan’s syndrome. A careful skeletal evaluation and body

habitus measurement can be helpful initial screening steps. Echocardiography can

be used to measure the degree of aortic root dilatation or associated atrioven-

tricular valve prolapse (eg, mitral valve prolapse [MVP]). Affected patients

should be on b-blockers and have echocardiography approximately every

6 months to monitor aortic root dimensions.

Arrhythmogenic right ventricular dysplasia

Many other cardiovascular conditions have been associated with SCD in

young athletes but are uncommon. Arrhythmogenic right ventricular dysplasia

(ARVD) deserves special mention because it was implicated as the leading cause


of SCD in competitive athletes in a specific region of Italy and has become a

diagnostic dilemma [16,37]. Italian literature may show a higher percentage than

the American literature because, while HCM was implicated as the leading cause

of SCD in competitive athletes in the US, AVRD was implicated as the leading

cause of death in the Italian study. This may be due to genetic or geographic pre-

disposition or may be the result of the methodology that was used in the studies.

Specifically, the systematic use of echocardiography as a part of the athletic

screening process in parts of Italy may have identified and restricted a significant

number of athletes who had HCM. Because ARVD seems to be more difficult to

identify premortem, the number of resultant ARVD sudden deaths would be high

compared with those that are caused by HCM; many of the athletes who had

HCM already had been identified and disqualified before any complications.

ARVD is a heart muscle disorder that is characterized pathologically by

myocyte death and subsequent fibro-fatty tissue replacement of the right ven-

tricular myocardium. The extent of infiltrated myocardium is variable and may

cause sudden death by functional failure or by producing fatal arrhythmias. The

cause of ARVD is unknown. The noninvasive diagnostic study of choice is MRI

[38]. This study is more likely to be able to differentiate HCM from ARVD,

which may not be possible with echocardiography alone. The specific criteria that

involve myocardial thinning; dyskinesis; fat infiltrate; specific cardiac MRI pulse

sequences that work best; and, especially, the need for special expertise in

performing and interpreting the examination for diagnosing or ruling out ARVD,

are problematic and debatable.

Valvular disease

Aortic stenosis and MVP are rare causes of SCD in young athletes [2,4].

Aortic stenosis is an unlikely source of SCD among athletes, primarily because it

is readily identified on clinical examination by its characteristically loud systolic

crescendo-decrescendo murmur. As a result, these individuals are likely to be

restricted from participation in athletic activities [29]. MVP is a common finding

among the general population; it occurs in approximately 5% of individuals.

Despite this high prevalence, it has been implicated as a direct source of SCD

among young competitive athletes in only a handful of instances [29]. As a result,

a diagnosis of MVP does not require restriction from athletic participation at any

level, unless there is evidence of significant cardiac functional compromise [36].

Long QT syndrome

Long QT syndrome (LQTS) is a disorder that is characterized by lengthening

of the repolarization phase of the ventricular action potential which leads to

torsades de pointes, polymorphic ventricular tachycardia, and SCD. LQTS may

be congenital or acquired. Congenital LQTS is a heritable ion-channel disease

that is caused by several genetic mutations of the sodium-potassium pump. Ac-


quired factors can predispose certain athletes to LQTS through electrolyte ab-

normalities (low potassium, magnesium, calcium), marked bradycardia (which

occurs with athletes at rest), intracranial pressure changes (subarachnoid hemor-

rhage, stroke), and HIV [39,40].

The diagnosis of LQTS is primarily clinical and should be pursued if athletes

complain of unexplained symptoms that vary from dizziness to syncope. If a

family history of sudden death is known or the patient is symptomatic, then an

ECG should be evaluated. Up to 94% of patients who have congenital LQTS

have corrected QT intervals of greater than 440 milliseconds on ECG.

Commotio cordis

Commotio cordis is discussed in detail by Zangwill and Strasburger elsewhere

in this issue.

Athletic heart syndrome

The athletic heart syndrome (AHS) is a constellation of physiologic adapta-

tions to exercise that include, but are not limited to, cardiac chamber enlargement,

increased ventricular wall thickness, and increased resting vagal tone. These

physiologic changes may mimic pathologic cardiovascular findings on physical

examination and diagnostic studies.

The first documented report of AHS was in 1899, when Henschen recognized

that competitive cross-country skiers had larger hearts than sedentary controls

[2,40]. He further demonstrated a positive correlation between an athlete’s car-

diac size and his race performance, and, therefore, considered this to be a

beneficial adaptation to training.

In the early 1900s, technologic advances afforded the earliest insights into this

type of cardiac enlargement. Using radiologic and electrocardiographic data,

these cardiac adaptations were believed to be similar to the cardiac changes of

prolonged untreated hypertension. This supported the theory that the increased

cardiac size in athletes was a pathologic response to the increased cardiac stress

of exercise. The opinion of the medical community has come full circle regarding

the athletic heart. It is now believed that the AHS represents a constellation of

normal physiologic adaptations to training that allow normal or improved cardiac

function in contrast to the cardiac dysfunction of pathologic hypertrophy [41].

To understand AHS, it is essential to understand the normal physiologic re-

sponse of the cardiovascular system to exercise. Exercise training affects the

cardiovascular system peripherally and centrally to increase VO2max. The pe-

ripheral response occurs mainly in the skeletal muscle, where adaptations improve

oxygen extraction. These changes include increased numbers of capillaries,

mitochondria, and oxidative enzymes that allow improved uptake and use of

oxygen. The central adaptations occur in the heart to maximize oxygen delivery

to the exercising skeletal muscle. The primary adaptation to exercise is an


increase in stroke volume (SV) that directly improves cardiac output. This in-

crease in SV occurs as a result of physiologic cardiac dilation and hypertrophy.

Associated with this increase in SV is a decrease in resting heart rate (HR).

Because the cardiac output that is needed at rest remains constant before and after

training, the increase in SV obtained involved a comparable decrease in resting

heart rate (CO = SV � HR). These physiologic changes may occur in sufficient

magnitude to alter the normal physical examination, ECG, and other diagnostic

studies, and may, as a result, mimic pathologic cardiac conditions. Collectively,

these changes are termed the AHS.

Although AHS is a physiologic adaptation, the associated physiologic changes

can make it difficult to differentiate this benign condition from the potentially

fatal cardiac abnormalities that occasionally occur in young athletes. Numerous

physical examination findings are associated with AHS, including alterations in

cardiac rate and rhythm. This is likely due to the increased vagal tone that ac-

companies extreme cardiac conditioning. Other than bradycardia, the rest of the

vital signs usually are within normal limits [42]. Left ventricular hypertrophy

frequently can be documented through percussion or a laterally-displaced point of

maximal impulse. Cardiac auscultation reveals normal S1 and S2, commonly

with a systolic ejection murmur. This physiologic murmur must be differentiated

from the characteristic pathologic murmurs, and, most commonly, the subaortic

outflow murmur of obstructive HCM. Typically, the physiologic murmur inten-

sity increases and decreases proportionally with left ventricular filling. Therefore,

in the supine position, the physiologic murmurs are the most intense because

of increased left ventricular filling. When standing (or with Valsalva maneuver)

the murmur is less intense because of decreased left ventricular filling. Usually,

diastolic murmurs are not associated with AHS and should be evaluated

thoroughly. ECG abnormalities are common in athletic individuals. Bradycardia,

sinus arrhythmia, and first-degree heart block are reported frequently in resting

athletes [4,26]. When associated with AHS, these abnormalities cause no

symptoms and resolve during exercise. If athletes who have these abnormalities

complain of syncope or presyncope, a full work-up should be pursued.

Echocardiography has enhanced the understanding of AHS significantly.

Echocardiography can be used to diagnose disease and discriminate between

trivial (benign) or significant cardiac abnormalities [5,42]. Because of the

inordinately low pretest probability for congenital/acquired cardiac abnormalities

in an asymptomatic young athlete, no diagnostic study significantly modifies the

diagnosis. The candidates for echocardiographic evaluations are athletes who

have an abnormally high pretest probability of having a cardiac abnormality

(ie, symptomatic athletes).

Prevalence

The precise prevalence of cardiovascular-related SCD in young athletes is

unknown because comprehensive data are lacking; however, it is believed to be


uncommon, with estimates in the United States of 1 in 200,000 competitors [43].

The true prevalence is likely to be higher for a variety of reasons. First, the

pathologist who performs the postmortem in young athletes rarely has experience

of the conditions that are involved so subtle cases are missed. Second, some

conditions, such as the ion channelopathies, that predispose to fatal arrhythmia

are not associated with structural heart disease and so the cause of death may be

unclear. Third, the lack of a national registry for SCD in athletes leads to its

underestimation. There is reliance on media coverage, which focuses on high

profile athletes and on voluntary hospital reporting. In addition, retrospective data

from referral centers about the cause of sudden death in young athletes are subject

to bias, depending on the particular expertise or area of interest of the institu-

tion. Fourth, in the event SCD in an athlete, the coroner’s priority is to exclude

foul play rather than to establish the cardiovascular diagnosis. The design of a

screening strategy must take into account the fact that SCD in athletes is an

infrequent event and that only a small proportion of participants in organized

sports in the United States is at risk [2,44].

Each of the lesions that is known to be responsible for sudden death in young

athletes occurs infrequently in the general population and range from the com-

mon, such as HCM (1:500) [22] to the rare, such as coronary artery anomalies,

arrhythmogenic right ventricular dysplasia, long QT syndrome, or Marfan’s syn-

drome, for which reliable estimates of frequency are lacking. Therefore, it is

reasonable to estimate that congenital malformations that are relevant to athletic

screening probably account for a combined frequency of approximately 0.2% in

athletic populations [1].

Although the prevalence of athletic field deaths in the United States is not

known with certainty, it seems to be in the range of 1:100,000 to 1:300,000 high

school-aged athletes; it is disproportionately higher in boys [2,4]. Among older

athletes, the frequency of SCD that is due principally to coronary artery disease,

may exceed that of younger athletes (1:15,000 joggers and 1:50,000 marathon

runners) [32,45].

Ethical questions

There is general consensus that within a benevolent society there is a re-

sponsibility on the part of physicians to initiate prudent efforts to identify life-

threatening diseases in athletes to minimize cardiovascular risk associated with

sport. Specifically, there seems to be an implicit ethical (and possibly legal)

obligation on the part of educational institutions (eg, high schools and colleges)

to implement cost-efficient strategies to ensure that their athletes are not subject

to unacceptable medical risks. Despite sufficient resources, it is recognized that

there may not be a high motivation among professional teams or athletes to

implement cardiovascular screening. This may be due to the economic pressures

that are inherent in such a sports environment, for which athletic participation is a

pathway to opportunity and financial benefit often is substantial.


The extent to which preparticipation screening efforts can be supported at

any level of competitive athletics is mitigated by cost-efficiency considerations,

practical limitations, and the awareness that it is not possible to achieve a zero-

risk circumstance in competitive sports [34]. There often is an implied accept-

ance of risk on the part of athletes.

It is important to clearly acknowledge the limitations that are associated with

preparticipation screening to: (1) inform the public, which might otherwise

harbor important misconceptions about the principles and efficacy of athletic

screening; and (2) offer appropriate guidance to physicians and health care work-

ers who are responsible for screening.

Although educational institutions and professional sports organizations must

use reasonable care in conducting their athletic programs, there is no clear legal

precedent regarding their duty to require or conduct preparticipation screening of

athletes to detect medically-significant abnormalities. In the absence of binding

requirements established by law or by athletic governing bodies, most institutions

and teams rely on their team physician or other medical personnel to determine

appropriate medical screening procedures. A physician who has cleared an athlete

to participate in competitive sports is not necessarily legally liable for an injury or

death that is caused by an undiscovered cardiovascular condition.

Legal considerations

Malpractice liability for failure to discover a latent asymptomatic cardiovas-

cular condition requires proof that a physician deviated from customary or ac-

cepted medical practice in his or her specialty in performing preparticipation

screening of athletes and that use of established diagnostic criteria and methods

would have disclosed the medical abnormality.

Current customary practice

There are no universally accepted standards for the screening of high school

and college athletes, nor are there approved certification procedures for health

care professionals who perform screening examinations. Some form of medical

clearance by a physician or other trained health care worker, usually consisting of

a history and physical examination, seems to be customary for high school

athletes. Appropriate models of the preparticipation examination have been

developed by a number of medical organizations and investigators [46,47].

The American Heart Association (AHA) provided a consensus panel statement

for health professionals with guidelines for preparticipation cardiovascular

screening of young competitive athletes [1]. The Sudden Death and Congenital

Defects Committee of the AHA recommended a uniform cardiovascular screen-

ing program, including history and physical examination, to be the most cost-

effective protocol.


Effectiveness and limitations of screening tests

Preparticipation screening by history and physical examination alone (without

noninvasive testing) is not sufficient to guarantee detection of many critical

cardiovascular abnormalities in large populations of young trained athletes.

Hemodynamically significant congenital aortic valve stenosis is probably the

lesion that is most likely to be detected reliably during routine screening because

of its characteristically loud heart murmur. Detection of HCM by standard

screening is unreliable because many patients have the nonobstructive form of

this disease, that characteristically is expressed by only a soft heart murmur

or none at all [24,48]. Furthermore, most athletes who have HCM do not expe-

rience syncope or have a family history of premature sudden death due to the

disease [4,49].

The standard personal history conveys a generally low specificity for detection

of many cardiovascular abnormalities that lead to SCD in young athletes, par-

ticularly those that are associated with symptoms, such as chest pain or impaired

consciousness. In older athletes, however, a personal history of coronary risk

factors and a family history of premature ischemic heart disease can be useful for

identifying those individuals who are at risk.

Preparticipation cardiovascular screening of high school and college athletes

traditionally has been performed in the context of a standard personal and family

history and physical examination. Such standard evaluations frequently fail to

identify cardiovascular abnormalities (including HCM) in competitive athletes

who ultimately die of underlying disease [4].

A national AHA expert panel recently recommended a more focused system-

atic and standardized history and physical preparticipation screening process

to enhance the likelihood of identification of potentially lethal abnormalities. On

a national scale, the addition of noninvasive tests (eg, echocardiography) was

judged to be unworkable because of prohibitive costs and several practical issues,

although theoretically, such testing would substantially increase detection of

certain important lesions, such as HCM [1].

Furthermore, inadequacies in the preparticipation screening process have

been cited. The approved history and physical examination questionnaires

(which serve as a guide to the examination) may be suboptimal for 25% or

more of high school [22,50] and college-aged athletes [23,51]. There is no

available screening design that can detect all affected athletes and medi-

cal clearance for sports does not denote the absence of cardiovascular di-

sease necessarily.

Medical history and physical examination

Medical history has low specificity for most cardiac diseases that lead to sud-

den death; only a minority of individuals who have HCM, ARVD, and congenital

coronary artery anomalies (CCAAs) (less than 30%) [2,4,6,30] reported symp-


toms (eg, impaired consciousness, palpitations, chest pain) before death. Fur-

thermore, physical examination usually is unremarkable in HCM because most

patients have the nonobstructive form of the disease without heart murmurs;

physical examination also is negative in most CCAAs.

Cardiac abnormalities that are likely to be detected with the standard screening

protocol include Marfan’s syndrome, systemic hypertension, and valvular disease

(eg, aortic valve stenosis). Many evaluations are conducted as mass events in a

noisy public place, such as the field or the gymnasium; therefore, it is not sur-

prising that screening athletes on the basis of history and physical examination

and without noninvasive testing fails to identify most critical cardiovascular

abnormalities. This was confirmed by the analysis that was conducted by Maron

et al [4] in 134 young athletes who suffered sudden death despite the fact that

they had undergone preparticipation medical evaluation [2]. Of the 115 athletes

who were evaluated by history and physical examination, cardiac disease was

suspected in only 4 (3%), and only in 1 patient (Marfan’s syndrome) was a cor-

rect diagnosis made.

Echocardiography

The addition of noninvasive diagnostic tests to the screening process in young

athletes clearly has the potential to enhance detection of certain cardiovascular

defects. For example, the two-dimensional echocardiogram is the principal diag-

nostic tool for clinical recognition of HCM and demonstrates otherwise un-

explained asymmetric left ventricular wall thickening, the characteristic symptom

of this disease [24,48,52]. Screening for HCM with DNA testing for a variety of

known mutations in genes that encode proteins of the sarcomere is not practical

or feasible for large populations, given the substantial genetic heterogeneity of

the disease [19,21,53].

Echocardiography also can be expected to detect other relevant abnormalities

that are associated with sudden death in young athletes, such as valvular heart

disease, aortic root dilatation, and left ventricular dysfunction (with myocarditis

and dilated cardiomyopathy). Such diagnostic testing cannot guarantee identi-

fication of all important lesions and some diseases may not be detectable with

any screening method. For example, identification of many CCAAs usually

requires a sophisticated echo laboratory examination using views and methods

that are specifically targeted. In selected young athletes, this can raise a strong

suspicion (or even identify) anomalies, such as the left main coronary artery from

the right sinus of Valsalva [54,55]. In the lack of special interest and special

techniques like harmonies, high frequency, or 3D imaging echo in this type of

examination, MRI probably is the most efficient tool in uncovering these

abnormalities. Usually, arrhythmogenic right ventricular dysplasia cannot be

diagnosed reliably solely with echocardiography and ECG; the best available

noninvasive test for this disease is MRI, which is expensive and not available

universally [38,56].


Cost effectiveness

Cost-efficiency issues are important when assessing the feasibility of screen-

ing large athletic populations [43,57,58]; however, in most cases, adequate

financial, institutional, and personnel resources are not available for such

endeavors. In situations in which the full expense of testing is the responsibility

of administrative bodies, such as schools, universities, or professional teams, the

costs are probably prohibitive and range from $400 to $2000 per echocardio-

graphic study (average $600). If the occurrence of HCM in a young athletic

population is assumed to be 1:500, at $500 per study, theoretically it would cost

$250,000 to detect one previously undiagnosed case.

Screening protocols that incorporate mass noninvasive testing at greatly

reduced costs have been described [57,58]; however, these efforts have been in

unique circumstances that involved donated equipment and professional time

for all but technician-related costs. Some investigators suggested an inexpensive

shortened-format echocardiogram, that is limited to parasternal views and lasts

for about 2 minutes, for population screening [57,58]. Nevertheless, public

service projects based largely on volunteer efforts usually cannot be sustained

because of changing priorities for the use of available resources, and, there-

fore, are unlikely to be implemented on a scale that is necessary to provide

effective screening of all high school and collegiate athletes. Another impor-

tant limitation of screening with two-dimensional echocardiography is the po-

tential for false-positive or false-negative results. False-positive results may

arise from assignment of borderline values for left ventricular wall thicknesses

(or particularly large values for cavity size) that require formulation of a dif-

ferential diagnosis between the normal physiological adaptations of an athlete’s

heart [26,57–59] and pathologic conditions, such as HCM or other cardiomyo-

pathies [59,60]. Such clinical dilemmas (which cannot be resolved definitively

in some athletes) generate heavy emotional, financial, and medical burdens for

the athlete, family, team, and institution by virtue of the uncertainty that is

created and the requirement for additional testing. False-negative results may

occur because the phenotypic expression of HCM may not be evident or

complete until adolescence [27,61]. Consequently, in selected young athletes

(younger than 15 years) who have HCM, left ventricular hypertrophy may be

absent or mild and echocardiographic findings may not be diagnostic of that

disease [27].

12-lead electrocardiogram

The 12-lead ECG has been proposed as a more practical and cost-efficient

alternative to routine echocardiography for population-based screening [60,61].

The ECG is abnormal in approximately 95% of patients who have HCM [62]; is

frequently abnormal in other potentially lethal lesions, such as coronary anoma-

lies [63]; and usually identifies the important, but uncommon, long QT syndrome


[64,65]. Recent data indicate that a certain proportion of genetically-affected

relatives in families who have long QT syndrome may have little or no phe-

notypic expression on the ECG, however [65].

In preparticipation screening, the ECG compares unfavorably with the

echocardiogram because of its insensitivity for recognition of structural cardio-

vascular malformations. The ECG also has a low specificity as a screening test in

STATE OF OREGON SCHOOL SPORTS PRE-PARTICIPATION EXAMINATION

NAME: BIRTHDATE:___/___/___

ADDRESS:_____________________________________________________________________ PHONE:_______________

Athlete and Parent/Guardian: Please review all questions and answer them to the best of your ability.

Physician: Please review with the athlete details of any positive answers.

YES NO Don’t Know

__ __ __ 1. Has anyone in the athlete’s family died suddenly before the age of 50 years?

__ __ __ 2. Has the athlete ever passed out during exercise or stopped exercising because of dizziness or chest pain?

__ __ __ 3. Does the athlete have asthma (wheezing), hay fever, or coughing spells during or after exercise?

__ __ __ 4. Has the athlete ever broken a bone, had to wear a cast, or had an injury to any joint?

__ __ __ 5. Does the athlete have a history of a concussion (getting knocked out) or seizures?

__ __ __ 6. Has the athlete ever suffered a heat-related illness (heat stroke)?

__ __ __ 7. Does the athlete have a chronic illness or see a physician regularly for any particular problem?

__ __ __ 8. Does the athlete take any medicine?

__ __ __ 9. Is the athlete allergic to any medications or bee stings?

__ __ __ 10. Does the athlete have only one of any paired organ (eyes, ears, kidneys, testicles, ovaries, etc.)?

__ __ __ 11. Has the athlete ever had prior limitation from sports participation?

__ __ __ 12. Has the athlete had any episodes of shortness of breath, palpitations, history of rheumatic fever or

unusual fatiguability?

__ __ __ 13. Has the athlete ever been diagnosed with a heart murmur or heart condition or hypertension?

__ __ __ 14. Is there a history of young people in the athlete’s family who have had congenital or other heart

disease: cardiomyopathy, abnormal heart rhythms, long QT or Marfan’s syndrome? (You may

write “I don’t understand these terms” and initial this item, if appropriate.)

__ __ __ 15. Has the athlete ever been hospitalized overnight or had surgery?

__ __ __ 16. Does the athlete lose weight regularly to meet the requirements for your sport?

__ __ __ 17. Does the athlete have anything he or she wants to discuss with the physician?

Explain any YES answers here:

Parent/Guardian’s Statement: I have reviewed and answered the questions above to the best of my ability. I and my child understand and accept that there are

risks of serious injury and death in any sport, including the one(s) in which my child has chosen to participate. I hereby give permission for my child to participate in sports.

I hereby authorize emergency medical treatment and/or transportation to a medical facility for any injury or illness deemed urgently necessary by a licensed trainer, coach or medical practitioner.

I understand that this sports pre-participation physical examination is not designed nor intended to substitute for any recommended regular comprehensive health assessment by the family’s licensed medical practitioner, nor to discover hidden or unknown illness or injury reasonably outside the realm of sports participation.

Signed:______________________________________________________ Date:___________________________________ Parent/Guardian

Fig. 2. School sports preparticipation examination form. (Courtesy of David J. Sahn, MD, Portland,

OR, and the Oregon Scholastic Activities Association; with permission).


athletic populations because of the high frequency of ECG alterations that are

associated with the normal physiologic adaptations an athlete’s heart makes to

training [66]. In screening large populations of older trained athletes, the routine

use of exercise testing to detect coronary artery disease is limited by its low

specificity and pretest probability [67].

PRE-PARTICIPATION PHYSICAL EXAMINATION Name ___________________________________________________________________________ Date of Birth ___/___/___ Height _______ Weight ________ % Body fat (optional) _______ Pulse ________ BP ___/___ ( ___/___ , ___/___ ) Rhythm: Regular ____ Irregular ____ Vision R 20/____ L 20/____ Corrected: Y N Pupils: Equal ____ Unequal ____

NORMAL

ABNORMAL FINDINGS

INITIALS*

MEDICAL Appearance

Eyes/Ears/Nose/Throat

Lymph Nodes

Heart: Precordial activity

1st & 2nd heart sounds

Murmurs

Pulses: brachial/femoral

Lungs

Abdomen

Skin

MUSCULOSKELETAL Neck

Back

Shoulder/arm

Elbow/forearm

Wrist/hand

Hip/thigh

Knee

Leg/ankle

Foot

* Station-based examination only CLEARANCE

____ Cleared ____ Cleared after completing evaluation/rehabilitation for: _________________________________________________________ _____________________________________________________________________________________________________ _____________________________________________________________________________________________________ ____ Not cleared for: ________________________________ Reason: _________________________________________________ Recommendations: ___________________________________________________________________________________________ _____________________________________________________________________________________________________ _____________________________________________________________________________________________________ Name of physician (print/type): ________________________________________________________________ Date: ___/___/___ Address ____________________________________________________________________________ Phone (____)___________ Signature of Physician_________________________________________________________________________________________

Fig. 3. Preparticipation physical examination form. (Courtesy of David J. Sahn, MD, Portland, OR,

and the Oregon Scholastic Activities Association; with permission).

Table 1

Suggested examination protocol for the physician

Musculoskeletal

Have patient: To check for:

Stand facing examiner Extremities joints, general habitus

Look at ceiling, floor, over shoulders, touch

ears to shoulders

Cervical spine motion

Trapezius strength

Shrug shoulders (against resistance) Deltoid strength

Abduct shoulders 90�, hold against resistance Shoulder motion

Externally rotate arms fully Elbow motion

Flex and extend elbows Elbow and wrist motion

Arms at sides, elbows 90� flexed, Hand and finger motion, deformities

pronate/suspinate wrists Symmetry and knee/ankle effusion

Spread fingers, make fist Hip, knee, and ankle motion

Contract quadriceps, relax quadriceps Shoulder symmetry, scoliosis

‘‘Duck walk’’ 4 steps away from examiner Scoliosis, hip motion, hamstrings

Stand with back to examiner

Knees straight, touch toes

Calf symmetry, leg strength

Rise up on heels, then toes

Murmur evaluation

Auscultation should be performed sitting,

supine, and squatting in a quiet room using

the diaphragm and bell of a stethoscope

Auscultation finding of: Rules out:

S1 heard easily; not holosystolic, soft,

low-pitched

Ventricular septal defect and mitral regurgitation

Tetralogy, atrial septal defect, and pulmonary

hypertension

Normal S2 Aortic stenosis and pulmonary stenosis

No ejection or midsystolic click Patent ductus arteriosus

Continuous diastolic murmur absent Aortic insufficiency

No early diastolic murmur Coarctation

Normal femoral pulses (Equivalent to brachial

pulses in strength and arrival)

Marfan’s screen

Screen all men taller than 60000 and all women

taller than 501000 in height with echocardiogram

and slit lamp examination when any two of the

following are found:

Family history of Marfan’s syndrome (this finding

alone should prompt further investigation)

Cardiac murmur or midsystolic click

Kyphoscoliosis

Anterior thoracic deformity

Arm span greater than height

Upper to lower body ratio more than 1 SD

below mean

Myopia

Ectopic lens



The Oregon protocol

In 2001, Sahn and Goldberg developed a protocol (Figs. 2, 3; Table 1) for the

screening of school athletes in Oregon, concordant with AHA Consensus Panel

recommendations and with Glover and Maron’s study [50]. After a statewide

school and regional policies survey of Oregon’s high school and middle school

athletes, in collaboration with the Oregon State Activities Association, who

adopted their proposal for their sport preparticipation screening in grades 7 to

12. The student athletes will undergo screening every 2 years. In 2001, the Oregon

Senate Bill 160, ‘‘The Courtney Bill,’’ mandated the use of this protocol statewide.

The Oregon preparticipation protocol mandates [68]:

1. Detailed family medical history and physical examination, using Sahn-

Goldberg protocol with a parent/guardian signoff on accuracy;

2. A physical examination, performed by health care professionals who are

trained in cardiovascular risk identification in a quiet room, in addition to

the targeted use of three noninvasive tests;

3. Electrocardiogram, or stress test for identified risk on history and physi-

cal examination;

4. Handheld two-dimensional and color Doppler echocardiogram performed

by an expert;

5. For suspected risk of coronary artery malformation, cardiac MRI

angiography.

The completed protocol forms provide a statewide online database for de-

termining failed risk identification. The program includes: (1) training of the

health care professional to follow a prescribed protocol that include taking family

medical histories, performing physical examinations, and selecting additional

noninvasive tests for students who are found to be at risk; (2) a database that

allows data from the prescreening to be tracked for a national outcomes study;

and (3) all necessary educational materials for school administrators, athletic

training and coaching staff, parents, and adolescents. In addition to information

about the purpose and benefits of preparticipation cardiac screening, the educa-

tional components of the program include comprehensive information on leading

healthy lifestyles (information on nutrition, substance abuse, and other issues that

are important during adolescence and relevant to sports participation).

Summary

Resources are not available to evaluate all young athletes before participation

in competitive sports. Therefore, the cardiovascular evaluation of young athletes

needs to be targeted at high-risk areas and focus on individuals who are at

greatest risk, who have symptoms, and who have family history of sudden death

or premature cardiac disease. It is hoped that the support and involvement of


amateur and professional sporting bodies would improve the safety of athletic

participation; however, sometimes they resent disqualification of their most capa-

ble athletes or have inherent conflict of interest as do many of the families of

youngsters who are at risk.

There are no data related to how many expected deaths can be avoided by any

combined screening detection protocol. Thus, a national study with progressively

complex use of testing protocols (simplest physical examination and history up

to a cardiac MRI), combined with outcome arms is needed to establish the effi-

ciency, cost-effectiveness, sensitivity, and false positive detections of possi-

ble abnormalities that had been previously noted in the various protocols for

screening that are in use.

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