San Antonio Medical BRAC Integration Office, 916-1000 Incidence of Sudden Cardiac Death Associated with Physical Exertion in the United States Military

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San Antonio Medical BRAC Integration Office, 916-1000

Incidence of Sudden Cardiac Death Associated with Physical Exertion in

the United States Military

Samuel O. Jones, MD, MPH, FACC, FHRSColonel, US Air Force

Associate Professor, USUHSArrhythmia Service, Cardiology Division

San Antonio Military Medical Center

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• Conflicts: None

• The information and opinions expressed in this document are solely those of the authors and do not represent an endorsement by or the views of the Uniformed Services University of the Health Sciences, the United States Air Force, the Department of Defense, or the United States Government.

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San Antonio Medical BRAC Integration Office, 916-1000 3

Background

• Sudden Cardiac Death (SCD) is a tragic and devastating event– SCD which occurs to an athlete during sports or

physical exertion generates immense public attention• Increasingly recognized, a significant percentage

of cases occur during physical exertion, due to the inherent elevated risk.

• Incidence rates vary and precise data may be difficult– Varying definitions, incomplete ability to identify

cases, and different populations studied.

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Background• Relative risk of SCD is elevated during or

immediately post exertion– Physicians Health Study 16.9 x RR– Police officers 40.6 x (during restraints)– Firefighters 12.1 to 136 times greater during fire

suppression as compared to non-emergency duty • Pathophysiology

– wall stress, double product, ischemia– Acute events, plaque disruption, thrombogenicity– Electrolyte shift, volume changes

Albert CM. NEJM 2000;343:1355Varvarigou V. BMJ 2014;349: 6534Kales SN. NEJM 2007;235:1207

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Incidence of SCD w/ Exertion

• Young patients 12-35 in Denmark 1.2 per 100,000• General population of sports related deaths in

France 0.46 per 100,000 (? as high as 1.7 ?)• Marathon runners 2005-2010 rate of 1.25 per

100,000• Triathlon 1.5 per 100,000

Marijon E. Circ 2011;124:672Holst AG.. Heart Rhythm.2010; 7: 1365Kim JH. NEJM 2012; 366:130Harris K JAMA 2010;303:1255

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Background

• U.S. military records provide excellent data for analysis given – complete capture of all deaths– well-defined population– comprehensive electronic medical record– accessible surveillance systems

• Study aimed to calculate the incidence rate of SCD related to exertion in the U.S. military– Secondarily, determine etiologies, classify according to

activities, and characterize demographic and risk profiles of decedents.

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SCD in the Athlete

• Earliest case report of SCD in the athlete?

• Pheidippides (530 BC- 490 BC)• Ran from battlefield near

Marathon to Athens to announce Greek victory over Persians

• Upon giving the message, he collapsed and died

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The Problem

• Definition of “athlete” may be broad– In total, there are estimated 5 million HS athletes– 500,000 collegiate– 5,000 professional– Extend to firefighters? 1.2 million AD military?

• Young, vigorous, represent healthy lifestyle– Sudden death does not fit our beliefs

• Each event is a high profile case, generating public outcry to prevent these conditions

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Incidence of SCD

• Organized High School/College Athletes– 1:134,000/Year (Male) (7.47:million/Year)– 1:750,000/Year (Female) (1.33/million/Year)

• Air Force Recruits– 1:735,000/Year

• Marathon Runners– 1:50,000 Race Finishers (Mean Age 37yo)

• In brief, ~ 300 deaths/year

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Causes of SCD in the young

• HCM• ARVC• Coronary artery anomalies• Premature CAD• LQTS/ Brugada• Myocarditis• Preexcitation syndromes

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Methods

AF Medical Examiner Tracking System• Surveillance system • Autopsy reports• Death certificates• Official investigations

Military EHR• Clinical• Laboratory• Radiographic• Prescription data

All decedents meeting the case definition from Jan 1, 2005 to Dec 31, 2010 were included

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Criteria

Sudden Cardiac Death• Autopsy-confirmed

heart disease with clinical circumstances c/w cardiac etiology

• Circumstances were c/w cardiac arrhythmia in absence of other conditions that could explain death

Exertion-related• A death or initiation of

terminal life support within 1 hr of physical exertion.

• Un-witnessed but unexpected death where individual had been exercising prior to death.

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Methods

• Full time active duty service members along with National Guard and Reserves

• Analysis of environmental heat load at time of exertion via wet bulb globe temperature (WBGT)

• Physical activities and clinical history preceding SCD were obtained via witness interviews

• Clinical data from EHR– BMI, lipids, blood pressure, smoking– Recent clinical history to including symptoms within

prior 6 months

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Case Determination

Personnel

All Cases Active Component Cases

Reserve/Guard Cases

n =200 % n=135 % n=65 %

Age

<35 years 75 37.5 63 46.7 12 18.5

≥35 years 125 62.5 72 53.3 53 81.5

Sex

Male 195 97.5 133 98.5 62 95.3

Female 5 2.5 2 1.5 3 4.6

Race

White 117 58.5 77 57.0 40 61.5

Black 63 31.5 43 31.9 20 30.8

Other 20 10.0 15 11.1 5 7.7

Demographic Characteristics of Cases of Sudden Cardiac Death with Exertion


Reserve/Guard Cases

n =200 % n=135 % n=65 %

Age

<35 years 75 37.5 63 46.7 12 18.5

≥35 years 125 62.5 72 53.3 53 81.5

Sex

Male 195 97.5 133 98.5 62 95.3

Female 5 2.5 2 1.5 3 4.6

Race

White 117 58.5 77 57.0 40 61.5

Black 63 31.5 43 31.9 20 30.8

Other 20 10.0 15 11.1 5 7.7



Reserve/Guard Cases

n =200 % n=135 % n=65 %

Age

<35 years 75 37.5 63 46.7 12 18.5

≥35 years 125 62.5 72 53.3 53 81.5

Sex

Male 195 97.5 133 98.5 62 95.3

Female 5 2.5 2 1.5 3 4.6

Race

White 117 58.5 77 57.0 40 61.5

Black 63 31.5 43 31.9 20 30.8

Other 20 10.0 15 11.1 5 7.7


Deaths Person-YearsIncidence Rate Per

100,000 Person Years (95% Confidence Interval)*

Incidence Rate Ratio (95% Confidence

Interval) †

Total 135 8,298,660 1.63 (1.37-1.92) Age

<35 years 63 6,425,421 0.98 (0.76-1.25) 1.00 [reference] ≥35 years 72 1,873,184 3.84 (3.03-4.81) 3.70 (2.66-5.14)

Race White 77 5,763,967 1.34 (1.06-1.66) 1.00 [reference]

Black 43 1,433,290 3.00 (2.20-4.00) 2.60 (1.81-3.72)

Other 15 1,101,346 1.36 (0.79-2.20) 1.30 (0.78-2.18)Sex

Male 133 7,103,646 1.87 (1.57-2.21) 1.00 [reference]

Female 2 662,398 0.30 (0.51-1.00) 5.28 (2.16-12.93)Race and Sex

White Male 77 5,101,569 1.51 (1.20-1.88) Black Male 41 1,093,016 3.75 (2.73-5.04) Other Male 15 909,037 1.65 (0.96-2.66)




Interval) †

Total 135 8,298,660 1.63 (1.37-1.92) Age



Black 43 1,433,290 3.00 (2.20-4.00) 2.60 (1.81-3.72)

Other 15 1,101,346 1.36 (0.79-2.20) 1.30 (0.78-2.18)Sex

Male 133 7,103,646 1.87 (1.57-2.21) 1.00 [reference]






Interval) †

Total 135 8,298,660 1.63 (1.37-1.92) Age



Black 43 1,433,290 3.00 (2.20-4.00) 2.60 (1.81-3.72)

Other 15 1,101,346 1.36 (0.79-2.20) 1.30 (0.78-2.18)Sex

Male 133 7,103,646 1.87 (1.57-2.21) 1.00 [reference]






Interval) †

Total 135 8,298,660 1.63 (1.37-1.92) Age



Black 43 1,433,290 3.00 (2.20-4.00) 2.60 (1.81-3.72)

Other 15 1,101,346 1.36 (0.79-2.20) 1.30 (0.78-2.18)Sex

Male 133 7,103,646 1.87 (1.57-2.21) 1.00 [reference]



All CasesCases By Age Group

n = 200 %

<35 years ≥35 years

n = 75 % n =125 %

Atherosclerotic CVD 110 55.0 12 16.0 98 78.4

Idiopathic 30 15.0 23 30.7 7 5.6

Anomalous Coronary Arteries 19 9.5 16 21.3 3 2.4

Cardiomegaly/ Cardiomyopathy (excluding HCM)

18 9.0 12 16.0 6 4.8

HCM 7 3.5 4 5.3 3 2.4

Hypertensive CV Disease 5 2.5 2 2.7 3 2.4

Myocarditis 5 2.5 3 4.0 2 1.6Valvular Disorder 3 1.5 2 2.7 1 0.8

ARVC 3 1.5 1 1.3 2 1.6


n = 200 %


n = 75 % n =125 %


Idiopathic 30 15.0 23 30.7 7 5.6



18 9.0 12 16.0 6 4.8

HCM 7 3.5 4 5.3 3 2.4



ARVC 3 1.5 1 1.3 2 1.6


n = 200 %


n = 75 % n =125 %


Idiopathic 30 15.0 23 30.7 7 5.6



18 9.0 12 16.0 6 4.8

HCM 7 3.5 4 5.3 3 2.4



ARVC 3 1.5 1 1.3 2 1.6

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Results

• In age ≥35 years, cardiac risk factors present– 80% had BMI > 25, 32% hyperlipidemia,

24% hypertension, 15% smoking• No deaths occurred at extremes of temperature

– WBGT<85 degrees or indoors• Predominant activity was running or elliptical use

in 60%. • 20% of all events occurred during mandatory run

of physical fitness test– Of these, 2/3 occurred after the test completed

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Limitations

• Information was obtained retrospectively and from case materials that were not collected systematically

• Missing data points • Population of predominantly young males who

voluntarily joined the service may not translate to other populations

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Conclusions

• From 2005-2010, the overall incidence in U.S. military members (1.63 per 100,000) was similar to most reported corresponding civilian SCD rates.

• Compared within groups, higher incidence rates were present in age ≥35 years, African-Americans, and males.

• The most common diagnosis depended on age– Age ≥35 years CAD– Age <35 years idiopathic and anomalous coronary

arteries

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Thank You

Physical Activity Preceding SCD

30

All Cases

Cases By Age Group

n = 200 % <35 years ≥35 years

n = 75 % n =125 %

Running/Elliptical 119 59.5 54 72.0 65 52.0

Other* 20 10.0 4 5.3 16 12.8

PT†/Unit PT

17 8.5 1 1.3 16 12.8

Walking‡ 13 6.5 4 5.3 9 7.2

Swimming 8 4.0 6 8.0 2 1.6

Basketball 7 3.5 3 4.0 4 3.2

Weight Lifting, etc§ 7 3.5 2 2.7 5 4.0

Bicycling 4 2.0 1 1.3 3 2.4

Football 1 0.5 0 0.0 1 0.8

Soccer 1 0.5 0 0.0 1 0.8

Tennis 1 0.5 0 0.0 1 0.8

Unknown 2 1.0 0 0.0 2 1.6*Generalized exercise, returning from gym, furniture moving, construction, mowing lawn, dancing †PT, physical training ‡Includes road marches and marching with body armor in formation §Includes Pull ups, Sit-ups, Combatives

Cardiac Risk Factors


n =200 %


n =75 % n =125 %Hyperlipidemia 42 21.0 2 2.7 40 32.0

Smoker 33 16.5 14 18.7 19 15.2

Hypertension 31 15.5 1 1.3 30 24.0

Family Hx of CAD 25 12.5 6 8.0 19 15.2

Family Hx of SCD 7 3.5 4 5.3 3 2.4

Previous Hx CAD 4 2.0 0 0.0 4 15.2

Diabetes 2 1.0 0 0.0 2 2.0

*Prevalence values represent the minimum burden of these factors, due to missing data.

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SCD- US military

• DoD registry 1998-2008– AD members, 15 million pt-yrs (~1.5 million/yr)– Over 14,000 sudden deaths

• 902 due to likely SCD with full records (~90/yr)– Mean age 38, predominantly males – 79% definitely cardiac– 21% sudden unexplained death (autopsy did not

clearly reveal a cause• Significant percentage occurred during exertion

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JACC 2011

Incidence of SCD in Athletes

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Incidence of SCD

• Organized High School/College Athletes– 1:134,000/Year (Male) (7.47:million/Year)– 1:750,000/Year (Female) (1.33/million/Year)

• Marathon Runners– 1:50,000 Race Finishers (Mean Age 37yo)

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ACC/AHA Recommendations (2007)

Personal history

1. Exertional chest pain/discomfort

2. Unexplained syncope/near-syncope not clearly attributable to neurocardiogenic mechanism

3. Excessive and unexplained dyspnea/fatigue, associated with exercise

4. Prior recognition of a heart murmur

5. Elevated systemic blood pressure

Family history

6. Premature death (sudden and unexpected) before age 50 years in ≥ 1 relative

7. Disability from heart disease in a close relative ≤ 50 years of age

8. Knowledge of heritable CV disease:

(HCM/DCM, long-QT syndrome, Marfan syndrome, or clinically important arrhythmias)Circulation 2007; 115:1643-1655

Prevention: AHA Guidelines

Electrophysiologist’s view of the world

“Syncope and sudden death are really the same thing…

except in one case you wake up”

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ACC/AHA Recommendations (2007)

Circulation 2007; 115:1643-1655

Physical examination

9. Heart murmur

10. Diminished or asymmetric femoral pulses (to exclude aortic coarctation)

11. Physical stigmata of Marfan syndrome

12. Asymmetric or elevated (>140/90 mmHg) brachial artery blood pressure

Prevention: AHA Guidelines

• What about ECG?

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Sudden Death in the YoungMaron Corrado US Military

n=286 n=277 n=108

Age 17 (9-40) 23 (12-35) 21 (18-35)

Region Registry Italy US military

Hypertrophic cardiomyopathy 102 (35.7%) 23 ( 8.3%) 8 ( 7.4%)

Anomalous coronary artery 37 (12.9%) 8 ( 2.9%) 21 (19.4%)

Atherosclerotic CAD 10 ( 3.5%) 58 (20.9%) 10 ( 9.3%)

Right ventricular dysplasia 11 ( 3.8%) 37 (13.4%) 1 ( 0.9%)

Structurally normal hearts 71 (25.6%) 44 (40.7%)

Incidence per 105 person-years 1.0 11.1

Maron BJ, et al. J Am Coll Cardiol 2003;41:974–80 Corrado D, et al. J Am Coll Cardiol 2003;42:1959–63 Eckart RE, et al. Ann Int Med 2004;141:829– 834

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Screening- US perspective

• Multiple issues with Italian data – Association does not prove causality

• US different than Italy– Population 5 x as great, different disease prevalence

• ECG is an imperfect test – 5-20% chance of abnormal ECG with many false pos

• Follow-up testing more of an issue in US • Cost prohibitive (estimated over $2 Billion annual

costs for US)

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Legal / Ethical Issues

• Nay-sayers of screening:– Inherent risk is understood and accepted– Impossible to achieve zero-risk– In the big public health picture- low prevalence

• Assuming a limited pot of money, should we spend this on other items?

– Societal double standard for competitive athletes• Who is responsible?

– Individual/ physician? – Team/school/government?

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Lesson from Jim Fixx

• High profile author who popularized running in the 1980’s– Preached jogging made people live

longer

• Had sudden death while running along road at age 52

• Autopsy revealed severe diffuse 3 vv CAD

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I want to die like my father did, peacefully in his sleep

Not screaming like the passengers in his car.

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Case

• A 27 yo male -syncopal episode while playing basketball. Did have LH prior to attack. Completely oriented afterwards; no incontinence.

• PMH, Meds, ROS: unremarkable

• Questionable family history

http://www.findagrave.com/cgi-bin/fg.cgi?page=pis&GRid=6525322&PIgrid=6525322&PIcrid=1607685&PIpi=8468189&

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Anomalous Coronaries

Documents

San Antonio Medical BRAC Integration Office, 916-1000 Incidence of Sudden Cardiac Death Associated with Physical Exertion in the United States Military