Pre-participation ECG screening in military recruits- the IDF experience

1
Pre-participation ECG screening in military
recruits- the IDF experience

• Alon Grossman M.D MHA1, 2, 3, Alex Prokupetz
  MHA1, 2, Igor Lipchenca MD 4
• IAF aero medical center, Tel Hashomer, Israel
• IDF medical corps
• Department of Internal Medicine E, Rabin Medical
  Center Beilinson Campus affiliated to Tel Aviv
  University Sackler Medical School, Israel
• Leviev Heart Center, Sheba Medical Center and Tel
  Aviv University, Tel Hashomer, Israel

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Introduction

• Despite the large numbers of athletes undergoing
  pre-participation screening, there is a
  continuing debate regarding the optimal method of
  screening
• The main concern in performing mass ECG screening
  in athletes is the costly additional work up
  required based on resting ECG findings

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Introduction

• Professional guidelines in the US do not
  recommend use of either ECG or echocardiography
  for screening of college athletes1
• On the other hand, 12-lead ECG has been supported
  for screening purposes among athletes by the
  Sport Cardiology section of the European society
  of Cardiology and Medical Commission of the
  International Olympic Committee and has been
  shown to reduce mortality in this population2
• 1. Maron BJ, Thompson PD, Ackerman MJ, et al.
  Recommendations and considerations related to pre
  participation screening for cardiovascular
  abnormalities in competitive athletes 2007
  update a scientific statement from the American
  Heart Association Council on Nutrition, Physical
  Activity, and Metabolism endorsed by the
  American College of Cardiology Foundation.
  Circulation. 2007 1151643-1655
• 2. Corrado D, Basso C, Pavei A, Michieli P,
  Schiavon M, Thiene G. Trends in sudden
  cardiovascular death in young competitive
  athletes after implementation of a
  pre-participation screening program. JAMA 2006
  29615931601

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Background

• Recruits to elite units in the IDF undergo
  pre-participation ECG prior their enlistment
• This process has been performed sporadically in
  the last years but all ECGS are performed at the
  IAF aero medical Center since January 2010
• All elite units candidates undergo a preliminary
  medical selection process at the IDF recruitment
  center (History PE)
• Only those who are physically healthy are allowed
  to enlist to elite units and only they undergo
  pre-participation ECG
• This population consists of 17-19 years old male
  subjects

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Background

• All ECGS are evaluated by a single cardiologist
• Those requiring further evaluation, complete the
  evaluation prior to enlistment
• A military physician from the IAF aero medical
  center summarizes the medical evaluation and
  decides whether the candidate is eligible to
  enlist to a special unit

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Aims

• To characterize causes of referral to continued
  investigation based on resting ECG findings
• To summarize the additional work-up performed
• To summarize the rate of significant findings
  resulting in disqualification of military
  candidates in this population

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Results

• 1,455 subjects underwent pre-participation ECG in
  the year 2010
• 1,388 studies (95.39) interpreted as normal
• 67 referred to further evaluation

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Causes for referral
Number of cases ( of total findings) Definition Cause of referral
16 (23.9) Non specific T wave changes
14 (20.9) PR segment shorter than 120 milliseconds) with or without a delta wave Pre-excitation pattern
11 (16.4) S1R5,6 wave voltage greater than 35 mm in precordial leads and/or R-wave greater than 15 mm in peripheral lead I and/or 12 mm in aVL LVH
9 (13.4) Rates slower than 50 BPM Sinus bradycardia
6 (8.9) AV blocks of various degree, LBBB or RBBB, LAHB or LPHB Blocks
5(7.5) Atrial or ventricular premature beats
3 (4.5) upward ST-segment elevation in 2 or more peripheral or precordial leads, beginning from an elevated J point and continuing with an upsloping shape into the T-wave Early repolarization pattern
3 (4.5) corrected QT interval (QTc) greater than 440 milliseconds Long QT interval
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Additional investigations
Adenosine test Holter Stress test Echo ECG finding
0 1 8 17 T wave changes
0 1 2 2 Early repolarization
0 2 2 1 Long QT
11 7 7 1 Pre excitation pattern
0 2 3 2 Atrial or ventricular premature beats
0 0 1 16 LVH
0 3 7 7 Blocks
0 6 8 0 Sinus bradycardia
11 22 38 46 Total
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Clinical Diagnosis
Final diagnosis () ECG finding
BAV (1) VSD (1) LVH (1) T wave changes
LVH (1) Early repolarization
Dilated left ventricle (1) Atrial or ventricular premature beats
LVH (1) Non compacted apex (1) LVH
None Long QT, pre-excitation pattern, sinus bradycardia, blocks
7 Total number
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example 1
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Example 2

• ICRBBB with non-specific T wave changes in
  inferior leads
• Echocardiography interpreted as normal
• No further w/u required

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Example 3

• Early repolarization pattern particularly in V2
• Echocardiography-normal
• No further w/u required

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Discussion

• Screening for cardiovascular disease among
  athletes and military candidates is imperative as
  sudden death is obviously tragic and potentially
  preventable
• Debate continues regarding the optimal method of
  screening, this ranging from reliance solely on
  history and physical examination to performance
  of 12-lead ECG and echocardiography

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Discussion

• The total rate of ECGS defined as abnormal in
  this cohort was 4.6, a percentage much lower
  than previously reported
• Yet, even in a previous report by Pellicia et al
  (8) in which 11.8 of ECGs were interpreted as
  abnormal, additional evaluation was requested in
  only 4.8 of ECGs, disregarding some of the
  findings noted on routine ECG
• This rate is similar to that reported in this
  study and probably represents the true rate of
  ECG findings requiring further evaluation in
  young athletes
• Corrado D, Basso C, Schiavon M, Thiene G.
  Screening for hypertrophic cardiomyopathy in
  young athletes. N Engl J Med 1998339 364369
• Pelliccia A, Culasso F, Di Paolo FM, Accettura D,
  Cantore R, Castagna W, Ciacciarelli A, Costini G,
  Cuffari B, Drago E, Federici V, Gribaudo CG,
  Iacovelli G, Landolfi L, Menichetti G, Atzeni UO,
  Parisi A, Pizzi1 AR, Rosa M, Santelli F, Santilio
  F, Vagnini A, Casasco M, and Di Luigi L.
  Prevalence of abnormal electrocardiograms in a
  large, unselected population undergoing
  pre-participation cardiovascular screening. Eur
  Heart J 2007 28(16) 2006-2010.

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T waves

• T wave changes was the most common cause for
  continued investigation in the cohort
• This is probably due to the non specific nature
  of this finding
• Disqualifying findings were identified in 18.75
  of evaluations in these subjects
• Whether these clinical findings were associated
  with the ECG findings or were incidental is
  unclear

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PRE EXCITATION PATTERN

• Signs of pre-excitation were identified in 14
  subjects who comprised 0.96 of the study
  population
• This is a higher percentage than previously
  reported (0.2)
• Probably resulted from the high awareness to this
  condition among interpreting cardiologists
• No cases of pre-excitation syndrome identified
• This is similar to a previous report from the
  Israeli air force
• Ferrer MF. Electrocardiographic variations,
  arrhythmias, pacemakers. In Lew EA, Gajewski J.
  Medical Risks Trends in Mortality by age and
  time elapsed. New York, NY Praeger 1990.
• Grossman A et al Use of adenosine test for the
  exclusion of pre-excitation syndrome in
  asymptomatic individuals. Ann Noninvasive
  Electrocardiol 2011 Apr 16 (2) 180-183.

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LVH criteria

• Signs of LVH were identified in only 7.56 of the
  study population
• This is significantly lower than reported in
  previous studies (up to 45)
• This is surprising given the young age of the
  population and the fact that the subjects were
  all very physically active
• Disqualifying findings were identified in 18.2
  of these subjects
• Pelliccia A et al Prevalence of abnormal
  electrocardiograms in a large, unselected
  population undergoing pre-participation
  cardiovascular screening. Eur Heart J 2007
  28(16) 2006-2010

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LIMITATIONS

• A selective cohort (healthy, physically active
  underwent ECG during screening for athletic
  activity)
• Single physician interpreting all ECGS (high
  inter-observer variability reported in the
  literature)

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Conclusions

• T wave changes, although non-specific, may be a
  sign of cardiac disease
• Pre-excitation pattern is of low specificity for
  the diagnosis of PES, but because of the lethal
  potential of this condition, adenosine should be
  performed in subjects with a suspicious pattern

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Conclusions

• ECG-LVH criteria have a low sensitivity in young
  subjects, but because of the fatal potential of
  HOCM and because the specificity of the ECG is
  very high, echocardiography should be performed
  to all those with ECG criteria
• Policy makers should take into account the large
  number of echocardiographies that will be
  performed in order to identify subjects with true
  LVH

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Conclusions

• Sinus bradycardia and conduction disturbances
  (low degree AVB and hemiblocks) probably result
  from increased vagal tone and require no
  additional work-up

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Thank you