University of Groningen. The young athlete's heart Bessem, Bram

University of Groningen The young athlete's heart Bessem, Bram IMPORTANT NOTE: You are advised to consult the publisher's version (publisher's PDF) if you wish to cite from it. Please check the document version below. Document Version Publisher's PDF, also known as Version of record Publication date: 2017 Link to publication in University of Groningen/UMCG research database Citation for published version (APA): Bessem, B. (2017). The young athlete's heart: An electrocardiographic challenge [Groningen]: Rijksuniversiteit Groningen Copyright Other than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons). Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum. Download date: 04-10-2018

CHAPTER THE ELECTROCARDIOGRAM OF HIGH-LEVEL JUNIOR SOCCER PLAYERS; COMPARING THE ESC VS. THE SEATTLE CRITERIA Bram Bessem, Matthijs C. de Bruijn and Wybe Nieuwland Br J Sports Med. 2015 Aug;49(15):1000-6

54 C H A P T E R ABSTRACT Introduction: Sudden cardiac death in young athletes is a devastating event. The screening and detection of potentially life-threatening cardiac pathology by ECG is difficult due to high numbers of false-positive results, especially in the very young. The Seattle ECG criteria (201) were introduced to decrease false-positive results. We compared the Seattle ECG criteria with the European Society of Cardiology ECG criteria of 2005 and 2010 for cardiac screening in high-level junior soccer players. Methods: During the 2012-201 season all data from cardiovascular screenings performed on the youth division of two professional soccer clubs were collected. The total study population consisted of 19 male adolescent professional soccer players, aged 10-19 years. Five players dropped out of this study. Results: Applying the ESC criteria of 2005 and 2010 to our population resulted in a total of 89 (47%) and 62 (%) abnormal ECGs. When the Seattle ECG criteria were applied, the number of abnormal ECGs was 6 (%). The reduction was mainly due to a reclassification of the long QT cut-off value and the exclusion of right atrial enlargement criteria. All ECGs abnormalities using the Seattle criteria related to T-wave inversion criteria. Conclusion: The Seattle ECG criteria seem very promising for decreasing false-positive screening results for high-level junior soccer players.

T H E E L E C T R O C A R D I O G R A M O F H I G H - L E V E L J U N I O R S O C C E R P L A Y E R S ; T H E E S C V S. T H E S E A T T L E C R I T E R I A 55 INTRODUCTION On 19 March 2012 a talented Dutch junior soccer player suffered a cardiac arrest during practice. He was rushed to the hospital, where he died the next day at the age of 1. The loss of a child is a devastating event that has a high impact on the local community. When a child dies during sport activities, which should promote health, the impact is even bigger. Aiming to prevent cardiac events during sports, the European Society of Cardiology (ESC) proposed a screening protocol in 2005. This protocol was based on 25 years of experience gained by Corrado et al., and consisted of a questionnaire, a physical examination and an electrocardiogram (ECG). When abnormalities are found, further examination, including an echocardiogram, is warranted. These recommendations triggered a scientific debate about the most appropriate screening strategy. Maron et al. and the American Heart Association stated that the addition of an ECG to screening would be impractical, due to expected high false-positive test results which would lead to unnecessary further testing, anxiety about outcomes for the athlete, and possibly unmerited disqualification from sports. In practice, some sporting programs include ECG screening, others do not. There has been much research to optimize the ECG criteria and minimize false-positive screening results. This caused the ESC ECG criteria to be revised by Corrado et al. in 2010. More recently, after an international summit in 2012, a second revision was made by Drezner et al. in 201, known as the Seattle Criteria. We aimed to compare the ECG criteria outcome of the ESC recommendations of 2005 and 2010 and the Seattle ECG criteria of 201 in talented junior soccer players aged 10-19 years.

56 C H A P T E R METHODS During the 2012-201 season all data from cardiovascular screenings performed on the youth division of two professional soccer clubs were collected. All youth teams of both clubs played at the highest national level. The total study population consisted of 19 male adolescent professional soccer players, aged 10-19 years. Written informed consent was obtained from all participants and their parents/legal guardians, and an Independent Review Board statement was provided. Electrocardiogram (ECG) A standard 12-lead resting ECG was collected by a sports physician (Welch Allyn CardioPerfect software, v. 1.6.4). All ECGs were scored by the principal investigator, using the criteria provided by Corrado et al. in 2005, the revised criteria provided by Corrado et al. in 2010, and the criteria provided by Drezner et al. in 201. 1- It should be noted that the ESC criteria of 2005 and 2010 where developed for athletes aged 12-5 and the Seattle criteria where developed for athletes age 14-5. Other variables Data on age (at the screening), ethnicity, height, weight and blood pressure were collected. Ethnicity was self-reported. The options of choice were White-Caucasian, Black-African (Morocco / Turkey / Other), Black-Caribbean, Asian, Mixed and Other. Body surface area was calculated using the Mosteller formula ( (L(cm) x M(kg)) / 600). 4 Training intensity was calculated by averaging 5 weekly programs. It was established whether the player was international. Positive screening result When there was an abnormal finding on the questionnaire, the physical examination and/or the electrocardiogram (ECG), the athlete was revered to the (paediatric) cardiologist for further primary examination. These primary examinations included an echocardiogram, exercise testing and a 24hr ECG monitoring. When these tests weren t able to clear the athlete, additional secondary testing was

T H E E L E C T R O C A R D I O G R A M O F H I G H - L E V E L J U N I O R S O C C E R P L A Y E R S ; T H E E S C V S. T H E S E A T T L E C R I T E R I A 57 done including, amongst others, a cardiac MRI. When a cardiovascular disease was diagnosed, we excluded the player for this study. For the ECG screening criteria we used the Seattle criteria of 2012 Reference ranges for the echo cor where based on the data provided by Prior and La Gerche. 5 Exclusion criterion Youth players with a known cardiovascular disease or diagnosed with a cardiovascular disease by a (paediatric) cardiologist during the season 2012-201 were excluded. Data analysis Data analysis was performed using Excel (200). RESULTS Population Of the 19 players eligible for the study, four dropped out because they no longer played at a high level at the date of the screening. One player was excluded due to an already diagnosed AVNT. A total of 188 players were included in this study. All players with a positive screening result could be cleared by the (paediatric) cardiologist using only the primary additional testing (echocardiogram, exercise testing and 24hr ECG monitoring). The population was evenly distributed over the different age categories with an age range of 10-19 years. The average blood pressure was 115/69 mmhg. A total of 29% of the players was of non-caucasian ethnicity, with a total of 15% being of black ethnicity. A relative high number of non- Caucasian players were from Turkey, Morocco or the Caribbean (22/54, 41%). There were 9% international players. For the population demographics, see Table 1.

58 C H A P T E R Population Average (SD) Range Age (years) 14.9 (2.2) 10.8 19.2 Height (cm) 167.2 (1.5) 19.5 202.5 Weight (kg) 55.9 (14.4) 0.6 99.5 BSA (m²) 1.60 (0.27) 1.09 2.28 Blood pressure (mmhg) Systolic 115 (12) 85 140 Diastolic 69 (9) 50 90 Training volume (hr/wk) 10 7.5 15 Number Percentage Age category <1yr 5 28% 1-14yr 47 25% 15-16yr 47 25% >16yr 41 22% Ethnicity White - Caucasian 14 71% Black - Total 29 15% Black - African (Other) 7 4% Black - African 6 % Black - African 5 % Black - Afro-Caribbean 11 6% Asian - Other 11 6% Other 1 1% Mixed 11 6% Unknown 2 1% International player 16 9% Table 1. Population demographics (Total N=188) Electrocardiogram (ECG) ECG characteristics The average heart rate was 69 beats/min. No player had a heart rate below 40 beats/min. PQ time ranged from 108ms to 222ms. The QRS time range was 68ms to 117ms. Corrected QT time ranged from 5ms to 468ms. An overview of the ECG characteristics is shown in Table 2.

T H E E L E C T R O C A R D I O G R A M O F H I G H - L E V E L J U N I O R S O C C E R P L A Y E R S ; T H E E S C V S. T H E S E A T T L E C R I T E R I A 59 Training-related (group 1) ECG changes Corrado 1 and Drezner divided ECG changes into group-1 and group-2 changes. ECG changes related to training and fitting the athlete s heart profile are included in group 1. Almost three-quarters (72%) of our population had one group-1 change and 64 persons (4%) had more than one group-1 change. Most group-1 changes were seen in the category of sinus arrhythmia (29%), sinus bradycardia (28%) and incomplete RBBB pattern (26%). For an overview of trainingrelated (group 1) ECG changes, see Table.

60 C H A P T E R ECG characteristics Age (N=5) Age (N=47) Age (N=47) Age (N=41) Total (N=188) Median (SD) Range Median (SD) Range Median (SD) Range Median (SD) Range Median (SD) Range Percentile Heart Rate beats/min 76 (11) 50 94 69 (14) 46 109 65 (12) 45 111 59 (11) 4 88 67 (1) 4 111 47 94 nd th QRS axis **** degree 7 (24) -2 106 78 (21) 1 17 79 (2) 8 110 76 (26) -20 109 77 (24) -2 17 0 109 PR time Ms 145 (20) 115 222 18 (20) 108 210 146 (20) 118 215 161 (21) 110 215 147 (22) 108 222 114 212 QRS time Ms 80 (9) 68 110 87 (9) 69 107 89 (10) 70 117 91 (11) 74 112 87 (11) 68 117 71 111 QTc time Ms 420 (22) 5 461 421 (2) 72 468 412 (25) 58 466 407 (21) 65 448 415 (2) 5 468 65 460 R in V1 *** mm (2) 0 11 () 1 14 (2) 0 10 2 (2) 0 8 (2) 0 14 0 10 S in V1 *** mm 10 (4) 1 21 9 (5) 0 21 10 (6) 8 7 (4) 2 19 9 (5) 0 8 21 S in V2 mm 22 (7) 7 7 2 (9) 4 45 21 (8) 9 48 21 (7) 4 5 22 (8) 4-48 8 40 S in V5 mm (1) 0 6 2 (2) 0 6 2 (2) 0 11 (2) 0 6 2 (2) 0 11 0 6 R in V5/V6* mm 17 (5) 7 7 17 (6) 8 42 19 (5) 8 29 18 (4) 9 27 18 (5) 7 42 9 0 R or S in standard lead ** mm 14 (4) 6 2 14 (5) 7 26 15 (5) 6 26 12 (4) 6 24 14 (4) 6 26 7 24 Table 2. ECG characteristics (Total N=188) * Biggest R was used. ** Biggest R or S was used. *** N=187 due to missing V1 in 1 ECG **** N=184 due to undetermined axis in 4 ECGs

T H E E L E C T R O C A R D I O G R A M O F H I G H - L E V E L J U N I O R S O C C E R P L A Y E R S ; T H E E S C V S. T H E S E A T T L E C R I T E R I A 61 Age <1 yr (N=5) Age 1-14 yr (N=47) Age 15-16 yr (N=47) Age >16 yr (N=41) Total (N=188) Training-related (group 1) ECG changes N % N % N % N % N % Sinus bradycardia < 60/min 5 9 % 1 28 % 11 2 % 2 56 % 52 28 % Sinus arrhythmia Present 19 6 % 11 2 % 16 4 % 8 20 % 54 29 % Rhythm Atrial 0 0 % 1 2 % 1 2 % 0 0 % 2 1 % Junctional 0 0 % 0 0 % 0 0 % 1 2 % 1 1 % AV block 1 st degree 1 2 % 1 2 % 1 2 % 2 5 % 5 % 2 nd degree (Mobitz I) 0 0 % 0 0 % 0 0 % 0 0 % 0 0 % Incomplete RBBB 11 21 % 11 2 % 16 4 % 10 24 % 48 26 % Isolated QRS voltage criteria for LVH Sokolow index 5mm 6 11 % 11 2 % 10 21 % 2 5 % 29 15 % Early repolarisation 9 17 % 8 17 % 5 11 % 9 22 % 1 16 % Total group 1 changes 4 64 % 70 % 7 79 % 2 78 % 16 72 % Table. Training-related (group 1) ECG changes

62 C H A P T E R The ESC and Seattle criteria Table 4 shows the results of the ECG screening using the criteria published by Corrado et al. in 2005 2 and in 2010, 1 and the criteria published by Drezner et al. in 201. European Society of Cardiology ECG criteria of 2005 Applying the 2005 ESC ECG criteria to our population resulted in89 (47%) abnormal ECGs. The highest numbers of abnormal ECGs are found with the voltage criteria (27%), long QT criteria (15%), right atrial enlargement criteria (10%) and RVH criteria (7%). European Society of Cardiology ECG criteria of 2010 Applying the 2010 ESC criteria results in a total of 62 (2%) abnormal ECGs. This is a reduction of 2% compared with the criteria of 2005. The biggest reduction was caused by the exclusion of the isolated voltage criteria. The highest numbers of abnormal ECGs are found with the long QT criteria (15%), right atrial enlargement criteria (10%), RVH criteria (5%) and T-wave inversion criteria (%). Seattle ECG criteria of 201 When applying the 201 Seattle ECG criteria, the number of abnormal ECGs was 6 (%). This is a reduction of 90% compared with the 2010 criteria. The biggest reduction was caused by the adjustment of the long QT cut-off value and the exclusion of the right atrial enlargement criteria. All abnormal ECGs were found with the T-wave inversion criteria.

T H E E L E C T R O C A R D I O G R A M O F H I G H - L E V E L J U N I O R S O C C E R P L A Y E R S ; T H E E S C V S. T H E S E A T T L E C R I T E R I A 6 N=188 ESC 2005 ESC 2010 Seattle 201 2005 N (%) 2010 N (%) Seattle N (%) P-wave QRS complex LA enlargement RA enlargement Axis Voltage Abnormal Q- waves Bundle branch block RVH* Negative portion of the P-wave in lead V1 0.1mV in depth and 0.04s in duration Peaked P-wave in leads II and III or V1 0.25mV in amplitude Right axis deviation ( 120 ) Left axis deviation (-0 to -90 ) R/S Standard lead ( 2mV) Negative portion of the P-wave in lead V1 0.1mV in depth and 0.04s in duration Peaked P-wave in leads II and III or V1 0.25mV in amplitude Right axis deviation (>110 ) Left axis deviation (-0 to -90 ) Prolonged P-wave duration of >120ms in leads I or II with negative portion of the P-wave 1mm in depth and 40ms in duration in lead V1-0 (0%) 0 (0%) 0 (0%) 19 (10%) 19 (10%) - - 1 (1%) 4 (2%) - Left axis deviation (-0 to -90 ) 0 (0%) 0 (0%) 0 (0%) - - 2 (12%) - - S V1 or V2 ( mv) - - 6 (19%) - - R V5 or V6 ( mv) - - 5 (%) - - Total - - 50 (27%) - - Q-waves 0.04s in duration or 25% of the height of the ensuing R-wave or QS pattern in two or more leads Right bundle branch block or left bundle branch block with QRS duration 120ms Q-waves >4 mm deep in any lead except III, avr Complete bundle branch block (QRS 120ms) and/or hemiblock - IV conduction delay (>110ms) R/R' V1 0.5mV and R/S 1 ST segment ST depression ST segment in two or more leads T-wave inversion/ T-wave QT interval Rhythm Conduction flattening T-wave flattening or inversion in two or more leads R-V1 + S-V5 >10.5mm ST segment in two or more leads T-wave flattening or inversion in two or more leads >mm in depth or >40ms in duration in two or more leads (except for III and avr) 0 (0%) 0 (0%) 0 (0%) Left bundle branch block with QRS 120ms, predominantly negative QRS complex in lead V1 (QS or rs), and upright monophasic R-wave in leads I and V6 0 (0%) 0 (0%) 0 (0%) IV conduction delay ( 140ms) - 4 (2%) 0 (0%) R-V1 + S-V5 >10.5mm & right axis >120 0.5mm in depth in two or more leads >1mm in depth in two or more leads V2 V6, II and avf, or I and avl (excludes III, avr and V1) 14 (7%) 9 (5%) 0 (0%) 0 (0%) 0 (0%) 0 (0%) 9 (5%) 6 (%) 6 (%) Long QT QTc >440ms (Male) QTc >440ms (Male) QTc 470ms (Male) 28 (15%) 28 (15%) 0 (0%) Short QT - QTc 60ms QTc 20ms - 2 (1%) 0 (0%) Premature ventricular complex Ventricular arrhythmias Atrial tachyarrhythmias Premature ventricular beats Severe ventricular arrhythmias Supraventricular tachycardias, atrial flutter or atrial fibrillation Sinus bradycardia Heart rate 40/min Heart rate 0/min or sinus pauses s Ventricular preexcitation** AV-block Brugada pattern - 2 PVCs per 10s tracing - Couplets, triplets and non-sustained ventricular tachycardia 0 (0%) - 0 (0%) 0 (0%) - 0 (0%) - Supraventricular tachycardia, atrialfibrillation, atrial-flutter 0 (0%) - 0 (0%) Heart rate 0/min or sinus pauses s PR <120ms PR <120ms PR <120ms & delta wave & QRS >120ms 0 (0%) 0 (0%) 0 (0%) 8 (4%) 8 (4%) 0 (0%) First (PR 200ms) - - 5 (%) - - Second Second (other than Mobitz I) Second (other than Mobitz I) 0 (0%) 0 (0%) 0 (0%) Third Third Third 0 (0%) 0 (0%) 0 (0%) - High take-off and downsloping ST segment elevation followed by a negative T-wave in 2 leads in V1 V High take-off and downsloping ST segment elevation followed by a negative T-wave in 2 leads in V1 V - 0 (0%) 0 (0%) Total abnormal ECGs 89 (47%) 62 (2%) 6 (%) Table 4. Results of the ESC ECG criteria of 2005 & 2010 and the Seattle ECG criteria * N=187 due to missing V1 in 1 ECG ** N=185 due to ECG not having sinus rhythm

64 C H A P T E R T-wave inversion Data for players with ECGs with T-wave inversions are displayed in Table 5. Seven of the nine players with T-wave inversion showed a convex (domed) ST segment elevation followed by an (end portion) negative T-wave in V1-V/V4. An example is shown in Figure 1. Two of the nine showed T-wave inversion in the lateral leads. All these ECGs are considered abnormal by the ESC criteria of 2005. The 2010 ESC and the Seattle criteria both recognize a common early repolarisation variant in black athletes of Afro- Caribbean decent characterized by domed/convex ST segment elevation followed by T wave inversion confined to leads V1-V4 (as shown in Figure 1). Therefore athletes #2, # and #7 would be classified as normal by these criteria. This early repolarisation pattern does not apply to Caucasians, and thus athletes #1, #4, and #9 are classified as abnormal. Likewise, T wave inversion beyond V4 (ie into V5 or V6) is abnormal (athletes #5 and #6). It should also be noted that persistent juvenile T wave inversion in the anterior precordial leads occurs in up to 8% of pre-puberty athletes (ie 14 or younger). 6,7 Thus, this may be contributing to abnormal findings in athletes #1 and #4 (although as neither the ESC criteria nor the Seattle criteria define juvenile T wave inversion, these ECGs are classified as abnormal if following the criteria strictly).

T H E E L E C T R O C A R D I O G R A M O F H I G H - L E V E L J U N I O R S O C C E R P L A Y E R S ; T H E E S C V S. T H E S E A T T L E C R I T E R I A 65 Age (years) HR (/min) Height (cm) Weight (kg) BSA (m²) Ethnicity 1. 12 77 162.0 45.6 1.4 White - Caucasian 2. 14 64 151.5 5.0 1.21 Black- Afro- Caribbean. 14 70 174.0 65.0 1.77 Black- Afro- Caribbean 4. 14 46 170.0 54.2 1.60 White - Caucasian 5. 15 65 171.5 69. 1.82 Black- Afro- Caribbean 6. 16 69 172.0 58. 1.67 White - Caucasian 7. 17 56 172.0 60.6 1.70 Black African (Other) Location of T- wave inversion Type of T-wave inversion V1-V4, III Convex ST, end portion T- wave negative; III negative V1-V4 Convex ST, end portion T- wave deep negative V1-V, III Convex ST, end portion T- wave negative; III negative V1-V, III Convex ST, end portion T- wave negative; III negative V1-V5(V6), III, AvF V-V6, II, III, AvF 8. 17 79 178.0 59.0 1.71 Unknown V1-V4, III (AvF, II) 9. 19 56 187.6 80.0 2.04 White - Caucasian Convex ST, end portion T- wave negative; III negative All negative, none deep negative V1-V4 Convex ST, end portion T- wave deep negative Convex ST, end portion T- wave deep negative, III (II, AvF) negative V1-V Convex ST, end portion T- wave deep negative Table 5. Description of the players with abnormal repolarisation patterns (Total N=9) DISCUSSION The challenge of limiting false-positive screening results applies particularly in the case of very young athletes. Our study shows that the ECGs of young professional soccer players have a wide range of normal values as well as a high degree of training-related ECG changes, and that use of the Seattle ECG criteria described by Drezner et al. results in a much lower rate of false-positive screening results compared to the ESC ECG criteria of 2005 and 2010. 1-

66 C H A P T E R ECG characteristics This study shows the ECG characteristics of a highly trained population of professional adolescent soccer players. Only few articles describe normal ECG characteristics in an adolescent population, and even fewer describe an adolescent athletic population such as the one in our study. Rijnbeek et al. described the ECG characteristics of a 200 healthy non-athletic males aged to 16 years. 8 Our athletic population demonstrated a much wider range (for example, looking at the measured PR time, Rijnbeek et al. measured an upper value of 178ms, while the upper values we measured reached 222ms.) Similarly Mason et al. 9 described the ECGs of a population of 79,74 subjects participating in a drug trial; 145 of them were aged 10-19 years, and 776 are male. In the article Mason describes the median value and the 2 nd and 98 th percentiles for the PR interval (median 141ms, 2 nd 98 th 104 186ms), QRS interval (median 89ms, 2 nd 98 th 65 108ms) and axis (median 60, 2 nd 98 th 0 102), and QTc time (median 40ms, 2 nd 98 th 52 448ms). All median values found by Mason are comparable to our median values, yet if we compare the 2 nd and 98 th percentiles of the PR interval and the QTc time with our population we see that the athletic population has more extreme values than the non-athletic population. When comparing our results with the adolescent athletic population we see similar results. Sharma et al., for example, described the ECGs of 1000 junior athletes (mean age 15.7, range 14 18). 10 When we compare Table 2 of this article with the data displayed in Table 2 of the article by Sharma et al., we see much the same results. When our results are compared to the results found by Somauroo et al., however, we see less profound extreme values. 11 These differences with our results may be explained by the fact that the population of Somauroo consists of soccer players older (mean age 16.7 range 15. 18.) than the population we describe.

T H E E L E C T R O C A R D I O G R A M O F H I G H - L E V E L J U N I O R S O C C E R P L A Y E R S ; T H E E S C V S. T H E S E A T T L E C R I T E R I A 67 Training-related ECG changes This study shows a high degree (72%) of training-related ECG changes, as defined by Corrado et al. and Drezner et al. as group-1 changes. 1, These high numbers of changes are also found by Sharma et al., 10 Bohm et al. 12 and Brosnan et al. 1 (resp. 80%, 66% and 87%). All these studies show much higher amounts of sinus bradycardia than ours though (resp. 28% vs. 80%, 56% and 54%). An explanation for this difference could be a more nervous state of our relative younger population (resp. 14.9 years range 11-19 vs.15.7 years range 14-18, 21 years range 16-8, and 20 years range 16-5). Table 2b shows that the amount of sinus bradycardia increases with age, and in the >16 age group it is 56%. This amount correlates much better with the percentages found by Sharma et al., Bohm et al. and Brosnan et al. 10,12,1 European Society of Cardiology vs. Seattle criteria One of the major problems with using the ECG as a screening tool is the number of false-positive screening results. European Society of Cardiology ECG criteria of 2005 and 2010 Results on false-positive screening outcome using the ESC ECG criteria of 2005 ranged from 10-40% 14-20 REF). With increasing knowledge on distinguishing ECG abnormalities resulting from intensive physical training and those potentially associated with an increased cardiovascular risk, a consensus statement on interpretation of electrocardiograms in athletes was published by the ESC in 2010. 1 This statement divided ECG abnormalities into a group-1 (common and training-related) and a group- 2 (uncommon and training-unrelated) category. Using this statement let to a decrease in falsepositive screening outcomes of 40-80%. 21,22 The false-positive screening rate using this statement ranged from 2.8 20%. 1,21-27

68 C H A P T E R Seattle ECG criteria of 201 In 2012 an international group of experts convened in Seattle to update these ECG criteria into what is known as the Seattle criteria. One of the goals of these criteria was to decrease false-positive screening results. To our knowledge, only Brosnan et al. 1 have evaluated screening results using the Seattle ECG criteria and compared them to the 2010 ESC ECG criteria. Their positive screening outcome was reduced from 17% using the 2010 criteria to 4.2% using the 201 Seattle criteria (reduction of 75%). The reduction was mainly due to a reclassification of the QTc intervals, of the T-wave inversion isolated to V1 2, and of the ECG with either isolated right axis deviation or right ventricular hypertrophy on voltage criteria. Applying the 2005 ESC ECG criteria in our population would result in a positive screening outcome in 47% of cases. This number is unacceptable in the use of a screening tool and leads to many false-positives and unnecessary additional testing. This result is higher than the previously reported 10-40%. The reason for this could be because our population consist of a high number of young (<16yr) high-level soccer players. This young age and sports level could be the reason for the higher number of ECG abnormalities. When applying the 2010 ESC ECG criteria the positive results drop to 2% (a reduction of 2%). This number is much higher than the previously reported 2.8 20%. Reasons for this discrepancy could be that in the 2010 criteria the cut-off values were not clearly defined and therefore could be interpreted differently by investigators. For example, Brosnan et al. 1 used 120 as a cut-off value for IVCD, whereas the consensus statement of 2010 1 recommends a cut-off value of 110. Another example is the description of the cut-off value for short QTc syndrome. In the consensus statement of 2010 different values were mentioned (80ms, 60ms, 0ms), and they recommend 80ms. Brosnan et al. 1 used 60ms for the 2010 ESC ECG criteria cut-off value, whereas Drezner et al. 21 recommend 40ms. Furthermore, most other studies do not describe the used cut-

T H E E L E C T R O C A R D I O G R A M O F H I G H - L E V E L J U N I O R S O C C E R P L A Y E R S ; T H E E S C V S. T H E S E A T T L E C R I T E R I A 69 off values and only refer to the 2010 consensus statement, which makes comparison difficult. These possible different interpretations could partly explain why we found a much higher positive screening result compared to other researchers. Another possible explanation for the higher amount of positive screening outcomes could be the above-mentioned high numbers of young (<16yr) highlevel soccer players in our population. Using the Seattle ECG criteria, the positive screening outcome drops to %. This is a reduction of 90% compared to the 2010 criteria. The reduction was mainly due to a reclassification of the long QT cut-off value and the exclusion of the right atrial enlargement criteria. All the positive screening results were found with the T-wave inversion/flattening category. Of the nine ECGs with T-wave flattening/inversion, seven show T-wave inversion/flattening only in the anterior leads (V1-V/V4). Of these seven ECGs, three where of athletes with Black- Afro- Caribbean / Black-African ethnicity and are therefore classified as normal. Of the remaining four ECGs, two where of athletes aged 14 years and younger. As described by Papadakis, Migliore and Drezner,,6,7 the anterior lead T-wave inversion/flattening may be a juvenile pattern in athletes aged 14 years and therefore be a normal finding among these athletes. If we considered these ECGs as normal, the positive screening results with the Seattle ECG criteria would decrease even further, to only 4c (2%) ECGs. Limitations Ideally we would have a higher population size when describing ECG characteristics and screening outcomes. Our population size is small and therefore these results should be looked at with caution. However, it is difficult to find large numbers of high-level athletes, especially below the age of 16. In sports medicine and cardiological literature, only Sharma and Migliore 10 have described larger populations of similar age and sports level.

70 C H A P T E R A second limitation is the absence of echocardiographic data of the players. The lack of follow-up is another limitation. As described by Pelliccia and Migliore, in a few cases the presence of repolarisation abnormalities in young athletes may represent the initial expression of underlying cardiomyopathies. 7,28 Undetected cardiac abnormalities may therefore be present in players in this population, which may lead to exclusion from this study. This chance is very small though. CONCLUSION ECG characteristics of high-level junior soccer players show more extreme range values than the nonathletic population. The Seattle ECG criteria appear to have a much higher screening specificity than the 2005 and 2010 ESC ECG criteria, and seem very promising for decreasing false-positive ECG screening results for high-level junior soccer players. Future studies should extend these analyses to other age groups and examine the costs and benefits 29 of screening with the Seattle criteria.

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