Detection on ECG (or suspicion from history) of supraventricular tachyarrhythmias should prompt evaluation, including an echocardiogram, ambulatory ECG monitor, and exercise https://www.uptodate.com/contents/athletes-with-arrhythmias-electrocardiographic-abnormalities-and-conduction-disturbances/print 11/27 7/5/23, 10:33 AM Athletes with arrhythmias: Electrocardiographic abnormalities and conduction disturbances - UpToDate treadmill test, and referral to a heart rhythm specialist is generally indicated for consideration of electrophysiology study and ablation. Individuals with proven supraventricular tachycardia without preexcitation should be educated on how to perform vagal maneuvers (such as carotid sinus massage or, preferably, Valsalva maneuver) to facilitate termination of the arrhythmia. Ventricular premature beats Ventricular premature beats (VPBs) are common in athletes of all age groups and occur in those with or without structural heart disease. VPBs may be idiopathic or secondary to the cardiomyopathies, ion channelopathies, or other diseases such as myocarditis, myocardial infarction, or sarcoidosis. The presence of two or more VPBs in a 10- second ECG tracing is considered abnormal and warrants further investigation. Largely, their prognostic importance is based upon the possible association with underlying structural heart disease ( table 1). Exclusion of underlying cardiac disease is the first step in these individuals and should be performed with echocardiography. With regard to the ECG characteristics, the morphology of the VPBs is relevant, with those presenting with an RBBB or LBBB, wide QRS, and superior axis (originating from the left ventricle or RV free wall) and those exacerbating during effort having high index of suspicion for underlying cardiac disease. Additional features associated with higher probability of cardiac disease are the high frequency (>2000 VPBs in 24- hour ECG monitoring) and the complexity (couplets, or nonsustained ventricular tachycardia [VT] associated to VPBs) [9]. Athletes with VPBs who do not have structural heart disease do not appear to have an increased risk of cardiovascular events [23,24]. (See "Premature ventricular complexes: Clinical presentation and diagnostic evaluation" and "Athletes with arrhythmias: Treatment and returning to athletic participation", section on 'Ventricular premature beats'.) Ventricular tachycardia Monomorphic VT may be idiopathic (eg, RV outflow tract VT or left anterior fascicular [Belhassen-type]) or secondary to underlying cardiac disease. Most otherwise fit individuals who present with polymorphic VT have underlying structural heart disease. Further evaluation is essential for either of these presentations. The evaluation should include a thorough family history, an echocardiogram to evaluate for structural heart disease, ambulatory ECG monitoring, and an exercise ECG test. Depending on the results, further evaluation may be indicated, including CMR imaging to assess for arrhythmogenic RV cardiomyopathy or other cardiomyopathies, or genetic testing. All individuals with sustained monomorphic or polymorphic VT should be referred to a heart rhythm specialist. (See "Cardiac evaluation of the survivor of sudden cardiac arrest" and "Ventricular tachycardia in the absence of apparent structural heart disease" and "Athletes with arrhythmias: Treatment and returning to athletic participation", section on 'Ventricular arrhythmias'.) https://www.uptodate.com/contents/athletes-with-arrhythmias-electrocardiographic-abnormalities-and-conduction-disturbances/print 12/27 7/5/23, 10:33 AM Athletes with arrhythmias: Electrocardiographic abnormalities and conduction disturbances - UpToDate SUMMARY AND RECOMMENDATIONS Prevalence A broad range of ECG abnormalities can be seen in trained athletes, particularly increased QRS voltage and repolarization abnormalities ( table 1). (See 'Prevalence' above.) Clinical approach to reading the ECG in athletes For practical purposes, ECG changes in athletes can be classified into three main groups ( figure 1): one related to whether the ECG abnormality is likely to be a physiologic result of chronic training (normal ECG changes in athletes), one in which the ECG finding is borderline abnormal, and the third related to whether the ECG finding occurs independently of training and thus may be an expression of a pathologic condition (borderline or abnormal ECG changes in athletes). (See 'Clinical approach to reading the ECG in athletes' above.) Normal ECG findings Common ECG abnormalities ("normal" in athletes) are frequent and are not associated with an increased risk of underlying cardiac disease and incidence of adverse events during exercise. (See 'Normal ECG findings' above.) Borderline ECG findings Borderline ECG findings may represent pathologic or innocent ECG alterations. (See 'Borderline ECG findings' above.) Abnormal ECG findings Abnormal ECG findings are significantly more likely to represent pathology rather than a normal response to training. As such, patients with an abnormal ECG finding should undergo further evaluation to search for cardiac pathology. (See 'Abnormal ECG findings' above.) Sport participation The approaches to risk stratification and returning to participation/competition in athletes who have an abnormal ECGs or a cardiovascular disease are discussed in detail separately. (See "Athletes: Overview of sudden cardiac death risk and sport participation" and "Athletes with arrhythmias: Treatment and returning to athletic participation".) Use of UpToDate is subject to the Terms of Use. REFERENCES 1. Maron BJ, Levine BD, Washington RL, et al. Eligibility and Disqualification Recommendations for Competitive Athletes With Cardiovascular Abnormalities: Task Force 2: Preparticipation Screening for Cardiovascular Disease in Competitive Athletes: A Scientific Statement From https://www.uptodate.com/contents/athletes-with-arrhythmias-electrocardiographic-abnormalities-and-conduction-disturbances/print 13/27 7/5/23, 10:33 AM Athletes with arrhythmias: Electrocardiographic abnormalities and conduction disturbances - UpToDate the American Heart Association and American College of Cardiology. J Am Coll Cardiol 2015; 66:2356. 2. Pelliccia A, Maron BJ, Culasso F, et al. Clinical significance of abnormal electrocardiographic patterns in trained athletes. Circulation 2000; 102:278. 3. Brosnan M, La Gerche A, Kalman J, et al. Comparison of frequency of significant electrocardiographic abnormalities in endurance versus nonendurance athletes. Am J Cardiol 2014; 113:1567. 4. Serra-Grima R, Estorch M, Carri I, et al. Marked ventricular repolarization abnormalities in highly trained athletes' electrocardiograms: clinical and prognostic implications. J Am Coll Cardiol 2000; 36:1310. 5. Pelliccia A, Culasso F, Di Paolo FM, et al. Prevalence of abnormal electrocardiograms in a large, unselected population undergoing pre-participation cardiovascular screening. Eur Heart J 2007; 28:2006. 6. Sheikh N, Papadakis M, Ghani S, et al. Comparison of electrocardiographic criteria for the detection of cardiac abnormalities in elite black and white athletes. Circulation 2014; 129:1637. 7. Corrado D, Pelliccia A, Heidbuchel H, et al. Recommendations for interpretation of 12-lead electrocardiogram in the athlete. Eur Heart J 2010; 31:243. 8. Drezner JA, Ackerman MJ, Anderson J, et al. Electrocardiographic interpretation in athletes: the 'Seattle criteria'. Br J Sports Med 2013; 47:122. 9. Sharma S, Drezner JA, Baggish A, et al. International Recommendations for Electrocardiographic Interpretation in Athletes. J Am Coll Cardiol 2017; 69:1057. 10. Gati S, Sheikh N, Ghani S, et al. Should axis deviation or atrial enlargement be categorised as abnormal in young athletes? The athlete's electrocardiogram: time for re-appraisal of markers of pathology. Eur Heart J 2013; 34:3641. 11. Kim JH, Noseworthy PA, McCarty D, et al. Significance of electrocardiographic right bundle branch block in trained athletes. Am J Cardiol 2011; 107:1083. 12. Brosnan MJ, te Riele ASJM, Bosman LP, et al. Electrocardiographic features differentiating arrhythmogenic right ventricular cardiomyopathy from an athlete's heart. J Am Coll Cardiol EP 2018; 4:1613. 13. Aro AL, Anttonen O, Tikkanen JT, et al. Intraventricular conduction delay in a standard 12- lead electrocardiogram as a predictor of mortality in the general population. Circ Arrhythm Electrophysiol 2011; 4:704. https://www.uptodate.com/contents/athletes-with-arrhythmias-electrocardiographic-abnormalities-and-conduction-disturbances/print 14/27 7/5/23, 10:33 AM Athletes with arrhythmias: Electrocardiographic abnormalities and conduction disturbances - UpToDate 14. Platonov PG, Calkins H, Hauer RN, et al. High interobserver variability in the assessment of epsilon waves: Implications for diagnosis of arrhythmogenic right ventricular cardiomyopathy/dysplasia. Heart Rhythm 2016; 13:208. 15. Munger TM, Packer DL, Hammill SC, et al. A population study of the natural history of Wolff- Parkinson-White syndrome in Olmsted County, Minnesota, 1953-1989. Circulation 1993; 87:866. 16. Furlanello F, Bertoldi A, Bettini R, et al. Life-threatening tachyarrhythmias in athletes. Pacing Clin Electrophysiol 1992; 15:1403. 17. Klein GJ, Yee R, Sharma AD. Longitudinal electrophysiologic assessment of asymptomatic patients with the Wolff-Parkinson-White electrocardiographic pattern. N Engl J Med 1989; 320:1229. 18. Indik JH, Pearson EC, Fried K, Woosley RL. Bazett and Fridericia QT correction formulas interfere with measurement of drug-induced changes in QT interval. Heart Rhythm 2006; 3:1003. 19. Corrado D, Basso C, Schiavon M, Thiene G. Screening for hypertrophic cardiomyopathy in young athletes. N Engl J Med 1998; 339:364. 20. Maron BJ, Ackerman MJ, Nishimura RA, et al. Task Force 4: HCM and other cardiomyopathies, mitral valve prolapse, myocarditis, and Marfan syndrome. J Am Coll Cardiol 2005; 45:1340. 21. Corrado D, Basso C, Buja G, et al. Right bundle branch block, right precordial st-segment elevation, and sudden death in young people. Circulation 2001; 103:710. 22. Boraita A, Santos-Lozano A, Heras ME, et al. Incidence of Atrial Fibrillation in Elite Athletes. JAMA Cardiol 2018; 3:1200. 23. Biffi A, Pelliccia A, Verdile L, et al. Long-term clinical significance of frequent and complex ventricular tachyarrhythmias in trained athletes. J Am Coll Cardiol 2002; 40:446. 24. Biffi A, Maron BJ, Verdile L, et al. Impact of physical deconditioning on ventricular tachyarrhythmias in trained athletes. J Am Coll Cardiol 2004; 44:1053. Topic 991 Version 25.0 https://www.uptodate.com/contents/athletes-with-arrhythmias-electrocardiographic-abnormalities-and-conduction-disturbances/print 15/27 7/5/23, 10:33 AM Athletes with arrhythmias: Electrocardiographic abnormalities and conduction disturbances - UpToDate GRAPHICS Seattle criteria classifying the normal and abnormal electrocardiogram findings in athletes Normal ECG findings in athletes 1. Sinus bradycardia ( 30 bpm) 2. Sinus arrhythmia 3. Ectopic atrial rhythm 4. Junctional escape rhythm 5. 1 AV block (PR interval >200 ms) 6. Mobitz Type I (Wenckebach) 2 AV block 7. Incomplete RBBB 8. Isolated QRS voltage criteria for LVH Except: QRS voltage criteria for LVH occurring with any non-voltage criteria for LVH such as left atrial enlargement, left axis deviation, ST segment depression, T-wave inversion, or pathological Q waves 9. Early repolarization (ST elevation, J-point elevation, J-waves, or terminal QRS slurring) 10. Convex ("domed") ST segment elevation combined with T-wave inversion in leads V1 V4 in black/African athletes These common training-related ECG alterations are physiological adaptations to regular exercise, considered normal variants in athletes and do not require further evaluation in asymptomatic athletes Abnormal ECG findings in athletes Abnormal ECG Definition finding T-wave inversion >1 mm in depth in two or more leads V2 V6, II and aVF, or I and aVL (excludes III, aVR and V1) 0.5 mm in depth in two or more leads ST segment depression Pathologic Q >3 mm in depth or >40 ms in duration in two or more leads (except for III and waves aVR) QRS 120 ms, predominantly negative QRS complex in lead V1 (QS or rS), and upright monophasic R wave in leads I and V6 Complete left bundle branch block https://www.uptodate.com/contents/athletes-with-arrhythmias-electrocardiographic-abnormalities-and-conduction-disturbances/print 16/27 7/5/23, 10:33 AM Athletes with arrhythmias: Electrocardiographic abnormalities and conduction disturbances - UpToDate Any QRS duration 140 ms Intraventricular conduction delay Left axis deviation 30 to 90 Left atrial enlargement Prolonged P wave duration of >120 ms in leads I or II with negative portion of the P wave 1 mm in depth and 40 ms in duration in lead V1 Right ventricular hypertrophy R V1+S V5 >10.5 mm AND right axis deviation >120 pattern Ventricular pre- PR interval <120 ms with a delta wave (slurred upstroke in the QRS complex) and excitation wide QRS (>120 ms) QTc 470 ms (male) Long QT interval* QTc 480 ms (female) QTc 500 ms (marked QT prolongation) Short QT interval* QTc 320 ms Brugada-like ECG High take-off and downsloping ST segment elevation followed by a negative T wave in 2 leads in V1 V3 pattern <30 bpm or sinus pauses 3 s Profound sinus bradycardia Atrial tachyarrhythmias Supraventricular tachycardia, atrial fibrillation, atrial flutter 2 PVCs per 10 s tracing Premature ventricular contractions Ventricular arrhythmias Couplets, triplets, and non-sustained ventricular tachycardia ECG: electrocardiogram; bpm: beats per minute; AV: atrioventricular; RBBB: right bundle branch block; LVH: left ventricular hypertrophy; PVC: premature ventricular contraction; ms: milliseconds. The QT interval corrected for heart rate is ideally measured with heart rates of 60 to 90 bpm. Consider repeating the ECG after mild aerobic activity for borderline or abnormal QTc values with a heart rate <50 bpm. From: Drezner JA, Ackerman MJ, Anderson J, et al. Electrocardiographic interpretation in athletes: The "Seattle Criteria". Br J Sports Med 2013; 47:123. Reproduced with permission from BMJ Publishing Group Ltd. Copyright 2013. Graphic 102509 Version 3.0 https://www.uptodate.com/contents/athletes-with-arrhythmias-electrocardiographic-abnormalities-and-conduction-disturbances/print 17/27 7/5/23, 10:33 AM Athletes with arrhythmias: Electrocardiographic abnormalities and conduction disturbances - UpToDate Algorithm showing international consensus standards ECG interpretation in athletes and need for subsequent evaluation ECG: electrocardiogram; LVH: left ventricular hypertrophy; RVH: right ventricular hypertrophy; RBBB: right bundle branch block; AV: atrioventricular; LBBB: left bundle branch block; bpm: beats per minute; PVC: premature ventricular contraction; SCD: sudden cardiac death. Reproduced with permission from: Drezner JA, Sharma S, Baggish A, et al. International criteria for electrocardiographic interpretation in athletes. Br J Sports Med 2017; 51:704. Copyright 2017 BMJ Publishing Group Ltd. Graphic 115355 Version 1.0 https://www.uptodate.com/contents/athletes-with-arrhythmias-electrocardiographic-abnormalities-and-conduction-disturbances/print 18/27 7/5/23, 10:33 AM Athletes with arrhythmias: Electrocardiographic abnormalities and conduction disturbances - UpToDate Electrocardiogram (ECG) showing common right bundle branch block (RBBB) Electrocardiogram showing characteristic changes in the precordial leads in complete RBBB. The asynchronous activation of the two ventricles increases the QRS duration (0.13 seconds). The terminal forces are rightward and anterior due to the delayed activation of the right ventricle, resulting in an rsR' pattern in the anterior-posterior lead V1 and a wide negative S wave in the left-right lead V6 (and, not shown, in lead I). Courtesy of Ary Goldberger, MD. Graphic 64393 Version 7.0 Normal ECG https://www.uptodate.com/contents/athletes-with-arrhythmias-electrocardiographic-abnormalities-and-conduction-disturbances/print 19/27 7/5/23, 10:33 AM Athletes with arrhythmias: Electrocardiographic abnormalities and conduction disturbances - UpToDate Normal electrocardiogram showing normal sinus rhythm at a rate of 75 beats/minute, a PR interval of 0.14 seconds, a QRS interval of 0.10 seconds, and a QRS axis of approximately 75 . Courtesy of Ary Goldberger, MD. Graphic 76183 Version 4.0 https://www.uptodate.com/contents/athletes-with-arrhythmias-electrocardiographic-abnormalities-and-conduction-disturbances/print 20/27 7/5/23, 10:33 AM Athletes with arrhythmias: Electrocardiographic abnormalities and conduction disturbances - UpToDate 12-lead electrocardiogram (ECG) showing typical left bundle branch block Electrocardiogram in typical complete left bundle branch block. The asynchronous activation of the 2 ventricles increases the QRS duration (0.16 seconds in this example). The abnormal initial vector results in loss of "normal" septal forces as manifested by absence of q waves in leads I, aVL, and V6. The late activation of the left ventricle prolongs the dominant leftward progression of the middle and terminal forces, leading to a positive and widened R wave in the lateral leads. Both the ST segment and T wave vectors are opposite in direction from the QRS, a "secondary" repolarization abnormality. Courtesy of Ary Goldberger, MD. Graphic 61594 Version 9.0 Normal ECG https://www.uptodate.com/contents/athletes-with-arrhythmias-electrocardiographic-abnormalities-and-conduction-disturbances/print 21/27 7/5/23, 10:33 AM Athletes with arrhythmias: Electrocardiographic abnormalities and conduction disturbances - UpToDate Normal electrocardiogram showing normal sinus rhythm at a rate of 75 beats/minute, a PR interval of 0.14 seconds, a QRS interval of 0.10 seconds, and a QRS axis of approximately 75 . Courtesy of Ary Goldberger, MD. Graphic 76183 Version 4.0 https://www.uptodate.com/contents/athletes-with-arrhythmias-electrocardiographic-abnormalities-and-conduction-disturbances/print 22/27 7/5/23, 10:33 AM Athletes with arrhythmias: Electrocardiographic abnormalities and conduction disturbances - UpToDate 12-lead electrocardiogram (ECG) from a patient with the Brugada syndrome shows downsloping ST elevation ST segment elevation and T wave inversion in the right precordial leads V1 and V2 (arrows); the QRS is normal. The widened S wave in the left lateral leads (V5 and V6) that is characteristic of right bundle branch block is absent. Courtesy of Rory Childers, MD, University of Chicago. Graphic 64510 Version 10.0 https://www.uptodate.com/contents/athletes-with-arrhythmias-electrocardiographic-abnormalities-and-conduction-disturbances/print 23/27 7/5/23, 10:33 AM Athletes with arrhythmias: Electrocardiographic abnormalities and conduction disturbances - UpToDate Electrocardiographic and electrophysiologic features of Mobitz type II second-degree atrioventricular block The PR and RR intervals are constant, but the third atrial beat (A) is not conducted (arrow). His bundle electrocardiography (HBE) shows constant AH (85 msec) and HV (95 msec) intervals and normal AH but no HV conduction in the nonconducted beat. The last finding indicates that the block is distal to the His bundle, in contrast with the more proximal location of Mobitz type I atrioventricular block. Adapted from: Josephson ME, Clinical Cardiac Electrophysiology: Techniques and nd Interpretations, 2 ed, Lea & Febiger, Philadelphia 1993. Graphic 79539 Version 7.0 Normal rhythm strip Normal rhythm strip in lead II. The PR interval is 0.15 sec and the QRS duration is 0.08 sec. Both the P and T waves are upright. Courtesy of Morton F Arnsdorf, MD. Graphic 59022 Version 3.0 https://www.uptodate.com/contents/athletes-with-arrhythmias-electrocardiographic-abnormalities-and-conduction-disturbances/print 24/27 7/5/23, 10:33 AM Athletes with arrhythmias: Electrocardiographic abnormalities and conduction disturbances - UpToDate Single-lead electrocardiogram (ECG) showing sinus rhythm with third degree (complete) AV block Sinus rhythm with third degree (complete) heart block. There is independent atrial (as shown by the P waves) and ventricular activity, with respective rates of 83 and 43 beats per minute. The wide QRS complexes may represent a junctional escape rhythm with underlying bundle branch block or an idioventricular pacemaker. Courtesy of Ary Goldberger, MD. Graphic 72863 Version 6.0 Normal rhythm strip Normal rhythm strip in lead II. The PR interval is 0.15 sec and the QRS duration is 0.08 sec. Both the P and T waves are upright. Courtesy of Morton F Arnsdorf, MD. Graphic 59022 Version 3.0 https://www.uptodate.com/contents/athletes-with-arrhythmias-electrocardiographic-abnormalities-and-conduction-disturbances/print 25/27 7/5/23, 10:33 AM Athletes with arrhythmias: Electrocardiographic abnormalities and conduction disturbances - UpToDate Third degree (complete) atrioventricular block with wide QRS escape rhythm The P waves are completely dissociated from the QRS complexes and the PR intervals are variable. The atrial or PP rate (75 beats per minute) is faster than the ventricular or RR rate (30 beats per minute), establishing complete atrioventricular blockade as the etiology. The QRS complexes are wide indicating that the escape rhythm is ventricular. Graphic 51446 Version 5.0 Normal rhythm strip Normal rhythm strip in lead II. The PR interval is 0.15 sec and the QRS duration is 0.08 sec. Both the P and T waves are upright. Courtesy of Morton F Arnsdorf, MD. Graphic 59022 Version 3.0 https://www.uptodate.com/contents/athletes-with-arrhythmias-electrocardiographic-abnormalities-and-conduction-disturbances/print 26/27 7/5/23, 10:33 AM Athletes with arrhythmias: Electrocardiographic abnormalities and conduction disturbances - UpToDate Contributor Disclosures Mark S Link, MD No relevant financial relationship(s) with ineligible companies to disclose. Antonio Pelliccia, MD No relevant financial relationship(s) with ineligible companies to disclose. Peter J Zimetbaum, MD Consultant/Advisory Boards: Abbott Medical [Lead extraction]. All of the relevant financial relationships listed have been mitigated. Ary L Goldberger, MD Other Financial Interest: Elsevier book royalties [Clinical electrocardiography]. All of the relevant financial relationships listed have been mitigated. Todd F Dardas, MD, MS No relevant financial relationship(s) with ineligible companies to disclose. Contributor disclosures are reviewed for conflicts of interest by the editorial group. When found, these are addressed by vetting through a multi-level review process, and through requirements for references to be provided to support the content. Appropriately referenced content is required of all authors and must conform to UpToDate standards of evidence. Conflict of interest policy https://www.uptodate.com/contents/athletes-with-arrhythmias-electrocardiographic-abnormalities-and-conduction-disturbances/print 27/27