has been free of arrhythmias for three months and, after appropriate information of the risks, he/she accepts the higher risk of sports-related arrhythmias and ICD appropriate and inappropriate discharge [1]. The decision regarding athletic participation should also be made with consideration of the underlying arrhythmogenic condition. Any sport in which there is a risk of traumatic injury to the device or lead system should be discouraged ( figure 1). https://www.uptodate.com/contents/athletes-with-arrhythmias-treatment-and-returning-to-athletic-participation/print 11/33 7/5/23, 11:14 AM Athletes with arrhythmias: Treatment and returning to athletic participation - UpToDate The best available data about outcomes among athletes with ICDs come from the ICD Sports Safety Registry. Among a cohort of 440 persons with ICDs (201 of whom had ventricular fibrillation [VF]/ventricular tachycardia [VT] prior to ICD implantation) who participated in organized sports and were followed for a median of 44 months, there were no deaths or VF/VT requiring external defibrillation [14]. However, there was an increased risk of shocks with exercise; 46 patients (10 percent) received an appropriate shock during participation in sports. Of those experiencing shock during sports, 14 percent quit all sports and 25 percent reduced sporting activity. In addition, another 44 patients (10 percent) experienced definite or possible lead malfunctions. In a post-hoc analysis from the ICD Sports Safety Registry which reviewed the data from 129 young athletes ( 21 years of age; mean age 16 years) followed for a median of 42 months, 35 athletes (27 percent) received a total of 49 shocks (29 appropriate, 20 inappropriate) [15]. No deaths or injuries occurred during sport participation, although lead malfunction occurred in 20 percent of patients over 10 years. The optimal approach to ICD programming in athletes is uncertain, but likely similar to the approach to programming in non-athletes. Among the same 440 patient cohort from the ICD Sports Safety Registry, 62 percent of participants were programmed with a high-rate cutoff ( 200 beats per minute) and 30 percent with a long-detection interval (defined as ">nominal" or standard programming intervals) [16]. Patients programmed with a high-rate cutoff received significantly fewer total and inappropriate shocks, and those with long-detection interval had fewer total shocks. A full discussion of the approach to optimal ICD programming is presented separately. (See "Implantable cardioverter-defibrillators: Optimal programming".) Furthermore, it is advised for athletes with an ICD to undergo exercise testing if there is a history of atrial fibrillation with a potentially rapid ventricular rate, a need for low tachyarrhythmia detection rates, or the potential to raise the sinus rate to near the ICD VT detection level. (See "Implantable cardioverter-defibrillators: Overview of indications, components, and functions".) SUMMARY AND RECOMMENDATIONS Arrhythmias are not infrequently documented in athletes and can result in significant symptoms and impaired athletic performance. Rarely are supraventricular arrhythmias fatal; however, sudden cardiac death resulting from a malignant ventricular tachyarrhythmia is a devastating event in young and apparently healthy persons. (See 'Introduction' above.) https://www.uptodate.com/contents/athletes-with-arrhythmias-treatment-and-returning-to-athletic-participation/print 12/33 7/5/23, 11:14 AM Athletes with arrhythmias: Treatment and returning to athletic participation - UpToDate Syncope that occurs during exertion suggests a potentially life-threatening arrhythmic etiology (eg, aortic stenosis, hypertrophic cardiomyopathy, ventricular arrhythmia, etc) and should be evaluated urgently. On the other hand, syncope occurring after exertion (eg, during cooling off period) is more likely reflex in origin, similar to the vasovagal faint. (See 'Syncope' above.) Altered atrioventricular (AV) nodal conduction (eg, first degree AV block and Mobitz type I second degree AV block) can result from increased vagal tone, which is normally seen as an adaptive response to certain types of athletic conditioning and is generally not a cause for concern. However, higher degrees of AV conduction abnormality (eg, Mobitz type II second degree AV block and third degree AV block) will require attention prior to participation in athletics. (See 'AV conduction abnormalities' above.) Sinus bradycardia and sinus tachycardia that are appropriate for the clinical situation are not considered abnormal, and further testing is not necessary. Asymptomatic sinus pauses or sinus arrest of less than three seconds duration are not uncommonly seen in normal athletes and are of no clinical significance. However, longer pauses, sinoatrial exit block, and sinus node dysfunction are abnormal. (See 'Sinus node dysfunction' above.) Atrial premature beats are common in the general population and in athletes, and are not generally associated with underlying structural heart disease or symptoms. Premature ventricular complexes (PVCs) are also common in athletes of all age groups and occur in those with or without structural heart disease; the identification of PVCs should prompt an evaluation for the presence of underlying pathologic substrate. (See 'Atrial or junctional premature beats' above and 'Ventricular premature beats' above.) Sustained atrial fibrillation and/or atrial flutter are uncommon in athletes. A full cardiac evaluation, should be performed and referral to an arrhythmia specialist for any patient with one of these arrhythmias. (See 'Atrial fibrillation' above and 'Atrial flutter' above.) Atrioventricular nodal reentrant tachycardia (AVNRT) is a common arrhythmia in young athletes and is often associated with symptoms resulting from a rapid heart rate. Patients with infrequent episodes of AVNRT, or those with minimal or well-tolerated symptoms, may opt for a conservative management approach with either no specific therapy or pharmacologic suppression. If pharmacologic therapy fails or if the side effects result from chronic medical therapy, catheter ablation remains the preferred option. (See 'Atrioventricular nodal reentrant tachycardia' above.) Patients with Wolff-Parkinson-White (WPW) pattern manifest ventricular pre-excitation on the surface electrocardiogram (ECG). When this pattern is associated with documented https://www.uptodate.com/contents/athletes-with-arrhythmias-treatment-and-returning-to-athletic-participation/print 13/33 7/5/23, 11:14 AM Athletes with arrhythmias: Treatment and returning to athletic participation - UpToDate tachycardia or symptoms referable to tachycardia, the patient is said to have the WPW syndrome. The most common arrhythmia occurring in patients with WPW is an atrioventricular reentrant tachycardia (AVRT), although atrial fibrillation and other arrhythmias may arise. Athletes with ventricular pre-excitation on the ECG and symptoms of palpitations, presyncope, or syncope, or with documented arrhythmia (ie, WPW syndrome) should undergo invasive electrophysiologic testing for both diagnostic and potential therapeutic (ie, catheter ablation of the accessory pathway) purposes. (See 'Wolff- Parkinson-White syndrome' above.) Most individuals with sustained or nonsustained symptomatic monomorphic or polymorphic ventricular tachycardia have underlying structural heart disease. Since these arrhythmias are potentially life-threatening, further evaluation is essential prior to the resumption of athletic activity. (See 'Nonsustained ventricular tachycardia' above and 'Sustained ventricular tachycardia' above.) Recommendations regarding the ability to participate in competitive athletics or intense athletic training are discussed in the relevant sections of the text. In general, athletes with symptomatic supraventricular arrhythmias, WPW, ventricular arrhythmias, and symptomatic bradyarrhythmias should be referred to a cardiac electrophysiologist. Use of UpToDate is subject to the Terms of Use. REFERENCES 1. Zipes DP, Link MS, Ackerman MJ, et al. Eligibility and Disqualification Recommendations for Competitive Athletes With Cardiovascular Abnormalities: Task Force 9: Arrhythmias and Conduction Defects: A Scientific Statement From the American Heart Association and American College of Cardiology. J Am Coll Cardiol 2015; 66:2412. 2. Pelliccia A, Fagard R, Bj rnstad HH, et al. Recommendations for competitive sports participation in athletes with cardiovascular disease: a consensus document from the Study Group of Sports Cardiology of the Working Group of Cardiac Rehabilitation and Exercise Physiology and the Working Group of Myocardial and Pericardial Diseases of the European Society of Cardiology. Eur Heart J 2005; 26:1422. 3. Kim JH, Noseworthy PA, McCarty D, et al. Significance of electrocardiographic right bundle branch block in trained athletes. Am J Cardiol 2011; 107:1083. https://www.uptodate.com/contents/athletes-with-arrhythmias-treatment-and-returning-to-athletic-participation/print 14/33 7/5/23, 11:14 AM Athletes with arrhythmias: Treatment and returning to athletic participation - UpToDate 4. Corrado D, Pelliccia A, Heidbuchel H, et al. Recommendations for interpretation of 12-lead electrocardiogram in the athlete. Eur Heart J 2010; 31:243. 5. Talan DA, Bauernfeind RA, Ashley WW, et al. Twenty-four hour continuous ECG recordings in long-distance runners. Chest 1982; 82:19. 6. Abdon NJ, Landin K, Johansson BW. Athlete's bradycardia as an embolising disorder? Symptomatic arrhythmias in patients aged less than 50 years. Br Heart J 1984; 52:660. 7. Stein R, Medeiros CM, Rosito GA, et al. Intrinsic sinus and atrioventricular node electrophysiologic adaptations in endurance athletes. J Am Coll Cardiol 2002; 39:1033. 8. Bj rnstad H, Storstein L, Meen HD, Hals O. Ambulatory electrocardiographic findings in top athletes, athletic students and control subjects. Cardiology 1994; 84:42. 9. Wang, YG, Mariman, et al. Various electrocardiographic and electrophysiologic presentations of normal and abnormal sinus node. J Cardiovasc Electrophysiol 1992; 3:187. 10. Brugada J, Katritsis DG, Arbelo E, et al. 2019 ESC Guidelines for the management of patients with supraventricular tachycardiaThe Task Force for the management of patients with supraventricular tachycardia of the European Society of Cardiology (ESC). Eur Heart J 2020; 41:655. 11. Pediatric and Congenital Electrophysiology Society (PACES), Heart Rhythm Society (HRS), American College of Cardiology Foundation (ACCF), et al. PACES/HRS expert consensus statement on the management of the asymptomatic young patient with a Wolff-Parkinson- White (WPW, ventricular preexcitation) electrocardiographic pattern: developed in partnership between the Pediatric and Congenital Electrophysiology Society (PACES) and the Heart Rhythm Society (HRS). Endorsed by the governing bodies of PACES, HRS, the American College of Cardiology Foundation (ACCF), the American Heart Association (AHA), the American Academy of Pediatrics (AAP), and the Canadian Heart Rhythm Society (CHRS). Heart Rhythm 2012; 9:1006. 12. Heidbuchel H, Carr F. Exercise and competitive sports in patients with an implantable cardioverter-defibrillator. Eur Heart J 2014; 35:3097. 13. Pelliccia A, Solberg EE, Papadakis M, et al. Recommendations for participation in competitive and leisure time sport in athletes with cardiomyopathies, myocarditis, and pericarditis: position statement of the Sport Cardiology Section of the European Association of Preventive Cardiology (EAPC). Eur Heart J 2019; 40:19. 14. Lampert R, Olshansky B, Heidbuchel H, et al. Safety of Sports for Athletes With Implantable Cardioverter-Defibrillators: Long-Term Results of a Prospective Multinational Registry. Circulation 2017; 135:2310. https://www.uptodate.com/contents/athletes-with-arrhythmias-treatment-and-returning-to-athletic-participation/print 15/33 7/5/23, 11:14 AM Athletes with arrhythmias: Treatment and returning to athletic participation - UpToDate 15. Saarel EV, Law I, Berul CI, et al. Safety of Sports for Young Patients With Implantable Cardioverter-Defibrillators: Long-Term Results of the Multinational ICD Sports Registry. Circ Arrhythm Electrophysiol 2018; 11:e006305. 16. Olshansky B, Atteya G, Cannom D, et al. Competitive athletes with implantable cardioverter- defibrillators-How to program? Data from the Implantable Cardioverter-Defibrillator Sports Registry. Heart Rhythm 2019; 16:581. Topic 113533 Version 17.0 https://www.uptodate.com/contents/athletes-with-arrhythmias-treatment-and-returning-to-athletic-participation/print 16/33 7/5/23, 11:14 AM Athletes with arrhythmias: Treatment and returning to athletic participation - 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 waves >3 mm in depth or >40 ms in duration in two or more leads (except for III and 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-treatment-and-returning-to-athletic-participation/print 17/33 7/5/23, 11:14 AM Athletes with arrhythmias: Treatment and returning to athletic participation - 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 pattern R V1+S V5 >10.5 mm AND right axis deviation >120 Ventricular pre- excitation PR interval <120 ms with a delta wave (slurred upstroke in the QRS complex) and 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 pattern High take-off and downsloping ST segment elevation followed by a negative T wave in 2 leads in V1 V3 <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 Couplets, triplets, and non-sustained ventricular tachycardia arrhythmias 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-treatment-and-returning-to-athletic-participation/print 18/33 7/5/23, 11:14 AM Athletes with arrhythmias: Treatment and returning to athletic participation - UpToDate Single-lead electrocardiogram (ECG) showing first degree atrioventricular (AV) block I Electrocardiogram of lead II showing normal sinus rhythm, first degree atrioventricular block with a prolonged PR interval of 0.30 seconds, and a QRS complex of normal duration. The tall P waves and P wave duration of approximately 0.12 seconds suggest concurrent right atrial enlargement. Courtesy of Morton Arnsdorf, MD. Graphic 67882 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-treatment-and-returning-to-athletic-participation/print 19/33 7/5/23, 11:14 AM Athletes with arrhythmias: Treatment and returning to athletic participation - UpToDate Electrocardiogram showing Mobitz type I (Wenckebach) atrioventricular block Single-lead electrocardiogram showing Mobitz type I (Wenckebach) second-degree atrioventricular block with 5:4 conduction. The characteristics of this arrhythmia include: a progressively increasing PR interval until a P wave is not conducted (arrow), a progressive decrease in the increment in the PR interval, a progressive decrease in the RR interval, and the RR interval that includes the dropped beat (0.96 sec) is less than twice the RR interval between conducted beats (0.53 to 0.57 sec). Courtesy of Morton Arnsdorf, MD. Graphic 73051 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-treatment-and-returning-to-athletic-participation/print 20/33 7/5/23, 11:14 AM Athletes with arrhythmias: Treatment and returning to athletic participation - UpToDate Classification of sports based on peak static and dynamic components during competition This classification is based on peak static and dynamic components achieved during competition; however, higher values may be reached during training. The increasing dynamic component is defined in terms of the estimated percentage of maximal oxygen uptake (VO max) achieved and results in an increasing cardiac output. The increasing static component is related to the estimated percentage of maximal 2 voluntary contraction reached and results in an increasing blood pressure load. The lowest total cardiovascular demands (cardiac output and blood pressure) are shown in the palest color, with increasing dynamic load depicted by increasing blue intensity and increasing static load by increasing red intensity. Note the graded transition between categories, which should be individualized on the basis of player position and style of play. Danger of bodily collision (refer to UpToDate content regarding sports according to risk of impact and educational background). https://www.uptodate.com/contents/athletes-with-arrhythmias-treatment-and-returning-to-athletic-participation/print 21/33 7/5/23, 11:14 AM Athletes with arrhythmias: Treatment and returning to athletic participation - UpToDate Increased risk if syncope occurs. Reproduced from: Levine BD, Baggish AL, Kovacs RJ. Eligibility and disquali cation recommendations for competitive athletes with cardiovascular abnormalities: Task force 1: Classi cation of sports: Dynamic, static, and impact: A scienti c statement from the American Heart Association and American College of Cardiology. J Am Coll Cardiol 2015; 66:2350. Illustration used with the permission of Elsevier Inc. All rights reserved. Graphic 105651 Version 9.0 https://www.uptodate.com/contents/athletes-with-arrhythmias-treatment-and-returning-to-athletic-participation/print 22/33 7/5/23, 11:14 AM Athletes with arrhythmias: Treatment and returning to athletic participation - 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-treatment-and-returning-to-athletic-participation/print 23/33 7/5/23, 11:14 AM Athletes with arrhythmias: Treatment and returning to athletic participation - 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-treatment-and-returning-to-athletic-participation/print 24/33 7/5/23, 11:14 AM Athletes with arrhythmias: Treatment and returning to athletic participation - 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-treatment-and-returning-to-athletic-participation/print 25/33 7/5/23, 11:14 AM Athletes with arrhythmias: Treatment and returning to athletic participation - 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-treatment-and-returning-to-athletic-participation/print 26/33 7/5/23, 11:14 AM Athletes with arrhythmias: Treatment and returning to athletic participation - 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-treatment-and-returning-to-athletic-participation/print 27/33 7/5/23, 11:14 AM Athletes with arrhythmias: Treatment and returning to athletic participation - 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-treatment-and-returning-to-athletic-participation/print 28/33 7/5/23, 11:14 AM Athletes with arrhythmias: Treatment and returning to athletic participation - 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-treatment-and-returning-to-athletic-participation/print 29/33 7/5/23, 11:14 AM Athletes with arrhythmias: Treatment and returning to athletic participation - UpToDate Algorithmic approach to risk stratification of asymptomatic patients with Wolff-Parkinson-White ECG pattern ECG: electrocardiogram; EPS: electrophysiology studies; AVRT: atrioventricular reciprocating tachycardia; AF: atrial fibrillation; WPW: Wolff-Parkinson-White. Preexcitation on the surface ECG is identified by a short PR interval (less than 120 milliseconds) leading into QRS, which is widened with a slurred upstroke (delta wave). Preexcitation is defined as intermittent when an ECG at any point in time shows the loss of preexcitation. In patients who are unable to perform exercise testing (eg, very young patients), ambulatory ECG monitoring or, rarely, sodium channel blocker challenge with procainamide is an alternative to assess for persistent or intermittent preexcitation. All approaches to risk stratification in patients with ventricular preexcitation are imperfect and can be associated with false positives as well as false negatives. https://www.uptodate.com/contents/athletes-with-arrhythmias-treatment-and-returning-to-athletic-participation/print 30/33 7/5/23, 11:14 AM Athletes with arrhythmias: Treatment and returning to athletic participation - UpToDate Options for invasive EPS include the standard transvenous intracardiac EPS or a transesophageal atrial EPS. Refer to the UpToDate topic on treatment of symptomatic arrhythmias in patients with WPW. For most asymptomatic patients with preexcitation and no high- risk features identified on EPS, particularly those over age 35 to 40 years, we suggest observation. However, in some asymptomatic patients, particularly children, some electrophysiologists discuss and/or proceed with catheter ablation as a therapeutic option even in the absence of high risk features. Refer to UpToDate content on treatment of WPW for additional information. Graphic 119379 Version 3.0 https://www.uptodate.com/contents/athletes-with-arrhythmias-treatment-and-returning-to-athletic-participation/print 31/33 7/5/23, 11:14 AM Athletes with arrhythmias: Treatment and returning to athletic participation - UpToDate Recommendations for risk stratification for sudden cardiac death proposed by the European Society of Cardiology (ESC): Wolff-Parkinson-White syndrome Finding Recommendations Short (<250 ms) RR interval during atrial fibrillation Class IIa Short (<270 ms) anterograde refractory period of the accessory pathway Class IIa Multiple accessory pathways Class IIa Loss of pre-excitation ajmaline or procainamide test (lower risk) Class IIb Syncope Class III Classification Class I: Conditions for which there is evidence and/or general agreement that a given procedure or treatment is useful and effective. Class II: Conditions for which there is conflicting evidence and/or a divergence of opinion about the usefulness/efficacy of a procedure or treatment. Class IIa: Weight of evidence/opinion is in favor of usefulness/efficacy. Class IIb: Usefulness/efficacy less well established by evidence/opinion. Class III: Conditions for which there is evidence and/or general agreement that the procedure/treatment is not useful and in some cases may be harmful. Recommendations from the European Society of Cardiology for additional risk stratification for sudden cardiac death in patients with specific clinical findings in the setting of Wolff-Parkinson-White syndrome. Priori SG, Aliot E, Blomstrom-Lundqvist C, et al. Eur Heart J 2001; 22:1374. Graphic 51644 Version 3.0 https://www.uptodate.com/contents/athletes-with-arrhythmias-treatment-and-returning-to-athletic-participation/print 32/33 7/5/23, 11:14 AM Athletes with arrhythmias: Treatment and returning to athletic participation - 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. Scott Manaker, MD, PhD Other Financial Interest: Expert witness in workers' compensation and in medical negligence matters [General pulmonary and critical care medicine]; National Board for Respiratory Care [Director]. All of the relevant financial relationships listed have been mitigated. Peter J Zimetbaum, MD Consultant/Advisory Boards: Abbott Medical [Lead extraction]. 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-treatment-and-returning-to-athletic-participation/print 33/33