Background

In 1930, Drs. Louis Wolff, John Parkinson, and Paul White characterized a condition that was described as an abnormally short PR interval, bundle branch block, and episodes of tachycardia and/or atrial fibrillation, which was subsequently named Wolff-Parkinson-White (WPW) syndrome. Continued investigation has furthered clinical understanding of WPW to its current definition: a re-entry circuit involving an accessory pathway (AP) with anterograde and retrograde conduction. Anterograde conduction across the AP causes the defining electrocardiographic (ECG) features of WPW: a short PR interval and slurring of the QRS upstroke—delta wave—signifying ventricular pre-excitation. Patients with symptomatic WPW are often diagnosed after an episode of supraventricular tachycardia (SVT) or sudden cardiac arrest. Others are identified incidentally on ECG.

Historically, patient management decisions have been based on the asymptomatic/symptomatic dichotomy. This approach has been called into question. In >2,000 patients with WPW, symptomatic patients were more likely than asymptomatic patients to undergo ablation. However, there were no differences in characteristics derived from clinical or electrophysiology study (EPS) findings.Present data confirm that asymptomatic WPW is not without risk, and, although malignant arrhythmia correlate better with EPS-derived risk stratification than do symptoms, EPS data are imperfect predictors. Therefore, a low threshold for ablation should be considered. Asymptomatic WPW cases are becoming more prevalent as ECGs are performed for screening purposes or unrelated illnesses.

The importance of this topic is reflected in the 2012 Pediatric and Congenital Electrophysiology Society/Heart Rhythm Society (PACES/HRS) Expert Consensus Statement on the Management of the Asymptomatic Young Patient With a WPW (Ventricular Preexcitation) ECG Pattern, which describes recommendations for the management of patients with asymptomatic WPW.¹ However, since this publication, much has been published about asymptomatic WPW and its associated risk of sudden cardiac death (SCD). The pediatric electrophysiology community is aligned on this; yet, within the broader pediatric cardiology community, practice variation persists. A survey of pediatric electrophysiologists found that most do not trust noninvasive measures of anterograde refractoriness to identify low-risk APs with sufficient sensitivity to defer ablation.² When considering the improvement in ablation outcomes and unreliability in symptom recognition,³ the predominance of SCD events in patients of prepubertal and pubertal ages, and questions about clinicians' ability to accurately assess risk, watchful waiting is no longer universally accepted as the default position regarding asymptomatic pediatric patients with WPW.⁴ This was reflected in the 2024 Heart Rhythm Society (HRS) Expert Consensus Statement on Arrhythmias in the Athlete, which recommends considering ablation for all athletes with WPW pattern on ECG.⁵

Goals and Details of the Algorithms

The Clinical Practice Algorithms for WPW Pattern in Pediatric Patients were developed with the primary objective of creating a decision support tool to help clinicians and other health care providers in the management of WPW in children with and without symptoms. The goal of these algorithms is to establish a standardized approach in managing WPW syndrome and WPW pattern on ECG. Guidance on initial management, ablation indications and timing, subsequent outpatient follow-up, and frequency of testing from birth through 18 years of age is provided.

Two clinical practice algorithms were developed: one for WPW in patients weighing <20 kg and another for WPW in patients weighing ≥20 kg. Because children and adults with WPW have different outcomes and risk, only recommendations for patients <18 years of age were provided. Although there are recent data about safely performing catheter ablation in the very young when there is drug-refractory SVT or life-threatening arrhythmia,⁶ most electrophysiologists still consider patients <15-20 kg to have an increased risk of a complication. Although the recommended minimum weight for EPS and ablation is 15 kg,⁷ the Quality Working Group of the American College of Cardiology (ACC) Adult Congenital and Pediatric Cardiology (ACPC) acknowledges that this weight cutoff varies among institutions. Additionally, Janson et al. recently identified that the adverse event rate after an EPS is greater, albeit still low, in patients weighing <30 kg.⁸ For these reasons, the Quality Working Group has included the addendum that the weight cutoff for considering an EPS will vary depending on institutional preference and after shared decision-making (SDM) with the patient and family that weighs the risks and benefits of procedural complications against the risk of life-threatening arrhythmia.

Each pathway starts with the initial standard clinical workup and proceeds to a decision tree. Because recent data contradict the 2012 PACES/HRS expert consensus statement concerning the risk in intermittent pre-excitation versus persistent pre-excitation,^1,9 this risk is not considered a branching point in these algorithms and intermittent and persistent pre-excitation are considered together. Although most children with WPW have a structurally and functionally normal heart, there are some congenital heart diseases with an increased risk of WPW (Ebstein malformation of the tricuspid valve and congenitally corrected transposition of the great arteries). Additionally, there is a rare but defined association between pre-excitation and asynchrony resulting in decreased left ventricular function.¹⁰ Therefore, all children with WPW should undergo an echocardiogram.

The Quality Working Group supports an SDM model in communicating risks and benefits of catheter ablation with the patient and family. The group also supports SDM when discussing activity restrictions for asymptomatic patients, discussing the risks of participating in physical activity and competitive sports compared with the benefits to their physical and mental health with continued participation in physical activities. In the 2024 HRS expert consensus statement, patients with WPW are not restricted from physical activity because SCD from WPW can occur with activities of daily life, not just physical activity.⁵

Methods: Development of the Algorithms

The WPW algorithms were created by the Quality Working Group of the ACC ACPC member section, which is composed of experienced pediatric and adult congenital cardiologists with multidisciplinary expertise and diverse training and practice backgrounds. Recommendations on best practices were developed using the same quality-driven approach used in previous ACC practice algorithms. Current clinical evidence on WPW and existing guidelines were used in the development of these evidence-based algorithms, as well as group consensus based on clinical practice if evidence was lacking or there were conflicting reports in the literature.

Future Directions

The WPW clinical practice algorithms can be used by clinicians and health care providers as a support tool for decision-making. A standardized and systematic approach will reduce practice variation, thus improving resource utilization. The clinical application of the algorithms can form the basis for multicenter research to evaluate the impact on patient outcomes.

References

1. Pediatric and Congenital Electrophysiology Society (PACES); Heart Rhythm Society (HRS); American College of Cardiology Foundation (ACCF); 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(6):1006-1024. doi:10.1016/j.hrthm.2012.03.050
2. Chubb H, Campbell RM, Motonaga KS, Ceresnak SR, Dubin AM. Management of asymptomatic Wolff-Parkinson-White pattern by pediatric electrophysiologists. J Pediatr. 2019;213:88-95.e1. doi:10.1016/j.jpeds.2019.05.058
3. Dubin AM, Jorgensen NW, Radbill AE, et al. What have we learned in the last 20 years? A comparison of a modern era pediatric and congenital catheter ablation registry to previous pediatric ablation registries. Heart Rhythm. 2019;16(1):57-63. doi:10.1016/j.hrthm.2018.08.013
4. Etheridge SP, Escudero CA, Blaufox AD, et al. Life-threatening event risk in children with Wolff-Parkinson-White syndrome: a multicenter international study. JACC Clin Electrophysiol. 2018;4(4):433-444. doi:10.1016/j.jacep.2017.10.009
5. Lampert R, Chung EH, Ackerman MJ, et al. 2024 HRS expert consensus statement on arrhythmias in the athlete: evaluation, treatment, and return to play. Heart Rhythm. 2024;21(10):e151-e252. doi:10.1016/j.hrthm.2024.05.018
6. Blaufox AD, Felix GL, Saul JP; Pediatric Catheter Ablation Registry. Radiofrequency catheter ablation in infants </=18 months old: when is it done and how do they fare?: short-term data from the pediatric ablation registry. Circulation. 2001;104(23):2803-2808. doi:10.1161/hc4801.100028
7. Philip Saul J, Kanter RJ; WRITING COMMITTEE, et al. PACES/HRS expert consensus statement on the use of catheter ablation in children and patients with congenital heart disease: Developed in partnership with the Pediatric and Congenital Electrophysiology Society (PACES) and the Heart Rhythm Society (HRS). Endorsed by the governing bodies of PACES, HRS, the American Academy of Pediatrics (AAP), the American Heart Association (AHA), and the Association for European Pediatric and Congenital Cardiology (AEPC). Heart Rhythm. 2016;13(6):e251-e289. doi:10.1016/j.hrthm.2016.02.009
8. Janson CM, Shah MJ, Kennedy KF, et al. Association of weight with ablation outcomes in pediatric Wolff-Parkinson-White: analysis of the NCDR IMPACT Registry. JACC Clin Electrophysiol. 2023;9(1):73-84. doi:10.1016/j.jacep.2022.08.023
9. Mah DY, Sherwin ED, Alexander ME, et al. The electrophysiological characteristics of accessory pathways in pediatric patients with intermittent preexcitation. Pacing Clin Electrophysiol. 2013;36(9):1117-1122. doi:10.1111/pace.12144
10. Guo B, Dai C, Li Q, Li W, Han L. Hazards of ventricular pre-excitation to left ventricular systolic function and ventricular wall motion in children: analysis of 25 cases. Cardiol Young. 2019;29(3):380-388. doi:10.1017/S1047951118002500