Underestimated recurrence rates after ablation for Wolff-Parkinson-White syndrome and impact on follow-up practices

The risk of recurrence after accessory pathway (AP) ablation in patients with Wolff-Parkinson-White (WPW) syndrome ranges between 5-12%.(1)Backhoff D. Klehs S. Müller M.J. et al.Long-Term Follow-Up After Radiofrequency Catheter Ablation of Accessory Atrioventricular Pathways in Children.JACC Clin Electrophysiol. 2018; 4: 448-455Google Scholar, (2)Dubin A.M. Jorgensen N.W. Radbill A.E. 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: 57-63Google Scholar, (3)Etheridge S.P. Escudero C.A. Blaufox A.D. et al.Life-Threatening Event Risk in Children With Wolff-Parkinson-White Syndrome: A Multicenter International Study.J Am Coll Cardiol EP. 2018; 4: 433-444Google Scholar Given practice variation in duration of follow up after successful AP ablation, data on recurrence risk is largely limited to the first year following catheter ablation(2)Dubin A.M. Jorgensen N.W. Radbill A.E. 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: 57-63Google Scholar. Cases of late recurrence at our institution prompted us to describe our institutional experience including long-term risk of recurrence of WPW pattern on ECG, accessory pathway characteristics before and after recurrence, and the proportion of recurrence that is symptomatic or asymptomatic to better guide follow-up practices. We conducted a retrospective cohort study of WPW patients, age ≤ 21 years, who underwent electrophysiology study (EPS) and successful catheter ablation at our institution (2000-2022), with at least one follow-up ≥ 1-month post-ablation. Surgically corrected heart disease, concomitant ablation for separate arrhythmic substrate (e.g. atrioventricular nodal reentrant tachycardia), and prior ablations at outside institutions were excluded. Recurrence was defined as return of manifest pre-excitation on ECG, ambulatory monitor, or recurrence of the same manifest AP on repeat EP study. Cumulative incidence plot was used to depict time to recurrence, and the log-rank test was used to compare time-to-recurrence curves by groups, using SAS 9.4 software (SAS Institute, Cary, NC). The study was approved by the Cleveland Clinic Foundation Institutional Review Board. Of the 179 WPW patients (median age of 14 years), 143 (79.9%) had palpitations and 16 (8.9%) had intermittent pre-excitation prior to ablation. Of patients with intermittent pre-excitation, 14 (88%) were symptomatic. Over a median follow-up of 28.4 months (IQR 25%, 75%), 15 (8.4%) patients experienced manifest AP recurrence: 11 (73.3%) were asymptomatic and detected during routine follow up, and 4 (26.7%) came to attention due to palpitations. The cumulative recurrence at 6 and 12 months were 6.5% and 7.2% respectively, with the majority of recurrence occurring in the first 6 months (Figure 1). The latest recurrence occurred 12.3 years after ablation; recurrent palpitations prompted ambulatory rhythm monitor which revealed intermittent pre-excitation. Patients with multiple APs (p=0.023; 12-month recurrence-free rate: 74.5% multiple APs vs 94.7% single AP) or right-lateral APs (p = 0.026; 12-month recurrence-free rate: 81.7% right-lateral vs 94.8% other) were more likely to have recurrence. Accessory pathway effective refractory period (APERP) and shortest pre-excited R-R interval (SPERRI) were available for only 81 (45.3%) and 69 (38.5%) patients, respectively. Median APERP and SPERRI where available were 320 and 310 ms at baseline without isoproterenol. Patients with recurrence had a median baseline APERP and SPERRI of and 315 and 295 ms; median after recurrence was 280 and 270 ms. Ten patients with recurrence underwent repeat EP study which confirmed recurrence of the same accessory pathway, while 5 did not have repeat EP study during the follow up period. Indication for repeat EPS included: military clearance (n = 1), pre-excited atrial fibrillation (n = 1), syncope (n = 1), and supraventricular tachycardia (n = 7). No patients had major procedural complication. Our study highlights the importance of routine long-term follow up in pediatric patients with WPW following catheter ablation as the risk of AP recurrence persists beyond the first year "anniversary". Importantly, we found that most cases of recurrence are asymptomatic, placing the onus on the physician to follow these patients longer and to appropriately counsel patients and families on long-term procedural success. Also, our reported recurrence rate is likely underestimated due to limited follow up. Backhoff et al found an overall recurrence rate of 10.8%, with 2.2% patients having late recurrence > 1-year post-ablation with a longer median follow-up of 5.6 years, and comparable recurrence range from 1 day up to 7.3 years post-ablation. Pathway characteristics were not reported in this population. Importantly, invasive AP characteristics did not consistently change after recurrence in our population. Moreover, recent research shed light on the limitations of non-invasive and invasive testing as predictors risk life threatening events.(3)Etheridge S.P. Escudero C.A. Blaufox A.D. et al.Life-Threatening Event Risk in Children With Wolff-Parkinson-White Syndrome: A Multicenter International Study.J Am Coll Cardiol EP. 2018; 4: 433-444Google Scholar Both of these findings highlight the complexity associated with management of recurrent pre-excitation, particularly in the asymptomatic patient. Rather than declaring victory and considering WPW patients "cured" after a year, we suggest long term follow up for all patients after AP ablation and encourage patient education regarding a rare possibility of late recurrence.