Dionne A, Gauvreau K, O’Leary E, Mah DY, Abrams DJ, Alexander ME, DeWitt ES, Bezzerides VJ, Triedman JK, Walsh EP.Circ Arrhythm Electrophysiol. 2020 Nov;13(11):e008848. doi: 10.1161/CIRCEP.120.008848. Epub 2020 Oct 5.PMID: 33017181
Take Home Points:
- Despite high acute success rates for catheter ablation of accessory pathways in pediatric patients, recurrence risk remains significant.
- Both patient-specific and ablation-specific factors contribute to risk of recurrence.
- Duration of consolidation time after successful pathway elimination appears to have some association with risk of recurrence.
Comment from Dr. Philip Chang (Gainesville, FL), section editor of Congenital Electrophysiology Journal Watch: This study by Dionne et al retrospectively reviewed their single-center experience of the ablation of accessory pathways (AP) in pediatric patients with the specific aim of identifying risk factors for pathway recurrence after acutely successful ablation. All pediatric patients who underwent AP catheter ablation between 2013-2018 were included, which yielded a primary study cohort of 525 patients and 558 procedures. Patient- and procedure-related variables were collected and analyzed together with post-ablation outcomes (primarily early- to mid-term recurrence). The primary cohort included patients with congenital heart disease and pediatric patients ranging from infancy to late-adolescence. Standard procedural setup and performance, likely similar among most centers, was described.
Among the 558 procedures performed, acute success was achieved in 97% with a recurrence rate of 8% over a median follow-up period of 0.4 years. 10% of cases were in patients with congenital heart disease (Ebstein’s anomaly most common). The median time to recurrence was 0.5 months (IQR 0-2.4 months).
The authors noted no difference in acute success between AP locations or presence of multiple AP’s. Right sided and posteroseptal AP’s had higher recurrence compared to left sided AP’s. Having multiple AP’s was associated with higher risk of recurrence. Cryoablation using any tip size was associated with higher risk of recurrence. Recurrence of AP conduction during the procedure before eventual successful elimination as well as time to AP elimination during ablation were not associated with recurrence risk. As would be expected, lack of electroanatomic mapping and placement of empiric ablations were associated with higher recurrence risk. Presence of CHD was also associated with higher recurrence.
The authors found that consolidation time after successful AP elimination was associated with recurrence with a time cutoff of 90 seconds. This was clearly distinguished from total ablation delivery time and referred specifically to the amount of additional ablation delivered after a previously successful AP ablation lesion. There was variability in the pattern of consolidation (on successful site, around successful site, or both) and frequency (between procedural eras 2013-2015 vs. 2016-2018). Consolidation was less frequently performed for posteroseptal and septal pathways. For right and left sided AP’s, consolidation time <90 seconds was associated with higher recurrence. This was not seen in posteroseptal/septal AP ablations though. Consolidation time >90 seconds was less likely for each AP in patients with multiple AP’s.
Multi-variate analysis showed multiple AP’s and consolidation time <90 seconds to remain significantly associated with risk of recurrence.
This study highlights some of the advances in pediatric AP ablation and sheds insight on where deficiencies still remain. Patient-specific variables including the presence of congenital heart disease, multiple AP’s, and non-left sided AP’s are more commonly seen in patients with AP recurrence after initial acute ablation success. Procedural variables such as non-EAM, empiric ablation delivery, and cryoablation approaches are also associated with higher recurrence risk.
The application of consolidation lesions is an interesting variable that appears to have some influence on recurrence risk. The findings from this study challenge some traditional dogmas of what is considered an adequate successful ablation, risks of collateral damage from aggressive consolidative ablations, and concerns over delaying acute/early recurrence with application of consolidation lesions at suboptimal targets. In this study, consolidation time >90 seconds seemed to be associated with lower recurrence risk. It is possible that longer consolidation time makes up for the possibility of the initial successful lesion being slightly suboptimal in location/contact/tip orientation or addresses more complex AP substrates such as branches or slanted orientations.
There are some limitations with this study, some of which were highlighted by the authors. Intra-operator variability was not controlled for and could certainly have affected outcomes. The authors noted that longer follow-up data was lacking for a sizeable portion of the cohort, which could underestimate true recurrence rates. The type of consolidation delivery was also not uniformly or systematically delivered, though time appeared to be a primary factor in predicting recurrence. Most cases in the study utilized non-irrigated ablation and EAM technique (approach to mapping and EAM system used) was not specifically assessed, which leaves out procedural variables such as high density EAM mapping, irrigated vs. non-irrigated ablation, and contact force assessment – all of which could have impact on ablation outcomes and recurrence as well. Conceptually, we would expect these tools when properly applied to facilitate acute success and reduced recurrence. Overall, the study provides great data to consider how to adjust our techniques in certain patient subgroups and AP types to potentially achieve greater long-term success.