Effects of Ventilation and Catheter Position on Catheter Movement on the Tricuspid Annulus during Ablation in Children

Comparison of Outcomes of Pediatric Catheter Ablation by Anesthesia Strategy: A Report From the NCDR IMPACT Registry

[Figure: see text].

"If at first you don't succeed": repeat ablations in young patients with supraventricular tachycardia

PURPOSE

Success rates for catheter ablation of supraventricular tachycardia (SVT) in the young exceed 90%. While studies have described reasons for initial ablation failure, less is known about outcomes of repeat ablation attempts. The purpose of this study was to report acute and mid-term success rates for second ablation attempts in young patients, as well as to analyze factors that may affect these outcomes.

METHODS

Retrospective single-center study of all patients undergoing a second ablation attempt for WPW (Wolff-Parkinson-White) or SVT from 2008 to 2017. Inclusion criteria are all patients < 21 years old at the time of their first ablation who underwent a second ablation attempt. An intention to treat analysis was performed.

RESULTS

Fifty-five patients met inclusion criteria, with a median age of 15 years (IQR 12-16). The most common arrhythmia mechanisms at repeat procedure were single accessory pathways (n = 32, 58%) and AVNRT (n = 14, 25%). Six patients (11%) were found to have a different SVT mechanism than at initial ablation. Acute success at repeat ablation was achieved in 48 patients (87%). At mid-term follow-up (10.5 months, IQR 0.6-25), four patients (8% of acute successes) experienced SVT recurrence. The overall success rate of repeat ablations, accounting for acute and mid-term failures, was 80%.

CONCLUSIONS

In this report of 55 young patients who underwent repeat ablation for WPW and/or SVT, acute and mid-term success rates were 87% and 80%, respectively. These data may help inform decision-making when caring for patients with persistent or recurrent SVT after an initial ablation attempt.

A Prospective Assessment of Optimal Mechanical Ventilation Parameters for Pediatric Catheter Ablation

Catheter stability, an important factor in ablation success, is affected by ventilation. Optimal ventilation strategies for pediatric catheter ablation are not known. We hypothesized that small tidal volume and positive end-expiratory pressure are associated with reduced ablation catheter movement at annular positions. Subjects aged 5-25 years undergoing ablation for supraventricular tachycardia (SVT) or WPW at two centers from March 2015 to September 2016 were prospectively enrolled and randomized to receive mechanical ventilation with either positive end-expiratory pressure of 5 cm H₂O (PEEP) or 0 cm H₂O (ZEEP). Movement of the ablation catheter tip at standard annular positions was measured using 3D electroanatomic mapping systems under two conditions: small tidal volume (STV) (3-5 mL/kg) or large TV (LTV) (6-8 mL/kg). 58 subjects (mean age 13.8 years) were enrolled for a total of 266 separate observations of catheter movement. STV ventilation was associated with significantly reduced catheter movement, compared to LTV at all positions (right posteroseptal: 2.5 ± 1.4 vs. 5.2 ± 3.1 mm, p < 0.0001; right lateral: 2.7 ± 1.6 vs. 6.3 ± 3.5 mm, p < 0.0001; left lateral: 1.8 ± 1.0 vs. 4.3 ± 1.9 mm, p < 0.0001). The presence or absence of PEEP had no effect on catheter movement. In multivariable analysis, STV was associated with a 3.1-mm reduction in movement (95% CI 2.6-3.5, p < 0.0001), adjusting for end-expiratory pressure, annular location, and patient size. We conclude that STV ventilation is associated with reduced ablation catheter movement compared to a LTV strategy, independent of PEEP and annular position.