Success rates in pediatric WPW ablation are improved with 3-dimensional mapping systems compared with fluoroscopy alone: a multicenter study.

INTRODUCTION: Three-dimensional mapping (3-D) systems are frequently used for ablation of supraventricular tachycardia. Prior studies have demonstrated radiation dosage reduction with 3-D, but there are no data on whether 3-D improves the efficacy of ablation of Wolff-Parkinson-White syndrome (WPW). We sought to determine if 3-D improves the success rate for ablation of WPW in children. METHODS: Multicenter retrospective study including patients ≤21 years of age with WPW undergoing ablation from 2008 to 2012. Success rates using the 2 techniques (3-D vs. fluoroscopy alone [FLUORO]) were compared. RESULTS: Six hundred and fifty-one cases were included (58% male, mean age 13 ± 4 years, 366 [56%] 3-D). Baseline characteristics including gender, weight, accessory pathway (AP) location, number of APs, and repeat ablation attempts were similar between the 2 groups (3-D and FLUORO) The 3-D group was slightly younger (12.7 ± 4.0 vs. 13.3 ± 4.0 years; P = 0.04) and less likely to undergo ablation utilizing cryoenergy (38 [10%] vs. 56 [20%]; P < 0.01). The 3-D group had a higher acute success rate of ablation (355 [97%] vs. 260 [91%]; P < 0.01). No differences were seen in recurrence (16 [5%] vs. 26 [9%]; P = 0.09) or complication rates (1 [0.3%] vs. 1 [0.4%]; P = 0.86) between the groups. On multivariable analysis, 3-D was shown to significantly improve success at ablation with an odds ratio of 3.1 (95% CI 1.44-6.72; P < 0.01). CONCLUSIONS: Use of 3-D significantly improved success rates for ablation of WPW in children. The increase in acute success associated with 3-D suggests it is an important adjunct for catheter ablation of WPW in children.

The pharmacokinetics of esmolol in pediatric subjects with supraventricular arrhythmias.

Esmolol is often used in the acute management of children with arrhythmias and/or hypertension; however, pharmacokinetic studies of the drug in children have been limited. The objective of this study was to determine the pharmacokinetics of esmolol in children with a history of supraventricular arrhythmias (SVT) who were scheduled for diagnostic electrophysiology study or a catheter ablation procedure. Subjects were stratified into two age groups: 2-11 and 12-16 years. After an episode of stimulated or spontaneous SVT, esmolol was administered intravenously as a 1,000 microg/kg bolus followed by continuous infusion at 300 microg/kg/min. Blood samples were collected before, at 5, 10 and 15 min after the loading dose, and 3, 6, 9, 12, 15 and 20 min after the end of the infusion. Plasma concentration of esmolol was quantitated by a specific LC/MS assay. Pharmacokinetic data were available for 25 subjects. Arterial esmolol concentrations were approximately five times greater than venous concentrations. Esmolol had an extremely short distribution half-life (0.6 min), a rapid terminal elimination half-life (6.9 min), and a rapid clearance (119 +/- 51 mL/min/kg) which was not related to subject age or weight. Seventeen of the subjects (63%) converted to normal sinus rhythm in an average of 2 min (range 0-5 min). The pharmacokinetics of esmolol and its efficacy in terminating SVT in children is similar to that observed in adults.