Implantation of permanent pacemaker and ICD leads in children using a three-dimensional electroanatomic mapping system as an aid to fluoroscopy.

BACKGROUND: Three-dimensional electroanatomic mapping systems (3D mapping) allow the creation of an anatomic representation of the cardiac anatomy and real-time monitoring of transvenous pacing catheters. Their use to facilitate pacemaker (PM) and implantable cardioverter defibrillator (ICD) lead placement in the pediatric population has not been well defined. We sought to review our experience using 3D mapping as an adjunct to fluoroscopy for positioning of permanent PM and ICD leads in pediatric patients. METHODS: We performed a retrospective review of all patients ≤21 years of age who underwent PM or ICD implantation with the aid of the Ensite Velocity system (Ensite) from May 2012 to September 2014. Fluoroscopy was utilized in addition to 3D mapping to aid obtaining vascular access, to visualize fixation of the lead to the myocardium, and to evaluate lead length within the vasculature. RESULTS: Nineteen patients (mean age 14.6 ± 4.4 years) underwent placement of active fixation PM leads (N = 17) and/or ICD leads (N = 10) with the aid of Ensite. All leads were successfully placed (eight atrial, 19 ventricular). Fluoroscopic exposure was a mean of 3.2 minutes (± 2.8, 0.1-10.5). There was one lead dislodgement. CONCLUSIONS: Ensite was used successfully as an adjunct to fluoroscopy in all patients in whom it was attempted to aid the placement of permanent transvenous PM and ICD leads. Future evaluation could focus on the use of 3D mapping systems to further minimize or eliminate fluoroscopy from PM and ICD implantations.

Cryoablation of anteroseptal accessory pathways with a his bundle electrogram on the ablation catheter.

BACKGROUND: Radiofrequency catheter ablations of anteroseptal (AS) accessory pathways (AP) in pediatric patients have higher incidence of atrioventricular (AV) block than other AP locations. We report our experience using cryoablation in pediatric patients where a His bundle electrogram was noted on the ablation catheter at the site of the successful ablation. METHODS AND RESULTS: We retrospectively reviewed all patients ≤21 years that underwent cryoablation for an AS AP from 2005 to 2012 at our institution (n=70). Patients with a His bundle electrogram noted on the cryoablation catheter at the location of the successful lesion were identified (n=6, 8.5%). All six patients had ventricular preexcitation. Median age of 15.9 years (7.2 - 18.2). AV nodal function was monitored during the cryoablation with intermittent rapid atrial pacing conducted through the AV node (n=2), with atrial extra-stimulus testing (n=2), or during orthodromic reentrant tachycardia (n=2). Acute success occurred in all patients. Two patients had early recurrence of AP conduction. Both patients underwent a second successful cryoablation, again with a His bundle electrogram on the cryoablation catheter. At a median follow-up of 13 months (3 to 37 months) there was no recurrence of accessory pathway conduction and AVN function was normal. CONCLUSION: In a small number of pediatric patients with AS AP with a His bundle electrogram seen on the ablation catheter, the use of cryotherapy was safe and effective for elimination of AP conduction without impairment of AV nodal conduction.