Effectiveness of Radiofrequency Catheter Ablation of Outflow Tract Ventricular Arrhythmias in Children and Adolescents.

Outflow tract ventricular arrhythmias (OTVAs) are common in children; however, experience is limited on their radiofrequency catheter ablation (RFCA). The purpose of this study was to assess the outcomes of mapping and ablation of pediatric OTVAs and to evaluate the role of ECG algorithms in distinguishing the origin of OTVAs. We compared retrospectively collected single-center data on 92 consecutive pediatric patients (58 male; age, 8.2 ± 2.9 [range 3.6-18] years) who underwent RFCA for OTVAs from 2009 to 2015. Two independent and blinded observers analyzed ECG data. Of these children, 69 (75 %) were of RVOT origin. RFCA was given up in 1 case, and the acute success rate was 92.3 % (84/91), the 1-year follow-up recurrence rate was 8.3 % (7/84) and the complications of the procedure were 2.2 % (2/92). And 3D versus 2D mapping-guided RFCA was associated with significantly (p < 0.05) higher acute success rate (96.1 % [49/51] vs. 87.5 % [35/40]), and lower X-ray exposure (742.5 ± 323.1 vs. 1432.3 ± 605.5 mGy cm2 ) and 1-year recurrence rate (4.1 % [2/49] vs. 14.3 % [5/35]). The positive predictive value of four types of ECG algorithms used in adults for LVOT origin was only 47.7-65.4 %. In these cases, four identified as RVOT origin and two identified as LVOT origin by ECG underwent successful ablation on the other side of outflow tract finally. And these six children who underwent successful RFCA in both sides of outflow tract had no follow-up recurrence. OTVAs in children originate mostly from RVOT. RFCA can be used for ablation of pediatric OTVAs effectively and safely. In some cases, successful RFCA should be ablated in both sides of outflow tract. ECG-based prediction of OTVA origin as used in adults is limited in children.