OBJECTIVETo explore safety, indications and advantages of mapping and ablation of arrhythmia in children guided by Carto and Ensite system.

METHODSGuided by Carto system, radiofrequency catheter ablation (RFCA) was performed on 8 pediatric patients with tachycardia whose mean age was (6.2 + or - 1.7) years, mean weight was (18.0 + or - 2.0) kg. Guided by Ensite system, RFCA was performed on 10 pediatric patients with arrhythmia, 8 of them were ablated guided by Ensite Array system: 6 cases with premature ventricular contractions (PVCs), 2 cases with right atrial tachycardia, their mean age was (11.3 + or - 1.2) years, and mean weight (40.0 + or - 5.0) kg. The other two cases with W-P-W syndrome were ablated guided by Ensite Navx system.

RESULTGuided by Carto system, 8 cases were successfully mapped and ablated: 6 cases had incision atrial tachycardia, 1 case had left atrial tachycardia and 1 case had right atrial tachycardia. In 1 case with incision atrial tachycardia the condition recurred after 3 months, and was ablated again successfully. Guided by Ensite Array system, 6 cases with PVCs (in 2 originating from the right ventricular inflow tract and in 4 originating from the right ventricular outflow tract) and 2 cases with right atrial tachycardia were successfully mapped and ablated, PVCs of the first 6 cases were reduced from (32 333 + or - 4509) 24 h to (0-4)/24 h after ablation. In 1 case with automatic atrial tachycardia, mapping could not be done by Ensite Array system, because P wave could not be identified from T wave. Single bolus of adenosine 20 mg was given within 30 s to let ventricles stop for 2 s (cardio-ventricular pacing standby) until T wave vanished, mapping and ablation were operated again successfully, but another atrial tachycardia occurred 1 day later. Guided by Ensite Navx system, 2 cases with W-P-W syndrome were successfully ablated, operation under X-rays lasted for 8 and 10 min. In none of the 9 patients the disease recurred after follow-up for 6 months.

CONCLUSIONCarto system is suitable for mapping and ablation in pediatric patients with continuous tachycardia, especially with incision atrial tachycardia; Ensite Array system fits children older than 10 years with right heart discontinuous arrhythmia; and Ensite NavX system can set up model and display endocardial anatomic structure quickly. Compared with two-dimensional mapping system, the three-dimensional mapping system (Carto and Ensite) can display the origin of arrhythmia and activation sequence clearly, decrease difficulty of operation efficiently and diminish operation time under X-ray.