[Radiofrequency catheter ablation in the treatment of arrhythmias in children--efficacy, safety of the method, predictors of the procedural course and acute success].

BACKGROUND: Radiofrequency current ablation (RFCA) is a safe and efficient method of treatment in adult patients with symptomatic arrhythmias. Recently RFCA is being also used in the treatment of children with cardiac arrhythmias, however its value in this set of patients is poorly documented. Aims of our study were to assess the feasibility and safety of RFCA procedures in children with symptomatic supraventricular and ventricular arrhythmias, and to identify the parameters which influence the probability of acute success and RFCA course. METHODS: Consecutive 110 patients aged less than 18, who underwent RFCA due to the symptomatic arrhythmias at our center were included into a retrospective analysis. The patients presented mainly with the preexcitation syndrome (57%), 13.6% had ectopic ventricular arrhythmias, in 17.3% nodal reentrant tachycardia, in 8.2% intraatrial reentry tachycardia (IART), whereas in 5.4% ectopic atrial tachycardia (EAT) was diagnosed. Three patients had multiple arrhythmias. In ten subjects congenital heart defect was diagnosed in the past, which was treated surgically in 8. Analyzed parameters included: RFCA success-rate, procedure duration, fluoroscopy-time, perioperative complications and arrhythmia recurrence-rate during 6 months follow-up. RESULTS: Ablation was successful in 101 (91.8%) patients and abolished 104 out of 113 (92%) treated arrhythmias. Out of 9 patients with unsuccessful RFCA, three had congenital heart defect. Two complications occurred intra-operatively in two patients: in one patient pneumothorax was observed following jugular vein puncture, which resolved spontaneously without the need of drainage, in the second patient transient atrioventricular conduction block occurred during radiofrequency current application. Mean procedure duration in the studied population was 118.9 +/- 46 min, fluoroscopy exposure equaled 22.3 +/- 17min. In twelve patients (10.9%) arrhythmia recurred during the follow-up period. The longest procedure duration was observed in patients with EAT and IART, the longest fluoroscopy-time in subjects with IART, whereas the shortest fluoroscopy was observed in patients with the ventricular ectopic arrhythmias. Success-rates, complications, and recurrence-rates did not differ irrespectively from arrhythmia treated. The only independent predictor of unsuccessful RFCA was the presence of congenital cardiac defect (adjusted OR 0.15, p<0.05). The presence of cardiac defect, procedure performed without electroanatomic mapping system and less experienced operators were the parameters associated with longer fluoroscopic exposure. CONCLUSIONS: Radiofrequency current ablation is a safe and efficient method of treatment in children with arrhythmias. The presence of congenital heart defect was a factor influencing unfavorably the probability of successful RFCA. Procedural course was related to the experience of electrophysiology team, the use of advanced mapping systems and presence of cardiac defect.