Abstract: Objective To investigate the efficacy and safety of radiofrequency catheter ablation(RFCA)for children with tachyarrhythmia of various types. Methods A total of 972 patients with tachyarrhythmia who underwent electrophysiological study and RFCA during Aug. 2000 and Aug. 2021 were selected, including 580 males and 392 females, median age 10 years, median body weight 38 kg. The immediate success rate of the procedure, recurrence rate and complications were summarized. The ablation efficacy in children with congenital heart disease(CHD)and cardiomyopathy, the overall procedure time, fluoroscopy time and success rate in different periods were analyzed. Results Among the 972 patients, 6 were complicated with dilated cardiomyopathy, 5 with tachycardia cardiomyopathy, 1 with arrhythmogenic right ventricular cardiomyopathy, and 25 with CHD, mostly atrial septal defects. Atrioventricular reentrant tachycardia(AVRT)was observed in 444(45.68%)patients, atrioventricular nodal reentrant tachycardia(AVNRT)in 221(22.74%)patients, ventricular tachycardia/premature ventricular contraction(VT/PVC)in 232(23.87%)patients, atrial tachycardia(AT)in 62(6.38%)patients, and atrial flutter(AF)in 9(0.92%)patients. The mechanism of tachycardia could not be determined in 4(0.41%)patients. Totally 938 children underwent RFCA.The immediate success rate was 99.04%, and recurrence rate was 6.89%. The mean procedure duration was 100(70-120)min, and the mean fluoroscopy time was 3.30(0.50-9.41)min. The 437 AVRT patients had an immediate success rate of 98.86%,and a recurrence rate of 6.48%. The 219 AVNRT patients had an immediate success rate of 100%, and a recurrence rate of 5.02%. The 225 VT/PVC patients had an immediate success rate of 99.11%, and a recurrence rate of 8.97%. The 49 AT patients had an immediate success rate of 97.96%, and a recurrence rate of 10.42%. The 8 AF patients had an immediate success rate of 87.50%, with no recurrence. Major complications occurred in 10(1.07%)patients, including left pneumothorax in 5 cases, complete left bundle branch block in 1 case, Ⅱ° atrioventricular block in 1 case, thrombus in 1 case, pericardial effusion in 1 case and pleural effusion in 1 case. Compared with children with normal cardiac structure and function, children with CHD and cardiomyopathy had the same immediate success rate but significantly higher recurrence rate(P<0.05). There was no significant difference in the immediate success rate between the early stage(2000—2010)and late stage(2011—2021)(P>0.05). However, as the technology matured, the recurrence rate and the radiation exposure time were significantly reduced(P<0.05). Conclusion RFCA is safe and effective for children with tachyarrhythmia, with high success rate and low recurrence and complication rates.

Key words: Radiofrequency catheter ablation, Tachyarrhythmia, Congenital heart disease, Cardiomyopathy, Ablation efficacy, Child