Objective To evaluate the feasibility,effectiveness and safety of Carto3 three-dimensional electrophysiological mapping system in guiding radiofrequency ablation (RFA) for paroxysmal supraventricular tachycardia (PSVT).Methods The clinical data of a total of 28 patients with PSVT (Carto group),who received RFA guided by Carto3 three-dimensional electrophysiological mapping system during the period from March 2015 to February 2016,were retrospectively collected.Other 36 parents with PSVT,who received fluoroscopy-guided RFA during the period from March 2014 to February 2015,were collected as control group.The X-ray irradiation time,success rate of operation,operation time,complication and recurrence rate were calculated and the results were compared between the two groups.Results The mean fluoroscopy time in Carto group was (2.6±2.3) min,which was significantly less than (15.8±9.5) min in the control group (P＜0.001),and among them zero X-ray irradiation was obtained in 8 patients who had atrioventricular nodal reentrant tachycardia (AVNRT).The operation success rates of Carto group and the control group were 100％ (28/28) and 94.4％ (35/36) respectively (P＞0.05).The operation time in Carto group and the control group was (162.7±34.4) min and (149.4±46.2) min respectively (P＞0.05).In Carto group no any complications occurred,and in the control group one patient with AVNRT developed transient degree Ⅱ atrioventricular block during ablation process.All patients were followed up for 6 months,and no recurrence was observed in all patients of both groups.Conclusion For the treatment of PSVT,RFA guided by Carto3 three-dimensional electrophysiological mapping system is safe and effective,it can significantly reduce the X-ray irradiation time,even zero X-ray radiation in some AVNRT patients,meanwhile,this technique does not increase operation time and operation risk.