After a follow-up study of 13-39 months, the clinical effect of catheter ablation in 8 patients with WPW syndrome and recurrence of SVT was reported. Five cases of left free-wall accessory pathway underwent catheter ablation attempts by direct current shocks delivered in coronary sinus. 3 of them were free from SVT without any medications after ablation, 1 case was improved. The other one was unsuccessful. Catheter ablation was attempted by delivery of shocks at coronary sinus orifice in 3 patients with posteroseptal accessory pathway. Arrhythmias were controlled without the need of drug therapy in 2 cases and the clinical symptoms were relieved in 1 case after shocks. We consider that the catheter ablation attempted to block the conduction of left free-wall and posteroseptal accessory pathway induces much less damages than surgical ablation and offers the advantages of shorter hospitalization, lower cost and a much shorter convalescence. The authors stated that it is a viable alternative to surgical ablation for those patients who are not responsive or allergic to drugs or those who are not willing to take a life-long period of medications. Some concerns for increasing the success rate and reducing the complications of ablation were also discussed.