<正> Radiofrequancy ablation is a popular and effective approach to cure arrhythmia.The present study is an analysis of the electrophysiological mechanism,charateristics and the best treatment of supraventricular tachycardia.Therecords of arrhythmia radiofrequancy ablation regestry were reviewed betweenDecember,1996 and July,1997.33 patients with supraventricular tachycardiawere examine by programmed electrial stimulation(PES,esophagus andintracardia PES),cured by radiofrequency ablation and its electrophysiologicalmechanism and characteristics was analyzed.Of all the patients,the rate ofAVNRT is 24.3%,that of AVRT is 75.7%,in which 68% were left pathways,32% right pathways.All the 33 patients were radiofrequency ablated,31patients were cured,the other two recurred within one month,and ablated again,no recurrence again,So we concluded that most supraventricular tachycardiawere caused by reentrant,catheter ablation is a safe and cured treatmant forsupraventricular tachycardia caused by reentrant.