Abstract: Objective:To investigate the sedative and analgesic effects of dexmedetomidine(Dex) in patients with paroxysmal supraventricular tachycardia(PSVT) undergoing radiofrequency catheter ablation(RFCA).Methods:Thirty patients with PSVT undergoing RFCA were randomly assigned to Dex group(n=15) and NS group(n=15).All patients were performed with local infiltration anesthesia at the puncture site.In Dex group, the patients were received Dex on maintenance dose of 0.05 μg·kg^-1·h^-1 to the end of RFCA procedure followed by loading dose of 1 μg/kg within a 10 min infusion, the patients in NS group were received 0.9% saline with same volume.The parameters including mean arterial pressure(MAP), heart rate(HR), visual analogue scale(VAS), and the observer's assessment of alertness/sedation scale were assessed at different time points.Additionally, the times of stopping procedure because of intolerant pain, peri-operative adverse events and patients' satisfaction were recorded.Results:Compared with NS group, MAP, HR and VAS were significantly decreased in Dex group(P<0.01).Patients in Dex group presented a favorite sedation without troubles in trigging tachycardia and delayed recovery, meanwhile, the times of stopping procedure because of intolerant pain was significantly decreased(P<0.01), and the satisfaction was higher than in NS group(P<0.05).Conclusions:Application of Dex in patients with PSVT undergoing RFCA presents a good sedation and analgesia, alleviates the changes of hemodynamics induced by procedural stress without any delayed recovery and respiratory inhibition, and achieves high satisfaction.However, the occurance of bradycardia should be noticed during loading dose infusion.