10 beats/min) to be with frequent monomorphic ventricular ectopic beats originating in the right outflow tract. Using activation-mapping for the earliest endocardial activation of spontaneous monomorphic ventricular ectopic beats, the site was ablated by RFCA.Results The immediate successful rate was 100% (28/28). Holter monitoring before and after ablation found monomorphic ventricular ectopic beats:15.836-32.419 beats/24 h vs 0-1.236 beats/24 h.Following-up of 6-24 months found all the 28 patients living in normal state.No complication occurred.Conclusion RFCA of frequent monomorphic ventricular ectopic beats originating in the right outflow tract is safe and effective.

Objective To study the role of ventricular responses(VR) in radiofrequency catheter ablation (RFCA) of idiopathic ventricular tachycardia(VT).Methods Thirteen patients underwent RFCA by using a combination of surface ECG,activition mapping and VR.The ablation targets were primarily selected by activition mapping and was determined by the VR in RFCA,and then,the final ablation target was determined and ablated where VR and VT had the same ECG results.Results Thirteen patients were successfully ablated.The VRs showed:the VR induced by RFCA in sinus rhythm was just the same as VT;intermittent sinus rhythm appeared between VT;two couple or couplets,or premature beats appeared intermittently in sinus rhythm,and finally sinus rhythm appeared;the VR induced by RFCA was not the same as VT.Conclusion The ablation target should be the site where the VR induced by RFCA is just the same as VT;the occurence of VR that is just the same as VT can be the predictor of successful ablation.