Abstract: AIM:To investigate the electrocardiographic characteristics and to evaluate the efficacy and safety of using a single catheter for radiofrequency catheter ablation in monomorphic premature ventricular contractions (PVCs) originating from right ventricular outflow tract (RVOI). METHODS: Electrocardiographic characteristics and the results of radiofrequency catheter ablation were analyzed in 52 patients who had normal cardiac structure but monomorphic PVCs originating from right ventricular outflow tract and were treated with a single catheter for radiofrequency catheter ablation. Using pace mapping method, the target points of ablation were the same pacing ventricular wave forms as monomorphic ventricular premature. RESULTS: The surface electrocardiogram of PVCs originating from the right outflow tract showed rs, m, QS or R wave on lead I, QS wave was seen on lead aVR and aVL and Tall R wave was seen on lead II, III, aVL, V5 and V6. Precordial lead R wave transition occurred on lead V3 or V4 or behind them. Successful ablation was achieved at sites of RVOT septum (n=26), RVOT free wall (n=21), His region (n=1) and the pulmonary valve (n=1). Among the PVCs originating from the RVOT septum, seven were from the anterior wall, five from the mid-region and 14 from the posterior wall. For PVCs originating from the RVOT free wall, six were from the anterior wall and 15 from the posterior wall. Forty-nine of the 52 patients with PVCs were successfully abolished and immediate success rate of ablation was ~94% (49/52). The procedure time was 30-150 min and the fluoroscopic time was 5-29 min. No recurrence was found during follow-up. CONCLUSION: PVCs originating from right ventricular outflow tract show some specific electrocardiographic characteristics. Single-catheter radiofrequency catheter ablation could effectively and safely treat normal cardiac structure patients who have normal cardiac structure but monomorphic PVCs originating from the right ventricular outflow tract.