Objective To investigate the method and the efficacy of applying irrigated tip catheter in radiofrequency ablation Methods The study included 6 patients (M/F 4/2, mean age 34 2?16 7), 2 patients had common atrial flutter, 2 had right outflow tract ventricular tachycardia (ROVT) and other 2 had epicardial atrioventricular accessory pathways All patients failed ablation with conventional radiofrequency (RF) ablation An irrigated tip catheter ablation was performed on these patients Results Bidirectional isthmus block was achieved in 2 patients with common atrial flutter; the successful ablation was achieved in 2 patients with ROVT; V A dissociation was appeared in 2 patients with epicardial atrioventricular accessory pathway, the mean application was 3 4?1 2, the mean time of procedure was 92 4?30 3 minutes, the mean exposure time of X ray was 29 3?12 6 minutes No side effects and no coronary damage was observed Conclusion Irrigated tip catheter ablation is safe and effective for achieving successfully ablation of tachycardia when conventional RF energy has failed