Background Achievement of complete conduction block in the cavotricuspid isthmus (CTI) is a curative ablation technique in patients with common atrial flutter (AFL). The present study was a prospective comparison of the efficacy of 2 ablation strategies in patients with common AFL: the continuous and point-by-point radiofrequency (RF) delivery techniques. Methods and Results Forty patients with common AFL were randomly assigned to either a group treated with a continuous RF delivery or to a group undergoing point-by-point RF ablation. In the first group, the RF energy was continuously delivered during a slow drag of the catheter tip from the tricuspid annulus to the inferior vena cava without stopping the application. In the second group, the RF ablation was performed using a point-by-point approach for 60 s at each point. All patients underwent ablation with an 8-mm-tip ablation catheter with a power limit of 50 W and a target temperature of 55°C. Complete CTI conduction block was achieved in all patients. The patient characteristics, including the anatomy of the CTI estimated by 3-dimensional computed tomography, were no different between the 2 groups. The procedure time (time from the start of RF delivery to the completion of CTI block), fluoroscopic time and total RF energy required to create the CTI block between the continuous and point-by-point groups were 7.3±5.6 vs 21.2±22.2 min (p<0.01), 7.2±4.4 vs 16.2±14.1 min (p<0.05), and 15,631±6,001 vs 24,072±16,140 joules (p<0.05), respectively. There were no complications or recurrences of AFL during the follow-up period in any of the patients. Conclusion In the curative treatment of common AFL, the continuous RF delivery approach could shorten the procedure and fluoroscopic time and reduce the total RF energy compared with the point-by-point RF ablation approach. (Circ J 2007; 71: 1922 - 1926)