Prospective randomized comparison of irrigated-tip versus conventional-tipcatheters for ablation of common flutter

Background-Radiofrequency (RF) ablation of common flutter requires the crea tion of a complete ablation line to produce bidirectional conduction block in the cavotricuspid isthmus. An irrigated-tip ablation catheter has been s hown to be effective in patients in whom conventional ablation has failed. This randomized study compares the efficacy and safety of this catheter wit h those of a conventional catheter for de novo flutter ablation. Methods and Results-Cavotricuspid ablation was performed with a conventiona l (n=26) or an irrigated-tip catheter (n=24). RF was applied for 60 minutes with a temperature-controlled mode: 65 degrees C to 70 degrees C up to 70 W with a conventional catheter or 50 degrees C up to 50 W (with a 17-mL/min saline flow rate) with the irrigated-tip catheter. The end point was the a chievement of bidirectional isthmus block, and a crossover was performed af ter 21 unsuccessful applications. Procedural ablation parameters as well as number of applications, x-ray exposure, procedure duration, impedance rise , and clot formation were compared for each group. A coronary angiogram was performed before and after each ablation for the first 30 patients. Comple te bidirectional isthmus block was achieved for all patients. Four patients crossed over from conventional to irrigated-tip catheters. The number of a pplications, procedure duration, and x-ray exposure were significantly high er with the conventional than with the irrigated-tip catheter: 13+/-10 vers us 5+/-3 pulses, 53+/-41 versus 27+/-16 minutes, and 18+/-14 versus 9+/-6 m inutes, respectively. No significant side effects occurred, and the coronar y angiograms of the first 30 patients after ablation were unchanged. Conclusions-Irrigated-tip catheters were found to be more effective than an d as safe as conventional catheters for flutter ablation, facilitating the rapid achievement of bidirectional isthmus block.