Objective:To investigate the feasibility and efficacy of catheter ablation guided by 3-dimensional mapping system in patients with focal atrial tachycardia. Methods:From August 2004 to October 2007,catheter ablation guided by CARTO system was performed in 42 consecutive patients with significantly symptomatic,drug refractory atrial tachycardia. The procedural end-point is the atrial tachycardia teminated and could not be induced by drug and/or programmed electrophysiological stimulation. Results:A total of 41 atrial tachycardia foci were successfully ablated in 42 patients(97.6%). The sites of origin included from the pulmonary vein(21/42,50%),near the mitral annulus(5/42,11.9%),the left auricle area(2/42,4.8%),the right auricle area(2/42,4.8%),left atrium roof(1/42,2.4%),left atrium posterior lateral wall(2/42,4.8%),paraHis bundle(1/42,2.4%),right atrium superior anterior wall(2/42,4.8%),right atrium inferior wall(1/42,2.1%),coronary sinus ostium(1/42,2.1%) and right atrium posterior septum(2/42,4.8%). There were no other clinical complications except for two cases of Femoral vein hematoma. Atrial tachyarrhythmia free rate was 95.2% (40/42) during the 4~18(9.95 ± 3.9) months in follow-up. Conclusion:Mapping and radiofrequency catheter ablation guided by 3-D mapping system was effective and safe in eliminating focal atrial tachycardia.