Objective To investigate the feasibility and effectiveness of radiofrequency catheter ablation （RFCA） to treat permanent atrial fibrillation （AF） under the guidance of Carto-Merge technique. Methods Fifteen male patients with permanent AF underwent RFCA under the guidance of Carto-Merge technique. The mean age was 54.00±10.44 years

and duration of AF was 23.66±14.93 months. Cardiac magnetic resonance angiography （MRA） was performed to obtain pre-procedural three-dimensional （3D） images on the anatomy of left atrium （LA） and pulmonary veins （PVs） before RFCA procedure. Then the electroanatomical map was integrated with 3D images of MRA to form Carto-Merge map that guided step-by-step ablation strategy of permanent AF. Circumferential PV ablation was performed first until complete PVs electric isolation confirmed by Lasso catheter. If AF was not terminated

lesion lines on roof of LA

mitral isthmus

and tricuspid isthmus were produced. Results The episodes of AF were terminated during RFCA in 2 patients

by direct current cardioversion in the remaining 13 patients. Transient AF occurred in 2 patients after ablation on 1st day and 1st week respectively

AF terminated spontaneously not long after taking metoprolol. One patient developed persistent atrial flutter （AFL） in 2 months after procedure and AFL was eliminated by the second ablation. Persistent AF recurred on 1st day

1st and 5th week respectively in 3 patients

and did not terminate after 3 months even though amiodarone was given. The remaining 12 patients were all free of AF during 2-11 months of follow-up. The recent success rate for RFCA of permanent AF was 80%. Conclusions Carto-Merge technique can effectively guide RFCA of permanent AF. When combined with single Lasso mapping

it can simplify the mapping

lower expenses

and enhance the success rate of RFCA of permanent AF.