Objective    Fixed ablation strategies for atrial fibrillation (AF) are empirical protocols regardless of the variety of AF. This study was aimed to observe the efficiency of an individualized ablation strategy of AF/atrial flutter (AFL) under the guide of Carto 3D mapping system and the effects of the right atrium in the ablation.     Methods    Eighty-two patients [42 males and 40 females with a mean age (48.5±10.3)] admitted in our department from Feb. 2007 to Jun. 2009 were enrolled

of which

53 patients were paroxysmal AF

14 patients were persistent AF and 15 patients were typical AFL

and their mean diameter of left atrium was (35.4±5.3) mm. Individualized ablation varied from segmental to circumferential was completed step by step under the guidance of Carto 3D mapping system. The burst stimulation (250 to 600 bpm) was applied to induce AF if there was no spontaneous AF

and the main procedure end point is electrical isolation of pulmonary veins(PVs) by circumferentia pulmonary veins ablation (CPVA) and complex fractional atrial electrogram (CFAE) ablation. Success was defined as symptomatic atrial tachyarrhythmias (ATa) free with no aid of any anti-arrhythmia drugs for at least 3 months.     Results    (1)After a mean follow-up of (13.4±3.3) months

the successful rate of ablation was 88.2% in patients with paroxysmal AF and AFL

but only 57.1%(P0.05) in persistent AF. Complications included pericardial tamponade (2 cases) and pseudoaneurysm (1 case)

but no symptomatic pulmonary vein stenosis was observed. (2) Ten cases of paroxysmal AF were originated from rapid firing foci (4 cases from the right atrium)

and circumferential targeted vein ablation was performed in 8 cases with no recurrence of ATa. CPVA were performed on the other 43 cases of paroxysmal AF

and patients coexisted with typical (4 cases) and atypical (6 cases) AFL undergoing tricuspid/mitral isthmus ablation. (3) Fourteen typical AFL underwent tricuspid isthmus ablation

of which bi-pulmonary CPVA was operated in 4 patients complicated with AF. (4) All 14 cases of persistent AF was converted to typical or atypical AFL

sinus rhythm by ablation (6 cases ) and by defibrillator (8 cases)

and half of them received tricuspid or mitral isthmus ablation.     Conclusion    This study suggests that the individualized ablation protocol based on the mechanism of AF/AFL is feasible and effective in sinus rhythm restoration

and the right atrium may be involved in trigger and substrate of AF mechanism.