the study of stable_sr for persistent atrial fibrillation

Conditions: Atrial Fibrillation

Summary: * background:the ablation outcomes for the treatment of persistent atrial fibrillation are not as satisfactory as paroxsymal af. the successful rate ranges from 30%-55%. we found a new novel strategy for the modification of la substrate during sinus rhythm based on our pilot study. * hypothesis: our new method may be more effective than conventional strategy. * objectives:the primary objective of this investigation is to compare the efficacy of two different af ablation strategies in patients with persistent af:study group: cpvi plus electrophysiologic substrate ablation in the left atrium during sinus rhythm ( stable-sr);control group: conventional stepwise approach for persistent af(cpvi + lines +cfe) .the secondary objectives of this investigation are to evaluate and compare the safety and procedural characteristics of both groups. * sample size: 220 * time line: 2013 q1-2014 q2

what's is stable-sr approach? in our center, the la substrate mapping was performed in patients with paroxysmal af and persistent af during sinus rhythm, particularly 20 normal subjects as control group as well. our study showed that along with the duration of af the average voltage of la deceased and the area of low voltage zone increased. the whole activation time of entire la would be longer. more complex fractionated electrograms was found in la. importantly, we identified the low voltage zone (voltage range: 0.1-0.4mv) and the transitional zone (voltage range: 0.4-1.3mv) in which most of complex fractionated electrograms located. based on our findings a new novel ablation strategy has emerged, which is modification of la substrate during sinus rhythm (cpvi+stable-sr). our sequential protocol included 5 steps. first cpvi should be completed followed by cti ablation to be blocked. then if af rhythm maintained cardioversion would be taken. high density mapping of la substrate would be done during sinus rhythm to identify the low voltage zone and transitional zone. linear ablation or/and spot ablation should be designed according to the mapping results. finally bidirectional conduction block should be demonstrated for all the linear lesion and all pulmonary veins would be checked for isolation.

Eligibility criteria:
inclusion criteria: * patients undergoing a first-time ablation procedure for af; * patients with persistent or long-lasting af; persistent af will be defined as a sustained episode lasting \> 7 days and less than 1 years; long-lasting persistent af will be more than 1 year and less than 5 years. * patients must be willing and able to comply with all peri-ablation and follow-up requirements. * patients with atrial fibrillation will to accept the procedure of ablation. * patients signed the written informed consent for the study. * patients can endure the required follow up. exclusion criteria: * patients with paroxysmal af; paroxysmal af will be defined as a sustained episode lasting \< 7days. * patients with contraindications to systemic anticoagulation with heparin or coumadin or a direct thrombin inhibitor. * patients with thromboemboli in laa. * patients with left atrial size ≥ 55 mm (2d echocardiography, parasternal long-axis view). * patients allergic for contrast or iodine. * patients with the scr \>3.5mg/dl or ccr \< 30 ml/min * patients with life expectancy \< 12 months * patients who are in the period of pregnant

Keywords: persistent atrial fibrillation;la substrate;ablation;voltage mapping