The primary objective of this investigation is to compare the efficacy of two different AF ablation strategies in patients with non-paroxysmal AF: CPVI plus electrophysiologic substrate ablation in the left atrium during sinus rhythm (STABLE-SR) and CPVI alone.

BACKGROUND: Atrial fibrillation (AF) is the most common cardiac rhythm disorder, which affects patients' morbidity and mortality. AF ablation has emerged as a promising treatment strategy, offering the possibility of a durable treatment. Currently, there is no general agreement regarding NPAF ablation strategy. Obviously, pulmonary vein isolation is the corner stone for all types of AF ablation. The consensus is that CPVI alone is insufficient for NPAF ablation. However, the recent clinical trials did not show the additional benefits of other substrate modification strategies. Furthermore, the widely used cryo-ablation dilutes the concept that NPAF needs additional substrate modification to further improve the clinical outcome. It seems that CPVI only as the optimal strategy is more commonly accepted for NPAF patients in most of the centers. Based on the results from our pilot study and STABLE-SR trial, we believe that fibrotic substrate modification beyond CPVI is very promising for NPAF ablation, but its superiority over CPVI alone needs a large scaled randomized trial to prove.

AIM OF THE STUDY: The primary objective of this investigation is to compare the efficacy of two different AF ablation strategies in patients with non-paroxysmal AF: CPVI plus electrophysiologic substrate ablation in the left atrium during sinus rhythm (STABLE-SR) and CPVI alone. The primary endpoint is freedom from AF and/or ATs with or without antiarrhythmic drugs (AADs) at 12months after a single-ablation procedure. AF and/or AT occurring in the first 3 months after the ablation (blanking period) was censored. Each episode lasts > 30 seconds. The secondary endpoint are incidence of peri-procedural complications, including stroke, PV stenosis, cardiac perforation, esophageal injury and death; procedure time; fluoroscopy time (including the total fluoroscopy time, during CPVI and after CPVI); the occurrence of the conversion from AF to AT, and its relationship with long-term outcome; the relationship between acute termination of AF and long term outcome.

STUDY DESIGN: This is a randomized, prospective, parallel, single-blind multicenter design. The enrollment target for this investigation is 300 patients. Patients are randomized in a 1:1 fashion into one of the investigation arms: CPVI plus electrophysiologic substrate ablation in the left atrium during sinus rhythm (STABLE-SR) and CPVI alone. Follow-up for these patients includes visits at 3 m, 6 m, 9 m, 12 m.

Inclusion Criteria:

• Patients age is 18-80 years;
• Patients with non-paroxysmal AF; non-paroxysmal AF will be defined as a sustained episode lasting > 7 days;
• Patients can sign the written informed consent for the study;
• Patients can endure the required follow-up.

Exclusion Criteria:

• Patients with previous radiofrequency ablation;
• Patients with PLT count less than 80×109/L, or with contraindications to systemic anticoagulation with heparin or Coumadin or a direct thrombin inhibitor;
• Patients with left atrial size ≥ 55 mm (2D echocardiography, parasternal long-axis view);
• Patients with thromboemboli in LA (TEE or MSCT);
• Patients with severe structural cardiac disease (medium or severe mitral regurgitation, DCM, HCM, or other severe valvular heart diseases);
• Patients with abnormal thyroid function;
• Patients with severe liver or renal dysfunction (AST or ALT > 3-fold of upper limit value; the SCr > 3.5 mg/dl or Ccr < 30 ml/min);
• Previous surgery history in last 3 months;
• Patients with life expectancy < 12 months; and
• Patients who are pregnant.