Objective: To evaluate the safety and efficacy of transcatheter atrial fibrillation ablation 1 month after WATCHMAN FLX left atrial appendage closure in patients with nonvalvular atrial fibrillation.

Atrial fibrillation (AF) is one of the most common persistent arrhythmias in the clinic, and its incidence increases significantly with age, posing a serious threat to public health worldwide. One of the most serious complications in patients with atrial fibrillation is thromboembolic events, especially cardiogenic stroke. Cardiogenic stroke caused by atrial fibrillation accounts for 20%-30% of all stroke cases, and the mortality and disability rates of patients after stroke are significantly increased. Studies have shown that about 90% of the thrombus in patients with NVAF comes from the left atrial appendage (LAA). Therefore, isolating the left atrial appendage from the atrium to prevent stroke has become an important strategy in the management of patients with atrial fibrillation. This surgical method is called left atrial appendage occlusion (LAAO).

Moreover, both international and national guidelines for arrhythmia management indicate that rhythm control and stroke prevention are equally important for patients with atrial fibrillation. Although left atrial ear closure is effective in reducing the risk of stroke associated with atrial fibrillation, it does not address arrhythmia in patients. For heart rhythm control, catheter ablation is one of the most effective treatments available. It has been proven to significantly improve sinus rhythm maintenance and quality of life in patients with atrial fibrillation in several randomized controlled trials (RCTS). These studies suggest that catheter ablation is the preferred method for rhythm control in patients with paroxysmal AF, with better long-term results than medical treatment.

To comprehensively solve the problem of rhythm control and stroke prevention in patients with atrial fibrillation, the combination of catheter ablation and left atrial ear closure is a feasible and promising treatment strategy. Catheter ablation is designed to restore sinus rhythm by interfering with the triggering mechanism of atrial fibrillation, while left atrial appendage closure reduces stroke risk by isolating the main site of thrombosis. The combination of the two surgical methods not only improves the rate of sinus rhythm maintenance in patients but also significantly reduces the risk of stroke and all-cause death.

At present, the combined application of these two surgeries is gradually increasing in clinical practice. Some studies and expert consensus suggest that combined treatment goals can be achieved through "one-stop surgery" (performing both catheter ablation and left atrial appendage closure in one procedure) or phased surgery (performing one procedure before the other). However, there is no consensus on the optimal surgical sequence. Some studies have shown that "one-stop" surgery may shorten the length of hospital stay, and reduce surgical risks and patients' economic burden in the same period [13]. A phased procedure allows doctors to better evaluate the results after the initial surgery and reduce the overall surgical risk for the patient.

In the consensus of atrial fibrillation management experts in China in 2021, Category Ⅱb recommendation for "one-stop surgery" was proposed, suggesting that for some patients with nonvalvular atrial fibrillation who have indications of both catheter ablation and left atrial artery occlusion, it is reasonable to perform left atrial artery occlusion at the same time of catheter ablation. Despite this, there is currently a lack of trials to verify the safety and effectiveness of different surgical sequences.

Therefore, the purpose of this study was to evaluate the safety and effectiveness of transcranial atrial fibrillation ablation with WATCHMAN FLX 1 month after left atrial appendicular closure, to provide evidence-based medical evidence for optimizing the comprehensive management of patients with atrial fibrillation, and to further explore the optimal combined application strategy of the two surgical methods in patients with nonvalvular atrial fibrillation.

Inclusion Criteria:

1. ≥18 years of age, diagnosed with nonvalvular atrial fibrillation;
2. Meet the indications for receiving WATCHMAN FLX left atrial appendicular closure and transcatheter atrial fibrillation ablation;
3. Preoperative imaging evaluation showed that the anatomical structure of the left atrial appendage was suitable for implantation with the WATCHMAN FLX device;
4. The patient agrees to participate in the study and signs the informed consent.

Exclusion Criteria:

1. valvular heart disease or other structural heart disease that causes atrial fibrillation;
2. left auricular thrombus or acute thrombotic event was found before surgery;
3. Patients with severe bleeding tendency or recent major bleeding events (such as massive gastrointestinal bleeding, cerebral hemorrhage, etc.);
4. Patients who are unable to complete postoperative follow-up (such as life expectancy of less than 1 year or poor compliance);
5. Other serious diseases (such as liver and kidney failure, active infection, etc.) were found in preoperative examination;
6. Pregnant or lactating women.

Diagnosed with symptomatic persistent atrial fibrillation, defined as: inability to spontaneously transition to sinus rhythm, lasting for more than 7 days, resistance or intolerance to at least Class I, II, or III antiarrhythmic drugs.