The goal of this clinical trial is to investigate the efficacy and safety of Qidong Yixin Granules in preventing recurrence in patients after radiofrequency catheter ablation for atrial fibrillation. The main question it aims to answer is:

Can Qidong Yixin Granules reduce the recurrence rate of atrial fibrillation within 1 year in patients undergoing radiofrequency catheter ablation for atrial fibrillation?

Participants will be randomly assigned, with a 50% chance of being allocated to either the study group or the control group. Regardless of which group a participant is assigned to, researchers will administer Qidong Yixin Granules or placebo within 48 hours after catheter ablation for atrial fibrillation. Group assignment is determined by computer-generated randomization, and no individual has the authority to interfere with the allocation result.

If a participant is assigned to the study group, they will receive oral Qidong Yixin Granules after atrial fibrillation ablation: one sachet each time, three times daily, for a 12-month treatment course.

If a participant is assigned to the control group, they will receive oral placebo matching Qidong Yixin Granules after atrial fibrillation ablation: one sachet each time, three times daily, for a 12-month treatment course.

Regardless of the group assignment, all participants will attend outpatient follow-up at 1, 3, 6, 9, and 12 months postoperatively. Electrocardiography (ECG) and ambulatory electrocardiography (Holter monitoring) will be performed at 1, 3, 6, and 12 months after surgery. Transthoracic echocardiography will be conducted at 3 and 12 months postoperatively. Anticoagulation will be administered for at least 3 months after surgery, and subsequent anticoagulation strategies will be determined based on the CHA₂DS₂-VASc score.

Inclusion Criteria:

• Age 18-80 years (inclusive);
• Diagnosed with non-valvular persistent atrial fibrillation, having failed at least one antiarrhythmic drug treatment, and scheduled to undergo initial ablation;
• Voluntarily participate in this study and sign an informed consent form. If the subject is unable to read or sign the informed consent form due to reasons such as lack of capacity, the informed consent process must be completed and signed by their legal guardian. If the subject is unable to read the informed consent form (e.g., illiterate subjects), the informed consent process must be witnessed and signed by a witness.

Exclusion Criteria:

• Valvular atrial fibrillation or paroxysmal atrial fibrillation
• NYHA functional class IV or LVEF <40%, LA diameter >55mm;
• Moderate to severe left ventricular hypertrophy (wall thickness >1.5cm);
• Patients with acute coronary syndrome or requiring stent implantation
• Patients with a history of cardiac surgery within the past 6 months or previous catheter ablation
• Duration of atrial fibrillation ≥5 years;
• Hyperthyroidism;
• Patients with atrial fibrillation and cardiomyopathy;
• Patients with bradyarrhythmia requiring pacemaker implantation
• Known bleeding diathesis, presence of left atrial/left atrial appendage thrombus, or severe hemostasis and coagulation dysfunction
• Severe hepatic or renal insufficiency ALT ≥3 × ULN or eGFR <45 ml/min/1.73 m²;
• Patients allergic to the components of the study drug;
• Patients who are currently participating or have participated in other interventional clinical studies within the past 3 months.
• Pregnant or lactating women, or those with an expected lifespan of <12 months;
• Other vulnerable groups, excluding the elderly/illiterate individuals, including those with mental illnesses, cognitive impairments, critically ill patients, etc
• Any other reasons deemed by the investigator as unsuitable for the patient's participation in this study