Pulmonary Vein Isolation (PVI)-Only Group

1. Pulmonary vein isolation (PVI) will be performed, and the procedure will be terminated without the administration of isoproterenol following the standard waiting period.
2. In cases where spontaneous triggers are observed following PVI, mapping and ablation of the identified triggers are permitted.
3. Post-procedural rhythm monitoring and follow-up will be conducted in accordance with the predefined study protocol.

Additional Non-Pulmonary Vein (Non-PV) Trigger Ablation Group

Isoproterenol will be administered starting at 5 μg/min, with stepwise increases to 10 μg/min and 20 μg/min at 3-5 minute intervals, as tolerated, aiming to achieve 85% of the maximum predicted heart rate, with a maximum dose of 30 μg/min.The total infusion duration will be at least 10 minutes.

• If systolic blood pressure (SBP) decreases by ≥20 mmHg from the baseline (prior to infusion), the isoproterenol infusion will be discontinued.
• If hypotension is anticipated or occurs during isoproterenol infusion, phenylephrine infusion may be administered to maintain SBP between 120-140 mmHg.
• For patients with a history of coronary artery disease, heart failure, or valvular heart disease, the maximum isoproterenol infusion rate may be limited to ≤10 μg/min at the discretion of the operator.

"A. Essential Standard Pre-Procedural Examinations for Catheter Ablation

• Transthoracic Echocardiography (TTE): Performed in all patients to evaluate the presence of structural heart disease, left atrial size, and left ventricular function. Findings guide the selection of antiarrhythmic medications and assist in determining procedural indications.
• Transesophageal or Intracardiac Echocardiography: Conducted in all patients prior to the procedure to detect thrombi within the left atrial appendage, thereby minimizing the risk of post-procedural cerebrovascular events.
• Three-Dimensional Cardiac CT Imaging (substitutable with Cardiac Magnetic Resonance Imaging if clinically indicated): Performed in all patients before the procedure to generate a three-dimensional anatomical model of the left atrium by integrating voltage mapping and contour data from CT images. This approach enhances procedural accuracy and reduces the incidence of procedure-related complications.
• The most recent test results prior to the procedure should be utilized preferentially; in the absence of recent data, prior examination results may be used as substitutes.

B. Administration of Medications Before and After Catheter Ablation

• Anticoagulant therapy will be administered for a period of one month prior to and for a minimum of two months following the catheter ablation procedure, in order to reduce the risk of thromboembolic events, including stroke. Should the risk of stroke remain elevated due to atrial fibrillation recurrence or other clinical considerations, continuation of anticoagulation therapy may be determined at the discretion of the treating physician.
• In cases where recurrence of atrial fibrillation is suspected, or if there is a clinically assessed high likelihood of recurrence, antiarrhythmic medications may be prescribed based on the clinical judgment of the physician.

Inclusion Criteria:

• Patients aged ≥19 years with persistent atrial fibrillation scheduled for catheter ablation.
• Refractory to or intolerant of at least one Class I or III antiarrhythmic drug.
• Undergoing first-time catheter ablation for atrial fibrillation.

Exclusion Criteria:

• Acute coronary syndrome within the past 3 months.
• Severe unrevascularized coronary artery disease: ≥70% stenosis in at least one major epicardial vessel with a diameter ≥2 mm.
• History of stroke or transient ischemic attack (TIA) within the past 3 months.
• Uncontrolled severe hypertension (systolic blood pressure ≥180 mmHg or diastolic blood pressure ≥120 mmHg).
• Severe untreated aortic valve stenosis.
• Symptomatic moderate-to-severe valvular heart disease.
• Aortic dissection.
• Heart failure with reduced ejection fraction (LVEF <40%).
• Severe pulmonary hypertension (resting RVSP >60 mmHg).
• Left atrial anteroposterior diameter >60 mm.
• Presence of cyanotic congenital heart disease.
• Obstructive hypertrophic cardiomyopathy (resting or provoked LVOT pressure gradient ≥30 mmHg).
• History of prior maze surgery or catheter ablation for atrial fibrillation.
• Active internal bleeding.
• Contraindications to anticoagulation therapy or rhythm control treatment.
• Presence of severe comorbid conditions or life expectancy <1 year.
• Drug or alcohol abuse.
• Pregnancy.
• Any other condition that, in the investigator's judgment, makes the patient unsuitable for study participation.