Comparison of Catheter Plus Marshall Vein Ablation vs. Catheter Ablation Alone in Persistent AF With Heart Failure

Inclusion Criteria: 1. Age between 18 and 80 years 2. For symptomatic patients with persistent atrial fibrillation: At least a 6-month history of atrial fibrillation; atrial fibrillation duration exceeding 7 days without spontaneous conversion to sinus rhythm; at least two episodes of persistent atrial fibrillation in the past 6 months even after rhythm conversion; poor tolerance or resistance to at least one Class I, II, or III antiarrhythmic drug 3. Diagnosed with heart failure: Echocardiogram showing left ventricular ejection fraction (LVEF) ≤40% 4. Patient willing to receive medication or surgical treatment 5. Patient willing to comply with the requirements before the study, during the study, and during follow-up and to sign an informed consent form 6. Capable of completing a 6-minute walk test 7. For women of childbearing potential, a negative pregnancy test result is required Exclusion Criteria: 1. Presence of thrombus in the left atrium 2. Left atrial diameter greater than 65 millimeters in the parasternal long-axis view, or left atrial volume exceeding 200 milliliters as measured by MRI or CT 3. Presence of significant congenital abnormalities or medical issues, deemed by the researcher as inappropriate for participation in the study 4. Reversible causes of atrial fibrillation, such as pericarditis, thyroid disease, acute alcohol intoxication, recent major surgery, or trauma 5. Currently suffering from valvular heart disease requiring surgical intervention 6. Currently suffering from coronary artery disease requiring surgical or percutaneous intervention 7. History of atrioventricular node ablation 8. Liver failure 9. Renal failure requiring dialysis 10. Contraindicated use of appropriate anticoagulation therapy 11. Participation in other experimental drug or device studies 12. Severe pulmonary disease 13. Previous catheter ablation for atrial fibrillation in the left atrium 14. Documented thromboembolic event within the past 90 days 15. Pregnant women