Pulsed-Field Ablation vs. Radiofrequency Ablation CombIned With Vein of Marshall Ethanol Ablation on Mitral Isthmus Block and Clinical Outcomes in Persistent Atrial Fibrillation

Pulsed-Field Ablation vs. Radiofrequency Ablation CombIned With Vein of Marshall Ethanol Ablation on Mitral Isthmus Block and Clinical Outcomes in Persistent Atrial Fibrillation: The PRIME-AF Randomized Clinical Trial

Atrial fibrillation (AF) is one of the most common clinical arrhythmias, and catheter ablation serves as a critical therapeutic approach. For persistent atrial fibrillation, several proposed ablation strategies-including the 2C3L technique, BOX lesion sets, and substrate modification-remain highly controversial regarding long-term success rates. Multiple studies suggest that linear ablation beyond pulmonary vein isolation (PVI) often fails to achieve durable block due to incomplete ablation lines, which significantly contributes to postoperative recurrence of atrial arrhythmias.

In recent years, electrophysiologists have explored various methods to improve mitral isthmus (MI) ablation, such as combined endo-epicardial ablation and radiofrequency ablation (RFA) combined with Marshall vein alcohol ablation. While RFA combined with anhydrous alcohol injection into the Marshall vein enhances MI block rates, it is associated with prolonged procedure time, unpredictable ablation zones, and higher complication risks (e.g., coronary artery spasm, pericarditis).

Pulsed field ablation (PFA), an emerging non-thermal ablation technology, offers potential advantages such as tissue selectivity, shorter procedure time, and fewer complications. Studies report that RFA achieves near 100% immediate block rates; however, there is a lack of sufficient comparative studies on the efficacy and safety between these two ablation approaches. This study aims to compare the clinical outcomes and safety profiles of PFA versus RFA combined with Marshall vein alcohol injection in patients with persistent AF.

Inclusion Criteria:

1. Persistent atrial fibrillation;
2. Ejection fraction >30%;
3. NYHA functional class I-III;
4. Left atrial diameter <55 mm on echocardiography;
5. Signed informed consent form;

Exclusion Criteria:

1. Pregnant or lactating women;
2. Patients with a life expectancy of less than 2 years due to non-cardiovascular factors;
3. Uncontrolled hyperthyroidism, severe liver or kidney dysfunction;
4. History of atrial fibrillation ablation;
5. History of heart transplantation, complex congenital heart disease, or rheumatic heart disease;
6. Contraindications to contrast agents, radiofrequency ablation, antiarrhythmic drugs, or anticoagulants;
7. Acute coronary syndrome, cardiac surgery, angioplasty, or cerebrovascular 8.accident within 12 weeks prior to enrollment;

9.Other conditions deemed unsuitable for participation by investigators; 10.Participation in other clinical trials.