A new study published in JAMA Network suggests that a combined approach of pulmonary vein isolation (PVI) with linear ablation and ethanol infusion via the vein of Marshall (EIVOM) can significantly improve outcomes for patients with persistent atrial fibrillation (AF). The PROMPT-AF trial, a multicenter, open-label, randomized trial conducted across 12 hospitals in China, found that this combined strategy led to a higher rate of freedom from atrial arrhythmia recurrence compared to PVI alone.
The study enrolled 498 patients aged 18 to 80 years with persistent AF lasting more than three months, all undergoing first-time AF ablation. Patients were randomized to either PVI alone or PVI plus EIVOM and linear ablation of the left atrial roof, mitral isthmus, and cavotricuspid isthmus. The primary outcome was freedom from documented atrial arrhythmias lasting more than 30 seconds without antiarrhythmic drugs within 12 months.
Key Findings of the PROMPT-AF Trial
After 12 months, 70.7% of patients in the PVI plus EIVOM and linear ablation group remained free from atrial arrhythmias without antiarrhythmic drugs, compared to 61.5% in the PVI alone group (hazard ratio, 0.73; 95% CI, 0.54-0.99, P = .045). This improvement was consistent across all pre-specified subgroups. However, the study did not demonstrate significant differences in secondary outcomes, such as freedom from atrial arrhythmia recurrence with or without antiarrhythmic drugs.
"The PROMPT-AF trial is the first randomized study to demonstrate that a linear ablation strategy including EIVOM in addition to PVI significantly reduced atrial arrhythmia recurrence compared with PVI alone," the authors stated. The study highlights the potential benefits of EIVOM in improving the durability of mitral isthmus lesions, which has been a challenge in previous ablation strategies.
Addressing the Challenges in Persistent AF Ablation
Pulmonary vein isolation (PVI) has been the cornerstone of catheter ablation for atrial fibrillation (AF). However, PVI alone is less effective for persistent AF compared with paroxysmal AF. Additional linear ablation beyond PVI has not been proved superior to PVI alone in randomized trials. Ethanol infusion of the vein of Marshall (EIVOM) facilitates ablation at the mitral isthmus and may lead to improved effectiveness of a linear ablation strategy.
Procedural Details and Safety
The combination of linear ablation plus EIVOM was associated with a longer mean procedure time (188.0 vs 140.8 minutes, P < .001) and fluoroscopy time (15.9 vs 5.1 minutes, P < .001). Bilateral PVI was successfully achieved in almost all patients in both groups. While the overall incidence of procedural-related adverse events was not significantly different between the groups (P = .15), pericarditis or pericardial effusion occurred in 7 patients in the intervention group compared to none in the PVI alone group.
Implications for Clinical Practice
The study suggests that linear ablation combined with EIVOM offers an additional benefit in rhythm outcomes for the ablation of persistent AF. According to the authors, achieving mitral isthmus block remains a significant challenge despite optimal contact force sensing and power settings. The use of EIVOM not only abolishes epicardial conduction but also facilitates mitral isthmus ablation by creating chemical lesions in the mid to distal mitral isthmus where reconnections are most prevalent, thereby reinforces the durability of mitral isthmus lesions.
Limitations and Future Directions
The study acknowledges several limitations, including the use of single-lead ECG patches for rhythm monitoring, which may underestimate atrial arrhythmia recurrence compared to implantable loop recorders. Additionally, the trial exclusively included patients with persistent AF lasting longer than 3 months, limiting the generalizability to those with shorter episodes.
Despite these limitations, the PROMPT-AF trial provides compelling evidence for the efficacy of a combined ablation strategy in patients with persistent AF. Further research, including the ongoing Marshall-PLAN trial (NCT04681872) and investigations into pulsed field ablation, may offer additional insights and refinements to this approach.
