Total isolation of the pulmonary veins still remains the cornerstone of catheter ablation for atrial fibrillation. However, only 50-60% of patients maintain sinus rhythm after two years. Various trials of alternative ablation strategies have not shown any superior results compared to pulmonary vein isolation (PVI). Now, a new study discovered that an innovative three-step ablation approach comprising ethanol infusion of the vein of Marshall provides greater freedom from arrhythmias in patients with persistent atrial fibrillation compared to PVI alone.

The Marshall-Plan ablation strategy involves: 1) PVI; 2) ethanol infusion of the vein of Marshall; and 3) a linear ablation set to block the three main anatomical isthmuses to the pulmonary veins (dome, mitral and cavotricuspid isthmus lines). This technique targets anatomical areas that are individually recognized as significant for initiating or maintaining atrial fibrillation, but have not been systematically addressed collectively. Investigators at University Hospital of Bordeaux (Bordeaux, France) had previously reported encouraging results from the use of this strategy in non-randomized studies. The current study compared the 12-month arrhythmia-free survival rate using the Marshall-Plan ablation strategy versus PVI only. This prospective, randomized, parallel group trial aimed to demonstrate superiority. The trial included 120 patients with symptomatic persistent atrial fibrillation lasting over a month. Participants had an average age of 67 years, with 21 (18%) being women.

Participants were randomly assigned to receive either the Marshall-Plan or PVI alone. They were followed up at 3, 6, 9, and 12 months, during which they underwent various tests including electrocardiograms (ECGs), echocardiography, stress tests, and 24-hour Holter monitoring. Recurrence of arrhythmias was detected using ECG teletransmission, with results sent to the hospital weekly and any time the patient experienced symptoms. The primary endpoint was the recurrence of atrial fibrillation or atrial tachycardia lasting over 30 seconds at 12 months (including a 3-month blanking period) after a single ablation procedure. Preliminary results at 10 months are presented, with follow-up ongoing until 12 months.

The total radiofrequency time was significantly longer in the PVI group (29 minutes) compared to the Marshall-Plan group (23 minutes; p<0.001). The complete lesion set was successfully achieved in 53 patients (88%) receiving the Marshall-Plan and 59 patients (98%) receiving PVI only. In an intention-to-treat analysis, arrhythmia recurrence after an average follow-up of 10 months was significantly higher in the PVI group compared to the Marshall-Plan group (18 vs. 8 patients? p=0.026).

“After 10 months of follow up, the success rate in the Marshall-Plan group was significantly better (87%) compared to the PVI only group (70%),” said principal investigator Dr. Nicolas Derval of the University Hospital of Bordeaux. “However, the results are still preliminary as follow up is not completed for all patients. While the findings indicate that the Marshall-Plan strategy holds promise for patients with persistent atrial fibrillation, they need to be confirmed in a multicentre trial.” 

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