Systematic replication of the Marshall-PLAN lesion set using two commercially-available PFA systems: a prospective feasibility analysis

A strategy of systematic Marshall bundle elimination, PVI, and linear ablation (the Marshall-PLAN) has shown promise in improving the outcomes of patients undergoing ablation for persistent AF. Concomitant with development of this strategy has been widespread adoption of PFA. To date, no study has systematically attempted replication of the Marshall-PLAN lesion set using PFA in patients with persistent AF.

To assess the feasibility of systematically replicating the left atrial Marshall-PLAN lesion set (PVI, roofline, and mitral isthmus line) using two commercially-available PFA systems.

30 patients referred for de novo ablation of persistent AF were recruited, the first 20 completed using the Farapulse, and the subsequent 10 using the Affera. All patients received PVI, roofline and endocardial mitral isthmus line using PFA, rigorous evaluation of the lesion set using high-density mapping and differential pacing, followed by adjunctive Vein of Marshall (VOM) ethanol infusion, CS ablation, and/or RF ablation to complete the lesion set if necessary. CTI ablation was performed in case of documented common flutter.

Patients were 83% male, aged 61±10 years, with mean BMI of 32±7. Mean CHADSVASc score was 3±2, mean LVEF 50±13%, and mean LAVi 46±16ml/m2, with 73% receiving antiarrhythmic therapy. There were no significant between-group differences.

The lesion set was completed in all 30 patients, but success of PFA alone was only 10% with Farapulse, improving to 70% with Affera. All patients had successful PVI with PFA alone. One patient in the Affera group required adjunctive RF ablation to block the roofline, and although one in the Farapulse group required an additional floor line this was completed without the need for RF ablation. Only 10% of patients in the Farapulse group had mitral isthmus block after endocardial PFA, increased to 40% with the addition of VOM ethanol infusion, 70% with RF ablation in the CS, and 100% with additional endocardial RF ablation. 30% of patients in the Affera group had mitral isthmus block after endocardial PFA, 80% following additional CS PFA, and 100% with the addition of VOM ethanol infusion.

Procedure time was similar between groups (Farapulse 168±39min vs Affera 149±33min, P=0.19). The only major complication was RCA vasospasm culminating in VF during PFA of the CTI using the Affera in one patient.

Replicating the left atrial lesion set of the Marshall-PLAN using PFA is possible, although generating mitral isthmus block using PFA alone is particularly challenging using the Farapulse and adjunctive VOM ethanol infusion and/or RF ablation are required in the vast majority. The Affera system will generate a complete lesion set in the majority, with adjunctive VOM ethanol infusion achieving mitral isthmus block in the remainder.