Background
The optimal ablation strategy for recurrent persistent atrial fibrillation (persAF) after initially successful pulmonary vein isolation (PVI) remains debatable. Dipole density (DD) guided catheter ablation (CA) in patients with persAF using the AcQMap® system has been proven to be feasible and effective. The latter is a non-contact high-resolution mapping system using a single array-shaped catheter providing 48 ultrasound probes and electrodes for 3D anatomy reconstruction and continuous DD mapping, displaying AF wave fronts, and enabling DD guided CA. However, long-term outcome data for DD guided CA in patients with recurrence of persAF is sparse.

Objective
We sought to obtain long-term outcome data in patients undergoing DD guided CA with recurrence of persAF and previous CA. Furthermore, a comparison of DD guided CA to conventional Redo-CA was conducted.

Methods
Long-term freedom from AF and atrial tachycardia (AT) after DD guided CA was obtained by repeated holter ecg and out clinic patient visits. For comparison with conventional Redo-CA using a contact force catheter and 3D-mapping system (ablation extent at operator’s discretion) a pair-matched analysis was performed.

Results
A total of 68 patients (34 DD guided CA and 34 conventional CA) underwent successful repeat CA for recurrence of persAF. After a follow-up of 864±464 days 21% (n=7) of patients after DD guided CA were free of any arrhythmia as compared to 50% (n=17) of patients after conventional CA (HR 1.70; p=0.059). Freedom from AF was 50% (n=17) in the DD group as compared to 68% (n=23) (HR 1.17; p=0.344) in the conventional group. In the DD group AT occurred in 32% (n=11) as opposed to 26% (n=9) (HR 1.20; p=0.530).
For DD guided CA the procedure duration was significantly longer (231±63 vs. 194±58 minutes; p=0.047). Furthermore, the fluoroscopy duration (35.53±14.67 vs. 19.88±10.53 minutes; p<0.0001) and dosage (8195.09±4803.99 vs. 5214.68±4263.85 mGy*cm2; p=0.0034) were significantly higher as compared to conventional CA.

Conclusion
Overall success rates irrespective of the ablation strategy used are modest. A long-term follow-up in patients after successful DD guided CA for recurrence of persAF after previous CA revealed no benefit for AF and AT free survival in comparison to conventional CA. Of note, procedure and fluoroscopy duration as well as dosage for DD guided CA were significantly higher and indicate a higher level of complexity in DD guided procedures.