Background: Atrial fibrillation (AF) is a complex arrhythmia and a leading cause of cardiovascular morbidity. Pulmonary vein isolation (PVI) is the mainstay therapy for paroxysmal atrial fibrillation (PAF). Although triggers from the pulmonary veins (PV) are encountered in up to 90% of patients undergoing PVI, the long-term outcome of a PVI-only strategy differs significantly between PAF and persistent atrial fibrillation (PeAF). Despite the lack of data from randomized trials comparing ablation strategies for PeAF, current guidelines suggest that adjuvant substrate modification should be considered in addition to PVI. However, recommendations as to suitable ablation approaches are vague. 

Objective: Morphology analysis and identification of the spatial distribution of non-PV AF drivers were obtained using a new non-contact unipolar high-resolution system deployed by a basket catheter with 48 ultrasounds transducers for 3D anatomy reconstruction and 48 electrodes enabling continuous dipole density mapping. 

Methods: Single-center analysis from 41 patients with persistent and long-standing persistent AF submitted to a novel noncontact dipole density mapping PVI approach (27 Redo-PVI patients); among them 6 Patients were excluded (without extra-PV triggers). 

 Three different wave front patterns were analyzed in left atrium (LA): 1) focal activity (FA), 2) localized rotational activation (LRA) and 3) localized irregular activation (LIA). Individualized Ablation strategy was performed with PVI followed by core ablation lesions and “anchored” to the nearest nonconduction boundary.  

Table 1: Baseline Characteristics

Results:  

A total of 157 patterns were identified prior to PVI, among them 58 FA, 43 LRA and 56 LIA. The posterior wall (n=55), anterior wall (n=55), septum (n=9) and roof (n=38). Ablation of all AF drivers were achieved in 22 Patients. Using the ablation approach, an anterior line, anteroseptal line or roof line ablation was performed in 20 patients. 

Conclusions: Analysis of such spatial distribution and morphology of AF drivers can help to understand AF mechanisms and subsequently guide extra-PVI adjuvant ablation strategies.