B-PO05-093 VALIDATION OF A NEW ABLATION INDEX PROTOCOL FOR LEFT ATRIAL LINEAR ABLATION

Abstract

Standardized contiguous and optimized radiofrequency ablation encircling ipsilateral pulmonary veins (PV) with high incidence of first-pass isolation has been established with the CLOSE protocol. In this study, we evaluated the acute outcome of a specific ablation index protocol for left atrial (LA) linear ablation. This prospective study comprised 81 patients (age: 67±14 y, male: 52 %) undergoing de-novo ablation for persistent atrial fibrillation (AF) or patients requiring substrate ablation beyond PV isolation. We hypothesized that point-by-point ablation with an ablation index of 600 for the anterior line and 500 for the roof line and an interlesion distance <6mm will result in a high rate of first-pass block. Touch-up ablation was performed in case of incomplete line block. Line integrity was evaluated with a high-density mapping catheter (Pentaray) and the coherent activation mapping tool (CARTO3 V7) during LAA pacing and differential pacing maneuver. First-pass block of the roof line was achieved in 70 (92 %) patients, while another 5 (7 %) patients required additional touch-up ablation to complete the line, resulting in a total of 75 (99 %) blocked roof lines. A first-pass anterior line block was observed in 47 (69 %) patients. An additional 17 (25 %) patients required touch-up ablation for block achievement, resulting in a total of 64 (94 %) blocked anterior lines. For the anterior line, the Bachmann bundle insertion was identified as the predominant location of gaps. The mean ablation index of roof line ablation was 512±14 and 610±13 in anterior line ablation. The mean overall procedure and fluoroscopy time was 136±30 min and 7.2±3.8 min, respectively. The mean RF ablation time for roof line was 8±5.4 min and for anterior line 14±5.9 min. Baseline rhythm was AF in 46 patients, which terminated by linear ablation in 19 (41%) patients. This new standardized Ablation Index protocol accomplishes first-pass block of left atrial linear lesions in the vast majority of patients. Furthermore, with additional touch-up ablation at gap sites, line block was achieved in almost all patients.