PO-01-192 USE OF A LARGE-FOOTPRINT FOCAL LATTICE CATHETER FOR MAPPING AND ABLATION OF ATRIAL FLUTTERS

Catheter ablation of atrial flutters (AFL), in particular atypical (ie non-cavotricupid isthmus dependent) AFL, can be eliminated with high-density electroanatomical mapping using multielectrode catheters used in concert with radiofrequency ablation (RFA). However, this requires 2 separate complex catheters: for mapping and for ablation. Further challenges include difficulties in establishing durable block across the isthmus of identified circuits, in particular (but not exclusively) the mitral isthmus. Recently, a large footprint lattice-tip catheter (Sphere-9, Affera-Medtronic Inc.) has been developed capable of both delivering either pulsed field (PF) energy or high-power RF energy, and performing high-density mapping using mini-electrodes located throughout the lattice-tip. To determine the feasibility and efficacy, both acute and chronic, of mapping and ablation of AFL using the lattice-tip catheter. As part of a 3-center, single-arm, first-in-human study of AF ablation with the lattice-tip catheter (NCT04141007, NCT04194307), spontaneous or induced AFLs were mapped and ablated using the lattice-tip catheter, in conjunction with a compatible mapping-system. The 7Fr lattice-tip catheter has a compressible 9-mm nitinol tip with 9 embedded mini-electrodes, and is able to deliver either RF or PF energy (each lesion 2-5 sec). During AF ablation in the 178-pt cohort (39% paroxysmal, 61% persistent), AFL was identified in 47 (26%) pts. This included typical AFL in 22 (12%) pts, peri-mitral AFL in 17 (10%) and other AFLs in 26 (15%). Mapping of the AFL circuits was performed exclusively using the lattice catheter. Cavo-tricuspid isthmus (CTI), LA roof, and mitral isthmus lines were targeted in 94%, 83%, and 70% of patients in whom AFLs were identified (some flutters were not targeted flutters if not considered clinically-relevant). Bidirectional conduction block was achieved in all (100%) of attempted lines. Over a 12-month follow-up, 37 of 47 pts (79%) were free from AFL recurrence. Atrial flutters are noted in a substantial number of patients undergoing catheter ablation of atrial fibrillation. The flexibility of a large-tip focal lattice catheter allows for facile post-PVI mapping and ablation of such flutters, while minimizing the need for additional equipment and catheter exchanges. Ablation using either RF or PF energy resulted in successful block across attempted linear lesions and excellent long-term success.