A Lattice-Tip Temperature-Controlled Radiofrequency Ablation Catheter for Wide Thermal Lesions

This study sought to evaluate the safety and acute performance of the lattice tip for the treatment of atrial flutter and fibrillation (AF). A novel catheter using an expandable lattice structure with a wide thermal footprint incorporating multiple surface thermocouples/mini-electrodes has been designed for high-resolution mapping and high-current, temperature-controlled radiofrequency ablation (RFA). Patients with typical right atrial flutter or AF were prospectively enrolled in a single-arm study at 3 centers. Patients with atrial flutter underwent cavotricuspid isthmus (CTI) ablation. Patients with paroxysmal AF underwent pulmonary vein isolation (PVI) and CTI if desired, and for patients with persistent AF, mitral isthmus and left atrial roof lines were also permitted. Mapping was performed with the lattice (Sphere-9) catheter and a novel compatible electroanatomic mapping system (Prism-1). RFA was performed in a point-by-point fashion (Tmax, 73°C to 80°C; range 2 to 7 s). Patients were followed for 3 months. A total of 71 patients underwent ablation: 65 PVI (38% with persistent AF) and 22 mitral isthmus, 24 roof, and 48 CTI lines. PVI was achieved in 64 of 65 (98.5%) by using the lattice alone and required a mean of 2.7 ± 0.70 RFA min. Mitral block was achieved in 100% by using 11.5 ± 10.7 applications and 1.0 ± 0.92 RFA min; only 1 patient required adjunctive epicardial coronary sinus ablation. Roof line and CTI block were achieved in 95.8% and 100% of patients, using 4.9 ± 1.9 and 5.9 ± 3.1 applications for 0.4 ± 0.16 and 0.5 ± 0.24 RFA min, respectively. At 3 months, there were no deaths, strokes, tamponade, or atrioesophageal fistula. This first-in-human study demonstrated clinical feasibility and safety for rapid high-current, temperature-controlled point-by-point PVI and linear ablation.