Lattice-tip vs. standard irrigated focal-tip catheter for radiofrequency ablation of the cavotricuspid isthmus - the LINEAR randomized trial

AIMS: Cavotricuspid isthmus (CTI) ablation is a cornerstone therapy for typical atrial flutter (AFl) and is commonly performed during atrial fibrillation (AF) ablation. In this multicentre randomized trial, we compared a lattice-tip catheter with an irrigated focal-tip catheter for radiofrequency CTI ablation (LINEAR study-ClinicalTrials.gov NCT07078760). METHODS AND RESULTS: Patients were randomized to a lattice-tip, dual-energy catheter (lattice-tip group) or to a standard 3.5-mm irrigated radiofrequency catheter (standard group) in two centres. In the lattice-tip group, only radiofrequency was utilized. The primary endpoint was the achievement and persistence of bidirectional CTI block after a 60-minute waiting period, confirmed by high-density electroanatomical mapping and adenosine testing. Secondary endpoints included the rate of first-pass block, the number of lesions, and the ablation time. Procedural complications were recorded. In total, 102 patients were randomized. The primary endpoint was achieved in significantly more patients in the lattice-tip as compared to the standard group (94.1% vs. 68.6%, P = 0.002). The lattice-tip catheter resulted in a significantly higher rate of first-pass block (90.2% vs. 60.8%, P = 0.001). CTI block required significantly shorter ablation time (41.3 ± 12.1 vs. 245.3 ± 91.3 s, P < 0.001) and a significantly lower number of lesions (8.3 ± 2.4 vs. 13.4 ± 4.5, P < 0.001) in the lattice-tip as compared to the standard group. No procedural complications were documented. CONCLUSION: The lattice tip catheter resulted in higher acute procedural success for radiofrequency CTI ablation compared to the standard irrigated focal-tip catheter. Future studies are needed to assess long-term efficacy and clinical outcomes.