Feasibility of mapping and ablation of atypical atrial flutter using a lattice-tip catheter toggling between radiofrequency and pulsed field energy

Background Atypical atrial flutter (AAFL) comprises complex macro-reentrant atrial arrhythmias arising from areas of scar or slow conduction following prior ablation, cardiac surgery, or atrial cardiomyopathy. Three-dimensional electroanatomic mapping (3D-EAM) is essential to define these circuits. Purpose To evaluate the feasibility of mapping and ablation of AAFL using a novel high-density 3D-EAM system. Methods We analyzed prospectively collected data on 673 consecutive patients who underwent high-density mapping and ablation between November 2024 and August 2025 with an expandable 9-mm lattice-tip, multipolar, dual-energy catheter. We included patients with AAFL in which activation mapping covered >80% of tachycardia cycle length. Ablation targeted the critical isthmus identified on the activation map. The primary efficacy outcome was defined as termination of the tachycardia at the initial ablation site or within the surrounding area. Secondary efficacy outcomes were procedural success and AFL recurrence during follow-up. Results A total of 65 patients (mean age 71.3±10.3 years, 36.9% female) were included. Most patients had undergone ≥1 previous atrial fibrillation ablation procedures (87.7%). The median AAFL cycle length was 257ms (234–290). Left-sided AAFL was identified in 86.2% of patients. Procedural success was achieved in all procedures (100%), with primary efficacy outcome reached in 79.4% of patients (34.9% at the first lesion, 44.4% within the surrounding area). During a median follow-up of 69 (48.8–116) days, atrial flutter recurrence occurred in 15% of patients, yielding estimated event-free survival rates of 88.3%, 85.1%, and 79.7% at 1, 3, and 6 months, respectively. Conclusion The study results demonstrate the feasibility of this novel system to successfully map and ablate AAFLs.