Ablation of atypical flutter using a dual-energy lattice-tip focal catheter and integrated mapping system: Addressing target tissue-form factor mismatch.

BACKGROUND: Ablation of persistent atrial fibrillation and atypical atrial flutter (AAFL) is limited by the durability of pulmonary vein isolation, progression of underlying atrial myopathy, and incomplete formation of linear and focal lesions from radiofrequency energy. Tissue characteristics and proximity to vulnerable tissue such as the esophagus and phrenic nerve play a role. Herein, we demonstrate that a focal form factor with dual-energy capability using predominantly pulsed field ablation (PFA) and integrated high-density mapping can yield improved results for complex AAFL circuits. METHODS: We analyzed data from consecutive patients at Minneapolis Heart Institute who underwent de novo or repeat ablations for AAFL or persistent atrial fibrillation between January and June 2025. Ablation was performed in all patients using the Affera (Medtronic) ablation system with the Sphere 9 dual-energy lattice tip focal form factor. Patients were followed for up to 6 months. RESULTS: Our cohort included 209 patients treated with Affera, of whom 74 patients (median age 72 [62,78], 55% male, and 99% Caucasian) underwent ablation for persistent atrial fibrillation or atypical atrial flutter. The mean procedural time was 94 min, with a median fluoroscopy time of 2.5 (0.0, 5.5) minutes and a median fluoroscopy dose of 3 (0,13) mGy. Acute procedural success was achieved in 99% of patients. No major cardiovascular and cerebrovascular events were reported within 30 days after the procedure. More than 80% of patients remained in sinus rhythm during a 6-month follow-up period. CONCLUSIONS: A significant percentage of patients presenting for ablation with the Affera system who had persistent atrial fibrillation or underwent repeat ablation demonstrated AAFL circuits. Sphere 9 is the first FDA-approved focal catheter with PFA capability for persistent atrial fibrillation, and our analysis of the Sphere 9 catheter with Affera in complex atrial flutter cases demonstrates safety, efficacy, and efficiency that may improve long-term outcomes in patients with complex atrial arrhythmias.