Is PFA ready for atypical atrial flutter?

Background Pulsed field ablation (PFA) has emerged as a non-thermal modality with high tissue selectivity and favorable acute safety in the treatment of atypical atrial flutter (AAF). Although PFA is hypothesized to improve acute procedural outcomes due to its rapid and homogeneous lesion formation, its long-term performance compared with radiofrequency (RF) ablation remains uncertain. Experimental and clinical observations suggest that reduced acute collateral and myocardial injury with PFA may paradoxically lead to incomplete substrate modification and higher arrhythmic recurrence over time. Methods We retrospectively analyzed 98 consecutive patients who underwent catheter ablation for AAF between January 2023 and September 2025. Baseline characteristics included age, sex, CHA2DS2-VASc score, LVEF, CT-derived left atrial volume index (LAVI), and history of prior AF ablation. Patients were treated with RF (n=60, 61%), PFA (n=35, 36%), or a combination of both (n=3, 3%). Acute success was defined as termination of the clinical flutter during ablation and non-inducibility of atrial arrhythmias at the end of the procedure. Long-term recurrence was defined as documented AAF or AF on ECG or Holter monitoring during follow-up. Median follow-up was 13 (6-21) months. Results Mean age was 69 ± 13 years, 47% were female, the mean CHA2DS2-VASc score was 3 ± 1, and the CT-LAVI was 67 ± 20 mL/m². Regarding ablation lesion sets, 33% of lines were delivered for pulmonary vein isolation, 24% targeted the posterior wall, 27% corresponded to a mitral isthmus line, and 16% were performed at other atrial sites. Acute procedural success was numerically higher with PFA compared with RF (90% vs 83%), although this difference did not reach statistical significance (p = 0.397). Of the total procedures, 24 (24,5%) were redo radiofrequency ablations. During follow-up, the outcome of interest occurred in 34 (34,7%) patients. In the mid-term, PFA was independently associated with a significantly higher risk of arrhythmia recurrence compared with RF (HR 2.62, 95% CI 1.31–5.26, p = 0.007). Conclusions In this contemporary cohort of AAF, approximately one-third of patients experienced arrhythmia recurrence. Although acute success was numerically higher with PFA, mid-term recurrence rates were greater in this group. This pattern may reflect the reversible or retractile characteristics of acute PFA lesions, which could limit long-term substrate modification. These results highlight the need to refine PFA lesion strategies in complex atrial arrhythmias and underscore the importance of prospective evaluation of long-term lesion durability.