Comparing pulsed field electroporation and radiofrequency ablation for the treatment of atypical atrial flutter

Introduction Atypical atrial flutter (AAFL) comprises macro–reentrant atrial tachycardias not dependent on the cavotricuspid isthmus, often occurring after prior atrial ablation or in the context of atrial remodeling. Catheter ablation is the cornerstone of definitive rhythm control. High-power short-duration radiofrequency (HPSD-RF) and non-thermal pulsed field ablation (PFA) have recently emerged as novel energy modalities with potential advantages in procedural safety and efficiency. While both have been extensively evaluated in atrial fibrillation, evidence in atypical flutter is limited. This study aimed to compare procedural characteristics, acute efficacy, and mid-term outcomes between PFA and conventional RF ablation for AAFL. Methods This single-center retrospective study included 91 consecutive patients who underwent AAFL ablation between January 2023 and September 2025 (mean age 70 ± 12 years; 46% female). Prior atrial fibrillation ablation had been performed in 42% of patients. All procedures were performed using the CARTO 3D electroanatomical mapping system. Efficacy was defined as arrhythmia termination of atypical flutter during energy delivery. Recurrence was defined as any documented episode of atrial fibrillation or atypical atrial flutter detected on ECG, Holter monitoring, or clinical records during follow-up. Median follow-up duration was 13 months (IQR 6–21). Results Acute procedural success was high and comparable between groups (PFA 84.4% vs. RF 85.5%; p = 0.89). The mean total procedure duration was numerically shorter with PFA (128 ± 165 min) compared with RF (154 ± 140 min), though not statistically significant (mean difference = 26 min; 95% CI –40 to 92; p = 0.44). After multivariate adjustment, no significant difference in procedural duration was observed. Fluoroscopy time was significantly longer with PFA (11.5 ± 6.6 min vs. 7.2 ± 6.2 min; mean difference = 4.3 min; 95% CI 1.3–7.4; p = 0.006), while radiation exposure was similar (PFA 154 ± 121 mGy vs. RF 127 ± 150 mGy; p = 0.45). During follow-up, arrhythmia recurrence occurred in 13 (23.6%) RF and 12 (37.5%) PFA patients (p = 0.17). Median time to recurrence was 332 days (IQR 128–447) for RF and 193 days (IQR 27–352) for PFA (p = 0.15), showing a non-significant trend toward earlier recurrence with PFA. One case of pericardial tamponade occurred in the RF group, successfully managed percutaneously. No deaths, stroke, or persistent phrenic nerve injury were observed. Conclusion Both PFA and RF ablation achieved high acute success and favorable safety profiles in the treatment of AAFL. Despite modest differences in procedural and fluoroscopic parameters, clinical outcomes were comparable. These findings support the feasibility and safety of PFA as an alternative energy source for complex atrial tachycardia ablation, while highlighting the need for larger prospective studies to validate long-term efficacy and optimize lesion delivery strategies.