Safety and feasibility of focal-bipolar pulsed field ablation for therapy of cavotricuspid isthmus-dependent atrial flutter

Background Cavotricuspid isthmus (CTI) ablation is the cornerstone of catheter ablation for typical atrial flutter (AFL). Pulsed field ablation (PFA) has emerged as an alternative therapy for AFL. However, ablation with currently available PFA systems at the CTI carries a notable risk of coronary artery spasm, particularly due to proximity to the right coronary artery, which can lead to severe procedural complications. Purpose To assess the safety and procedural efficacy of a novel focal-bipolar PFA system for CTI ablation, with a primary focus on the occurrence of coronary artery spasm. Methods This single-center observational study enrolled consecutive patients undergoing catheter ablation for AFL with CTI line completion using a novel focal-bipolar PFA system. Inclusion criterium was symptomatic typical AFL refractory to antiarrhythmic drugs. Bidirectional CTI block was confirmed via differential pacing and/or CTI non-excitability at high-output pacing (20mA/2ms). Procedural data, including total procedure time, fluoroscopy time, and number of PFA applications, were recorded. Safety endpoints included the absence of coronary spasm or ST-segment changes requiring intervention, pericardial effusion, and other periprocedural adverse events. Prophylactic nitroglycerine bolus (1mg) before PFA was administered in all patients. Results A total of 78 patients (mean age 66±9 years; 63% male) underwent CTI ablation with focal-bipolar PFA. The mean procedure duration was 28 ± 9 minutes, and the applied voltage ranged from 1400 to 2000 V. The mean number of PFA applications per patient was 15 ± 9. Additional radiofrequency applications were performed in 12 patients (15%), with a mean RF time of 65 ± 34 s and a mean power of 34 ± 12 W. Acute bidirectional block was achieved in 100% of cases, including those requiring supplementary RF ablation. No coronary artery spasm or ST-segment changes requiring intervention were observed. No tamponade, stroke, or major bleeding occurred during the procedures. Conclusion Focal-bipolar PFA is a safe and efficient approach for CTI ablation, not associated with the incidence of coronary artery spasm.