Cavotricuspid isthmus ablation using a pentaspline pulsed field ablation catheter: one-year outcomes

Abstract Background/Introduction Cavotricuspid isthmus (CTI) ablation using pulsed field ablation (PFA) has been shown to be feasible, effective, and safe (1,2). However, mid-term outcome data remain limited. Purpose To assess the one-year efficacy and safety of PFA-based CTI ablation. Methods This prospective study included consecutive patients undergoing combined atrial fibrillation (AF) and CTI catheter ablation using a pentaspline PFA catheter. Procedures were performed under general anesthesia using the direct flower configuration and preventive nitroglycerin injection, as previously described (1,2). Procedural success was defined as achievement of complete CTI block—confirmed by local signal amplitude reduction, differential pacing, double potentials along the CTI, and/or 3D electroanatomical mapping performed ≥20 minutes after the last PFA application—without any additional radiofrequency ablation. Patients were followed for 12 months with both symptom-driven and systematic Holter monitoring. The primary efficacy endpoint was freedom from recurrence of CTI-dependent atrial flutter. In the case of a redo procedure, CTI electroanatomical remapping data were analyzed. The primary safety endpoint was the occurrence of any major coronary or conduction event (coronary artery spasm, acute coronary syndrome, high-grade atrioventricular block, or de novo pacemaker implantation). Results Between June 2023 and November 2024, 103 patients (83% male; mean age 62 ± 12 years) were enrolled. Procedural success was achieved in 102/103 patients (99%). Transient high-grade atrioventricular block occurred in 2/103 patients (1.9%), and no coronary artery spasm was observed. At 12-month follow-up, freedom from CTI-dependent atrial flutter was documented in 102/103 patients (99%). In the patient with CTI-dependent atrial flutter recurrence, electroanatomical remapping identified a conduction gap across the CTI near the inferior vena cava. Additionally, seven patients underwent a redo procedure for recurrent AF. CTI electroanatomical remapping revealed an epicardial CTI conduction gap in 1/7 cases (14%; Figure). No primary safety endpoint events occurred. PR interval and QRS complex duration remained unchanged between baseline and 12 months (193 ± 99 ms vs. 184 ± 87 ms, p = NS; and 107 ± 28 ms vs. 106 ± 34 ms, p = NS, respectively). Conclusions At one-year follow-up, PFA-based CTI ablation using a standardized protocol demonstrated high efficacy and an excellent safety profile. Although clinical durability appears promising, the long-term persistence of PFA-induced CTI block warrants further investigation.