Ablation of cavo-tricuspid isthmus dependent atrial flutter using a focal monopolar pulsed-field ablation catheter: Feasibility, periprocedural coronary spasms and conduction disorders

Background: Pulsed-field ablation for the treatment of cavotricuspid isthmus (CTI)–dependent atrial flutter has been associated with coronary spasms (CS) and atrioventricular conduction disorders (CD). Objectives: The purpose of this study was to evaluate the feasibility of CTI ablation using a monopolar focal pulsed-field ablation (F-PFA) catheter and to assess the risk of CS and CD during and after the procedure. Methods: We prospectively enrolled patients with atrial flutter treated with an F-PFA system (CardioFocus, Marlborough, MA) or by focal radiofrequency ablation (RFA) using contact force–sensing catheters integrated into electroanatomic mapping systems. Intravenous nitroglycerin was administered prior to F-PFA. Feasibility and safety with a focus on CS or CD were assessed. In a subgroup of patients, the course of the right coronary artery and the His position were determined. Results: In total, 82 patients underwent CTI ablation with F-PFA (mean age 66 ± 8 years; 15 (18%) being female; CHA ₂DS ₂-VA score 1.6 ± 1.3) and 27 patients underwent CTI ablation with RFA (mean age 63 ± 9 years; 4 (23%) being female; CHA ₂DS ₂-VA score 2 ± 1.3). For F-PFA, the rate of first-pass block was higher (93% vs 55%) and the median (interquartile range) procedure times were shorter (7 [5–11] minutes vs 17 [15–19] minutes) than for RFA. In the F-PFA group, 4 patients (5%) had transient ST-segment elevation and 2 patients (2%) had transient complete atrioventricular block during ablation. There was a small but significant prolongation of the PQ interval after CTI ablation in the F-PFA group. Conclusion: CTI ablation using F-PFA is feasible, but operators should be aware of rare but critical CD and CS during the procedure, even when preventive measures such as nitroglycerin administration are used.