Efficacy and safety of cavo-tricuspid isthmus ablation using the linear-shaped pulsed field ablation catheter: LINEAR study

BACKGROUND: Cavotricuspid isthmus(CTI) using pulsed field ablation(PFA) is still challenging. METHODS: We prospectively enrolled 90 consecutive patients with atrial fibrillation(AF) and atrial flutter(AFL), who received CTI ablation using a linear-shaped PulseSelect PFA Loop catheter. Coronary angiography of the right coronary artery was performed before and just after PFA application. During the CTI ablation following PVI, the initial 45 patients did not receive prophylactic nitroglycerin administration (control group), and the latter 45 patients received systemic nitroglycerin administration of 1.5mg before the applications (NTG group). RESULTS: All patients achieved an acute line of block using only the PFA catheter, with 91.1% requiring two or fewer applications. Operators performed additional "bonus" applications, resulting in an average of 4.4 ± 1.4 applications per patient. After a mean waiting period of 24.7 minutes, high-density mapping revealed a re-conduction gap in 20 patients (22.2%). Of these 20 patients with reconduction, four had an epicardial bridge. Coronary artery spasm was observed in 51.1% of the control group. In contrast, prophylactic nitroglycerin administration significantly reduced the incidence of coronary spasm to 15.6% in the NTG group. No severe spasms were observed in the NTG group. Among nine patients who underwent a repeat ablation procedure due to clinical AF recurrence, CTI reconduction was found in five (55.6%). CONCLUSION: Linear-shaped PulseSelect CTI ablation readily achieves acute block, but early reconduction limits long-term durability despite consolidation applications. Without prophylactic NTG, there is a notable risk of coronary spasm, necessitating its routine use. Additionally, systematic postprocedural follow-up is needed to assess delayed coronary safety.