Optimal strategy for very high-power short-duration atrial fibrillation ablation: Acute efficacy and safety of pulmonary vein and box isolation.

Introduction: The optimal strategy for very high-power short-duration (vHPSD) ablation for atrial fibrillation (AF) is unclear. Data regarding the application of box isolation (BOXI) and its complications, particularly, pulmonary vein stenosis (PVS), remain scarce. We aimed to determine the optimal strategy for vHPSD in AF ablation by focusing on pulmonary vein isolation (PVI) and BOXI and assessing the acute efficacy and safety.

Methods: Patients with drug-refractory AF (n = 97) were divided into two groups: Strategy 1 (n = 50; 90 W for 4 s with PVI for the bottom line and 50 W with an ablation index [AI] of 450 for the roof line) and Strategy 2 (n = 47; based on the outcomes of Strategy 1, using AI-guided ablation). The acute efficacy and safety were compared between the groups. Pre- and post-ablation imaging was conducted to assess PVS.

Results: Strategy 1 yielded first-pass isolation (FPI) rates of 62.5 % (PVI) and 72 % (BOXI). The weak points were the thick parts of the atrial wall and the parts with epicardial connections. Strategy 2, which was improved by AI guidance, increased the FPI rates to 97.5 % (PVI) and 95 % (BOXI) and reduced the procedural and fluoroscopy times, respectively. Follow-up imaging showed that the PVS incidence remained low and did not significantly differ between the strategies.

Conclusion: AI-guided ablation enhanced the efficacy of vHPSD for PVI and BOXI in Strategy 2. Furthermore, our assessment of PVS demonstrated that vHPSD maintains a favorable safety profile with a low PVS incidence.