High-power radiofrequency ablation guided by ablation index for pulmonary vein isolation
Abstract Background: Proposed to facilitate pulmonary vein isolation (PVI), high-power ablation may cause extracardiac damage. This study evaluated the safety and efficacy of ablation index (AI) guided high-power ablation first in an animal model and subsequently in a clinical study.Methods:Outcomes of radiofrequency (RF) applications were compared in a swine ventricular endocardial model (n=10 each for 50W, 40W and 30W; AI=500), and in 100 consecutive patients with paroxysmal AF undergoing PVI (40W [last n=50] vs. 30 W [first n=50]; target AI=400/500 on posterior/anterior wall, respectively). Acute PV reconnection was assessed post adenosine administration 20 minutes after ablation.Results: In swine ventricular endocardial RF applications, use of 50W and 40W vs. 30W was associated with greater tissue lesion depth (5.06±0.16 and 4.38±0.13mm vs. 3.95±0.16mm; P<0.001) and smaller lesion maximum diameter (7.81±0.15 and 8.42±0.18mm vs. 9.08±0.15mm; P<0.001). Tissue necrosis caused by 50W vs. 40W and 30W was the deepest and largest (3.15±0.18mm vs. 2.71±0.17 and 2.42±0.13mm; and 5.58±0.18mm vs. 5.18±0.16 and 3.94±0.17mm; respectively; P<0.001). In PVI, use of 40W vs. 30W was associated with shorter procedure time (56.54±1.81min vs. 76.55±2.34min; p<0.001) and ablation time (35.85±14.87min vs. 51.01±17.99min; p<0.001); lower RF energy per point (909.02±354.57J vs. 1045±376.60J; p<0.001); higher first-pass PVI (87% vs. 72%; P<0.01); lower acute PV reconnection (22% vs. 41%; P<0.01); no complications in either group; and similar sinus rhythm maintenance at 12 months (92% vs. 84%; P=0.22).Conclusions: AI-guided high-power (40W) vs. conventional (30W) PVI was related to a reduced time for procedure and was considered safe, with diminished acute PV reconnection.