Ablation Index-guided high-power, short duration ablation shortens the procedure and ablation times with similar outcomes in long-term follow-up

High-power - short duration in PAF ablation

Abstract

Background: The single procedure success rate of durable pulmonary vein isolation (PVI) for paroxysmal atrial fibrillation (PAF) varies between 85 and 90 %. This prospective, randomized study investigated the efficacy of high-power, short duration (HPSD) ablation in a power-controlled mode versus standard power settings in terms of single-procedure arrhythmia-free survival, safety outcome and procedural times during a long-term follow-up of 31 months.
Methods and Results: A total number of 176 patients undergoing de-novo catheter ablation for PAF were randomized into two different treatment arms. In group A, PVI was performed using radiofrequency ablation (RFA) with standard power settings (30W) in a power-controlled mode. The ablation procedure in group B was also performed with RFA but with higher power settings (45W). To achieve complete pulmonary vein isolation, we used the ablation index (AI) and an interlesion distance of ≤ 6 mm with a surround flow catheter (Thermocool STSF, Biosense Webster, USA)). 88 patients were randomized into each group without significant differences in baseline characteristics. During a mean follow-up of 31.42 ± 7.83 months after a single procedure, 63 (72%) patients in group A were free of arrhythmia recurrences versus 68 (77%) patients in group B (p=0.09). The procedure time was significantly shorter in group B (group A: 115.35 ± 15.38 min vs group B: 96.45 ± 17.19 min; p<0.01). Fluoroscopy time and dose area product were also significantly lower in group B (group A: 9.66 ± 3.86 min vs group B: 5.45 ± 2.35 min; 330.84 ± 150.36 cGy/cm2 vs 202.51 ± 135.23 cGy/cm2; p<0.01). The total ablation time and the ablation time per patient was significantly shorter in group B (2736 min. vs. 1660 min. p <0.05; 36.48 min. vs. 21.01 min. p <0.05). The incidence of steam pops, either audible or visible by spike potentials was significantly higher in the high power group. In each group there were two patients with a significant, post-interventional inguinal hematoma which needed surgical repair. However, no pericardial effusions or neurological complications were seen.
Conclusion: This study concludes that RF-ablation using high-power settings (45W) in combination with ablation index and an interlesion distance of 6 mm is safe, leads to shorter procedure times, a lower total ablation time and shows no significant difference in arrhythmia free survival after 31 months as compared to a 30W setting. Caution is necessary in regard of esophageal heating and the higher incidence of steam pops. More studies are required to analyze the benefit and the drawbacks of intermediate power ablation.