Background:　Radiofrequency (RF) high-power ablation appears to be a novel concept in treating atrial fibrillation (AF). The ablation-index (AI) has been linked with durability of pulmonary vein isolation (PVI). To report the midterm clinical results of a new ablation technique using AI guided high-power (50W) ablation (AI-HP).

Methods and Results: Symptomatic AF patients were included and underwent wide-area circumferential PVI. Contact-force catheters were used, RF power was set to 50W targeting AI values (550/400 for anterior/posterior) and inter-lesion distance 6mm. luminal esophageal temperature (LET) was monitored during procedure; patients with LET≥39℃ underwent post-ablation esophageal-endoscopy. 72h-Holter ECGs were scheduled during follow-up. Procedural PVI was achieved in all (N=122, mean age: 68.2 years, male: 71.3%) patients, rate of first-pass PVI was 96.7 % per patient. Procedural mean RF time was 11.5 min, and mean RF time during posterior wall segment was 3.1 min. Per RF-lesion, the mean contact force, RF duration, AI and impedance-drop at anterior/posterior wall were 26±14g/23±12g, 16.2±7.5s/8.8±3.6s, 552±53/438±47, and 13±6Ω/9±5Ω, respectively. Mean PVI procedural-time: 55.8 min; mean procedural fluoroscopic time: 5.6 min. Three (2.5%) patients had asymptomatic endoscopic small erosion/erythema esophageal lesion, no serious adverse events were observed. During 15-month follow-up, overall single-procedure freedom from clinical recurrence of AF/atrial tachycardia (AT) off antiarrhythmic drug after blanking period was 85.2% (89.4% for paroxysmal AF, 80.4% for persistent AF). 

Conclusions: The AI-HP (50W) ablation appears an efficient technique in treating AF and lead to a high single-procedure arrhythmia-free survival at 15 months.