Catheter ablation of atrial fibrillation using ablation index-guided high-power technique: Frankfurt AI high-power 15-month follow-up.

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 the durability of pulmonary vein isolation (PVI). To report the midterm clinical results of a new ablation strategy using AI-guided high-power (50 W) 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 50 W targeting AI values (550/400 for anterior/posterior) and interlesion distance 6 mm. Luminal esophageal temperature (LET) was monitored during the procedure; patients with LET ≥39°C underwent post-ablation esophageal-endoscopy. Seventy-two-hour-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 ± 14 g/23 ± 12 g, 16.2 ± 7.5 s/8.8 ± 3.6 s, 552 ± 53/438 ± 47, and 13 ± 6 Ω/9 ± 5 Ω, 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 lesions, no serious adverse events were observed. During a 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).

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