Energy titration strategies with the endoscopic ablation system: lessons from the high-dose vs. low-dose laser ablation study

To assess the effects of low-dose (LD) and high-dose (HD) ablation on acute and chronic success in patients with atrial fibrillation (AF). While the concept of visually guided pulmonary vein isolation (PVI) has been established little is known on energy titration using laser ablation. In 60 patients with AF, PVI using the endoscopic ablation system (EAS) was performed in two groups. Visually guided ablation was carried out after obtaining optimal tissue contact with 5.58.5 W in the LD group and with 8.5 W in the HD group. Acute PVI after a single visually guided circular lesion set was achieved in 89 (HD) and 69 (LD), respectively, (P 0.0004). In 70 and 39 of patients all PVs were isolated after a single ablation circle in the HD and LD group, respectively, (P 0.009). After gap ablation all PVs were isolated with the EAS. More energy was deployed (6483 1834 vs. 5306 2258 Ws; P 0.0001) with less applications (31.6 8 vs. 35.2 15 applications per PV; P 0.03) leading to shorter procedure times (128 17 vs. 154 38 min; P 0.001). During median follow-up of 311 days (261346) recurrence rate was 17 and 40 in the HD and LD group, respectively. In both groups one phrenic nerve palsy was observed. For the first time, it was demonstrated that high ablation power affects acute and chronic outcomes. High-dose laser balloon ablation allows for an acute PVI rate of 89 solely by visually guided circular ablation and is associated with a chronic success rate of 83 after a single procedure.