Background: High Power Short Duration (HPSD) ablation has been shown to be feasible for atrial fibrillation (AF) ablation with short procedure times. The extent of fibrosis in the left atrium is routinely determined using a voltage map during the electrophysiological study. The aim of this study was to determine the impact of left atrial fibrosis on safety and efficacy of High Power Short Duration ablation of atrial fibrillation.

Methods and Results: 79 patients with atrial fibrillation (paroxysmal and persistent) receiving their first pulmonary vein isolation were included in the study. All procedures were performed as High Power Short Duration ablation with a fixed protocol for energy delivery of 50 watts (contact force 3-20g). Two different mapping systems were used. The extent of fibrosis in the left atrium was determined using a voltage map in all patients. Endpoint of ablation was complete PV entrance and exit block controlled by a at least 10-pole spiral catheter or a high density catheter. For comparison, we retrospectively divided the patients into a high fibrosis group (≥ 20 % fibrosis, 27 patients) and a low fibrosis group (< 20 % fibrosis, 51 patients). Patients in the high fibrosis group were older on average (71,33 vs. 61,8 years), and had a higher CHA2DS2-VASc score (3,1 vs. 2,0) than patients in the low fibrosis group. Left atrial diameter was similar in both groups. Isolation of pulmonary veins could be achieved in all patients. We observed no major complications in both groups. In the follow up there were 7 (25,9 %) symptomatic recurrences in the high fibrosis group and 9 (17,6 %) in the low fibrosis group. Procedure time and radiation duration were similar in both groups.

Conclusions: The extent of fibrosis in the left atrium has no relevant effect on the procedural aspects of HPSD ablation, but is a predictor of the long-term success of pulmonary vein isolation.