EDN1 and atrial fibrillation: Patients without AF recurrence demonstrated a further decrease of ET-1 levels three months after ablation getting closer to the level of the healthy volunteers (2.33 pg/ml vs. 2.57 pg/ml; p<0.01) whereas ET-1 levels in patients with AF recurrence remained unchanged at an elevated level (2.83 pg/ml vs. 2.96 pg/ml; p = 0.09; Fig 1-C).