Being the most common arrhythmia, atrial fibrillation (AF) is a high burden of public health with an increasing prevalence in our aging population. Interventional treatment of atrial fibrillation by catheter ablation is one of the treatment pillars in the complex field of better symptom control based on current Guidelines. Catheter ablation of atrial fibrillation is based on electrical isolation of the pulmonary veins (pulmonary vein isolation: PVI) from the left atrium. The main benefit and goal of PVI in AF patients is the reduction of AF-related symptoms, resulting in an improvement of quality of life. It was shown, that catheter ablation failed to prove a difference in AF recurrence after PVI compared to medical therapy in the first 18 month of follow-up. It was also shown, that these episodes will become more asymptomatic. This raises concerns that the symptomatic improvement might be the result of a placebo effect, which will be elucidated with this study.