<qa>  What is the study hypothesis that the complete linear PV isolation ablation is superior to the non-The study hypothesis ist that the complete linear PV isolation ablation is superior to the non-complete linear PV isolation on the outcome of patients with idiopathic drug-refractory atrial fibrillation. As a second hypothesis in this adaptive study design, the non-inferiority of the complete linear PV isolation strategy will be tested. 