<qa>  What is the endpoint of complete PV isolation proven by two circumferential mapping catheters?The proposed study protocol aims to investigate in prospective, randomized fashion the significance of complete versus incomplete PV isolation by RFC-induced linear lesions. The ablation will be randomized to a linear encircling around the ipsilateral PVs with the endpoint of complete PV isolation proven by two circumferential mapping catheters versus the same ablation procedure which will be terminated instantaneously when total PV isolation occurs, thereby allowing at least one conduction gap along the isolation line. An invasive re-evaluation is scheduled after 3 months for all pts to assess longterm PV conduction properties. 