Prof. Dr. med. Stephan Willems (Asklepios Klinik St. Georg) Study title:  Persistent AF catheter ablation: Re-PVI vs. Re-PVI + continuous complex activity mapping and ablation – AF-CAM Catheter ablation (sclerotheraphy using a cardiac catheter) of atrial fibrillation is a standard treatment for cardiac arrythmia. In the case of paroxysmal (periodically occurring) atrial fibrillation, the complete isolation of the pulmonary veins (PVI) can achieve high acute as well as long-term success rates. As soon as the atrial fibrillation transitions to the persistent (continuous) state, however, this treatment success decreases, which is highly likely a result of the advanced electrical remodelling (degenerative reconstruction) of the atria. In principle, it is possible to also treat these areas in the atrium during ablation, although it is currently unclear whether this would be more successful. Studies on the topic have yielded different results. The AF-CAM study is now systematically investigating whether the ablation of additional points in the atrium leads to increased treatment success in the long term in patients presenting for atrial fibrillation ablation for the second time due to persistent atrial fibrillation. The study is being conducted at the following sites: Prof. Dr. S. Willems, AK St. Georg Hamburg Prof. Dr. C. Meyer, Evangelical Hospital Düsseldorf Prof. Dr. D. Steven, University Hospital Cologne Funding: This is an investigator-initiated trial (IIT) that is funded by a research grant by the company Boston-Scientific.