Ablation of consecutive atrial tachycardia (AT) after ablation of atrial fibrillation (AF) or cardiac surgery can be challenging due to complex substrate and AT mechanisms. A substantial portion of patients is known to show various tachycardias and recurrences occur in a noticeable number of cases. With the availability of novel ultra-high-density mapping techniques characterization and understanding of AT mechanisms and underlying substrate can be improved. Aim of this prospective, multi-center, randomized study is to compare a standard AT ablation approach versus minimalized ablation of the clinical AT in regards to arrhythmia free survival.