Background: In recent years, catheter ablation has been accepted as the treatment-of-choice for drug-refractory atrial fibrillation (AF). It is centered around isolating pulmonary veins (PVs) and its success rate in curing AF is very high (56%-85%) (1). However, despite isolation of this dominant source of triggers, recurrent tachyarrhythmia is the major complication of this procedure with peri-mitral atrial flutter (PMFL) being the most common macro-reentrant arrhythmia in context of AF ablation (2). These often drug-refractory arrhythmias are frequently associated with more severe symptoms than the original AF (3) and warrant the necessity for redo-ablation.