Mapping of atrial fibrillation: lessons learnt

In this review, we evaluate how high-density and resolution epicardial mapping (HDREM) contributed to novel insights into the pathophysiology underlying atrial fibrillation (AF). The limited efficacy of pulmonary vein isolation for more persistent types of AF emphasizes the need for a more substrate-based treatment approach. However, mechanisms underlying mechanisms and substrates of AF are still incompletely understood and require detailed investigation. Electrical phenomena including signal fractionation, cycle length variability, focal waves, rotational activity, conduction velocity, -block, -anisotropy and endo-epicardial asynchrony during the different clinical stages of AF are discussed.