Atrial fibrillation (AF) is the most common sustained clinical arrhythmia, and is an increasing problem in terms of prevalence, complications, and health costs. 1 The options for treating AF are limited. Drug therapy has limited efficacy and non-trivial risks, such as ventricular arrhythmia. Although non-pharmacological treatment options like ablation are constantly improving, complications and recurrences continue to be problematic. 1, 2 Progression from paroxysmal to persistent to long-term persistent forms often appears to be inexorable and makes rhythmcontrol increasingly difficult. 2 Novel approaches are therefore needed for AF management to improve. 3 Significant therapeutic advancement is closely linked to improved understanding of underlying basic mechanisms. 4, 5 In this issues of Cardiovascular Research, Zahid et al. 6 report the results of studies that use innovative methods to understanding the mechanisms maintaining persistent AF, providing information of pathophysiological and potential practical significance. We will consider the problem that they address, the approach that they take, the importance of their findings and the limitations of their work.