Characterization of ventricular myocardium in atrial fibrillation: looking where the light is best.

Catheter ablation has been established as an important option in the treatment of patients with atrial fibrillation. This therapy currently carries a class I indication in patients with atrial fibrillation who have failed to respond to antiarrhythmic drug therapy and a class IIb indication in patients with paroxysmal atrial fibrillation untreated with antiarrhythmic agents (1). Although the evidence supports its role as an overall safe and effective treatment for this common arrhythmia, serious complications are not rare, and recurrent arrhythmia necessitating repeat procedures is a frequent and vexing problem (2). Tools to identify those more or less likely to gain a lasting benefit from this invasive procedure would be a welcome addition to the field.