Atrial fibrillation: mechanistic insights from biatrial (and triatrial) mapping

Percutaneous radiofrequency ablation of pulmonary vein potentials has been shown to eliminate atrial fibrillation in a subset of patients characterized by frequent and repetitive paroxysms of atrial fibrillation. However, pulmonary vein disconnection has had only limited success at curing patients with persistent atrial fibrillation. In those patients, left atrial substrate modification and linear ablation strategies have had substantially higher success rates. Furthermore, in other patients, elimination of right atrial triggers (superior vena cava) or modification of right atrial substrate has been required for elimination of atrial fibrillation. Finally, the realization that the coronary sinus is a third atrial chamber that can both initiate and maintain atrial fibrillation has provided new understanding to the pathogenesis of atrial fibrillation. From a clinical perspective, only careful anatomic and mapping strategies specifically aimed at each subset of patients with atrial fibrillation will allow for pattern recognition and establish which mechanisms are responsible for initiation and maintenance of atrial fibrillation. Only the latter will allow for increased long-term success rates of ablation of atrial fibrillation.