Dynamic alterations in right atrial activation during atrial fibrillation.

Atrial fibrillation (AF) is usually considered to be a disorganized rhythm. However, several reports have described areas of organized right atrial (RA) activation during AF. We describe a patient with focal paroxysmal AF with a consistent pattern of organized RA activity despite typically disorganized left atrial activity. The sequence of RA activation varied, depending on which pulmonary vein foci initiated the AF.