Observation of Atrial Fibrillation Dependent on an Intra-atrial Re-entrant Tachycardia Within the Right Atrium in a Repaired Tetralogy of Fallot.

Atrial fibrillation (AF) can occur predominantly associated with right atrial (RA) lesions in congenital heart disease, particularly when the RA cavity is dilated. RA electrical potentials occasionally appear organized during AF. We clearly mapped such areas circumscribed by an intra-atrial re-entrant circuit during an isoproterenol infusion, in a patient with a repaired tetralogy of Fallot, using an ultrahigh-density mapping system and its beat acceptance criteria function. Ablation of areas inside the re-entrant circuit successfully eliminated the AF. Our experience indicated that a macro-re-entrant tachycardia was a driver as well as a trigger of AF of this right-sided origin.