Atrial tachycardia related to local abnormal atrial activity.

A 42-year-old woman without a history of catheter ablation or cardiac surgery was referred to our institution for a paroxysmal atrial tachycardia (AT). Programed stimulation could not induce any AT. The AT spontaneously initiated during a continuous isoproterenol infusion. The earliest activation during the AT was recorded at the cavo-tricuspid isthmus, and local abnormal atrial activity (LAATA) was recorded during sinus rhythm at that same site. When rapid atrial activity was recorded at the cavo-tricuspid isthmus where the LAATA was recorded, an AT was induced. Radiofrequency ablation was performed over the entire area where the LAATA was recorded during sinus rhythm, rendering the AT non-inducible.