Focal Pseudo-Atrial Fibrillation after Radiofrequency Ablation of Focal Atrial Tachycardia

Focal pseudo-atrial fibrillation (AF) developed in a 30-year-old woman after radiofrequency (RF) ablation of focal atrial tachycardia (AT) originating from the coronary sinus ostium. Programmed atrial stimulation occasionally induced, accelerated or terminated AT, and a spiky prepotential preceded the earliest atrial electrogram at the AT focus. After the first RF application, repetitive bursts of accelerated tachycardia developed, mimicking AF on the surface ECG. An additional RF application where the spiky prepotential was observed, eliminated the focal pseudo-AF.