Selective Activation Re-Mapping Reveals the Mechanism in Apparently Unstable Atrial Tachycardias.

: Following atrial fibrillation (AF) ablation procedures, patients may present with atrial tachycardias (ATs) that show remarkable stability for short periods of time but degenerate in unstable forms right afterwards. In order to map these types of ATs, we applied the sequential mapping capabilities only for time segments where ATs exhibited constant cycle length (CL) and activation sequence, excluding the segments with unstable recordings. We herein describe two cases of ATs after AF ablation which were mapped with this technique that allowed for the successful identification and subsequent ablation of the tachycardia circuit.