Bidirectional rotating biatrial tachycardia

A 72-year-old man was treated for recurrent atrial tachycardia (AT) and underwent ablation. The AT was diagnosed as bi-AT based on the activation map and the postpacing interval. Another AT appeared and was diagnosed as bi-AT by the same method. Surprisingly, the circuits of both ATs were perfectly matched and rotated in opposite directions. The left atrial anteroseptal wall was ablated during the AT. The AT was immediately stopped and was no longer induced.