Electrophysiologic characteristics and ablation of an atypical atrial flutter in the right atrium

Ablation of Atypical Atrial Flutter. Subeustachian isthmus-dependent typica l atrial flutter has been well studied. We demonstrate a case with atypical atrial putter involving only the base of the right atrium around the infer ior vena cava, Entrainment pacing and mapping studies documented a distinct circuit traversing the subeustachian isthmus, propagating through the post erobasal right atrium, and skirting the inferior vena cava, Successful radi ofrequency ablation of the arrhythmia was accomplished by creating a linear lesion at the subeustachian isthmus, Mapping of the inferior vena cava reg ion and the demonstration of concealed entrainment are essential steps in e stablishing the mechanism of the atypical atrial flutter.