A Case of Biatrial-dependent Tachycardia.

We present an interesting case of atrial flutter in a patient with previous pulmonary vein isolation. The entirety of the atrial flutter cycle length was mapped to the left atrium; however, an atrial flutter could not be terminated from the left side. Subsequently, the right atrium was mapped and an area of earliest activation was noted in the junction between the superior vena cava and right atrium. Ablation performed in this area terminated the flutter. We believe that both the left atrium and the portion of the right atrium indicated were part of the circuit and herein discuss the likely mechanism of the biatrial dependence of this tachycardia.