Successful Catheter Ablation of Typical Atrial Flutter in a Patient with a Long Vertical and Diverticulum‐Like Cavotricuspid Isthmus

A long vertical vestibule with a diverticulum‐like morphology of cavotricuspid isthmus (CTI) was demonstrated by right atrial angiogram in a 47‐year‐old male patient in whom his typical atial flutter was difficult to be ablated. Compatible with the right atrial angiography, the diverticulum‐like CTI with a long vertical vestibule, pouch‐like recess, and a long transverse posterior component was also demonstrated on volume‐rendering reconstruction computed tomography and the virtual endoscopy showed prominent trabeculation inside the diverticulum‐like part of CTI. The bidirectional CTI conduction block was successfully achieved after ablating along the CTI guided by the right atrial angiography.