Human histopathologic findings following radiofrequency ablation of the tricuspid-inferior vena cava isthmus.

Radiofrequency (RF) ablation of the tricuspid valve-inferior vena cava isthmus is now the first line of treatment in the management of typical atrial flutter. Successful ablation is associated with conduction block in this region, although the histopathologic changes following this procedure have never been reported. We describe the pathologic changes following RF ablation of this region in an explanted heart of a patient undergoing heart transplantation 4 months after successful atrial flutter ablation. The findings confirm the ability of RF ablation to create in the isthmus a chronic full thickness fibrosis, which represents the histopathologic counterpart of the conduction block demonstrated at the end of procedure.