Typical atrial flutter with reentry around the tricuspid valve can easily be cured by ablating the cavotricuspid isthmus. In the reported case, transvenous access to the tricuspid valve was not possible because of a total cavopulmonal connection in congenital mitral atresia. Successful angioplasty of a small fenestration between the total cavopulmonal connection and the genuine right atrium (RA) allowed anterograde transvenous access to the RA. Electroanatomic RA mapping confirmed peritricuspid reentry, and successful ablation was performed.