A 63-year-old female patient with a history of pulmonary heart disease underwent radiofrequency ablation because ofa persistent atrial flutter. Endocardial mapping with the carto3 system confirmed atrial flutter counterclockwise reentryaround the tricuspid annulus. Routine ablation of the cavo-tricuspid isthmus line to bi-directional block was performed.However, tachycardia with the same cycle length was induced again. After remapping, the tachycardia was confirmedto be focal atrial tachycardia located in the crista terminalis. After ablation, the tachycardia was terminated and couldnot be induced again.