Incisional Atrial Tachycardia Masquerading As Counter-clockwise Atrial Flutter

Forty-four-year-old male patient with surgical closure of ostium secundum type atrial septal defect at the age of 9 years had undergone radiofrequency catheter ablation of the cavotricuspid isthmus because of recurrent drug-resistant typical isthmus-dependent atrial flutter, with bi-directional isthmus block achieved. Only few days later he started to suffer again high-rate tachycardia. An atypical atrial flutter was diagnosed on ECG (Figure 1). This one proved to be drug-resistant as well and recurred promptly after cardioversion.