[Coronary artery fistula into the right atrium complicated by atrial futter; report of a case].

: A 62-years-old woman with uncommon atrial flutter underwent the catheter ablation therapy. In the catheter ablation therapy and subsequent coronary angiography, a coronary artery fistula into the right atrium was found. A giant aneurysm formed in the junctional region between the coronary artery fistula and right atrium. The giant aneurysm might have been a course of uncommon atrial flutter. We ligated the coronary artery fistula to prevent the giant aneurysm rupture. Any events have not been observed after catheter ablation and ligation.