A 73 year old woman was admitted to our hospital with symptoms of congestive heart failure. Transthoracic echocardiography revealed an unusual chamber in front of the right ventricle which probably indicated a right coronary fistula. Coronary angiography demonstrated extremely dilated left and right coronary arteries and coronary artery fistulas that became to be tortuous configuration (below left: left coronary angiography, below right: right coronary angiography). Although both arteries seemed to connect to the right atrium, the exact effluent sites were not clearly identified. Six months later, she was readmitted to our hospital because of worsening congestive heart failure and died of unexpected fatal ventricular arrhythmia. At necropsy, both left and right coronary arteries dilated and were tortuously running the surface of the heart. After filling the coronary lumen with contrast material, 3-dimensional CT image was obtained to identify the anatomy of these fistulas. There was the remarkably dilated right coronary artery with the fistula, and the fistula arising from the left circumflex artery was clearly visualised (right, upper panel: a CT image of whole heart; right, lower panel: a CT image of coronary fistula subtracted from heart). Both left and right fistulas terminated at the coronary sinus vein and then drained into the right atrium.