We describe two cases with pulmonary atresia, intact ventricular septum (PA/IVS), and right ventricle-dependent coronary circulation, who suffered from myocardial ischemic symptoms. Case 1 : A female infant diagnosed with PA/IVS during the fetal period was born after 40 weeks of gestation, weighing 3,078 g. Aortography demonstrated that the right coronary artery (RCA) was interrupted at the proximal segment, and the left coronary artery (LCA) did not show any stenosis. Right ventriculogram revealed sinusoidal connections filling the distal part of the right coronary artery and fistulous communications to the left anterior descending artery. Temporary ST segmental depression in ECG during milk feeding or crying improved spontaneously with time. Bidirectional Glenn shunt (BDG) was performed at 3 months old, and she underwent Fontan repair at 4 years old. She is doing well with no evidence of myocardial ischemic change. Case 2 : A female infant was born after 39 weeks of gestation, weighing 3,062 g. Aortography demonstrated that the RCA was interrupted at the middle segment, and the distal area depended on the right ventricle. LCA ostium at the ascending aorta was absent. Multiple sinusoidal connections were seen in the right ventricular myocardium with filling of the LCAs but no reflux into the aortic sinuses. After ventricular tachycardia occurred at 2 months old, left ventricular function deteriorated. BDG with ligation of the arterial duct was performed at age 3 months. The arterial blood pressure was 76/53 (62) mmHg and pressure in SVC was 21 mmHg immediately after the operation. However, arterial oxygen saturation, right atrium venous oxygen saturation and left ventricular ejection fraction were 50%, 16%, and 10%, respectively. Although extracorporeal membrane oxygenation was established for circulatory and myocardial oxygenation support on the postoperative day 2, her left ventricular function did not recover and she died on postoperative day 5. It is difficult to rescue such a case in which almost all coronary circulation depends on the right ventricle filled with desaturated blood.