A 9-month-old boy underwent surgery for a right coronary artery–right ventricular fistula. Due to the left-to-right shunt, the volume of the pulmonary circulation was overloaded with a dysfunctional right ventricle. He was susceptible to myocardial perfusion insufficiency due to coronary artery “blood theft” and decreased diastolic pressure. Therefore, the key to perioperative management in such patients should focus on blood volume management, right ventricular function protection, and myocardial oxygen supply and oxygen consumption balance.