Isolated anomalous right coronary artery originating from the pulmonary artery (ARCAPA) is a rare congenital coronary anomaly that is asymptomatic and discovered incidentally in most cases. ARCAPA is generally not considered a fatal defect in infancy or childhood, although cases of sudden death have been reported. Here, we report a 2-month-old female infant who presented with a prolonged fever that was determined to be caused by rhinovirus infection. Myocardial ischemia of the left ventricular posterior wall was already seen on echocardiography, and ARCAPA was discovered incidentally. The patient underwent successful surgical reimplantation of the right coronary artery to the aortic root to re-establish dual ostial circulation.