Right pulmonary artery-to-left atrial fistula: a differential diagnosis of cyanosis without structural heart disease.

We present the case of a 19-year-old male who presented with late-onset cyanosis and a normal cardiovascular system examination. Contrast echocardiography revealed a right-to-left shunt. A right pulmonary artery-to-left atrial fistula was seen on the angiogram, which was surgically corrected. Early intervention is indicated to prevent complications in patients with this condition.