Giant congenital coronary artery fistula to left superior vena cava and right atrium with compression of left pulmonary vein simulating cor triatriatum--diagnostic value of magnetic resonance imaging.

A 3-year-old girl with a continuous murmur on auscultation was found to have left coronary artery to right atrial fistula simulating cor triatriatum sinister on echocardiography. Coronary angiography of the patient was also insufficient to clarify the exact pathologic anatomy. Magnetic resonance imaging showed that the main drainage of the aneurysmal coronary artery was to the left superior vena cava, resulting in a diffuse arteriovenous fistula in the lower lobe of the left lung by compressing its pulmonary vein.