We report a case of a 58 year-old male with polysplenia and left inferior vena cava draining into the right atrium via hemiazygous vein; the left superior vena cava and the coronary sinus in order. He presented dyspnea on exertion and atrial fibrillation. Originally, through findings of mediastinal widening in chest X-ray and the double lumen of the descending aorta in transesophageal echocardiography, he was erroneously diagnosed with aortic dissection. The anomalous venous connection was discovered via spiral CT and venography. We also found three to five small spleens via CT. We emphasize that normal left superior vena cava mimic aortic dissection on chest X-rays and transesophageal echocardiographys.