A 55-year-old man was electively admitted for coronary artery bypass surgery. His admission chest X-ray showed an abnormal cardiac silhouette with complete leftward displacement. He had a past history of blunt thoracic trauma due to a motor vehicle accident treated conservatively. We present our findings and surgical difficulty during an operation on a patient with a previously undiagnosed pericardial rupture. This is the first reported case of its kind in the cardiac surgical literature.