Absent pericardium during coronary bypass.

The importance of recognizing congenitally absent left pericardium in the setting of acquired cardiovascular disease was recently appreciated during a case of coronary artery bypass grafting. An associated defect in the left hemidiaphragm and an abnormal location of the left phrenic nerve were found. Careful dissection of the phrenic nerve from the surface of the heart and closure of the diaphragmatic defect were necessary to avoid injury to the former and prevent hernia through the latter structure. Absent left pericardium discovered during cardiac surgery requires attention to the location of the left phrenic nerve and recognition of associated defects in the diaphragm.